University School of Physical Education in Wrocław University School of Physical Education in Kraków vol. 14, number 2 (June), 2013 University School of Physical Education in Wrocław (Akademia Wychowania Fizycznego we Wrocławiu) University School of Physical Education in Kraków (Akademia Wychowania Fizycznego im. Bronisława Czecha w Krakowie) Human Movement quarterly vol. 14, number 2 (June), 2013, pp. 93 – 190 Editor-in-Chief Alicja Rutkowska-Kucharska University School of Physical Education, Wrocław, Poland Associate EditorEdward Mleczko University School of Physical Education, Kraków, Poland Editorial Board Physical activity, fitness and health Wiesław Osiński University School of Physical Education, Poznań, Poland Applied sport sciences Zbigniew Trzaskoma Józef Piłsudski University of Physical Education, Warszawa, Poland Biomechanics and motor control Tadeusz Bober University School of Physical Education, Wrocław, Poland Kornelia Kulig University of Southern California, Los Angeles, USA Physiological aspects of sports Andrzej Suchanowski Medical University of Bialystok, Białystok, Poland Psychological diagnostics of sport and exercise Andrzej Szmajke Opole University, Opole, Poland Advisory Board Wojtek J. Chodzko-Zajko Gudrun Doll-Tepper Józef Drabik Kenneth Hardman Andrew Hills Zofia Ignasiak Slobodan Jaric Toivo Jurimae Han C.G. Kemper Wojciech Lipoński Gabriel Łasiński Robert M. Malina Melinda M. Manore Philip E. Martin Joachim Mester Toshio Moritani Andrzej Pawłucki John S. Raglin Roland Renson Tadeusz Rychlewski James F. Sallis James S. Skinner Jerry R. Thomas Karl Weber Peter Weinberg Marek Woźniewski Guang Yue Wladimir M. Zatsiorsky Jerzy Żołądź University of Illinois, Urbana, Illinois, USA Free University, Berlin, Germany University School of Physical Education and Sport, Gdańsk, Poland University of Worcester, Worcester, United Kingdom Queensland University of Technology, Queensland, Australia University School of Physical Education, Wrocław, Poland University of Delaware, Newark, Delaware, USA University of Tartu, Tartu, Estonia Vrije University, Amsterdam, The Netherlands University School of Physical Education, Poznań, Poland University School of Physical Education, Wrocław, Poland University of Texas, Austin, Texas, USA Oregon State University, Corvallis, Oregon, USA Iowa State University, Ames, Iowa, USA German Sport University, Cologne, Germany Kyoto University, Kyoto, Japan University School of Physical Education, Wrocław, Poland Indiana University, Bloomington, Indiana, USA Catholic University, Leuven, Belgium University School of Physical Education, Poznań, Poland San Diego State University, San Diego, California, USA Indiana University, Bloomington, Indiana, USA University of North Texas, Denton, Texas, USA German Sport University, Cologne, Germany Hamburg, Germany University School of Physical Education, Wrocław, Poland Cleveland Clinic Foundation, Cleveland, Ohio, USA Pennsylvania State University, State College, Pennsylvania, USA University School of Physical Education, Kraków, Poland Translation: Michael Antkowiak, Tomasz Skirecki Design: Agnieszka Nyklasz Copy editor: Beata Irzykowska Statistical editor: Małgorzata Kołodziej Proofreading: Agnieszka Piasecka Indexed in: SPORTDiscus, Index Copernicus, Altis, Sponet, Scopus, CAB Abstracts, Global Health 8 pkt wg rankingu Ministerstwa Nauki i Szkolnictwa Wyższego © Copyright 2013 by Wydawnictwo AWF we Wrocławiu ISSN 1732-3991 http://156.17.111.99/hum_mov Editorial Office Dominika Niedźwiedź 51-612 Wrocław, al. Ignacego Jana Paderewskiego 35, Poland, tel. 48 71 347 30 51, [email protected] This is to certify the conformity with PN-EN-ISO 9001:2009 Circulation: 160 HUMAN MOVEMENT 2013, vol. 14 (2) contents ph y sic a l ac t i v i t y, f i t n e s s a n d h e a lt h Anna Burdukiewicz, Jan Chmura, Jadwiga Pietraszewska, Justyna Andrzejewska, Aleksandra Stachoń, Jarosław Nosal Characteristics of body tissue composition and functional traits in junior football players...............................................96 Anna Zwierzchowska Gender-based dimorphism of aerobic and anaerobic capacity and physical activity preferences in deaf children and adolescents ............................................................................................................................................102 applied sport sciences Mauro Gonçalves, Anderson Souza Castelo Oliveira Effects of elbow flexor muscle resistance training on strength, endurance and perceived exertion.................................110 Beata Makaruk, Henryk Sozański, Hubert Makaruk, Tomasz Sacewicz The effects of resisted sprint training on speed performance in women ............................................................................ 116 Tomasz Tasiemski, Joanna Bauerfeind Subjective assessment of sports success in wheelchair rugby – proposal of a new research tool........................................123 Piotr Kuczek On the possibility of applying achievement goal theory in competitive sports...................................................................129 biomechanics and motor control Emmanuel S. da Rocha, Álvaro S. Machado, Pedro S. Franco, Eliane C. Guadagnin, Felipe P. Carpes Gait asymmetry during dual-task obstacle crossing in the young and elderly....................................................................138 Dalwinder Singh, Sukhwinder Singh Effects of vertical and horizontal plyometric exercises on running speed...........................................................................144 Tomasz Niznikowski, Jerzy Sadowski, Andrzej Mastalerz The effectiveness of different types of verbal feedback on learning complex movement tasks.........................................148 physiological aspects of sports Marek Zatoń, Dariusz Dąbrowski Differences in the direction of effort adaptation between mountain bikers and road cyclists..........................................154 Krzysztof Durkalec-Michalski, Małgorzata Woźniewicz, Joanna Bajerska, Jan Jeszka Comparison of accuracy of various non-calorimetric methods measuring energy expenditure at different intensities.............................................................................................................................................................. 161 psychological diagnostics of sport an d exercise Monika Guszkowska, Katarzyna Sempolska, Agnieszka Zaremba, Marta Langwald Exercise or relaxation? Which is more effective in improving the emotional state of pregnant women?.........................168 Linda Schücker, Norbert Hagemann, Bernd Strauss Analogy vs. technical learning in a golf putting task: an analysis of performance outcomes and attentional processes under pressure............................................................................................................................... 175 Publishing guidelines – Regulamin publikowania prac............................................................................................................ 185 95 HUMAN MOVEMENT 2013, vol. 14 (2), 96– 101 Characteristics of body tissue composition and functional traits in junior football players doi: 10.2478/humo-2013-0010 Anna Burdukiewicz *, Jan Chmura, Jadwiga Pietraszewska, Justyna Andrzejewska, Aleksandra Stachoń, Jarosław Nosal University School of Physical Education, Wrocław, Poland Abstract Purpose. The aim of this study was to examine the body tissue composition and functional traits of young football players. Methods. Analysis was performed on 23 junior football players. Body mass and height were measured. Bioelectrical impedance was used to assess the players’ body composition (fat mass, muscle mass, body cell mass and extracellular mass). The body mass index, body cell mass index and the extracellular mass/body cell mass ratio were also calculated. Functional traits were assessed by a one-on-one football game in an enclosed space with the objective to score the highest number of goals in a timed setting. Measurements of HR rest, HR max and heart rate reserve were used to evaluate the efficiency of the subjects’ cardiovascular systems. Results. Insignificant differences in body tissue composition and cardiovascular efficiency were found regardless of what position was played. Overall, forwards were characterised by having the greatest height, the highest level of active body tissue development and the most efficient cardiovascular systems. Defenders were characterised by having larger body build, while midfielders displayed a significantly greater percentage of extracellular mass and EMC in relation to BCM. Conclusions. The results reveal that trends exist in the body tissue composition and cardiovascular efficiency of football players depending on which position they play. These differences reflect the varied physical efforts players perform during a match and should be taken into consideration when designing training programmes. Key words: body composition, heart rate, football Introduction The game of football requires players to perform periodically under high intensity by using aerobic energy sources that sometimes involves overloading the neuromuscular and hormonal systems. The ability of the neuromuscular system to produce maximum power in the lower extremities is particularly important for football players, since the ability to produce explosive efforts at maximum power and force together with a high contraction velocity seems to be one of the main physiological features which differentiate players at different training levels [1, 2]. On the other hand, the variation of sprint activity among football players is reflected in the variety of physiological responses players’ bodies produce. Results have shown that high intensity aerobic interval training leads to an increase in VO2max without negative interference effects on strength, jumping ability or sprint performance [3]. One of the most informative and easiest to examine parameters is heart rate, which characterises the efficiency of the cardiovascular system [4]. Research has shown that whole-day heart rate monitoring is an objective, unobtrusive method for measuring physical activity at the age of puberty. For athletes in training, these data are commonly collected from the monitoring * Corresponding author. 96 of heart rate changes and used to prevent the occurrence of fatigue [5]. It is commonly known that athletes performing to a high degree are characterised by an improved lowering of their resting heart rate (HR rest). Furthermore, the correlations observed between maximum heart rate (HR max), reflected as the highest heart rate achieved during exercise, and HR rest have been used to create an index that can compute VO2max [6]. This research revealed that the absolute and relative values of maximum heart rate and oxygen absorption were higher in young elite players in comparison to their peers at a lower training level [7]. In amateur football, the recording of HR was confirmed to be useful for training purposes and was also applied to characterise metabolic expenditure during physical effort [8]. Furthermore, with regard to young players, the influence of puberty on body height and functional capacity have also been well substantiated. Children and youth performing sports, in comparison to their nonexercising peers, displayed greater development of their somatic features, body efficiency and physical fitness [9]. Studies performed on pubertal youths indicate that the level of biological maturity influences the variation of development regarding physical efficiency, velocity and strength. The period of greatest body growth is frequently followed by a significant rise in static and explosive force development. Analogous changes in VO2max have been found to accompany the pubertal spurt of body height [10]. The application of multiple linear regres- HUMAN MOVEMENT A. Burdukiewicz et al., Body composition and functional traits sion analysis revealed the existence of a significant relationship between maturity advancement, growth and composite football skill scores in a group of football players at the age of puberty [11]. Positive regression coefficients were obtained for the occurrence of puberty and aerobic resistance. However, the coefficient for body height was negative, indicating the role of a lower centre of gravity in better football skill performance. However, Philippaerts et al. [12] observed that the period during the greatest height spurt coincides with the development of maximum balance ability, explosive force, running speed, upper-body muscular endurance, agility, cardiorespiratory endurance and anaerobic capacity. A plateauing of explosive force development, upper-body muscular endurance and running speed was observed after the pubertal height spurt, at which point body flexibility increasingly developed. Body tissue composition constitutes one of the factors that not only determine athletes’ motor fitness and sport level but also plays a role in training. Moreover, it varies tremendously across individuals in regards to age and body build. In this regard, adolescence is a very important phase in life due to various social factors that adolescents face and the numerous neuro-hormonally determined changes that affect body tissue composition. This includes the influence of growth hormone, which has, among others, been found to be of significant importance in the maturation of lean mass and muscle strength development at puberty and for young adults in general [13]. The results of research also indicate that a relationship exists between fat (determined by anthropometric measurement) and the beginning of puberty in both genders. In the case of young football players, development of choice body tissue components (lean tissue) has been noted as the result of improved physical performance [14, 15]. The development of adolescent boys is, in particular, characterised by an overall decrease in fat tissue and increase in BMI, which at this age reflects an increase in lean mass [16]. Youth involvement in sport (e.g. football) has also been credited in stimulating bone mass development. However, longitudinal research on a cadet football league (youths aged 11–14) did not reveal any acceleration in their morphological development, although it was revealed that muscle power, especially agility and coordination, distinguished the young football players from their untrained peers [17]. Therefore, in order further to investigate this issue, this study examined the features of body tissue composition and functional traits of a group of young 2nd league football players. Material and methods Twenty-three junior football players playing on a 2nd league team from Wrocław, Poland were recruited. The players’ mean age was 16.2 years ( ± 0.70) and had mean training period of 7.3 years (± 1.87). The university’s research ethics committee approved the study and all participants provided their written informed consent prior to data collection, which took place at the end of the 2009 competitive season. Information regarding what position they played in was obtained from their coach. Body mass and height were measured and used to calculate body mass index (BMI; body mass [kg]/body height [m]2). Body composition was assessed by bioelectrical impendance with a BIA-101/S analyser (tetrapolar version, electrodes placed on the hand–foot) integrated with Bodyimage 1.31 software (Akern, Italy). Body composition was measured before an exercise test, with fat mass (FM), muscle mass (MM), body cell mass (BCM) and extracellular mass (ECM) recorded. The components of body composition were expressed in kilograms or percentage of body mass. Body composition measurements were used to compute the body cell mass index (BCMI = BCM [kg] / body height [m]2) and the ratio of ECM/BCM (extracellular mass/body cell mass). The players’ functional abilities were measured in special test conditions in order to promote high-intensity exercise: individual players participated in a threeminute game of one-on-one football within an enclosed, circular cage (a diameter of 500 cm with 250 cm walls) with goals located on both sides (Hattrick Cage, Ludus Partner, Poland). The aim of the game was to score the highest number of goals. Resting heart rate (HRrest) was measured prior to the test, while maximum heart rate (HR max) was measured immediately after each game. Heart rate was monitored and analysed with a shortrange telemetry system (Polar Electro Oy, Finland). Heart rate reserve (HRR) was computed by subtracting HRrest from HR max. Statistica version 9.0 for Windows (StatSoft Inc., USA) was used for statistical analysis. Basic statistical characteristics were computed (mean, standard deviation). The Shapiro-Wilk’s test was used to evaluate normal distribution. One-way between-groups analysis of variance (ANOVA) with Tukey’s post hoc test was used to evaluate the variation of the values recorded for body tissue composition and the physiological features among the participants depending on their position (forwards n = 7, midfielders n = 9, defenders n = 7). Statistical significance was set at p 0.05. Results The anthropometric characteristics and functional abilities of the football players are presented in Table 1. The Shapiro-Wilk’s test indicates that body height and mass and the studied components of body composition and the players’ physiological response present normal distribution. Analysis of variance, applied to evaluate the variation of the analysed features between those playing as forwards, midfielders and defenders, did not reveal any statistically significant differences (Tab. 2) except 97 HUMAN MOVEMENT A. Burdukiewicz et al., Body composition and functional traits for the percentage of extracellular mass between forwards and midfielders. The results find that forwards are characterised by the highest body height, body cell mass, muscle mass and fat mass. HRmax and HRR values were also at a high level. Furthermore, forwards displayed the lowest levels of extracellular mass development, ECM/BCM and resting heart rate. Furthermore, the BMI and BCMI indices indicate that forwards had the largest body build as well as exhibiting the highest HRmax. When compared Table 1. Physical characteristics of the junior football players (N = 23) Variable Body mass (kg) Body height (cm) Fat mass (kg) Body cell mass (kg) Extracellular mass (kg) Muscle mass (kg) Fat mass (%) Body cell mass (%) Extracellular mass (%) Muscle mass (%) BMI (kg ∙ m–2) BCMI (kg ∙ m–2) ECM/BCM HR rest (b ∙ min–1) HR max (b ∙ min–1) HRR (b ∙ min–1) Mean SD 66.0 173.7 10.4 32.6 22.9 39.7 15.7 49.5 34.8 60.3 21.9 10.8 0.7 78.96 181.26 102.30 5.62 3.69 2.64 2.92 2.25 3.41 3.29 2.90 2.53 3.17 1.36 0.88 0.07 12.05 10.40 13.43 with the other positions, their BCM percentage, muscle mass and heart rate reserve were at lower levels. Overall, midfielders displayed the smallest body size. This group also exhibited the lowest level of body fat and BMI and BCMI values. Their HRmax values were the lowest compared with the other positions. However, when compared with forwards and defenders, midfielders were characterised by a significantly greater amount of extracellular body mass and larger values of the ECM/ BCM index. Discussion The specificity of modern sport necessitates taking into consideration certain body build predispositions in order to determine what somatic criteria ought to be used when selecting potential athletes in given sport. The optimum adaptation of an athlete to the requirements of the sport they play in is in large part the result of their morphological structure and a targeted training regimen that modifies selected somatic parameters. For young athletes, in addition to the above factors, puberty also plays a large role in promoting significant changes in body morphology and tissue composition [18]. This period is characterised by an increase in height, mass, lean mass and bone mineral content. When compared with girls, the fat content of boys is at a lower level, where this predisposition is also reinforced by the large-scale involvement of young boys in sport. Although the physical load youths undergo depends on the sport, most training is sufficient enough to cause characteristic changes in the development level of various body com- Table 2. Physical characteristics of the junior football players grouped by playing position (mean ± SD) Playing position Variable Body mass (kg) Body height (cm) Fat mass (kg) Body cell mass (kg) Extracellular mass (kg) Muscle mass (kg) Fat mass (%) Body cell mass (%) Extracellular mass (%) Muscle mass (%) BMI (kg ∙ m–2) BCMI (kg ∙ m–2) ECM/BCM HR rest (b ∙ min–1) HR max (b ∙ min–1) HRR (b ∙ min–1) Forwards (n = 7) Midfielders (n = 9) Defenders (n = 7) p 67.21 ± 5.46 175.53 ± 2.28 11.39 ± 2.24 33.51 ± 3.27 22.31 ± 2.23 40.70 ± 3.71 16.91 ± 2.76 49.88 ± 2.85 33.22 ± 2.16* 60.59 ± 2.99 21.83 ± 1.69 10.89 ± 1.10 0.67 ± 0.07 77.14 ± 14.75 196.00 ± 11.75 104.14 ± 17.33 63.77 ± 6.30 172.67 ± 4.47 9.06 ± 2.37 31.49 ± 2.95 23.22 ± 2.66 38.36 ± 3.52 14.11 ± 3.08 49.49 ± 3.16 36.42 ± 1.82 60.29 ± 3.58 21.40 ± 1.12 10.54 ± 0.69 0.74 ± 0.07 77.33 ± 7.43 191.33 ± 7.02 101.78 ± 7.85 67.57 ± 4.58 173.36 ± 3.54 11.19 ± 2.93 33.20 ± 2.39 23.19 ± 1.86 40.40 ± 2.79 16.40 ± 3.64 49.19 ± 3.02 34.38 ± 2.72 59.87 ± 3.25 22.49 ± 1.23 11.06 ± 0.90 0.70 ± 0.08 82.86 ± 14.70 193.00 ± 9.61 101.14 ± 16.53 0.332 0.302 0.140 0.333 0.700 0.331 0.189 0.914 0.028 0.921 0.299 0.513 0.174 0.612 0.668 0.914 * significantly different from midfielders (p < 0.05) 98 HUMAN MOVEMENT A. Burdukiewicz et al., Body composition and functional traits position and functional features. For example, a study of young prepubertal football players revealed a decrease in body fat and an increase in lean body and bone mineral content in comparison with their control group peers [19]. A significant increase in bone mineral content around the femur neck and lumbar spine areas was also observed in male adults practicing recreational football for many years [20]. When comparing playing positions, body composition analysis on adult football players found observable differences between goalkeepers and outfield players [21]. Regarding youth, all players aside from goalkeepers revealed little difference in the development of their body composition. The results indicate that the lowest amount of fat tissue is observed in midfielders, although similar values were noted for forwards and defenders. However, greater variation of fat tissue levels has been revealed in adult players [22]. Significantly greater fat mass was discernible in midfielders in comparison with forwards and defenders. Lean body mass consists of body cell mass, extracellular fluid and extracellular solids [23]. Body cell mass, which is the mass of all metabolically active body cell components, plays a significant role in physical training. Chronic diseases such as AIDS, tumours or cancers and the ageing process all result in a decrease of BCM. The metabolic activity of BCM and its significant role in the human body is also evident in how diversified its development is, although depending on the physical activity an individual performs and their training level [24]. The results confirm previous studies that have indicated an insignificant variation in the somatic structure and body composition of outfield players in relation to players in other positions [25]. The largest BCM and muscle mass values are observed in forwards while the lowest in defenders. Melchiorri et al. [26] observed a similar trend by analysing the body composition of two professional male football teams from two different divisions. The higher ranked team displayed significantly lower levels of body fat in its defenders, while higher BCM values were noted among the forwards from both teams. Players who were individually ranked higher displayed greater cell mass, even though the two teams differed in age, body mass, height and BMI. The players analysed in this study did not display significant differences in body mass and tissue composition. Previous research has confirmed a correlation between athletes’ BMI and creatinine concentration although this is dependent on the practiced sport, type of training, involvement of aerobic and anaerobic meta bolism and the length of the competitive season [27]. Nevertheless, other research on athletes of both genders and people with eating disorders indicated that body cell mass index, in comparison to BMI, is better suited to monitor changes in the amount of muscle mass [28]. This results from the fact that the body cell mass index is more sensitive to changes in the nutri- tional status of an individual. In the examined group of footballers, the lowest values of both indices were observed in midfielders, while defenders displayed the greatest body mass and cell mass when taking body height into consideration. The obtained results may be further justified by the observed ascendency of the mesomorphic somatotype of defenders [29]. Extracellular mass contains all the metabolically inactive body tissues, and thus an increased ECM/BCM index value is frequently interpreted as a sign of malnutrition. However, a different trend is observed among football players, who feature a decrease in the relative amount of extracellular mass [30]. This has been linked to physical activity that requires larger power output, such as in endurance running and cross country skiing. In the group of football players examined in this study, the overall ECM/BCM index was found to be 0.7, which corresponds to those values in well-trained adult competitors [31]. When considering playing positions, the lowest index value was observed in forwards, while midfielders were characterised by the highest level of extracellular mass in relation to cell mass. The easiest way to measure the reaction of the cardiovascular system to effort is to determine the heart rate index, which has been significantly correlated to VO2max and blood lactate and saliva lactate levels. Heart rate reserve is also used as an indirect measurement of the intensity of metabolic changes and useful when comparing the endurance of players in different positions on the pitch [32]. The group of youth football players analysed in this study featured no statistically significant variation between resting heart rate, maximum heart rate or heart rate reserve. However, it should be emphasised that forwards displayed the lowest HR rest and the highest HR max and HRR during the test. Defenders were characterised by the highest values of resting heart rate and the lowest values of maximum heart rate and heart rate reserve. Based on the obtained results, it can be concluded that forwards are characterised by the highest level of cardio-vascular efficiency. Research conducted on 14–21 year-old football players revealed that forwards were characterised by greater endurance, velocity, agility and power, along with better muscle development and body leanness, than other players [33]. Goalkeepers, on the other hand, were characterised with greater height, mass, body fat and the lowest aerobic capacity. Midfielders displayed greater levels of agility and endurance, while defenders were characterised by the lowest body fat. Conclusions Analysis of the results revealed that there are certain differentiating trends in body tissue composition and cardiovascular efficiency among football players playing in different positions. Forwards were characterised by having the greatest height, highest levels of active body 99 HUMAN MOVEMENT A. Burdukiewicz et al., Body composition and functional traits tissue development and the most efficient cardiovascular systems. Defenders displayed larger body build, while midfielders were characterised by significantly higher values of extracellular mass and EMC in relation to BCM. These differences reflect the varied physical efforts players perform during a match and should be taken into consideration when designing training programmes. References 1. Wisloff U., Helgerud J., Hoff J., Strength and endurance of elite soccer players. Med Sci Sports Exerc, 1998, 30, 462–467. 2. Gorostiaga E.M., Izquierdo M., Ruesta M., Iribarren J., González-Badillo J.J., Ibáñez J., Strength training effects on physical performance and serum hormones in young soccer players. Eur J Appl Physiol, 2004, 91, 698–707, doi: 10.1007/s00421-003-1032-y. 3. McMillan K., Helgerud J., Macdonald R., Hoff J., Physio logical adaptations to soccer specific endurance training in professional youth soccer players. Br J Sports Med, 2005, 39, 273–277, doi: 10.1136/bjsm.2004.012526. 4. Tanaka H., Monahan K.D., Seals D.R., Age-predicted maximal heart rate revisited. J Am Coll Cardiol, 2001, 37, 153-156, doi: 10.1016/S0735-1097(00)01054-8. 5. Bricout V.-A., Dechenaud S., Favre-Juvin A., Analyses of heart rate variability in young soccer players: The effects of sport activity. Auton Neurosci, 2010, 154, 112–116, doi: 10.1016/j.autneu.2009.12.001. 6. Uth N., Sørensen H., Overgaard K., Pedersen P.K., Estimation of VO2max from the ratio between HRmax and HRrest – the Heart Rate Ratio Method. Eur J Appl Physiol, 2004, 91, 111–115, doi: 10.1007/s00421-003-0988-y. 7. Strøyer J., Hansen L., Klausen K., Physiological profile and activity pattern of young soccer players during match play. Med Sci Sports Exerc, 2004, 36, 168–174, doi: 10.1249/01.MSS.0000106187.05259.96. 8. Esposito F., Impellizzeri F.M., Margonato V., Vanni R., Pizzini G., Veicsteinas A., Validity of heart rate as an in dicator of aerobic demand during soccer activities in amateur soccer players. Eur J Appl Physiol, 2004, 93, 167–172, doi: 10.1007/s00421-004-1192-4. 9. Burdukiewicz A., Janusz A., Physical capacity and fitness of children and youths as related to their somatic development. Biol Sport, 1995, 12, 175–188. 10. Malina R.M., Eisenmann J.C., Cumming S.P., Ribeiro B., Aroso J., Maturity-associated variation in the growth and functional capacities of youth football (soccer) players 13–15 years. Eur J Appl Physiol, 2004, 91, 555–562, doi: 10.1007/s00421-003-0995-z. 11. Malina R.M, Ribeiro B., Aroso J., Cumming S.P., Characteristics of youth soccer players aged 13–15 years classified by skill level. Br J Sports Med, 2007, 41, 290–295, doi: 10.1136/bjsm.2006.031294. 12. Philippaerts R.M., Vaeyens R., Janssens M., van Renter ghem B., Matthys D., Craen R. et al., The relationship between peak height velocity and physical performance in youth soccer players. J Sports Sci, 2006, 24, 221–230, doi: 10.1080/02640410500189371. 13. Hulthén L., Bengtsson B.-Å., Sunnerhagen K.S., Hallberg L., Grimby G., Johannsson G., GH is needed for the maturation of muscle mass and strength in adolescents. J Clin Endocrinol Metab, 2001, 86, 4765–4770, doi: 10.1210/jc.86.10.4765. 100 14. Silvestre R., West C., Maresh C.M., Kraemer W.J., Body composition and physical performance in men’s soccer: A study of A National Collegiate Athletic Association Division Iteam. J Strength Cond Res, 2006, 20, 177–183, doi: 10.1519/R-17715.1. 15. Pantelis T. N., Anaerobic Power across Adolescence in Soccer Players. Hum Mov, 2011, 12 (4), 342–347, doi: 10.2478/v10038-011-0039-1. 16. Maynard L.M., Wisemandle W., Roche A.F., Chum lea W.C., Guo S.S., Siervogel R.M., Childhood body composition in relation to Body Mass Index. Pediatrics, 2001, 107, 344–350, doi: 10.1542/peds.107.2.344. 17. Mirkov D.M, Kukolj M., Ugarkovic D., Koprivica V.J., Jaric S., Development of anthropometric and physical performance profiles of young elite male soccer players: A longitudinal study. J Strength Cond Res, 2010, 24, 2677–2682, doi: 10.1519/JSC.0b013e3181e27245. 18. Bale P., Mayhew J.L., Piper F.C., Ball T.E., Willman M.K.J., Biological and performance variables in relation to age in male and female adolescent athletes. J Sports Med Phys Fitness, 1992, 32, 142–148. 19. Vicente-Rodríguez G., Ara I., Perez-Gomez J., SerranoSanchez J.A., Dorado C., Calbet J.A.L., High femoral bone mineral density accretion in prepubertal soccer players. Med Sci Sports Exerc, 2004, 36, 1789–1795. 20. Calbet J.A.L., Dorado C., Díaz-Herrera P., Rodríguez-Ro dríguez L.P., High femoral bone mineral content and density in male football (soccer) players. Med Sci Sports Exerc, 2001, 33, 1682–1687, doi: 10.1097/00005768-20011000000011. 21. Sutton L., Scott M., Wallace J., Reilly T., Body composition of English Premier League soccer players: Influence of playing position, international status, and ethnicity. J Sports Sci,2009,27,1019–1026,doi:10.1080/02640410903030305. 22. Wittich A., Oliveri M.B., Rotemberg E., Mautalen C., Body Composition of Professional Football (Soccer) Players Determined by Dual X-Ray Absorptiometry. J Clin Densitom, 2001, 4, 51–55. 23. Wang Z.M., Heshka S., Wang J., Gallagher D., Deurenberg P., Chen Z. et al., Metabolically active portion of fatfree mass: a cellular body composition level modeling analysis. Am J Physiol Endocrinol Metab, 2007, 292, 49–53, doi: 10.1152/ajpendo.00485.2005. 24. Andreoli A., Melchiorri G., Brozzi M., Marco A., Volpe S.L., Garofano P. et al., Effect of different sports on body cell mass in highly trained athletes. Acta Diabetol, 2003, 40, S122–S125, doi: 10.1007/s00592-003-0043-9. 25. Hazir T., Physical characteristics and somatotype of soccer players according to playing level and position. J Hum Kinet, 2010, 26, 83–95, doi: 10.2478/v10078-010-0052-z. 26. Melchiorri G., Monteleone G., Andreoli A., Callà C., Sgroi M., De Lorenzo A., Body cell mass measured by bioelectrical impedance spectroscopy in professional football (soccer) players. Sports Med Phys Fitness, 2007, 47, 408–412. 27. Banfi, G., Del Fabbro M., Relation between serum creatinine and body mass index in elite athletes of different sport disciplines. Br J Sports Med, 2006, 40 (8), 675–678, doi: 10.1136/bjsm.2006.026658. 28. 28. Talluri A., Liedtke R., Mohamed E.I., Maiolo C., Martinoli R., De Lorenzo A., The application of body cell mass index for studying muscle mass changes in health and disease conditions. Acta Diabetol, 2003, 40, S286– S289, doi: 10.1007/s00592-003-0088-9. HUMAN MOVEMENT A. Burdukiewicz et al., Body composition and functional traits 29. Orhan Ö., Sağir M., Zorba E., Kishali N. F., A comparison of somatotypical values from the players of two football teams playing in Turkcell Turkish super league on the basis of the players’ positions. J Phys Educ Sport Manag, 2010, 1, 1–10. 30. Randáková R., Effect of regular training on body composition and physical performance in young cross-country skiers: as compared with normal controls. Acta Univ Palacki Olomuc Gymn, 2005, 35, 17–35. 31. Bunc V., Body composition as a determining factor in the aerobic fitness and physical performance of Czech children. Acta Univ Palacki Olomuc Gymn, 2006, 36, 39–45. 32. Impellizzeri F.M., Rampinini E., Marcora S.M., Physio logical assessment of aerobic training in soccer. J Sports Sci, 2005, 23, 583–592, doi: 10.1080/02640410400021278. 33. Gil S.M., GIL J., Ruiz F., Irazusta A., Irazusta J., Physio logical and anthropometric characteristics of young soccer players according to their playing position: Relevance for the selection process. J Strength Cond Res, 2007, 21, 438–445, doi: 10.1519/R-19995.1. Paper received by the Editors: June 19, 2012 Paper accepted for publication: March 12, 2013 Correspondence address Anna Burdukiewicz Akademia Wychowania Fizycznego al. I.J. Paderewskiego 35 51-612 Wrocław, Poland e-mail: [email protected] 101 HUMAN MOVEMENT 2013, vol. 14 (2), 102– 109 Gender-based dimorphism of aerobic and anaerobic capacity and physical activity preferences in deaf children and adolescents doi: 10.2478/humo-2013-0011 Anna Zwierzchowska The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland Abstract Purpose. Research on the hearing impaired has revealed that the rate of change of physical fitness characteristics between both genders may be different than that of the hearing. The aim of the study was to verify the gender-based differentiation of aerobic and anaerobic capacity in a group of deaf children and adolescents (aged 10–18 years) and to evaluate their physical activity preferences. Methods. A semi-longitudinal study was conducted, with data collected three times over a period of two years. Aerobic capacity was measured by the PWC170 cycle test, anaerobic capacity by the Wingate test. A questionnaire was used to evaluate the physical activity preferences and favored leisure activities of the participants. Results. Significant genderbased differences were found in the aerobic and anaerobic capacity of the deaf boys and girls. A moderate correlation was noted for leisure time preferences. Conclusions. Deaf children feature no gender-based differences among their physical activity preferences. Environment plays a major role in stimulating the behavior of deaf children and adolescents. Key words: aerobic and anaerobic capacity, sexual (gender) dimorphism, deafness Introduction Disabilities, especially those that affect the musculoskeletal system, play a large role in reducing physical activity levels. However, often at times individuals with sensory impairments are not perceived as having the same limitations in performing physical activity as those with physical disabilities. This is especially so with hearing impairments, which are usually not regarded as limiting physical activity, although research on this subject has provided contradictory results. Many researchers state that the physical abilities of the deaf are highly differentiated and even sometimes lower than those found among an average hearing population [1–5], concluding that this may be the consequence of how physical education is shaped and taught to the deaf. A study by Ellis [6] revealed that one of the most important factors motivating deaf youth in performing physical activity is the emotional support and involvement of parents. A similar conclusion was reached by Dummer et al. [2], stating that there are no differences in the motor skills of deaf children and their hearing peers. This group of authors believes that the introduction of early intervention and special education programs already at the preschool age helped bridge any supposed impediment. Moreover, they recognized that environmental factors (type of school, lifestyle, parental attitude as well as their involvement in physical activity, and the availability of free play opportunities) also play an important role in motor development. Liberman et al. [4, 7] drew attention to the importance of several environmental factors, in particular on how physical education classes were conducted through the use of special programs and the role of physical education teachers in providing a behavioral role model 102 for participation in physical education. An additional factor noticed by auxologists and teachers of the deaf is the difference in interest in various forms of physical activity based on gender, which is believed to be a reflection of what physical activity can actually be performed [2, 8]. Research has confirmed that the gender difference between males and females is already visible at the preschool age and includes not only interest in various forms of physical activity but also motility [9]. The ontogenetic development of motor and morphological skills has been described as highly variable. Motor skills are largely the result of environmental conditioning, hence dimorphic variation cannot be as clearly defined as in the case of somatic characteristics. Therefore, it is difficult to expect that dimorphic traits in motility would not be present even when a hearing impairment is present. However, a few studies that have been conducted on the hearing impaired found that the rate and pace of characteristics that can emerge to differentiate both genders may be different than those among the hearing [3, 10–13]. Among girls, fewer differences were found to exist between those hearing and deaf than in the case of boys. Comparative studies on the physical development of deaf boys and girls have revealed significant differences in favor of girls. One of many conclusions reached by such studies was that deaf girls develop physical and motor skills better than boys [10–15]. It was also noted that deaf girls learn new motor skills quicker and show little or no differences when compared with their hearing peers than in the case of deaf boys. In contrast, deaf boys often showed significantly greater motor deficits than their hearing peers [2]. Haubenstricker and Seefeldt’s findings [8] on the hearing helped theorize HUMAN MOVEMENT A. Zwierzchowska, Aerobic and anaerobic capacity and physical activity of the deaf that the ability to learn basic motor skills is more similar between deaf boys and girls than among their hearing peers. Instead, the delay experienced by deaf boys in learning new motor skills may be caused by them presenting a physical fitness level lower than among the hearing. The aim of this study was to verify what gender differences exist among a group of deaf children and adolescents (10–18 years old) in their ability to perform aerobic and anaerobic tasks as well as what their physical activity preferences. In light of the formulated objective, the study was guided by the following research questions: 1. What is the preferred physical activity of deaf male and female youth? 2. Is gender a factor that differentiates the deaf in their ability to perform aerobic and anaerobic tasks? It was assumed that the preferred physical activity is an important factor differentiating aerobic and anaerobic exercise capacity. Material and methods Students attending special education schools for the deaf and hard of hearing from the Polish cities of Katowice, Kraków, and Racibórz comprised the target population. A sample was selected by adopting the criteria used in modern audiology as based on Parving [16]. The main criterion for inclusion was for the student to have been diagnosed of profound hearing loss (prelingual deafness) before the age of three and experiencing sensorineural hearing impairment. All cases where the etiology of deafness was unknown were excluded from the study. All of the participants had normal intelligence as well as showed no signs of any physical disabilities that could impair movement. The final sample included deaf students of both genders within the calendar age groups of 9.6–10.5 years, 12.6–13.5 years, and 15.6–16.5 years, where 17.7% had inherited deafness, 55.4% were prenatal cases, and 26.9% suffered a hearing impairment after the postnatal period up to age three. The study design was designed to be semi-longitudinal in nature and divided into three age groups within a 10–18 year old spread. It was conducted three times in 2004, 2005, and 2006 (all in the month of October) on the same deaf students within the mentioned three age groups, allowing the same age groups to be observed (9.6–12.5, 12.6–15.5, and 15.6–18.5 years old) (Tab. 1). A self-designed questionnaire was used to evaluate the physical activity preferences of the participants. It contained closed-ended questions with multiple-choice answers on how they enjoyed spending their leisure time. The questionnaire was completed with the help of a sign language interpreter who also provided instructions on how to complete the exercise tests measuring aerobic and anaerobic capacity. Each exercise task was preceded by a demonstration with a complete explanation of the instructions and conducted by the same research team each time. The study was approved by the Bioethics Committee of Scientific Research at the University School of Physi cal Education in Katowice, Poland as part of a project funded in part by the State Committee for Scientific Research. In addition, the legal guardians of the participants were informed of the nature of the experiment and provided their written consent. The participants were informed they may at any time leave the study without providing any reason and reminded that their personal information would remain private in accordance with all applicable data privacy laws. Physiological data was collected by lung vital capacity as well as the aerobic and anaerobic capacity of the participants was measured. Vital capacity (VC) was measured in l/min by use of Pony Graphic 3.7 spirometer (Cosmed, Italy). Respiratory rates were measured twice as per the manufacturer’s recommendation. Prior to taking a measurement, the participant was asked to breathe calmly for a short period of time and then inhale and exhale as hard as possible, performing a maximum inhalation and maximum exhalation. After exhaling the remaining residual air volume was measured. Aerobic capacity was assessed by VO2max · kg–1 and the PWC170 cycle test on an 828E cycle ergometer (Monark, Sweden), which from a technical point of view was the most accommodating for the participants due to their impairment. The task was thoroughly explained to the participants and motivation was provided throughout the test. First, the workload on the cycle ergometer needed to maintain a heart rate of 170 beats per minute was calculated (a higher value in the PWC170 test denotes that more work needs to be performed based on a correctly functioning cardiovascular system). It was determined that two five-minute trails at 30 and 60 W for Table 1. Participants grouped by age and gender Year 2004 2005 2006 10 (12) 13 (15) 16 (18) 2004–2006 Girls Boys Girls Boys Girls Boys n 6 6 6 16 14 15 6 6 6 6 6 6 12 10 10 10 9 10 56 51 53 Age in parentheses is the age of the participants at the conclusion of the study 103 HUMAN MOVEMENT A. Zwierzchowska, Aerobic and anaerobic capacity and physical activity of the deaf girls and 50 and 100 W for boys would be adequate. Throughout the test the participants’ heart rate was monitored. PWC170 was calculated by the formula: PWC170 = N1 – N2 · 170 – f1 f1 – f2 , where: N1– first test workload, N2– second test workload, f1 – heart rate at the fifth minute of the first test, f2 – heart rate at the fifth minute of the second test. Maximal oxygen uptake (VO2max) was then estimated based on the Astrand-Ryhming nomogram by taking into consideration steady heart rate at submaximal effort [17]. This provided two variables that could be used to assess aerobic endurance: maximal aerobic power (PWC170 [W/kg]) and and maximal oxygen uptake (VO2max [ml/kg x min]). Anaerobic capacity was measured by the 30-second Wingate Test, which is a non-invasive method that is suitable for repeated use and considered to be a reliable and accurate measure of anaerobic capacity, as anaerobic processes meet almost 90% of the overall energy demands of the test [18]. The test also registers the power output of a participant as a function of time (throughout the 30 second period of the test) as it increases and then decreases as the effects of fatigue set in. Analysis of power output as a function of time indicates that humans produce maximum power between the first 3–6 seconds of the test, followed by steady decrease until completion. This reveals the nature of the energy conversion process in the working muscles. The test was performed with the use of a different cycle ergometer (model 829, Monark, Sweden) that measures the duration of each pedal revolution. After receiving a visual cue, the participant’s task was to reach a maximum pedaling frequency as fast as possible and maintain this speed for 30 seconds. The load was matched individually to each participant by taking into account their body mass, age, and sex (75g per kg). Changes in power output were determined by the duration of each pedal revolution. The test was preceded by a five-minute warm-up on the cycle ergometer with a load suitable to reach a heart rate of 140–150 beat per minute. Anaerobic capacity and power output were measured with the following variables: maximal anaerobic power – MAP [W], average anaerobic power – AAP [W], time to reach maximal power – TMP [s], time under tension – TUT [s], and the rate of power loss – RPL [%]. Data were recorded and calculated by using MCE ver. 2.0 computer software. All statistical analysis was performed with Statistica v. 7.1 (Statsoft, USA) and Microsoft Excel software. The mean ( ), median, minimums and maximums, standard deviation (SD), and measures of skewness (SK) 104 and kurtosis (KU) were calculated for data that were expressed as a ratio variable. Normal distribution was assessed with the Shapiro-Wilk test. Univariate ANOVA and correlation analysis using Spearman’s rank correlation coefficient (rs) was also used. The results were treated as statistically significant at p < 0.05. The sexual dimorphism of the participants’ somatic characteristics were determined by the differences of the mean values in each successive year. However, several studies have shown that sexual dimorphism is more accurately measured by indicators that define body proportions and not individual morphological characteristics. Developmental differences between the studied boys and girls were determined by Mollison’s index of sexual dimorphism (SDI) [19]: SDI = – SD , where: SDI – the indicator of sexual dimorphism, – the arithmetic mean of the girls’ characteristics, – the arithmetic mean of the boys’ characteristics, SD – the standard deviation of the boys’ characte ristics. Dimorphic differences were treated as significant when the difference between the means ( ) was larger than the standard deviation (SD) of the group of males. The absolute value of the tested variable would indicate the degree of differentiation: the larger the value the larger its value of one standard deviation away from the mean of the boys’ results. A positive value would indicate that this characteristic is in favor of females. Results The responses obtained from the questionnaire found that the boys were decidedly less physically active than the girls, with a large majority of them preferring to spend their leisure time passively by watching TV or playing computer games (94.2% and 77.7%, respectively). However, the majority of boys reported that their more actively spent leisure time consisted of bicycling and team sports (80.5%), which was in contrast with the girls who preferred calmer activities such as playing outside and taking walks (51.8%). The results of the questionnaire indicated a lack of statistically significant differences in the leisure activity preferences of the deaf boys and girls. A moderate correlation was found between the boys’ and girls’ preference for passive forms of physical activity (rs = 0.629, p < 0.05) although no significant relationships were found among active forms of physical activity (Tab. 2, 3). Physical fitness was analyzed by measuring aerobic and anaerobic capacity. Analysis of the indicators of aerobic capacity and vital capacity (VC) found a statistically significant difference between the boys and girls only in PWC170 [W/kg]. Only the youngest group of girls HUMAN MOVEMENT A. Zwierzchowska, Aerobic and anaerobic capacity and physical activity of the deaf Type of activity Boys n = 35 % Girls n = 27 % Passive TV Computer Reading books Social games 8 25 1 2 22.8 71.4 3.2 5.7 12 9 2 4 44.4 33.3 7.4 14.8 Active Table 2. Preferred leisure activities by the deaf girls and boys Bicycling Swimming Taking walks, playing outdoors Skiing Team sports 20 3 57.7 8.6 9 3 33.3 11.1 4 7.1 14 51.8 2 8 7.4 22.8 4 4 14.8 11.4 Table 3. Spearman’s rank correlation coefficient (rs) the deaf boys and girls with regard to their preferred leisure activities Passive leisure activities Girls Boys Girls Boys x 0.629 0.629 x Girls Boys x 0.143 0.143 x Active leisure activities Girls Boys achieved better results than the boys, with the later tests finding that the boys achieved significantly better results up to the age of 18 (f = 5.6; p < 0.03). Gender had no statistically significant effect on the rate of maximal oxygen uptake, only age was a significant factor differentiating both groups. A decline of VO2max values was noticed in both the boys and girls. A some- what different picture is seen in the case of VC, whose values progressively rise over time, although no statistically significant differences were found between the boys and girls (Tab. 4). The sexual dimorphism index found dimorphic variation in favor of the males for PWC170 above the age of 12 and for VC above the age of 16. It is worth noting that the dimorphism index was highly fluctuated showing no clear trend. Furthermore, the dimorphism index calculated for VO2max pointed to no differences greater than one standard deviation away from the boys’ mean, which indicates that there is no significant variation between genders (Tab. 4). Analysis of the increases in PWC170 and VO2max finds that gender has no statistically significant effect on these values, with the only statistically significant difference found in the rate of change of vital capacity between 10 and 12 years of age (Fig. 1). The participants’ ability to perform brief anaerobic effort was based on the following five measured variables: maximal anaerobic power – MAP [W], average anaerobic power – AAP [W], time to reach maximal power – TMP [s], time under tension – TUT [s], and the rate of power loss – RPL [%]. Significant differences between the boys and girls were found for MAP and AAP (the oldest group composed of 16-, 17-, and 18-year-olds), RPL (11- and 17-year-olds), and TMP (17-year-olds), all in favor of the boys (Tab. 5). It should be noted that the time needed to reach these values was significantly higher than expected (3–6 seconds). Anaerobic capacity assessed using the dimorphism index indicates a regular progressive trend for MAP and AAP from the age of 13 onwards, whereas the absolute values point to significant differences between genders in favor of the boys starting from the age of 16. A similar situation, although reversed, was found with RPL, which measures the rate at which fatigue sets in. This variable was found to largely characterize the girl participants (indicating a smaller tolerance to fatigue). Table 4. Aerobic capacity and vital capacity of the deaf girls and boys VC Age ± SD 10 11 12 13 14 15 16 17 18 2.0 ± 0.5 1.9 ± 0.4 2.14 ± 0.6 2.9 ± 0.2 2.8 ± 0.4 3 ± 0.4 2.9 ± 0.3 2.7 ± 0.5 2.7± 0.6 ± SD 2.5 ± 0.3 2.3 ± 0.4 2.7 ± 0.8 3.4 ± 0.9 2.9 ± 0.6 3 ± 0.7 3.8 ± 0.5 3.9 ± 0.4 3.6 ± 0.5 VO2max PWC170 SDI –1.5 –0.8 –0.7 –0.4 –0.2 0.1 –1.6 –2.7 –1.7 ± SD 1.9 ± 0.8 1.6 ± 0.7 1.8 ± 0.3 1.5 ± 0.3 1.4 ± 0.2 1.9 ± 0.4 1.7 ± 0.7 1.5 ± 0.6 1.8 ± 0.6 ± SD 1.7 ± 0.6 1.8 ± 0.7 2.4 ± 0.7 2.0 ± 0.4 1.7 ± 0.2 2.3 ± 0.6 2.5 ± 0.7 2.5 ± 1.2 2.4 ± 0.5 SDI 0.2 –0.2 –0.8 –1.2 –1.6 –0.7 –1.2 –0.9 –1.0 ± SD 54.2 ± 18.8 48.5 ± 18.5 48.2 ± 13.2 40.1 ± 4.0 36.6 ± 4.0 40.4 ± 5.8 39.7 ± 9.4 39.2 ± 7.7 41.6 ± 9.3 ± SD 50.2 ± 11.3 49.1 ± 12.3 50.9 ± 11.3 49.2 ± 10.1 43.2 ± 3.8 48.4 ± 11.0 44.6 ± 7.6 48.0 ± 13.7 46.1 ± 7.7 SDI 0.3 –0.1 –0.2 –0.9 –1.6 –0.7 –0.6 –0.6 –0.6 * statistically significant difference between genders at p < 0.05; SDI – Mollison’s sexual dimorphism index; shaded values indicate a difference in dimorphic traits (SDI > SD ) 105 106 9.5 ± 1.2 9.4 ± 1.8 8.0 ± 1.3 7.5 ± 1.1 –2.2 –1.2 –1.9 –1.2 –0.9 0.1 –0.8 –0.5 –0.8 SDI 5.2 ± 0.9 5.5 ± 1.1 5.09 ± 1.7 5.5 ± 0.5 5.2 ± 0.4 5.7 ± 0.5 4.4 ± 1.9 4.1 ± 1.9 3.6 ± 1.7 ± SD 7.8 ± 0.7 7.4 ± 1.4 7.5 ± 0.7 7.2 ± 0.9 6.5 ± 0.9 6.1 ± 0.9 5.9 ± 1.7 4.9 ± 1.4 5.4 ± 1.6 ± SD AAP [W/kg] –3.3 –1.4 –3.1 –1.7 –1.4 –0.5 –0.9 –0.5 –1.0 SDI ± SD 11.5 ± 4.5 10.2 ± 1.4 11.7 ± 4.0 10.2 ± 3.4 16.2 ± 6.6 10.2 ± 3.0 12.8 ± 5.8 12.5 ± 2.6 10.4 ± 2.8 13.5 ± 2.5 12.0 ± 5 12.5 ± 3.3 10.8 ± 2.8 9.9 ± 5.2 12.7 ± 5.5 16.1 ± 7.8 15.2 ± 5.4 11.6 ± 4.4 ± SD TMP [s] 0.3 –0.9 –0.4 0.7 0.6 0.6 –0.3 –0.4 0.8 SDI 2.6 ± 1.3 2.5 ± 1.5 1.3 ± 1.2 3.6 ± 2.2 2.7 ± 1.2 1.6 ± 0.7 3.3 ± 2.7 3.08 ± 2.2 1.6 ± 1.0 ± SD * statistically significant difference between genders at p < 0.05; SDI – Mollison’s sexual dimorphism index; shaded values indicate a difference in dimorphic traits (SDI > SD ) 6.8 ± 1.4 18 9.5 ± 1.2 7.4 ± 0.4 15 6.9 ± 2.2 6.7 ± 1.0 14 7.3 ± 1.7 7.7 ± 1.2 13 16 8.7 ± 1.0 5.7 ± 2.2 17 6.3 ± 1.5 5.5 ± 2.3 11 12 7.6 ± 2.1 6.9 ± 2.0 ± SD 5.1 ± 1.7 10 ± SD Nonetheless, the SDI index was less than one standard deviation away from the boys’ means, which suggests that gender is not a differentiating factor here. The remaining variables assessing anaerobic capacity oscillated between zero and the absolute value of one standard deviation, indicating no significant differences between the genders (Tab. 5). Analysis on the rate of change of the variables measuring anaerobic capacity found that gender did have a statistically significant effect on increased TMP in the youngest age group. There were no statistically significant differences in the rate of change for the remaining variables between the two genders (Fig. 2). Age Figure 1. Rate of change for vital capacity and the indicators measuring the aerobic capacity of the deaf girls (G) and boys (B) among the three age groups (10–12, 13–15, and 16–18 years old) MAP [W/kg] * statistically significant difference at p < 0.05 – denotes change as a unit of time (year) for VC, PWC170, and VO2max Table 5. Anaerobic capacity of the deaf girls and boys 3.4 ± 2.8 2.0 ± 1.6 1.2 ± 2.5 3.5 ± 2.3 4.7 ± 4.6 1.0 ± 1.7 1.9 ± 0.8 2.1 ± 2.6 1.1 ± 1.3 ± SD TUT [s] 14.3 ± 8.1 16.8 ± 7.8 ± SD 16.9 ± 9.5 21.7 ± 9.7 12.6 ± 5.8 14.2 ± 3.8 28.7 ± 17.1 17.6 ± 5.8 24.7 ± 7.4 17 ± 4.8 ± SD –0.3 20.4 ± 7.2 0.23 22.3 ± 7.9 13.6 ± 6.7 11.1 ± 7.8 –0.01 25.6 ± 17.7 15.7 ± 7.1 0.03 22.5 ± 12.5 15.3 ± 2.6 –0.4 –0.2 1.6 0.3 0.4 SDI RPL [%] 1.0 1.4 1.4 2.7 0.7 1.9 1.9 1.2 0.1 SDI HUMAN MOVEMENT A. Zwierzchowska, Aerobic and anaerobic capacity and physical activity of the deaf HUMAN MOVEMENT A. Zwierzchowska, Aerobic and anaerobic capacity and physical activity of the deaf * statistically significant difference at p < 0.05 – denotes change as a unit of time (year) for maximal anaerobic power (MAP) AAP – average anaerobic power TMP– time to reach maximal power TUT – time under tension RPL – the rate of power loss Figure 2. The rate of change of variables measuring anaerobic capacity for the deaf girls (G) and boys (B) among the three age groups (10–12, 13–15, and 16–18 years old) Discussion Lung vital capacity has been medically verified to increase together with maturity, although it remains highly variable not only due to age but also gender [21]. This study confirmed the progressive rise of vital capacity in both females and males, with significant gender differences emerging after the age of 15. However, no significant sexual dimorphic differences in the rate of change of this physiological variable were found to occur in this group of deaf 10–18 year-olds. The progressive variability of various somatic characteristics defining human development have been found to determine individual exercise capacity. This was the most visible in the oldest group of deaf participants (16-, 17-, and 18-years-old), where gender was a factor differentiating their aerobic and anaerobic capacity with males showing a considerable advantage over their female peers. These findings correspond with the results of able-bodied young adults, due in part that the physio logical adaption of children’s bodies to exercise significantly differs than in mature adults. These differences are particularly noticeable in exercise performed at maximal and supramaximal intensities that use predominantly anaerobic energy processes. This is due to children having a less developed ability to resynthesize high-energy resources based on anaerobic energy processes as well as a reduced ability to neutralize the byproducts of anaerobic exercise. Hence, children obtain lower measures of maximal anaerobic power and feature less tolerance to homeostatic imbalance during physical effort [22, 23]. A study by Bar-Or [18] has also shown that children’s lower levels of anaerobic capacity may be caused by reduced capacity to use muscle glycogen during physical effort. This was evidenced by a slower rate of anaerobic glycolysis and lower blood lactate concentration levels in the working muscles when compared to adults. This relationship was verified in the present study of deaf children and youth, where the potential for effort increased with age and which was most visible among the group of deaf males. In terms of the differentiation between boys’ and girls’ anaerobic capacity, Cempla and Bawelski [24] were more critical of the opinion that boys featured a greater increase in 107 HUMAN MOVEMENT A. Zwierzchowska, Aerobic and anaerobic capacity and physical activity of the deaf maximal anaerobic power (MAP) relative to girls, although the results obtained in this study do not confirm their assessment. Research on the physical activity of disabled children and youth has indicated that the hearing impaired do not see themselves as individuals who are dysfunctional when compared to the rest of the population. This group has been found to have very high self-esteem in regards to their habits and ability to perform physical exercise, while at the same time reporting that they do not feel to have physical ability levels lower than their hearing peers [25]. Among a group of disabled indivi duals, the hearing impaired presented a high level of phy sical fitness [26]. Nonetheless, these observations have been contradicted by a number of empirical studies on the aerobic and anaerobic capacity of the deaf in comparison with the non-disabled [11, 27, 28]. However, few have concentrated on the gender-based differences of the deaf’s aerobic and anaerobic capacity. Shepard, Ward, and Lee [28] examined 15 boys and 14 girls (ages 12 to 15) finding that only 40% were found to meet the norms for their age and sex. These authors pointed out that age and gender did differentiate the results, which followed a progressive trend together with age, although these changes were statistically insignificant for the group of girls. They also drew attention to the increased adiposity of the deaf, especially in the case of females, which may have contributed to this finding. Other researchers have stated that deaf children and adolescents feature lower tolerance to effort during aerobic and anaerobic testing [11, 27]. The results of this study support this hypothesis especially in the case of females. The variable measuring power loss (RPL) was significantly lower among boys in the oldest age group, which reflects their higher (better) tolerance during short-term anaerobic exercise (Tab. 5). Here, the sexual dimorphism index had a positive value as the girls’ recovery process required more time, but was at the same time less than one standard deviation from the boys’ mean, finding that RPL was not a characteristic that differentiates gender. Of considerable interest is also one of the other analyzed variables, the time to reach maximal anaerobic power (TMP). The time to reach maximal power has been defined to occur at around 3–6 seconds. A surprising outcome in this study was that both the boys and girls had difficulty in reaching their maximum heart rate within this time frame. One of the only explanations for this result may be that this group was less motivated (volition). Motivation is an important factor not only for succeeding in sports but also, above all, guides individuals to engage in suitable fitness training. The concept of motivation has been defined as a “hypothetical construct” [29], as a state of readiness to take specific action stemming from both individual needs and external factors and which possesses a certain significance that cannot be completely defined through empirical evidence. Evidence of this fundamental problem can be found in the responses provided by the par108 ticipants in the questionnaire on their physical activity preferences, which indicated that individual forms of physical activity were highly preferred. Yet, it is common knowledge that nothing better motivates individuals than interpersonal relationships and healthy competition. It should be taken into account that deafness is a mitigating factor in social behavior (feelings of strong alienation from both able-bodied and disabled individuals) and might have been reflected in the participants’ res ponses. For example, their preference for these forms of physical activity are consistent with those found in a group of deaf students in Karachi, Pakistan [30]. It is worth noting that the deaf students from Karachi also ranked individual sports and forms of recreation first, while rating “improving health and the body” the least motivating factor for their participation in physical activity. Therefore, it is difficult to expect that deaf individuals would present large differences in their prefe rences for various forms of physical activity as is the case for the able-bodied. The findings of this study – showing a moderate correlation between girls and boys who prefer passive forms of leisure activities – allow us to assume that deafness acts to limit both the prefe rences and motivation for physical activity and is an issue that requires further investigation. Conclusions The ability to perform increasing amounts of aerobic and anaerobic work was found to increase together with age for both the deaf male and female participants. Gender-based differences were noted for aerobic (from the age of 12) and anaerobic capacity (from the age of 14). In contrast, no statistically significant differences were observed in the rate of developmental change that defines aerobic and anaerobic capacity. The study found no differences in the physical activity preferences of the deaf boys and girls, which is believed to show that deafness is a factor that limits and, consequently, unifies what forms of physical activity the deaf prefer to engage in. It is believed that the social environment plays a large role in stimulating the behavior of deaf children and adolescents. It was found that deaf boys perform aerobic and anaerobic effort increasingly better as they get older when compared with their female peers. Based on this study’s findings (TMP) and observations made during the tests, it is believed that motivation significantly affected the attained results, possibly due to communication and interpersonal difficulties. This signifies the need for providing additional external motivation for the hearing impaired when measuring exercise capacity and during physical education classes, making this a challenge to be met by both teachers and researchers. Such a conclusion was also reached by Jonsson and Gustafsson [31], who reported that motivation is an important criterion when measuring the respiratory efficiency of the hearing impaired. HUMAN MOVEMENT A. Zwierzchowska, Aerobic and anaerobic capacity and physical activity of the deaf References 1. Butterfield S.A., Gross motor profiles of deaf children. Percept Mot Skills, 1986, 62 (1), 68–70, doi: 10.2466/pms. 1986.62.1.68. 2. Dummer G.M., Haubenstricker J.L., Stewart D.A., Motor skill performances of children who are deaf. Adapt Phys Activ Q, 1996, 13 (4), 400–414. 3. Ellis M.K., Butterfield S.A., Lehnhard R.A., Grip strength performances by 6- to 19- year old children with and without hearing impairments. Percept Mot Skills, 2000, 90 (1), 279–282, doi: 10.2466/pms.2000.90.1.279. 4. Liberman L.J., Volding L., Winnick J.P., Comparing motor development of deaf children of deaf parents and deaf children of hearing parents. Am Ann Deaf, 2004, 149 (3), 281–289, doi: 10.1353/aad.2004.0027. 5. Zwierzchowska A., Żebrowska A. Evolution of anaerobic efficiency of deaf children from special schools using a Wingate test. Annals Universitatetis Mariae Curie-Skło dowska Sectio D Medicina, 2005, 60 (16), 452–456. 6. Ellis B.J., Essex M.J., Family environments, adrenarche, and sexual maturation: A longitudinal test of a life history model. Child Dev, 2007, 78 (6), 1799–1817, doi: 10.1111/ j.1467-8624.2007.01092. 7. Lieberman L.J., Dunn J.M., van der Mars H., McCubbin J., Peer tutors’ effects on activity levels of deaf students in inclusive elementary physical education. Adapt Phys Activ Q, 2000, 17 (1), 20–39. 8. Haubenstricker J.L., Seefeldt V., Acquisition of motor skills during childhood. In: Seefeldt V. (ed.), Physical activity and well-being. AAHPERD, Reston 1986, 41–102. 9. Migasiewicz J., Kiczko A., Somatic build relationships and overall physical fitness tests of motor performance in children of younger and older school age [in Polish]. In: Kowalski P, Migasiewicz J. (eds.), Sport swimming and athletics at school [in Polish]. AWF, Wrocław 1999, 23–33. 10. Maszczak T., Somatic and motor parameters of deaf children in Poland [in Polish]. PZGł, Warszawa 1977. 11. Zwierzchowska A., Gawlik K., A Comparative study of motor abilities of deaf and hearing children. In: Plinta R., Kosińska M., Niebrój L. (eds.), Health Care: coping with disability. Eukrasia 9, ŚAM Katowice 2005, 91–98. 12. Dziedzic J., Physical fitness of deaf children [in Polish]. Kultura Fizyczna, 1967, 8, 28–34. 13. Krawański A., Assessment of the physical development of young deaf and normal. [in Polish]. WFiS, Warszawa 1974, 5. 14. Zwierzchowska A., Gawlik K., Grabara M. Energetic and coordination abilities of deaf children. Human Kinetics, 2004, 11, 83–92. 15. Cieśla E., Assessment of the level of development morfofunctional children with hearing impairments and deaf. [in Polish]. In: Kruk Lasocka J., Sekułowicz M. (eds.), Early diagnosis and treatment of children with difficulties in development: an interdisciplinary problems [in Polish]. TWP, Wrocław 2004, 253–260. 16. Parving A., Hearing disorders in childhood some procedures for detection, identification, and diagnostic evaluation. Int J Pediatr Otorhinolaryngol, 1985, 9 (1), 31–57, doi: 10.1016/S0165-5876(85)80003-3. 17. Malarecki J., Capacity and physical fitness in the light of human physiology [in Polish]. Wychowanie Fizyczne i Sport, 1970, 4. 18. Bar-Or O., The Wingate anaerobic test. An update on methodology, reliability and validity. Sports Med, 1987, 4 (6), 381–394. 19. Arska-Kotlińska Z., Drozdowski Z., Manifestations of sexual dimorphism in human recessive traits in the population and targeted groups of physical activity. [in Polish]. In: Socha S. (ed.), Materiały II Krajowej Konferencji Naukowej „Problemy dymorfizmu płciowego w sporcie”. AWF Katowice–PTNKF, Katowice 1995, 79–82. 20. Stanisz A., Affordable rate statistics [in Polish]. Statsoft Polska, Kraków 1998. 21. Manzke H., Stadlober E., Schellauf H.P., Combined body plethysmographic, spirometric and flow volume reference values for male and female children aged 6 to 16 years obtained from “hospital normals”. Eur J Pediatr, 2001, 160 (5), 300–306, doi: 10.1007/s004310100724. 22. Klimek A., Physiological response of the respiratory system during repeated physical activity against aerobic capacity and anaerobic adult children [in Polish]. Studia i Monografie, AWF, Kraków 2004, 28. 23. Inbar O., Bar-Or O., Anaerobic characteristics in male children and adolescents. Med Sci Sports Exerc, 1986, 18 (3), 264–269. 24. Cempla J., Bawelski M., Development index reflecting changes in the relationship of anaerobic to aerobic exercise capacity [in Polish]. Antropomotoryka, 1998, 18, 49–56. 25. Longmuir P.E., Bar-Or O., Factors influencing the physical activity levels of youths with physical and sensory disabilities. Adapt Phys Activ Q, 2000, 17 (1), 40–53. 26. Hattin H., Fraser M., Ward G.R., Shephard R.J., Are deaf children unusually fit? A comparison of fitness between deaf and blind children. Adapt Phys Activ Q, 1986, 3 (3), 268–275. 27. Cumming G.R., Goulding D., Baggley G., Working capacity of deaf and visually and mentally handicapped children. Arch Dis Child, 1971, 46 (248), 490–494, doi: 10.1136/adc.46.248.490. 28. Shephard R., Ward R., Lee M., Physical ability of deaf and blind children. In: Berridge M.E, Ward G.R. (eds.), International perspectives on adapted physical activity. Human Kinetics, Champaign 1987, 355–362. 29. Vallerand R.J. Thill E.E., Introduction to the concept of motivation. In: Singer R.N., Hausenblas H.A, Janelle C.M. (eds.), Handbook of sport psychology. Wiley, New York 1993, 389–416. 30. Sulman N., Naz S., Motivational factors influencing the participation of deaf students in sports activities. Interdiscip J Contemp Res Bus, 2012, 3 (12), 481–488. 31. Jonsson Ö., Gustafsson D., Spirometry and lung function in children with congenital deafness. Acta Pediat, 2005, 94 (6), 723–725, doi: 10.1111/j.1651-2227.2005. tb01971.x. Paper received by the Editor: December 10, 2012 Paper accepted for publication: April 26, 2013 Correspondence address Anna Zwierzchowska Zakład Korektywy i WF Specjalnego Akademia Wychowania Fizycznego im. Jerzego Kukuczki ul Mikołowska 72a 40-066 Katowice, Poland e-mail: [email protected] 109 HUMAN MOVEMENT 2013, vol. 14 (2), 110– 115 EFFECTS OF ELBOW FLEXOR MUSCLE RESISTANCE TRAINING ON STRENGTH, ENDURANCE AND PERCEIVED EXERTION doi: 10.2478/humo-2013-0012 Mauro Gonçalves 1, Anderson Souza Castelo Oliveira 2 * 1 2 Department of Physical Education, Bioscience Institute, São Paulo State University, Rio Claro, Brazil Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark Abstract Purpose. To verify the effects of resistance training at the electromyographic fatigue threshold (EMGFT) based on one-repetition maximum strength (1RM), heart rate (HR), rate of perceived exertion (PE) and endurance time (EndT). Methods. Nineteen subjects (training group [TG]: n = 10; control group [CG]: n = 9), performed 1-min bicep curl exercises sets at 25%, 30%, 35% and 40% 1RM. Electromyography (biceps brachii and brachiorradialis), HR and PE were registered. Biceps brachii EMGFT was used to create a load index for an eight-week resistance training programme (three sets until exhaustion/session, two sessions/week) for the TG. The CG only attended one session in the first week and another session in the last week of the eight-week training period for EndT measurement. EndT was determined from the number of repetitions of each of the three sets performed in the first and last training sessions. After training, 1RM, EMGFT, EndT, HR and PE at the different bicep curl load intensities were again measured for both groups. Results. Increases in 1RM (5.9%, p < 0.05) and EndT (> 60%, p < 0.001) after training were found. In addition, PE was reduced at all load intensities (p < 0.05), while no changes were found for HR and EMGFT after training. Conclusions. Strength-endurance training based on the EMGFT improved muscular endurance and also, to a lesser extent, muscular strength. Moreover, the reduced levels of physical exertion after training at the same intensity suggest that endurance training exercises may improve comfort while performing strength exercises. Key words: elbow flexion, electromyography, endurance, perceived exertion, training Introduction Increased muscular strength, muscular volume (hyper trophy), endurance and fat tissue loss are the usual adaptations of skeletal muscle tissue to resistance training [1, 2]. In addition, neural drive facilitation measured by analysing surface electromyography (EMG) is also reported following resistance training, which is related to increased EMG activity for agonist muscles and reduced activation for antagonist muscles [3–6]. However, the literature on the topic shows controversial results in terms of EMG activity following resistance training, some reported increased EMG [3, 4], others an absence of changes [5] and also one a reduction [4] among the trained muscles. These contrasting observations relate to different training protocols, such as training volume/ duration, session frequency and intensity [1, 4]. Unfortunately, training intensities based on EMG data have been rarely studied, even though the use of the electromyographic fatigue threshold (EMGFT) has been previously discussed [7, 8] and suggested as an alternative training index [9]. The determination of EMGFT was originally suggested by using different load intensities performed until exhaustion, usually at one intensity per day [10]. However, * Corresponding author. 110 Oliveira et al. [8] verified that by performing shorter sets (30–60 seconds), the EMG slopes (EMG activity vs. time) and subsequent EMGFT are similar to those obtained after more exhaustive periods of exercise. Therefore, this allows accurate EMGFT to be determined within a single session. Previous investigations that applied EMGFT as a training intensity found increased elbow flexor strength and reduced EMG activity for the biceps brachii (BB) and brachioradialis (BR) muscles and, concomitantly, reduced activity for antagonist muscles (triceps brachii) [9]. Resistance training has been associated with neuromuscular and also metabolic and/or psychological adaptations. Previous investigation has found reduced heart rate (HR) following high-repetition lower limb resistance training [11], which may suggest an attenuation in the fatigue process during exercise. For the upper limbs, previous studies have reported increases in HR and perceived exertion (PE) at higher load levels [12–14]. Oli veira et al. [9] have verified on average HR at 140bpm and PE at 8 (on a scale of 0 to 10) for bicep curls at the end of a 1-min set at 40% one repetition maximum (1RM). Thus, low load intensities can elicit significant effort demands for smaller muscular groups. Metabolic and psychological measurements such as HR and PE have been well correlated to elbow flexor EMG activity during fatiguing exercises [13, 14], which may suggest similar modulation for neuromuscular and metabolic/psychological properties during exercise HUMAN MOVEMENT M. Gonçalves, A.S.C. Oliveira, Endurance training at EMGFT [12–14]. Based on the above, we hypothesized that resistance training focused on endurance performance, such performed at the EMGFT, can enhance time to exhaustion and reduce HR and PE. Such strength-endurance training may be aided by the use of individualized load intensities estimated from the EMGFT, which could eventually optimize endurance. Therefore, the aim of the present study was to investigate the effects of individualized resistance training on muscular endurance and metabolic/psychological demands during the bicep curl. Material and methods Nineteen healthy male (age 21 ± 1.1 years, height 174.2 ± 4.3 cm, body mass 71.4 ± 7.7 kg; mean ± SD) volunteered for the experiment. The characteristics of the participants are shown in Table 1. None had been taking part in any systematic form of upper limb resis tance training six months prior to the beginning of the study, and were asked to maintain their normal daily activities throughout the investigation period. All subjects were informed of the procedures, the risks and be nefits associated with participating in the study and signed an informed consent term previously approved by the Local Ethics Committee. The participants were randomly divided in two groups, a training group (TG, n = 10) and a control group (CG, n = 9), and tested over a 12-week period. The testing procedure was as follows: Week 1 – dynamic 1RM test was performed by both groups for the biceps curl; Week 2 – EMGFT was determined during one day of testing; from Week 3 to Week 10 – subjects in the TG took part in an endurance training program conducted twice a week for the elbow flexor muscles based on biceps brachii EMGFT [8]; the CG did not participate in any resistance training. The CG was asked not to participate in any re sistance training during the duration of the eight-week training period, but required to attend one training session in the first and last week (Weeks 3 and 10) of the resistance training programme when endurance time (EndT) for all sets was measured for both groups. An additional 1RM test was performed at the beginning of Week 7 in order to evaluate potential strength improvements. After the training period was completed, the test procedures from the first two weeks were repeated for both groups (in Weeks 11 and 12). Table 1. Anthropometric characteristics of participants in the control group (CG: n = 9) and training group (TG: n = 10); mean ± SD CG TG Age (years) Mass (kg) Height (cm) 20.8 ± 1.2 21.2 ± 1.4 73.76 ± 7.88 70.48 ± 7.73 177.95 ± 3.90 174.40 ± 5.50 1RM test and familiarization The procedure to assess maximal strength during the biceps curl exercise has been described elsewhere [9]. The initial load was set to 30kg and increased/decreased if necessary. The participants needed to perform the full range of motion, starting from a full extension in order to avoid compensation by the shoulders or trunk. Invalid trials were those in which the participant could not perform the full range of motion and/or performed trunk/shoulder compensative movements to raise the bar. The participants were familiarized with the bicep curl with a demonstration showing correct posture and movement rhythm. They were instructed to remain standing 1.5 m in front of a mirror with the trunk in a fixed position; their execution of the exercise was assisted by a frame specially designed to avoid compensation [9]. The rhythm was fixed at 40 bpm by a metronome (1.5 seconds for the concentric and 1.5 seconds for the eccentric phase of each repetition). In addition, the subjects were familiarized with the OMNI physical exertion scale [15], ranging from 0 (extremely easy) to 10 (extremely hard). This scale was positioned in front of the subject, fixed at eye height on the mirror frame. EMGFT determination, heart rate and perceived exertion The participants performed four sets of 1-min bicep curl exercises at 25%, 30%, 35% and 40% 1RM in a randomly selected order, with a 10-min rest interval provided between sets. Verbal encouragement and feedback on posture was constantly provided during movement execution. The rhythm was fixed at 40 bpm, similar to the one used in the familiarization session, and the range of motion was fixed from approximately 15° to 125° elbow flexion (0° = full elbow extension). EMG activity was recorded for the biceps brachii (BB) and brachioradialis (BR) muscles at each load intensity by using pairs of adhesive, pre-gelled silver/silver chloride MediTrace surface electrodes (Covidien, USA) with a 10 mm caption area placed at an inter-electrode distance of 20 mm. Surface EMG signals were recorded (model CAD 1026, Lynx, Brazil) at a 4000 Hz sampling frequency, amplified (1.000x) and band pass filtered (20–500 Hz). Further details about EMG acquisition and calculation are available elsewhere [9]. Offline kinematic analysis, synchronized with the surface EMG measurements, were used to determine 90° elbow flexion for every concentric action. The root mean square (RMS) was calculated in a 250 ms time-window commencing at 90° elbow flexion. Linear regressions between RMS vs. time for each set were then calculated, from which the slopes and intercepts were obtained. A new linear regression model was calculated for slopes vs. load, and the intercept of this linear regression was defined as the EMGFT for each participant [9, 10]. An illustration of the methods used for EMGFT estimation is presented in Figure 1. 111 HUMAN MOVEMENT M. Gonçalves, A.S.C. Oliveira, Endurance training at EMGFT Figure 1. Determination of electromyographic fatigue threshold (EMGFT): surface EMG signals are recorded during bicep curls at different load intensities (A); slope of the root mean square (RMS) values for each repetition are then extracted from the linear correlations (B); second linear correlation between slopes and load intensities generates a Y-intercept, defining the EMGFT (C) HR was recorded at 15 s into the set and at its end (60 s) by using a heart rate monitor (model S150, Polar, Finland). Concomitantly, subjects were asked to numerically rate how they felt their active muscles working using the previously cited PE scale as a guide. Training program based on EMGFT The training group’s resistance training programme was conducted during an eight-week period with two sessions held each week. The training sessions consisted of performing three sets of biceps curls exercise until exhaustion (failure to maintain complete range of motion and/or movement velocity/rhythm), each set was interspaced with 2-min rest. Training intensity (load) was individually determined by the biceps brachii EMGFT (%1RM). At the end of the fourth week, 1RM levels were re-evaluated in order to adjust the training intensity if necessary so as to maintain EMGFT as a percentage of the current strength. Throughout the sessions and during the sets the participants were strongly encouraged to give their maximum and maintain correct execution until exhaustion. tween-subject factor) on the dependent variables: 1RM; EMGFT for BB and BR; EndT for first, second and third sets; HR; and PE. In addition, in order to verify the effects of load intensity (25% x 30% x 35% x 40% 1RM) and exercise duration (15 s x 60 s) on HR and PE as de pendent variables, two-way ANOVA was used. Tukey’s post-hoc test was applied when necessary. The significance level was set at p < 0.05. Results Maximal strength and EMGFT No changes in 1RM strength were found for the CG throughout the test protocol (Week 1: 36.1 ± 3.9 kg, Statistical analysis Data was measured as mean ± SD for all variables. Two-way mixed model ANOVA was used to verify the effects of training protocol (PRE-training x POST-training – within-subject factor) and group (CG x TG – be112 Figure 2. Biceps brachii (BB) and brachioradialis (BR) electromyographic fatigue threshold (EMGFT) before (PRE) and after (POST) eight-week endurance training; mean ± SD HUMAN MOVEMENT M. Gonçalves, A.S.C. Oliveira, Endurance training at EMGFT * denotes significant difference in relation to 60 s time for both PREand POST-training (p < 0.01) † denotes significant difference in relation to 60 s time at 40% 1RM for both PRE- and POST-training (p < 0.05) Figure 3. Heart hate at the beginning (15 s) and the end (60 s) of biceps curl exercise at different load intensities for the Control Group and Training Group before (PRE) and after (POST) eight-week endurance training; mean ± SD Week 7: 36.7 ± 3.1 kg, Week 11: 37.1 ± 4.0 kg; p > 0.05). On the other hand, resistance training increased 1RM strength for the TG (Week 1: 36.9 ± 3.7 kg, Week 7: 38.9 ± 4.1 kg, Week 11: 39.3 ± 4.3 kg; p < 0.05). No significant effects of training were found for the TG on EMGFT (Fig. 2), with only an increasing trend observed after the training period (p = 0.08). No significant changes were also verified between BB and BR EMGFT, as well as between CG and TG (p > 0.05). Heart rate and perceived exertion Heart rate measurements performed before and after the study period found that both the CG and TG showed lower HR at 15 s of exercise when compared to 60 s for all load intensities (p < 0.05), except at 25% and 30% 1RM for the CG (Fig. 3). Load intensity had minor effects on HR; only for the TG by the end of the exercise (60 s) was HR at 25% 1RM significantly lower than that at 40% 1RM. The training program did not affect HR for any load intensity, moreover no significant differences between the CG and TG were found. Similar to HR, PE (Fig. 4) was lower at the beginning of the exercise (15 s) when compared to the end (60 s) for * denotes significant difference in relation to 60 s time for both PREand POST-training (p < 0.01) † denotes significant difference in relation to PRE-training (p < 0.05) ‡ denotes significant difference in relation to 60 s time at 40% 1RM for both PRE- and POST-training (p < 0.05) Figure 4. Perceived exertion at the beginning (15 s) and end (60 s) of bicep curl exercise at different load intensities for the Control Group and Training Group before (PRE) and after (POST) eight-week endurance training; mean ± SD both the CG and TG at all load intensities (p < 0.001). In addition, at 60 s, PE at 25% 1RM was significantly lower than at 40% 1RM (p < 0.01). Conversely to HR, lower PE levels were verified for all load intensities (p < 0.01) after training for 15 s and 60 s, except at 40% 1RM at 15 s. Due to this training effect, PE for the TG after completing the 8-week training programme (Week 12) was significantly lower than PE tested at the same time for the CG (p < 0.05) for all load levels and test times during the exercise. Elbow flexor endurance time EndT for the biceps curl was significantly lower from the first set in relation to the second and third set (p < 0.01) for both the CG and TG (Fig. 5). In addition to improving muscular strength, resistance training also improved EndT for the biceps curl exercise at the EMGFT (Fig. 5). Significant increases were found from the first set (68.6 ± 46%, p < 0.001) to the second set (81.9 ± 43%, p < 0.001) and third set (78.9 ± 38%, p < 0.001) at the end of the training period for TG, with no changes observed among the CG. 113 HUMAN MOVEMENT M. Gonçalves, A.S.C. Oliveira, Endurance training at EMGFT * denotes significant difference in relation to POST-training (p < 0.05) † denotes significant difference in relation to B2 and B3 (p < 0.05) ‡ denotes significant difference in relation to B3 (p < 0.05) Figure 5. Endurance time of biceps curl exercise for the first set (B1), second set (B2) and third set (B3) before (PRE) and after (POST) eight-week endurance training; mean ± SD Discussion The primary objective of the present study was to verify whether individualized resistance training based on EMGFT could improve muscular strength and endurance while reducing HR and PE, suggesting that muscular adaptations to endurance training can also reduce discomfort during resistance exercises. The main results of the study did confirm an increase in muscular strength with a reduction in perceived exertion. Moreover, resistance training based on EMGFT improved on average at least 60% of EndT, therefore endurance improvements by training at the EMGFT intensity can attenuate the discomfort felt when performing the bicep curl. Moreover, these results suggest that individualized training intensities may be essential in optimizing endurance training outcomes. Low-to-moderate intensities have been suggested in resistance training aimed at improving endurance [1], such as the one used in the present investigation (approxi mately 30% 1RM). Although substantial increases in strength post-endurance training were not expected, we found a ~6% increase in 1RM for the TG. This strength gain may be predominantly credited to neural adaptations such as muscle fibre recruitment or neural drive [2], which have also been previously related to increased EMG activity after maximal endurance training [9, 11]. Upon completion of the training programme, the participants were able to perform bicep curls for a longer period of time. It is noteworthy that the training protocol was performed until exhaustion for every set, which has been credited in inducing improvements in blood flow and muscular capillarity [16]. Increased capillarity also enhances muscular oxygenation and reduces metabolite accumulation (blood lactate, K+, inorganic phosphate, etc.) [16, 17]. Another study performed by this research group found reduced elbow flexor EMG activity at a fixed load intensity (%max) after a training 114 program similar to the presented protocol [18], suggesting that motor unit recruitment is also enhanced after endurance training [19]. In addition, increases in muscular strength have also been corroborated with maintaining fatiguing tasks for longer periods of time [4, 17]. Therefore, the present results suggest that endurance training based on low-intensity exercises improves muscle function and attenuates the effects of fatigue. Further investigations on the use of the EMGFT index in training routines should be conducted on other muscular groups such as the quadriceps and triceps surae. Heart rate is a parameter often used in monitoring workouts by measuring the effects of exercise intensity on the cardiovascular system [9, 11, 20]. In this study, HR measured when performing the bicep curls was higher by the end of each set, although at 25% and 30% 1RM the differences were found to be insignificant, which suggests low demand on the cardiovascular system at such low intensities [20]. Nonetheless, towards the end of exercise it is necessary to increase oxygen availability to the muscles and optimize metabolite removal, which promotes increases in blood circulation and, consequently, in HR [20]. Increased cardiovascular demand has been previously described in different types of elbow flexor exercises [9], however the specific training protocol used in the present study was unable to reduce HR levels. Training protocols applying high-repetition sets for larger muscular groups such as the quadriceps muscles were able to verify changes in HR [11]. Thus, perhaps the use of endurance training based on the EMGFT for larger muscular groups may elicit greater changes in HR. Physical exertion (PE) has previously been used to predict load intensity for isometric exercises [13, 14], and EMG activity for isometric tasks [12]. In this experiment, PE scales were used to verify the psychological aspects linked to metabolic and/or neuromuscular changes during exercise [12], thus verifying whether resistance training could influence PE during fatigue. In fact, reduced PE was found after resistance training, which has been suggested as an indirect measure of muscle fatigue and exercise performance [15]. Therefore, the present investigation confirms that endurance training protocols (such as those based on EMGFT) may be able to reduce discomfort caused by fatigue. Although not shown in the present investigation, elbow flexor EMG activity was reduced following this specific training protocol [19]. Although muscle recruitment and PE are regulated by the central nervous system, perhaps other peripheral contributions can alter force output/EMG [21] and PE [12–14]. Therefore, the underlying mechanisms behind muscular activation and PE may be somehow linked, since simultaneous inputs are sent for both muscular activation and sensation during exercise [21]. It can be suggested that the endurance training used in this study was able to reduce muscular activation and, consequently, produce less discomfort while performing the bicep curl exercise. HUMAN MOVEMENT M. Gonçalves, A.S.C. Oliveira, Endurance training at EMGFT Conclusions Resistance training targeting elbow flexor endurance improved 1RM strength and EndT during a bicep curl exercise. In addition, reductions in PE suggest that the exercise at the same training intensity was performed with less discomfort during sets. The individualized load intensities allowed substantial improvement in EndT, suggesting that EMGFT may be a useful alternative for prescribing a training program focused on improving endurance. Acknowledgements We wish to thank the participants in this study and the Co ordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) for their financial support. Oliveira A.S. is currently supported by a CAPES international PhD fellowship (No. 0293-09-1). References 1. Kraemer W.J., Ratamess N.A., Fundamentals of resistance training: progression and exercise prescription. Med Sci Sports Exerc, 2004, 36, 674-688. 2. Campos G.E.R., Luecke T.J., Wendeln H.K., Toma K., Ha german .FC., Murray T.F. et al., Muscular adaptations in response to three different resistance training regimens: specificity of repetition maximum training zones. Eur J Appl Physiol, 2002, 88, 50–60, doi: 10.1007/s00421-0020681-6. 3. Colson S., Pousson M., Martin A., Gottlieb G.L., Isokinetic elbow flexion and coactivation following eccentric training. J Electromyogr Kinesiol, 1999, 9, 13–20, doi: 10.1016/S1050-6411(98)00025-X. 4. Mcbride J.M., Blaak J.B., Triplett-Mcbride T., Effect of resistance exercise volume and complexity on EMG, strength, and regional body composition. Eur J Appl Physiol, 2003,90, 626–632, doi: 10.1007/s00421-003-0930-3. 5. Moore D.R., Burgomaster K.A., Schofield L.M. Gibala M.J., Sale D.G., Phillips S.M., Neuromuscular adaptations in human muscle following low intensity resistance training with vascular occlusion. Eur J Appl Physiol, 2004, 92, 399–406, doi: 10.1007/s00421-004-1072-y. 6. Pousson M., Amiridis L.G., Commetti G., Van Hoecke J., Velocity specific training in elbow flexors. Eur J Appl Physiol, 1999, 80, 367–372, doi: 10.1007/s004210050605. 7. Hug F., Nordes A., Guével A., Can the electromyographic fatigue threshold be determined from superficial elbow flexor muscles during an isometric single joint task? Eur J Appl Physiol, 2009, 107, 193–201, doi: 10.1007/s00421009-1114-6. 8. Oliveira A.S., Gonçalves M., Cardozo A.C., Barbosa F.S.S., Electromyografic fatigue threshold of the biceps brachii muscle during dynamic contraction. Electromyogr Clin Neurophysiol, 2005,45, 167–75. 9. Oliveira A.S, Gonçalves M., Positioning during resistance elbow flexor exercise affects electromyographic activity, heart rate and perceived exertion. J Strength Con Res, 2009, 23, 854–862, doi: 10.1519/JSC.0b013e3181a00c25. 10. Housh T.J., deVries H.A., Johnson G.O., Housh D.J., Evans S.A., Stout J.R. et al., Electromyographic fatigue thresholds of the superficial muscles of the quadriceps femoris. Eur J Appl Physiol, 1995, 71, 131–136, doi: 10.1007/ BF00854969. 11. Greco C.C., Oliveira A.S., Pereira M.P., Figueira T.R., Ruas V.D., Gonçalves M. et al., Improvements in metabolic and neuromuscular fitness after 12-week Bodypump® training. J Strength Cond Res, 2011, 25, 3422–3431, doi: 10.1519/JSC.0b013e3182160053. 12. Hummel A., Läubli T., Pozzo M., Schenk P., Spillmann S., Klipstein A., Relationship between perceived exertion and mean power frequency of the EMG signal from the upper trapezius muscle during isometric shoulder elevation. Eur J Appl Physiol, 2005, 95, 321–326, doi: 10.1007/ s00421-005-0014-7. 13. Hunter S.K., Critchlow A., Enoka R.M. Muscle endurance is greater for old men compared with strength matched young men. J Appl Physiol, 2005, 99, 890–897, doi: 10.1152/japplphysiol.00243.2005. 14. Hunter S.K., Rochette L., Critchlow A., Enoka R.M., Time to task failure differs with load type when old adults perform a submaximal fatiguing contraction. Muscle Nerve, 2005, 31, 730–740, doi: 10.1002/mus.20325. 15. Robertson R.J., Goss F.L., Rutkowskli J., Lens B., Dixon C., Timmer J. et al., Concurrent Validation of the OMNI Perceived Exertion Scale for Resistance Exercise. Med Sci Sports Exerc, 2003, 35, 333–341. 16. Westerblad H., Allen D.G., Recent advances in the understanding of skeletal muscle fatigue. Curr Opin Rheumatol, 2002, 14, 648–652. 17. Giannesini B., Cozzone P.J., Bendahan D., Non-invasive investigations of muscular fatigue: metabolic and electromyographic components. Biochimie, 2003, 85, 873–883, doi: 10.1016/S0300-9084(03)00124-X. 18. Oliveira A.S., Gonçalves M., EMG amplitude and frequency parameters of muscular activity: Effect of resistance training based on electromyographic fatigue threshold. J Electromyogr Kinesiol, 2009, 19, 295–303, doi: 10.1016/ j.jelekin.2007.07.008. 19. Kollmitzer J., Ebenbichler G.R., Sabo A., Kerschan A., Bochdansky T., Effects of back extensor strength training versus balance training on postural control. Med Sci Sports Exerc, 2000, 32, 1770–1776. 20. O’leary D.S., Heart rate control during exercise by baro receptors and skeletal muscle afferents. Med Sci Sports Exerc, 1996, 28, 210–217. 21. Søgaard K., Gandevia S.C., Todd G., Petersen N.T., Taylor J.L., The effect of sustained low-intensity contractions on supraspinal fatigue in human elbow flexor muscles. J Physiol, 2006, 573, 511–523, doi: 10.1113/jphysiol.2005. 103598. Paper received by the Editor: November 26, 2012 Paper accepted for publication: April 5, 2013 Correspondence address Anderson S.C. Oliveira Center for Sensory-Motor Interaction (SMI) Department of Health Science and Technology Aalborg University Fredrik Bajers Vej 7 D-3 DK-9220 Aalborg, Denmark e-mail: [email protected] 115 HUMAN MOVEMENT 2013, vol. 14 (2), 116– 122 THE EFFECTS OF RESISTED SPRINT TRAINING ON SPEED PERFORMANCE IN WOMEN doi: 10.2478/humo-2013-0013 Beata Makaruk 1 *, Henryk Sozański 2 , Hubert Makaruk 1, Tomasz Sacewicz 1 1 2 Biała Podlaska Faculty of Physical Education and Sport, Józef Piłsudski University of Physical Education, Warszawa, Poland Józef Piłsudski University of Physical Education, Warszawa, Poland Abstract Purpose. The main aim of the study was to examine the effects of resisted and standard sprint training on the kinematics of sprintrunning acceleration in women. Methods. Thirty-six untrained but physically active female college students were randomly assigned to one of three groups: a running resisted training group (RTG, n = 12), a standard training group (STG, n = 12), and a control group (CON, n = 12). All participants in the experimental groups trained three times a week for four weeks, followed by a 1-week training break, after which they trained again for four weeks. Pre-training, post-training and detraining (three weeks after completing the training programs) measures of mean running velocity, stride length, stride frequency, knee angle at toe off and footstrike, ground contact time, and flight time were analyzed by a 20 m sprint test. Results. The RTG improved mean running velocity and increased stride length and knee angle at toe off. Simultaneously, the RTG featured decreased stride frequency and increased ground contact time. The STG demonstrated an increase in mean running velocity due to higher stride frequency and a decrease in ground contact time. All of the measured parameters did not significantly decrease after the three-week detraining period. The control group featured no changes. Conclusions. Both resisted and standard sprint training improves speed in sprint-running acceleration in women by improving different sprint kinematic parameters. Key words: speed, acceleration performance, kinematics, stride length, stride frequency Introduction It is speed that to a large extent determines athletic success in sports [1]. Running speed is in a large part determined by running form, as it determines the body’s movement as a function of time and space by the diagonal, cyclical stride of the lower limbs. Running stride and therefore speed, from a mechanical point of view, is determined by two antagonistic kinematic parameters, stride length and stride frequency. This makes running at the fastest speed possible only by exhibiting a combination of optimum stride length and frequency. They are not, however, constant values; the contribution of each in creating a “golden ratio” depends on running gait phase as well as sex, age, competitive level. It has been suggested that stride frequency is dependent on nerve conduction velocity and thus strongly linked to genetic factors. Hence, research has focused more on the second parameter – stride length – and how it can be improved by adapting existing training techniques [2]. One of the most basic ways used to lengthen running stride is through the use of resisted training, a type of conditioning performed by adding external load by pulling a sled, tire, or a specially designed parachute; resisted bands; or by running uphill or against the wind. The greatest benefits provided by such forms of condi- * Corresponding author. 116 tioning are increases in the strength and power of the leg extensor muscles at toe off, mainly in the first stage of running – the acceleration phase [3, 4]. This relationship between increasing strength and power with running velocity has been observed by many researchers [5–7]. On the other hand, Saraslanidis [8], among others, did not find an increase in running velocity after an eight-week resisted running program, although measurements were taken only after completing a run. In tests carried out by Zafeiridis et al. [9], an eight-week program led to improvements in maximum velocity during acceleration (0–20 m) and in stride frequency, but not stride length. Similarly, Spinks et al. [10] noted a significant improvement in velocity when running short distances (up to 15 m) but noted no significant changes in stride length or frequency. In view of the lack of clear results on the effects of resisted sprint training on improving running velocity, as well as a lack of research and recommendations that take sex into account (all of the above mentioned tests were performed only on males), the aim of present study was to evaluate the effectiveness of resisted sprint training in women by measuring changes in running velocity and other kinematic parameters. With this in mind, the following research questions were formulated: 1. Does resisted running with the use of an external load improve speed in physically active women? 2. Does the type of the sprint training program differentiate the kinematic parameters of stride in women? HUMAN MOVEMENT B. Makaruk, H. Sozański, H. Makaruk, T. Sacewicz, Resisted sprint training in women 3. What are the long-term effects of resisted sprint training when compared with standard sprint training? Material and methods The research group consisted of 36 female physical education students who did not practice professional sports. However, in light of the participants’ field of study (8–10 h of physical activity per week), they can be specified as highly physically active individuals. The study group was randomly divided into three sub-groups: the first experimental group trained resisted running with an external load (RTG, n = 12), the second trained under normal sprint training technique (STG, n = 12), and the third was a control group (CON, n = 12) who participated only in the measurement sessions. Age, body height, and body mass are presented in Table 1. All were asked to refrain from participating in any physical activity outside of their normal university classes. The participants were informed about the aim of the study and research procedure, which was accepted by the Research Ethics Committee at Józef Piłsudski University of Physical Education in Warsaw, Poland. Testing The participants’ sprint performance was tested on three separate occasions: three days before the training programs for the experimental groups were to begin (pre-training), three days after the programs were completed (post-training), and then three weeks later (detraining). The test consisted of a 20-m sprint (R 20), run at the fastest speed possible. Participants began from a standing start position with the legs in stride, the front leg located just before the starting line and the rear leg approximately 30 cm behind. They were checked for proper starting posture, with a slight bend at the knees Table 1. Characteristics of the participants Group RTG(n = 12) STG(n = 12) CON(n = 12) Age (years) Body height (m) Body mass (kg) 22.0 ± 0.9 22.3 ± 0.8 21.9 ± 0.7 1.67 ± 0.07 1.66 ± 0.06 1.68 ± 0.08 61.5 ± 4.7 61.3 ± 5.4 62.1 ± 4.9 RTG – running resisted training group STG – standard training group CON – control group and the torso slightly bent forward. All participants performed the task in appropriate sportswear (t-shirt and shorts). The participants completed two trials; they were allowed to start at their leisure, no starting command was given. The run with the highest mean velocity was recorded for later analysis. All tests were performed at a track and field stadium at an ambient air temperature of 21–23 degrees Celsius with minor wind (0.3– 0.6 m · s –1), measured by an electronic anemometer (Slandi 2000, Poland) in the direction of track. Seven to eight min of rest was provided between trials [11]: the first four min consisted of absolute rest, the next three or four min were spent preparing for the run by performing dynamic stretching exercises, each of which were followed by shaking the leg muscles. A warm-up prior to measurement taking was performed, beginning with a low-intensity run (5 min) and dynamic stretching exercises (7–8 min) of the most involved muscle groups when sprinting, i.e., hip, knee, and ankle extensors and flexors [12]. The rest interval between each stretching exercise was 10–15 s. After the general warm-up, skipping exercises were performed (1 x 20 m) and another run at submaximal intensity (1 x 40 m). The warm up was performed while wearing a sweatshirt and sweatpants, which were removed just before completing the sprint test. The sprint test (R 20) was preceded by a pilot study whose aim was to determine the reliability of the R 20 test as well as calculate the external load for the participants who would take part in the resisted sprint training program. Previous studies have suggested an optimal load that can reduce normal running velocity by 10% [14]. For this purpose, a sled was constructed from two 70-cm circular runners held together by perpendicular tubing 45 cm in length. Located in the center of the sled was a vertical shaft on which disc weights (plates) were placed. A 5-m harness was used to connect the sled to a leather belt worn above the hip bones. The total weight of sled without additional plates was 3 kg. The participants performed three runs with an external load of 5%, 7.5%, and 10% body mass, performed in random order. The procedure and conditions for this pilot test were the same as when performing the R20 test. External load was determined by multiplying body mass by the percent of external load to be used (e.g., 5% body mass = 0.05), subtracting the mass of the sled [15]. Based on the cri- Figure 1. Resisted running with an external load 117 HUMAN MOVEMENT B. Makaruk, H. Sozański, H. Makaruk, T. Sacewicz, Resisted sprint training in women teria for selecting resisted running load (10% reduction in mean running velocity), a weight of 7.5% of body mass was used for eight of the participants, while for the remaining four a weight of 10% of body mass was used. Kinematic analysis Two digital cameras were used to record the sprint trials at a sampling rate of 100 Hz; video was later analyzed using SteamPix 3.34.0 software (Norpix, Canada). The cameras were set perpendicularly to the track at a distance of 24 m (Fig. 2), each filming a 10-m portion of the track including 1 m before and 1 m after the start and finish lines with an overlap of 2 m at the center. Only every 3rd and 4th stride were considered for analysis. Five tracking markers were placed on the right side of the body during measurement taking: at the height of anterior superior iliac spine, the greater trochanter of the femur, the lateral condyle of the tibia, the lateral malleolus, and the 5th metatarsal [15, 16]. Later, twodimensional kinematic analysis of the recorded test runs was performed using APAS-XP marker-tracking software (Ariel Dynamics, USA). The video was scaled with the use of a flat calibration system. The following kinematic parameters were measured during the tests, all of which were performed only on the right side of the body: mean running speed (m · s –1), calculated by first adding ground contact time and flight, then having this value divide stride length [16]; stride length (m), determined by the distance from the tip of the front shoe at toe off to the tip of the opposite shoe at footstrike; stride frequency, calculated on the basis of the number of steps in a certain period of time; knee angle at toe off and footstrike, measured by the angle between the thigh and lower thigh by a straight line passing through the greater trochanter of the femur and the lateral condyle of the tibia and a line passing through the lateral condyle of the tibia and lateral malleolus; ground contact time, as the time between footstrike and toe off; and flight time, measured as the time between toe off by one foot until footstrike by the opposite foot. The reliability of the above-measured parameters, determined by intraclass correlation coefficients (ICC), was found to be high and ranged between 0.79–0.92 [13]. Sprint training programs Due to the intensive nature of the sprint training programs, the participants in the two experimental groups (RTG and STG) concluded a three-week compensatory physical fitness course, held twice a week, before their actual training programs were to begin. Average duration of each class was approximately 50 min. The course focused on basic exercises aimed at improving sprint Table 2. Sprint training programs implemented by both experimental groups (resisted and standard sprint training) Week Training program Set x repetition x distance [m] Rest intervals* Set [min] x repetition [s] 1 2 3 4 5 6 7 8 9 3 x 3 x 20 4 x 3 x 20 3 x 3 x 25 4 x 3 x 25 Rest 3 x 3 x 30 4 x 3 x 30 3 x 3 x 35 3 x 3 x 20 3 x 60 3 x 60 3 x 90 3 x 90 Rest 4 x 120 4 x 120 4 x 150 4 x 150 * rest provided in accordance with previous recommendations [11] Figure 2. Graphic representation of the track used to measure sprint velocity at a distance of 20 m (R 20) 118 HUMAN MOVEMENT B. Makaruk, H. Sozański, H. Makaruk, T. Sacewicz, Resisted sprint training in women performance, with particular attention placed on proper execution. After completing the compensatory physical fitness course, groups RTG and STG began a nine-week speed training program (with a rest interval during the fifth week where no training was performed) with classes held three times per week (Tab. 2). The design of the sprint training programs included periodization, as its performance benefits have been scientifically verified in a number of studies [1, 17]. The training programs were conducted by a coach specializing in short-distance running. Time was measured with a 83520 stopwatch (Casio, Japan). Immediately after finishing a sprint, the participants received feedback on their time as well as motivational support, such as “maintain the same time” or “try to run faster”. In addition, sprint technique was continuously monitored, such as performing larger extensions of the rear leg at the knee at toe off or maintaining correct posture along the axis made between the ankle and hip of the propulsive leg (at toe off). The RTG performed all runs with the sled, whose weight was previously calculated for each individual; the STG ran with no external load. Pre-training Post-training Detraining $ – significantly different (p < 0.05) from the control group # – significantly different (p < 0.05) from pre-training values RTG – running resisted training group STG – standard training group CON – control group Figure 3. Mean ± SD running velocity measured pre-training, post-training, and three weeks after completing training (detraining) Pre-training Post-training Detraining Statistical analysis The collected data were summarized as mean and standard deviation (SD). The Shapiro-Wilk test was used to confirm whether the variables were normally distributed. Significant differences among the analyzed stride kinematic parameters were analyzed by a two-way repeated measures ANOVA. Tukey’s t test was applied if the results were statistically significant. Statistical significance was set at p 0.05. All statistical analysis was performed using Statistica v. 5.1 PL software (Statsoft, Poland). Results Figures 3–9 present the results as means ± SD for the kinematic parameters measured during the R 20 test before (pre-training) and after (post-training) the training programs as well as three weeks after completion (detraining). Statistical analysis found significant effects between: group (RTG, STG, CON) x time (post-training, post-training, and detraining), x mean running velocity (F4.66 = 4.92; p < 0.01), x stride length (F4.66 = 8.47; p < 0.001), x stride frequency (F4.66 = 2.72; p < 0.05), x knee angle at toe off (F4.66 = 3.42; p < 0.01); x knee angle at footstrike (F4.66 = 4.42; p < 0.01). Both experimental groups (RTG and STG) significantly increased their mean running velocity upon completing their training programs by 2.5% and 4.9% (p < 0.05), respectively, with the velocity attained by the STG being significantly higher (p < 0.05) than the control group. Mean running velocity of both experimental groups three weeks after completing training (detraining) did not significantly differ (p > 0.05) from post-training velocity. For stride $ – significantly different (p < 0.05) from the control group # – significantly different (p < 0.05) from pre-training values RTG – running resisted training group STG – standard training group CON– control group Figure 4. Mean ± SD stride length measured pre-training, post-training, and three weeks after completing training (detraining) Pre-training Post-training Detraining # – significantly different (p < 0.05) from pre-training values RTG – running resisted training group STG – standard training group CON– control group Figure 5. Mean ± SD stride frequency measured pre-training, post-training, and three weeks after completing training (detraining) 119 HUMAN MOVEMENT B. Makaruk, H. Sozański, H. Makaruk, T. Sacewicz, Resisted sprint training in women Pre-training Post-training Detraining RTG – running resisted training group STG – standard training group CON– control group # – significantly different (p < 0.05) from pre-training values RTG – running resisted training group STG – standard training group CON– control group Figure 6. Mean ± SD knee angle at toe off measured pre-training, post-training, and three weeks after completing training (detraining) Pre-training Post-training Detraining Figure 9. Mean ± SD flight time measured pre-training, post-training, and three weeks after completing training (detraining) length, the only significant differences were observed among the resisted training group (RTG) after completing the training program (by 5.9%; p < 0.05). In turn, stride frequency changed significantly (p < 0.05) in both experimental groups, for the RTG it decreased by 3.4%, while for the STG it increased by 3.3%. The RTG featured a significant increase in knee angle at toe off at post-training (by 2.3%; p < 0.05). Additionally, group RTG was the only one with a significant increase in ground contact time (by 7.2%; p < 0.05). For the control group none of the measured parameters changed significantly (p > 0.05). Discussion RTG – running resisted training group STG – standard training group CON– control group Figure 7. Mean ± SD knee angle at footstrike measured pre-training, post-training, and three weeks after completing training (detraining) Pre-training Post-training Detraining # – significantly different (p < 0.05) from pre-training values RTG – running resisted training group STG – standard training group CON– control group Figure 8. Mean ± SD ground contact time measured pre-training, post-training, and three weeks after completing training (detraining) 120 Pre-training Post-training Detraining The obtained results confirm the validity of using resisted sprint training in increasing running speed. The RTG, which trained for nine weeks by pulling an external load, improved mean running speed during the acceleration phase as well as increased stride length despite a decline in stride frequency. In addition, the effects of resisted sprint training were observable even in measurements taken three weeks after completing the training program (detraining). An improvement in running speed was also observed in the STG, suggesting that this form of training – probably due to its specificity – is also effective in improving running velocity. However, the mechanisms behind both groups’ velocity improvements proved to be different. Running stride length increased only in the RTG, which is an effect that has also been confirmed by Delecluse [18] when studying resisted sprint training. It is believed that increase in stride length is the result of performing a fuller leg extension at the knee with each additional step, as evidenced by the increasing rise in the knee angle at toe off. Some researchers believe [3] that this change indicates an increase in strength among hip and knee extensor muscles. The results of this study did confirm the findings of Zafeiridis et al. [9] or Spinks HUMAN MOVEMENT B. Makaruk, H. Sozański, H. Makaruk, T. Sacewicz, Resisted sprint training in women et al. [10], who did not observe any change in stride length. It is worth mentioning that the differences in the results between these researchers and the present study’s may stem from the use of different training techniques. Unfortunately, as is usual in scientific literature, details on the types of solutions used to monitor correct technique during movement execution are rarely provided. Therefore, if the methodology used was in fact the cause of such a discrepancy, this could be the result of ineffective controls, such as when providing instructions on extending the rear leg at the knee during toe off, this could have lead participants to perform an even larger bend at the knee than necessary, resulting in shorter stride length. Furthermore, the increase in stride length as observed in group RTG was found to be long-term, as three weeks after completing the training program (detraining) not only were there no decreases in stride length when compared with post-training values, but this para meter was still significantly higher than when measured pre-training. Nonetheless, not all of the effects of resisted sprint training were positive, such as the decrease in stride frequency. These findings are in complete discrepancy with those by Zafeiridis et al. [9], who observed an increase in stride frequency, and by Spinks et al. [10], who observed no significant change. We believe that group STG’s decrease in stride frequency may have been the result of increased stride length, and thus prolonged contact with the ground due to the larger distance that the body’s center of mass needed to cross. This observation is in line with other researchers [16, 19], who confirmed that stride length and stride frequency, determined by the ground contact time as well as flight time, are antagonistic parameters. Although shortening ground contact time is highly desirable in sprinting, it should be noted that longer ground contact time (within limits) is conducive to producing more force during toe off; this is advantageous, as Weyand et al. [20] observed, since running velocity is determined to a great extent by the force developed by the legs during the stance phase and not by the speed of the legs when in flight (swing phase). It is highly probable that the increase in stride frequency by group STG was due to shorter ground contact time, although this result was not statistically significant (p > 0.05). Shortened ground contact time has been linked with increased stiffness of the muscle-tendon unit, thus allowing for more efficient use of the extensioncontraction cycle [21], as Markovic et al. argued [22]. It also is worth emphasizing that no changes were observed in knee angle at the moment when the foot makes contact with the ground (footstrike) in either of the experimental groups, which may indirectly indicate poor technique during the forward swing phase. We assumed that greater knee angle is equivalent to increased stride length, especially in regards to the distance between the body’s center of mass and the point of foot- strike. Therefore, as this distance increases so does braking force [23], which consequently carries with it an increased risk in straining the rear thigh muscles [24]. This type of injury is very common among individuals who practice speed-strength sports [25]. One of the limitations of this study, besides the small sample size and relatively short duration of the training programs, is that only the lower limbs were subjected to analysis. However, the significance of omitting the upper limbs from analysis may be minimized by taking into consideration the results of Spinks et al. [10], who found no changes in the kinematic parameters of the upper limbs after standard and resisted sprint training, emphasizing the relatively minor role the upper limbs play in improving running speed [26]. It needs to be highlighted that the implementation of a resisted sprint training program requires carefully research, especially during the competitive season, as research has shown that this form of training significantly impacts a number of kinematic parameters that form the core of running technique, such as by lowering stride frequency. Significant changes introduced during the running season may lead to instable locomotor patterns and thus adversely affect running times. On the other hand, it would be desirable for future studies to determine which solutions are suitable for developing strength, especially when beginning training with the use of resisted training. This is important in light of the findings by Moira et al. [27], who noticed a decrease in running speed and a reduction in stride frequency (increased ground contact time and flight time) as the result of strength training, where solutions based on resisted training could provide an alternative to standard strength-building exercises. The above aspect also requires careful consideration when choosing the correct external load. We found that the weight used in this study (7.5% of body mass, but also 10%) was adequate in terms of the exercise potential of the relatively untrained, although physically active, female students. However, depending on the desired outcome, every situation requires an individual and careful assessment as to best decide the most optimal load. This includes taking into consideration not just sex, age or physical fitness level, but also the movement and functional specifics of a given sport and its requirements as to speed. Conclusions 1. The results of the present study indicate that resisted sprint training in women, by pulling an external load, improves short-distance running velocity. 2. Resisted sprint training led to increases in stride length and completing fuller leg extensions at the knee joint during toe off but, concomitantly, caused an decrease in stride frequency and increase in ground contact time. Standard sprint training was found to increase 121 HUMAN MOVEMENT B. Makaruk, H. Sozański, H. Makaruk, T. Sacewicz, Resisted sprint training in women stride frequency, without any significant changes in stride length. 3. The long-term effects of the sprint training programs (resisted and standard) used in present study were similar for both experimental groups. The three-week detraining period following the completion of the training programs had no significant effect on any of the running gait parameters. References 1. Sozański H., Witczak T., Starzyński T., The basis of speed training [in Polish]. COS, Warszawa 1999. 2. Maćkała K., Kowalski P., Sprint running training [in Polish]. AWF, Wrocław 2007. 3. Donati A., The association between the development of strength and speed. New Stud Athl, 1996, 2 (3), 51–58. 4. Murray A., Aitchison T.C., Ross G., Sutherland K., Watt I., McLean D., Grant S., The effect of towing a range of relative resistances on sprint performance. J Sports Sci, 2005, 23 (9), 927–935, doi: 10.1080/02640410400023332. 5. Mero A., Komi P.V., Gregor R.J., Biomechanics of sprint running. A review. Sports Med, 1992, 13 (6), 376–392, doi: 10.2165/00007256-199213060-00002. 6. Hunter J.P., Marshall R.N., McNair P.J., Relationships between ground reaction force impulse and kinematics of sprint-running acceleration. J Appl Biomech, 2005, 21 (1), 31–43. 7. Ciacci S., Di Michele R., Merni F., Kinematic analysis of the braking and propulsion phases during the support time in sprint running. Gait Posture, 2010, 31 (2), 209–212, doi: 10.1016/j.gaitpost.2009.10.007. 8. Saraslanidis P., Training for the improvement of maximum speed: flat running or resistance training? New Stud Athl, 2000, 15(3/4), 45–51. 9. Zafeiridis A., Saraslanidis P., Manou V., Ioakimidis P., Dipla K., Kellis S., The effects of resisted sled-pulling sprint training on acceleration and maximum speed performance. J Sports Med Phys Fitness, 2005, 45 (3), 284–290. 10. Spinks Ch.D., Murphy A.J., Spinks W.L., Lockie R.G., The effects of resisted sprint training on acceleration performance and kinematics in soccer, rugby union, and Australian football players. J Strength Cond Res, 2007, 21 (1), 77–85, doi:10.1519/00124278-200702000-00015. 11. Prus G., Zając A., Sprint training. Practical applications [in Polish]. Sport Wyczynowy, 1986, 2–3, 39–46. 12. Makaruk H., Makaruk B., Kędra S., Effects of warm-up stretching exercises on sprint performance. Phys Educ Sport, 2008, 52 (1), 23–26, doi: 10.2478/v10030-0080005-7. 13. Makaruk B., Makaruk H., Sacewicz T., Makaruk T., Kędra S., Długołęcka B., The accuracy and reliability of kinematic measurements in tests measuring running velocity [in Polish]. Pol J Sport Tourism, 2009, 16 (2), 85–92. 14. McFarlane B., Speed a basic and advanced technical model. Track Technique, 1994, 96, 4016–4020. 15. Lockie R.G., Murphy A.J., Spinks C.D., Effects of resisted sled towing on sprint kinematics in field-sport athletes. J Strength Cond Res, 2003, 17 (4), 760–767. 122 16. Paradisis G.P., Cooke C.B., The effects of sprint running training on sloping surfaces. J Strength Cond Res, 2006, 20 (4), 767–777, doi:10.1519/R-16834.1. 17. Hauschildt M.D., Integrating high-speed treadmills into a traditional strength and conditioning program for speed and power sports. Strength Cond J, 2010, 32 (2), 21–32, doi: 10.1519/SSC.0b013e3181caddd9. 18. Delecluse C.H., Influence of strength training on sprint running performance: Current findings and implications for training. Sports Med, 1997, 24 (3), 147–156, doi: 10.2165/00007256-199724030-00001. 19. Mero A., Komi P.V., Force-, EMG-, and elasticity-velocity relationships at submaximal, maximal and supramaximal running speeds in sprinters. Eur J Appl Physiol Occup Physiol, 1986, 55 (5), 553–561, doi: 10.1007/BF00421652. 20. Weyand P.G., Sternlight D.B., Bellizzi M.J., Wright S., Faster top running speeds are achieved with greater ground forces not more rapid leg movements. J Appl Physiol, 2000, 89 (5), 1991–1999. 21. Makaruk H., Sacewicz T., Effects of plyometric training on maximal power output and jumping ability. Hum Mov, 2010, 11 (1), 17–22, doi: 10.2478/v10038-010-0007-1. 22. Markovic G., Jukic I., Milanovic D., Metikos D., Effects of sprint and plyometric training on muscle function and athletic performance. J Strength Cond Res, 2007, 21 (2), 543–49, doi:10.1519/R-19535.1. 23. Corn R., Knudson D. Effect of elastic-cord towing on the kinematics of the acceleration phase of sprinting. J Strength Cond Res, 2003, 17 (1), 72–75. 24. Orchard J., Biomechanics of muscle strain injury. NZJ Sports Med, 2002, 30, 92–98. 25. Witvrouw E., Danneels L., Asselman P., D’Have T., Cambier D., Muscle flexibility as a risk factor for developing muscle injuries in male professional soccer players. A prospective study. Am J Sports Med, 2003, 31 (1), 41–46. 26. Hinrichs R.N., Upper extremity function in running. II: Angular momentum considerations. Int J Sport Biomech, 1987, 3, 242–263. 27. Moir G., Sanders R., Button Ch., Glaister M., The effect of periodized resistance training on accelerative sprint performance. Sports Biomech, 2007, 6 (3), 285–300, doi: 10.1080/14763140701489793. Paper received by the Editors: October 30, 2012 Paper accepted for publication: March 18, 2013 Correspondence address Beata Makaruk Wydział Wychowania Fizycznego i Sportu w Białej Podlaskiej Akademia Wychowania Fizycznego Józefa Piłsudskiego ul. Akademicka 2 21-500 Biała Podlaska, Poland e-mail: [email protected] HUMAN MOVEMENT 2013, vol. 14 (2), 123– 128 Subjective assessment of sports success in wheelchair rugby – proposal of a new research tool doi: 10.2478/humo-2013-0014 Tomasz Tasiemski *, Joanna Bauerfeind University School of Physical Education, Poznań, Poland Abstract Purpose. The main purpose of this study was to design and perform a preliminary psychometric analysis of a measure in the subjective assessment of sports success in wheelchair rugby (WR). An additional objective of this study was to assess potential differences in the subjective assessment of sports success between rugby players who play in the first and second Polish Wheelchair Rugby League (PWRL). Methods. Thirty WR players who played in the first (n = 11) and second PWRL (n = 19) completed the newly-created Subjective Assessment of Sports Success in Wheelchair Rugby (SASS-WR) scale and a questionnaire collecting demographic, career, and sports training data. Results. The SASS-WR scale was found to be a valid and reliable measure of sports success in WR. The final version consists of 12 items defining four dimensions of sports success: (1) Individual Sports Success of the Player, (2) National Sports Success of the Team, (3) International Sports Success of the Team, (4) Social and Personal Success of the Player. The players in the first league were significantly more focused on achieving individual sports success as well as having their team achieve national and international sports success when compared with the players in the second league. Social and personal success (the fourth dimension of the SASS-WR) was more important for the second league players than first league players, although this difference was not significant. Conclusions. The findings suggest that the SASS-WR scale can serve as a valuable diagnostic tool in assessing sports success among WR players. Key words: wheelchair rugby, subjective sports success assessment, spinal cord injury Introduction Success in team sports is determined by many factors, of which the most commonly mentioned are technical and tactical training as well as physical and mental preparation [1–3]. Research in this area on able-bodied athletes has been undertaken, however, little is known about the determinants of sports success among athletes with disabilities. This is especially so with regards to the psychological aspects that play a role here, which include the subjective perception of sports success by athletes with disabilities. Currently, the fastest growing team sport for individuals with disabilities in Poland is wheelchair rugby (WR), with the Polish Wheelchair Rugby League (PWRL) having grown to include already 20 official teams [4]. WR is intended mainly for individuals with cervical spinal cord injuries (SCI), although it is open to those who feature other locomotor disabilities as long as they have at least three limbs with functional deficits. However, WR is still a relatively new sport for individuals with disabilities; hence research on this discipline and its players is quite limited. Until now, most of the published scientific work has concentrated on testing strength levels and classifying players [5–8] or analyzing the impact of training on the functional abilities of WR players [9–13]. Defining sports success in WR can begin by under* Corresponding author. standing what motivations guide individuals with disabilities, especially those with SCI who decide to take up physical activity. Previous research found that, first of all, men differ from women with regards to their motivation for participating in sports [14]. Men with disabilities stressed the importance of achieving athletic status, while women claimed that developing friendships was much more important. Studies focused on individuals with SCI found that the main reason for engaging in phy sical activity was to maintain physical fitness levels and to improve upper-body strength [15, 16]. Among those individuals with SCI who participate in sports, men valued the opportunity to compete against one another higher than women, while women rated the possibility to control body weight higher than men [17]. In turn, those with SCI who were intensively involved in sports stressed that their main motivation was the pleasure derived from playing sports, with health and other social motivations less relevant [18, 19]. However, the motivations that guide professional athletes with disabilities, as is the case for those playing in the PWRL, are particularly important as it is teamwork that allows them to achieve sports success. Previous research found a significant relationship between team cohesion and sports success [20, 21]. In the case of individual sports, however, such a relationship was not found, with sports success even having a negative impact on team cohesion [22–24]. Therefore, it seems that athletes focused on sports success would be motivated more by sports-related goals than factors such as improving health. 123 HUMAN MOVEMENT T. Tasiemski, J. Bauerfeind, Sports success in wheelchair rugby Within this context, the main aim of the present study was to design and perform a preliminary psychometric analysis of a research tool that could be used in the subjective assessment of sports success in WR. An additional goal of the study was to assess potential differences in the subjective assessment of sports success between rugby players who play in the first and second PWRL. It was assumed that players in the first league would be more motivated in having their team achieve sports success than players in the second league. Material and methods Creating a scale Reliability of the scale In order to choose what phrasing would be most suitable in assessing players’ subjective perception of sports success in WR, an interview was conducted with 25 randomly selected players from both the first and second WR leagues in Poland. During the interview the players were asked to specify a maximum of 20 responses to the question: “How would you define sports success in WR?” After collecting the replies, a five-person expert panel was assembled consisting of a WR player, coach, and referee and the two authors of the present study to critically analyze the collected data. A consensus was reached on deleting responses that were either identical or closely related to each other, leading to the creation of a 14-item scale that was then tested in a pilot study. Participants in the pilot study For the pilot study, 30 additional players were recruited (29 men and 1 woman) from the first (n = 11) and second (n = 19) WR league (Tab. 1). The majority of the players were individuals with SCI (n = 26), while the remaining four were disabled due to other limb impairments. The mean age of the first league players was 34 years (SD = 4.51) while the mean for the second league players was 39 years (SD = 9.69); the difference between both groups for age was not statistically significant (t = –1.529; p = 0.137). In terms of the functional abilities of the players, among the first league group there were three athletes who were low-pointers (point values from 0.5 to 1.5, Table 1. Participants of the pilot study Team name Balian Poznań Flying Wings Rzeszów Jokers Bydgoszcz Brave Snails Lublin Piecobiogaz Poznań TetraGryf Szczecin 124 based on the classification system by the International Wheelchair Rugby Federation) and eight who were high-pointers (2.0–3.5 points). In the group of second league players, fourteen were low-pointers and five were high-pointers. The difference between the groups in terms of the players’ functional capacity was significant ( 2 = 6.111, p = 0.013). No significant differences were noted between the first and second league players in terms of basic data on the players’ experience and career, such as the number of years spent playing WR, the number of days per week spent training WR, and the number of minutes per day spent training WR (Tab. 2). Number of partici pants n PWRL Ranking in 2012 5 3 3 5 8 6 I I I II II II 1 3 9 12 13 15 The participating players (n = 30) completed the newlycreated Subjective Assessment of Sports Success in Wheelchair Rugby (SASS-WR) scale, subjectively rating the 14 items that were previously selected to describe the perception of sports success. The participants responded to the statement “Sport success in WR means to me…” by choosing their responses to each item on a 5-point Likert scale (1 = completely unimportant, 5 = extremely important). The reliability of the 14-point SASS-WR scale was found to be good (Cronbach’s alpha = 0.728), although after removing statements No. 12 and No. 14 the reliability of the scale increased to Cronbach’s alpha = 0.753 and Cronbach’s alpha = 0.747, respectively (Tab. 3). As a result, these statements were removed to increase the reliability of the scale, leaving 12 items. Results Extracting the SASS-WR scale’s factors Factor analysis was performed in order to extract the SASS-WR’s underlying dimensions. A scree plot pointed to four dimensions, which were extracted by Principal Component Analysis (Promax rotation with Kaiser normalization). Four of the scale’s items had a value greater than one, which accounted for 85% of the total explained variance. Each of the scale’s four dimensions consisted of three components (Tab. 4). Each of the four dimensions of the SASS-WR scale were named according to their semantic content, and their reliability was found to be satisfactory: 1) Individual Sports Success of the Player (Cronbach’s alpha = 0.775), 2) National Sports Success of the Team (Cronbach’s alpha = 0.861), 3) International Sports Success of the Team (Cronbach’s alpha = 0.979), and 4) Social and Personal Success of the Player (Cronbach’s alpha = 0.617). The responses of the participants for each statement were summed separately for each of the scale’s four dimensions (range: 3–15 points). A higher score indicated the greater importance of the component (dimension) for a player in their subjective assessment of sports success in WR (see Appendix). HUMAN MOVEMENT T. Tasiemski, J. Bauerfeind, Sports success in wheelchair rugby Table 2. Sports career and training frequency of the first and second WR league players Sports experience Years playing WR Days spent training WR per week Daily WR workout (min) 0.05; ** p *p I league (n = 11) ± SD II league (n = 19) ± SD t test (p) 7.36 ± 4.56 2.50 ± 1.07 106.36 ± 61.64 8.39 ± 4.63 2.03 ± 1.08 93.95 ± 40.88 0.559 0.257 0.512 0.01 Table 3. Reliability of the SASS-WR scale after removing individual items Cronbach’s alpha after removing the item No. SASS-WR items 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. Qualifying to be a player on my WR team’s roster Selected by the coach to play in a game Qualifying to be a player on the national WR team Team being highly ranked in a PWRL tournament Team being highly ranked in PWRL overall classification Team advancing to a higher group in PWRL Team winning first place in the European Championships Team qualifying for the World Championships Team winning first place in the World Championships Achieving social prestige Developing social contacts Pleasure derived from playing sports Improving my fitness level Overcoming my own weaknesses 0.699 0.693 0.720 0.722 0.713 0.689 0.694 0.699 0.701 0.705 0.724 0.753 0.718 0.747 Values in bold denote those items, when removed, improved the scale’s reliability Table 4. Matrix model of the SASS-WR scale Components No. SASS-WR items 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. Qualifying to be a player on my WR team’s roster Selected by the coach to play in a game Qualifying to be a player on the national WR team Team being highly ranked in a PWRL tournament Team being highly ranked in PWRL overall classification Team advancing to a higher group in PWRL Team winning first place in the European Championships Team qualifying for the World Championships Team winning first place in the World Championships Achieving social prestige Developing social contacts Improving my fitness level 1 2 3 4 0.960 0.935 0.753 0.858 1.021 0.769 1.002 1.012 0.904 0.833 0.894 0.478 Extraction method: Principal Component Analysis; rotation method: Promax with Kaiser normalization Sport success based on the opinions of WR players First league players, compared against second league players, placed more importance on achieving sports success in three of the SASS-WR scale’s dimensions (individual sports success and their team’s national and international success), with the differences between the two groups statistically significant (Tab. 4). This result confirmed the initial assumption that higher classified players in the PWRL (first league) are more motivated in achieving team success than players at a lower classification (second league). In turn, social and personal success (the fourth dimension of the SASS-WR) was more important for second league players than first league players, although this difference was not significant (Tab. 5). 125 HUMAN MOVEMENT T. Tasiemski, J. Bauerfeind, Sports success in wheelchair rugby Table 5. Sports success based on the opinions of the first and second league players SASS-WR dimensions Individual Sports Success of the Player National Sports Success of the Team International Sports Success of the Team Social and Personal Success of the Player *p 0.05; ** p II league (n = 19) ± SD 14.36 ± 1.43 14.45 ± 1.03 14.73 ± 0.91 11.27 ± 2.32 10.89 ± 2.55 13.05 ± 1.84 12.26 ± 3.78 12.84 ± 2.19 t test (p) 0.001** 0.028* 0.044* 0.075 0.01 Discussion Preliminary psychometric analysis of the proposed SASS-WR scale suggests that it can serve as a both relevant and reliable tool in assessing the motivations behind sports success in WR. The final scale consists of 12 items measuring four dimensions of sports success: 1) Individual Sports Success of the Player, 2) National Sports Success of the Team, 3) International Sports Success of the Team, and 4) Social and Personal Success of the Player. Noteworthy is the fact that the WR players, despite being clearly asked to indicate what sports success means to them (when initially creating the SASS-WR scale), pointed to a number of non-sports-related factors such as developing social contacts and improving their own fitness level. This implies that for individuals with a disability, even for those who are professionally involved in sports, the motivation behind taking up a sport is not only based on typical sports-related factors, such as qualifying to be a player of the national team or having their team in high standing. These results are consistent with the findings of other authors. The participants in Wu and William’s study [18] – individuals with SCI intensively practicing sports – placed “fun in doing sports” as their main motivation, followed by goals such as “physical fitness”, “health”, “competition” and “social aspects”. Similarly, research conducted by Furst, Ferr, and Megginson [19] on athletes with SCI (triathlon competitors) found that the main reason for them engaging in sports was “fun” and then mentioned “physical development and improving health”, “enjoying competition”, and “social aspects”. The participants of the present study, specifically the players in the first league, were found to be significantly more focused on achieving sports success than the players in the second league. The first league players obtained results at the upper limit of the scale, i.e., 14.4–14.7 points (out of a maximum of 15 points) in three of the scale’s dimensions, signifying their focus on both individual sports success as well as their team’s success, with these results being significantly higher than those of the second league players. This outcome can be interpreted in different two ways. On the one hand, it seems quite obvious that players playing at a higher level (first league) would be more focused on individual and team success than players who were not as successfully competitive (second league). On the other hand, the results 126 I league (n = 11) ± SD may have been influenced by the differences between the first and second league teams in terms of the functional abilities the players possess. Among those playing in the first league, the percentage of high-pointers to lowpointers was 73% to 27%, while in the second league this was the opposite, i.e. 26% to 74%, respectively. Highpointers (who primarily play on offense) may be more strongly motivated in achieving success in sports because they are mainly responsible for scoring points, while low-pointers (playing on defense) rarely leave the rear of the court and have a much smaller opportunity to score any points. The differences between the groups’ focus on different aspects of sports success should be verified in future research on groups of first and second league players although with a similar ratio of highpointers and low-pointers. The results of the present study suggest a relationship between team cohesion (understood as players being focused on the same goal) and sports success (understood as a team’s ranking in the PWRL). Carron et al. [20] demonstrated a very strong relationship between the success of a sports team and team cohesion when analyzing eighteen basketball and nine soccer teams (154 women and 140 men). Similar results were obtained by Mullen and Copper [21]. Generally speaking, the present study confirmed the positive relationship between sports success and team cohesion in team sports. In disciplines such as volleyball or soccer, each player provides a different skill set that is effective only when working together as a team. On the other hand, individual sports such as golf or bowling are entirely dependent on a player’s own skills and abilities, where the success of a team depends more on each individual’s performance. In such sports, team cohesion does not significantly affect sports success, and can even have a negative impact on sports success [22–24]. Certain limitations of the present study could have influenced the final results. Firstly, the obtained results were based on a relatively small sample of athletes (n = 30), and the two sub-groups were not equinumerous. Almost two-thirds of the surveyed players competed in the second league with the remaining one-third belonged in the first league. In addition, as was already mentioned earlier, the different ratio of high-pointers to low-pointers in both groups (first and second league) could have affected the final results of this study. HUMAN MOVEMENT T. Tasiemski, J. Bauerfeind, Sports success in wheelchair rugby Conclusions The findings suggest that the SASS-WR scale can serve as a valuable diagnostic tool in assessing sports success among WR players. The present-day process of professionalizing sports for athletes with disabilities in Poland, in particular WR, requires reliable tools to assess not only the physiological, motor, and technical parameters of its players but also assess their psychological make-up, as all of these factors constitute the ability of team to achieve sports success. Future research should confirm the SASS-WR scale’s psychometric properties on a larger group of athletes and verify its sensitivity with regard to differences in the competitive level of both the participants and their teams. It would also be useful to assess whether the SASS-WR scale can serve as a reliable tool for assessing WR players from other European countries. References 1. Stølen T., Chamari K., Castagna C., Wisloff U., Physiology of soccer: an update. Sports Med, 2005, 35 (6), 501–536, doi: 10.2165/00007256-200535060-00004. 2. Van-Yperen N.W., Duda J.L., Goal orientations, beliefs about success, and performance improvement among young elite Dutch soccer players. Scand J Med Sci Sports, 1999, 9 (6), 358–364, doi: 10.1111/j.1600-0838.1999. tb00257.x. 3. Graczyk M., Portrait of a psychologist, its role and tasks carried out in light of the opinion of Olympic coaches [in Polish], Medycyna Sportowa, 2007, 5, 247–253. 4. Results of the 2012 Polish Wheelchair Rugby League. January 2013. Available from URL: http://rugby.far.org.pl/ aktualnosc,112,Podsumowanie+sezonu.html. 5. Morgulec N., Kosmol A., Molik B., Specific fitness level and classification system in wheelchair rugby. In: Żak S., Spieszny M., Klocek T. (eds.), Team games in physical education and sport [in Polish]. Studia i monografie AWF, Kraków 2005, 335–337. 6. Szymczak Ł., Laurentowska M., An assessment of anaerobic performance of individuals with quadriplegia training wheelchair rugby [in Polish]. Medycyna Sportowa, 2009, 25, 35–36. 7. Morgulec-Adamowicz N., Kosmol A., Bogdan M., Molik B., Rutkowska I., Bednarczuk G., Game efficiency of wheelchair rugby athletes at the 2008 Paralympic Games with regard to player classification. Hum Mov, 2010, 11 (1), 91–95, doi: 10.2478/v10038-010-0002-6. 8. Sarro K.J., Misuta M.S., Malone L., Burkett B.L., Barros R.M., Correlation between functional and kinematical variables in elite wheelchair rugby players. In: Jensen R., Ebben W., Petushek E., Richter C., Roemer K. (eds.), XXVIII International Symposium on Biomechanics in Sports: Conference Proceedings Archive, July 19–23, 2010, Marquette, USA, 28, 124–125. 9. Adnan Y., McKenzie A., Miyahara M., Self-efficacy for Quad Rugby skills and activities of daily living. Adapt Phys Activ Q, 2001, 18 (1), 90–101. 10. Dallmeijer A.J., Hopman M.T.E., van As H.H.J., van der Woude L.H.V., Physical capacity and physical strain in persons with tetraplegia; The role of sport activity. Spinal Cord, 1996, 34 (12), 729–735, doi:10.1038/sc.1996.133. 11. Furmaniuk L., Cywińska-Wasilewska G., Kaczmarek D., Influence of long-term wheelchair rugby training on the functional abilities of persons with tetraplegia over a two year period post-spinal cord injury. J Rehabil Med, 2010, 42 (7), 688–690, doi: 10.2340/16501977-0580. 12. Morgulec N., Kosmol A., Influence of sport activity on the functional abilities of individuals with spinal cord injury (SCI-C) [in Polish]. Lider, 2009, 12, 26–29. 13. Morgulec N., Skrzypczyk R., Development of wheelchair rugby and its influence on the functional abilities of individuals with quadriplegia [in Polish]. Wychowanie Fi zyczne i Sport, 2003, 47, 535–544. 14. Fung L., Participation motives in competitive sports: A cross-cultural comparison. Adapt Phys Activ Q, 1992, 9 (2), 114–122. 15. O’Neill S.B., Maguire S., Patient perception of the impact of sporting activity on rehabilitation in a spinal cord injuries unit. Spinal Cord, 2004, 42 (11), 627–630, doi: doi: 10.1038/sj.sc.3101651. 16. Tasiemski T., Bergström E., Savic G., Gardner B.P., Sports recreation and employment following spinal cord injury – a pilot study. Spinal Cord, 2000, 38 (3), 173–184. 17. Tasiemski T., Kennedy P., Gardner B.P., Blaikley R.A., Athletic identity and sports participation in people with spinal cord injury. Adapt Phys Activ Q, 2004, 21 (4), 364–378. 18. Wu S.K., Williams T., Factors influencing sport participation among athletes with spinal cord injury. Med Sci Sports Exerc, 2001, 33 (2), 177–181. 19. Furst D.M., Ferr T., Megginson N., Motivation of disabled athletes to participate in triathlons. Psychol Rep, 1993, 72 (2), 403–406, doi: 10.2466/pr0.1993.72.2.403. 20. Carron A.V., Bray S.R., Eys M.A., Team cohesion and team success in sport. J Sports Sci, 2002, 20 (2), 119–126, doi: 10.1080/026404102317200828. 21. Mullen B., Copper C., The relation between group cohesiveness and performance: An integration. Psychol Bull, 1994, 115 (2), 210–227, doi: 10.1037/0033-2909.115.2.210. 22. Carron A.V., Chelladurai P., Cohesion as a factor in sport performance. Int Rev Sport Sociol, 1981, 16, 2–41. 23. Landers D.M., Lüschen G., Team performance outcome and cohesiveness of competitive coacting groups. Int Rev Sport Sociol, 1974, 9, 57– 69. 24. Williams J.M., Widmeyer W.N., The cohesion–performance outcome relationship in a coaching sport. J Sport Exerc Psychol, 1991, 13 (4), 364–371. Paper received by the Editors: January 29, 2013 Paper accepted for publication: April 5, 2013 Correspondence address Tomasz Tasiemski Zakład Sportu Osób Niepełnosprawnych Akademia Wychowania Fizycznego im. Eugeniusza Piaseckiego ul. Królowej Jadwigi 27/39 61-871 Poznań, Poland e-mail: [email protected] 127 HUMAN MOVEMENT T. Tasiemski, J. Bauerfeind, Sports success in wheelchair rugby Appendix: SASS-WR scale SUBJECTIVE ASSESSMENT OF SPORTS SUCCESS IN WHEELCHAIR RUGBY (SASS-WR) This questionnaire is designed to assess how wheelchair rugby players perceive sports success. Please rate how important the following statements are to you on a scale of 1 (completely unimportant) to 5 (extremely important). Sports success in wheelchair rugby means to me… (please circle your answer): 1. Qualifying to be a player on my wheelchair rugby team’s roster 1 2 3 4 5 2. Selected by the coach to play in a game 1 2 3 4 5 3. Qualifying to be a player on the wheelchair rugby national team 1 2 3 4 5 4. Team being highly ranked in a PWRL tournament 1 2 3 4 5 5. Team being highly ranked in PWRL overall classification 1 2 3 4 5 6. Team advancing to a higher group in PWRL 1 2 3 4 5 7. Team winning first place in the European Championships 1 2 3 4 5 8. Team qualifying for the World Championships 1 2 3 4 5 9. Team winning first place in the World Championships 1 2 3 4 5 10. Achieving social prestige 1 2 3 4 5 11. Developing social contacts 1 2 3 4 5 12. Improving my fitness level 1 2 3 4 5 * PWRL – Polish Wheelchair Rugby League INSTRUCTIONS FOR RESEARCHERS The SASS-WR has four dimensions, measuring: I. INDIVIDUAL SPORTS SUCCESS OF THE PLAYER (Statements No. 1–3) II. NATIONAL SPORTS SUCCESS OF THE TEAM (Statements No. 4–6) III. INTERNATIONAL SPORTS SUCCESS OF THE TEAM (Statements No. 7–9) IV. SOCIAL AND PERSONAL SUCCESS OF THE PLAYER (Statements No. 10–12) The responses that fall under each dimension need to be summed up (their numerical value). A higher score (range: 3–15 points) indicates the greater importance of this component (dimension) for a player’s subjective perception of sports success in wheelchair rugby. 128 HUMAN MOVEMENT 2013, vol. 14 (2), 129– 137 On the possibility of applying achievement goal theory in competitive sports doi: 10.2478/humo-2013-0015 Piotr Kuczek State Higher School of Vocational Education, Tarnów, Poland Abstract Purpose. There exist numerous empirical proofs as well as theoretical bases showing that task motivational orientation and task climate allow students and athletes to function better and be more efficient. What is not certain is whether the same applies to athletes competing at the professional level. The aim of this study was to analyze whether task orientation and task-oriented climate help professional athletes avoid experiencing high levels of anxiety, thereby providing a favorable foundation for performance in high-level competition. Methods. Basketball players from the Polish II League (amateur) and Extraleague (professional) were surveyed. Motivational orientation, motivational climate, and anxiety levels were measured by the Perception of Success Questionnaire (POSQ), Perception of Significant Others’ Sport Success Criteria Questionnaire (PSOSSCQ), and Sport Anxiety Scale (SAS), respectively. Results. The reliability of the research tools on a Polish population was confirmed. Motivational climate was associated with motivational orientation; task orientation and a task-oriented climate were found to not reduce anxiety levels. Conclusions. The results do not confirm the application of achievement goal theory in high-level competitive sports. Key words: motivation, anxiety, motivational climate Introduction The motivation behind achievement and success as well as the natural propensity for rivalry and competition has been one of the most significantly debated issues in psychology for the last six decades. It should come as no surprise that the use of this theory in recreational and competitive sports has garnered considerable interest by researchers. This stems from the fact that competitive sport is an arena where motivation is not only of colossal significance in regard to its final outcome but that it also plays a role in the phenomenon of persevering or quitting. Achievement goal theories are deeply rooted in psychology and even in philosophy, being a direct precursor of Lepper’s overjustification hypothesis [1] and Deci’s Cognitive Evaluation Theory [2]. It has to be emphasized, however, that these two theorists dealt with the differences between external and internal motivation, while goal orientation theory deals with two kinds of internal motivation that work in achieving various goals. The motivational theories currently being used originate from work conducted in the field of education and have been modified for use in sports [3–5]. Disregarding the differences in terminology, all of these theories can be distinguished by two types of guiding orientations (attitudes). The first, termed task orientation, consists of combining the effect of an action with effort. For individuals with such an orientation, spending a great deal of energy in achieving a goal does not suggest that they have poorer abilities. Instead, the effort placed in fostering one’s own self-development is treated as having a value and, consequently, nullifying in some respect the objective, or goal, itself. Such individuals are believed to have no need to compare themselves with others or to a set of specific standards; instead, they demonstrate their abilities only to appease themselves, as something convergent with their effort rather than the final effect. This may be interpreted as saying those who work hard and try to improve themselves have already achieved success in some manner. However, Dweck and Leggett [4], offered a slightly different definition of this phenomenon by defining it as perceiving the changeability or permanence of one’s own capacities. A task-oriented person regards their capacities as a group of acquired features and are changeable, subject to modeling and development. The other orientation, as described by Nicholls, is ego orientation [3], which consists of having effort and talent remain non-differentiated, where talent and effort are notions that overlap each other. This approach emphasizes a stark contrast between effort and ability. Individuals with such an orientation need to prove their own abilities in an entirely different way. They believe that the more effort put into achieving a goal, the less talent they actually possess; hence the reason why their aim is to achieve maximum capability with minimum effort. Since the effort is treated as possessing no value of itself, what remains important, in effect, is the final outcome and preferably when it outranks the results of others or by attaining a certain defined standard. To someone who is ego-oriented, one’s own development has little influence on their “sense” of success. According to Dweck and Leggett [4], this stems from the fact that individuals with such an orientation consider capacity and talent as permanent features, resulting in the belief that all and any attempts to improve them are performed in vain. 129 HUMAN MOVEMENT P. Kuczek, Motivational orientation theory and sports As Nicholls asserts [3], the ontology of task orientation motivation presents itself earlier than ego orientation. Only when children reach the age of 12–13 do they begin to notice the role of talent. They also start to understand why their peers, who more often than not try to do their best, do not feature the achievement level as those who are lazy. Children begin to realize that only effort lets them achieve their maximum capability but that it cannot help overcome their own limitations. The problem of the source and causes of ego orientation motivation was investigated by Ames [5], who demonstrated that the process is affected by such factors as the type of task that is to be performed, the evaluation method, the level of an individual’s independence, task grouping and division, and reward. Both empirical evidence and theoretical analysis have concluded that task orientation is the most beneficial in the proper motivational and emotional development of young students and athletes. Nicholls [3] emphasizes that task-oriented individuals identify success with effort, hence one of the reasons why they try to use effort itself as the source as well as path leading to success. An egooriented individual believes that real success and satisfaction are derived from displaying the highest gained capability with minimum effort. Consequently, it can be expected that, given two athletes, the individual featuring higher task orientation would place more effort in a given task. A similar line of logic is present when choosing a task based on its difficulty. It is believed that choosing a task of medium difficulty, which still poses a challenge to an individual, can ensure the notion of attaining real success in sports. Accordingly, only such a choice is considered rational. Nicholls [3] posits that a task-oriented individual would naturally choose a task of medium difficulty, as would an ego-oriented individuals that might have better sense of their own competence. However, as an individual begins experience more difficulty in demonstrating competence in a given task, they begin to gravitate towards less attractive goals as a way of avoiding failure. As a result, such individuals would then choose a very easy or a very difficult (i.e., impossible) task. In the first example, such an individual would definitely be able to cope with and perform the task; in the other case, they would simply treat themselves as just another example of those unable to complete such a difficult task. This defense strategy might even be considered efficient were it not for the fact that, in sports, one has to choose goals that are difficult but at the same time accomplishable. There is a great deal of evidence to support the belief that task-oriented individuals feel less anxiety than egooriented ones [5, 6]. The difference is especially seen in individuals who are convinced that their competence is low or when a difficult situation is encountered. This is because when faced with a difficult situation, accompanied by a lack of confidence in one’s own capabilities, one feels a threat to one’s self-image. As had 130 been previously stated, a goal-oriented individual regards one’s features as capable of undergoing development. Consequently, such an individual does not treat such a situation as an attack on one’s integrity even in a state of hopelessness, as they understand that they can always improve and overcome their own weaknesses, progressing so as to eliminate the problems they are faced with regardless of the fact that at the present time they are faced with an insurmountable obstacle. An ego-oriented individual behaves in a completely opposite way. Anxiety coincides with the feeling of satisfaction that an individual derives from their effort, and is a facet particularly visible in sports [7]. A student or athlete can feel satisfaction regardless of the results they have achieved. They feel satisfied with process of accepting a challenge, attempting to meet it, and improving their capabilities. For ego-oriented students and athletes, it is victory that counts the most, which they can achieve only when performing at an appropriate sports or educational level. Therefore, as Roberts asserts [8], such athletes do derive satisfaction from practicing sports but only when they regard their capacity as being high. Comparing one’s achievements with others, which for egooriented athletes is what determines worth, means that only winners can feel truly satisfied. The aforementioned reflections point to the benefits of developing goal orientation motivation in young athletes, enabling them to act as best they can in light of the task at hand. This issue, however, is not so clear in the case of athletes who have already achieved a high level of competence. In light of the findings of some authors [9, 10], it is questionable whether motivational orientation theory, which has been found to work well in the fields of education and youth sports, can be fully transferred and efficiently applied to the realm of professional sports and whether professional athletes may benefit as much from task orientation and being embedded in a task climate. Therefore, the aim of the present study was to study this issue by sampling amateur and professional athletes by the use of specially developed questionnaires used to assess motivational orientation. In addition, as these questionnaires were to be used for the first time in the country of Poland, the reliability of the translations was checked to see if did not weaken the strengths of these tests. Material and methods A representative sample of basketball players from the Polish Extraleague (professional) and the II League (amateur) was used, numbering 65 (mean age 25.0 years) and 47 individuals (mean age 22.66 years), respectively. All players in the leagues were included regardless of their nationality; however, representatives of other Central and Eastern Europe (Lithuanians, Serbs, Croatians, Russians) were excluded due to potential language difficulties. HUMAN MOVEMENT P. Kuczek, Motivational orientation theory and sports Data was collected before or after a training session in the city/town the player represented in testing conditions that provided anonymity. The players were informed about the objective of the study and its scientific character as well as the confidentiality of the results. Instructions on how to fill out the questionnaires were provided. The players were assured that there were no right or wrong answers and asked to respond as honestly as possible. They then began filling out the questionnaires, which took about 10–15 minutes to complete. The questionnaires consisted of measuring the motivational climate, motivational orientation as well as the anxiety level of the players. Players whose native language was English (i.e., Americans) received the original version of the tests in English [11, 12]. Polish players received a translated version. Motivational climate was measured by Roberts et al.’s Perception of Significant Others’ Sport Success Criteria Questionnaire (PSOSSCQ) [13]. The aim of this tool is determine the motivational climate which an athlete competes in. The questionnaire consists of 16 suggested answers that pertain to the perceived motivational climate created by individuals who are important to the athlete. It is preceded by the task orientated question of “When playing my sport, my coach feels that I have success when…”. The athlete then rated various responses on a 1–5 Likert scale. Typical answers which testify to the task climate include “I do my best” or “I overcome difficulties”; answers reflecting the ego climate include “I beat other individuals” or “I show other individuals I am the best”. Motivational orientation was assessed using Roberts et al.’s Perception of Success Questionnaire (POSQ) [13]. This tool is designed to help researchers answer questions on the motivational attitude of athletes. It consists of 12 suggested answers measured on a 1–5 Likert scale to the question: “When playing sport, I feel most successful when…”. For the ego orientation, typical answers included “I accomplish something others cannot do” or “I am the best”; task orientated responses included “I work hard” or “I show personal improvement”. In order to measure anxiety, Smith et al.’s Sport Anxiety Scale (SAS) [12] was used, which had been designed specifically for the need of assessing athletes. The test consists of 21 items athletes are supposed to agree or disagree with on a four-point Likert scale (definitely not = 1, rather not = 2, rather yes = 3, definitely yes = 4). Answers that testify to the presence of somatic anxiety include, for instance, statements such as “My body feels tense”; answers that measure cognitive anxiety and concentration disruption include statements such as “I have self-doubts” and “I’m concerned I won’t be able to concentrate”, respectively. Additionally, with a view to establishing the value and usefulness of particular players in a team, the participants’ coaches were asked to rank their players from highest to lowest, a higher number for players they con- sidered to be the most valuable whereas the lowest indicated those whose value they perceived in the team to be lowest. Data computation was performed with Statistica ver. 9 (Statsoft, USA). Results The results of the psychometric tests translated into Polish measuring motivational climate and orientation as well as anxiety level found that the translated versions of the tests are sufficiently reliable and applicable for dissemination in Poland. Cronbach’s alpha for the Perception of Significant Others’ Sport Success Criteria Questionnaire (PSOSSCQ), measuring motivational climate, was 0.7973 and 0.8276 for the task and ego climates, respectively. The deletion of any of the questions did not considerably affect the results. Escarti et al. [11] obtained similar results with values of 0.87 and 0.92 for the task and ego climates, respectively. The relatively minor difference between these values notwithstanding, the translation of the PSOSSCQ and the impact of any cultural differences only slightly weakened the Polish version’s reliability. The Perception of Success Questionnaire was found with Cronbach’s alpha of 0.8274 and 0.8009 for task and ego orientations, respectively. Deletion of any of the questions did not considerably affect the results. The results of the present study were found to be in line with those provided by the creators of the test. For example, while studying a population of athletically active Ameri can students (mean age 20.8 years), the creator’s obtained values of 0.82 and 0.87 for the task and ego orientations, respectively [13]. Research on a group of both female and male American basketball players (mean age 19.5 years) by Kavusssanu and Roberts [14] obtained Cronbach’s alpha equal to 0.88 in both the task and ego orientations. The results presented above come quite close to those obtained in the Task and Ego Orientation in Sport Questionnaire scale (TESOSO), designed by Duda et al. [15], for measuring motivational orientations in sports, where Cronbach’s alpha for task and ego orientations were found to be 0.72 and 0.82, respectively. The psychometric results of the Polish version of Roberts et al.’s test show that the translated version is wellsuited for use in sports and that its reliability does not considerably deviate from the original or from the results of similar tests. Cronbach’s alpha for the Sports Anxiety Scale (SAS) was, respectively, 0.8513, 0.8648, and 0.6178 for cognitive anxiety, somatic anxiety, and concentration disruption. Only Question #1 proved to be weak in the test (correlation of 0.39), which may have resulted from a poor translation. The original test used the word “nervous”, which is semantically connected with anxiety, apprehension, fear, stage fright, etc. The Polish equivalent that was used is more connected with being roused, over131 HUMAN MOVEMENT P. Kuczek, Motivational orientation theory and sports excited, and angry. The difference may have been large enough so as to considerably weaken this question. Non etheless, similar values of reliability were obtained by other researchers working with the original version of the test, obtaining Cronbach’s values of 0.84, 0.90, and 0.71 for cognitive anxiety, somatic anxiety, and concentration disruption, respectively [16]. As can be seen, the highest Cronbach’s alpha value was found measuring somatic anxiety, the lowest for concentration disruption. Even though the results shown above seem to testify to the better reliability of the original English version, the translated version is strong enough to be used in analyzing Polish athletes. A comparison of the professional (Extraleague) and amateur (II League) players found significant differences only between two variables: task orientation and age, with the amateur players being much younger than the professionals and more task-oriented. The remaining differences among the variables were found to be statistically insignificant (Tab. 1). The results confirmed that task orientation decreased with age and that the motivational climate recognized by an individual is connected with their orientation. What was not confirmed were reports on the positive influence of task orientation on anxiety level. Reversely, it was ego orientation that correlated negatively with anxiety level, with the strength of the correlation higher for Extraleague players than those in the II league (Tab. 2). Correlation analysis performed separately on the two groups of athletes (amateur and professional) showed different interactions between certain parameters. In the group of II league players, age negatively correlated with the level of each anxiety component, whereas it positively correlated with their value to the team (as measured by their coach) and ego motivational climate. Such correlations were not found among the Extraleague players (Tab. 3, 4). Moreover, the item “value to the team” showed a correlation between ego climate and ego orientation among II league players whereas no such correlation was found among the Extraleague players; instead, a slightly negative correlation was observed. In view of the relatively small number of American Table 1. Groups characteristic and primary statistics Age Ego climate Task climate Ego orientation Task orientation Cognitive anxiety Somatic anxiety Mean EX league Mean II league p N EX league N II league SD EX league SD II league 25.00 3.62 3.95 3.85 4.25 2.13 1.82 22.66 3.65 4.19 4.01 4.54 2.26 1.94 0.0053 0.8473 0.0535 0.2510 0.0192 0.2689 0.3037 65 63 63 65 65 63 63 47 46 46 46 46 46 47 4.32 0.76 0.69 0.69 0.73 0.57 0.52 4.26 0.75 0.52 0.72 0.48 0.68 0.63 EX league – players from the Polish basketball Extraleague II league – players from the Polish basketball II league SD – standard deviation 1.00 0.09 0.01 0.12 0.04 –0.14 –0.06 –0.12 * Correlation is statistically significant at 0.05 132 1.000 0.151 0.558* 0.025 –0.024 –0.229* 1.000 0.341* –0.067 –0.296* –0.268* 1.000 0.144 –0.018 –0.201* 1.000 0.604* 0.415* 1.000 0.528* Concentration disruption Task orientation Ego orientation Task climate Ego climate 1.000 0.493* 0.467* 0.246* –0.069 –0.153 –0.287* Somatic anxiety 1.00 0.16 0.06 –0.11 0.05 –0.21* –0.21* –0.07 –0.09 Cognitive anxiety Age Team position Ego climate Task climate Ego orientation Task orientation Cognitive anxiety Somatic anxiety Concentration disruption Team position Age Table 2. Correlation analysis of a whole control group (Spearman Rank Order Correlations) 1.000 HUMAN MOVEMENT P. Kuczek, Motivational orientation theory and sports Ego orientation Task orientation 1.000 0.356* 0.468* 0.055 –0.219* –0.184 –0.326* 1.000 –0.024 0.443* 0.058 0.021 –0.330* 1.000 0.192 –0.130 –0.219* –0.161 1.000 0.089 –0.065 –0.332* 1.000 0.742* 0.483* 1.000 0.541* Concentration disruption Task climate 1.000 0.257* –0.079 0.295* 0.040 –0.149 –0.124 –0.079 Somatic anxiety Ego climate 1.000 0.203* 0.331* 0.129 0.132 –0.136 –0.317* –0.373* –0.270* Cognitive anxiety Team position Age Team position Ego climate Task climate Ego orientation Task orientation Cognitive anxiety Somatic anxiety Concentration disruption Age Table 3. Correlation analysis for II league (Spearman Rank Order Correlations) 1.000 * Correlation is statistically significant at 0.05 1.000 0.159 –0.026 –0.192 Concentration disruption 1.000 0.415* –0.025 –0.391* –0.384* Somatic anxiety 1.000 0.236* 0.579* –0.022 –0.081 –0.213* Cognitive anxiety 1.000 0.586* 0.471* 0.353* 0.064 –0.127 –0.259* Task orientation Ego orientation 1.000 –0.035 0.042 –0.025 0.025 –0.144 –0.017 –0.168 Task climate 1.000 0.167 –0.121 –0.191 0.030 –0.188 –0.102 0.218* 0.086 Ego climate Age Team position Ego climate Task climate Ego orientation Task orientation Cognitive anxiety Somatic anxiety Concentration disruption Team position Age Table 4. Correlation analysis for Extraleague (Spearman Rank Order Correlations) 1.000 0.448* 0.339* 1.000 0.509* 1.000 * Correlation is statistically significant at 0.05 participants who completed the original English versions of the tests, the results of these players were subjected to only quantity analysis. Considerable differences were found in the mean values of task climate, task orientation, and all of the anxiety components (Tab. 5). However, the limited amount of data collected from these players prevented any conclusive statements from being made. Nonetheless, the large differences among the means of the studied parameters are definitely surprising. What is of particular interest is the fact that the Americans who play in the Polish leagues and who had been rated as among the best in their own teams by their coaches showed considerably higher levels of task orientation. This is at odds with the results of the Polish players. Although this issue lies outside the scope of the present study, future research should attempt to explain this difference. Discussion The results of the present study found that task climate and task orientation do not cause individuals from experiencing less negative emotional states such as anxiety or experiencing disruption in concentration. The positive impact of motivational orientation and the negative impact of ego orientation on anxiety levels, the satisfaction derived from effort, choosing positive life strategies, and the amount of effort put into completing tasks have been verified in many studies, mainly in the field of education [17]. Both theoretical and experimental evidence also confirms the positive impact of a task climate and the negative impact of ego climate [6]. However, the results obtained in the present study differed from these hypotheses and need to be explained. The possibility and legitimacy of applying motivational 133 HUMAN MOVEMENT P. Kuczek, Motivational orientation theory and sports Table 5. Comparison of Polish and American players Age Ego climate Task climate Ego orientation Task orientation Cognitive anxiety Somatic anxiety Concentration disruption Mean EX league Mean Americans p N EX league N Americans SD EX league SD Americans 25.80 3.68 4.05 3.88 4.33 2.01 1.78 1.72 28.10 4.21 4.61 3.96 4.92 1.35 1.16 1.16 0.1436 0.0577 0.0169 0.7338 0.0143 0,0016 0,0012 0.0021 84 81 81 84 84 82 82 81 10 9 9 10 10 10 10 10 4.66 0.76 0.67 0.70 0.74 0.62 0.58 0.55 4.75 0.88 0.38 0.96 0.14 0.42 0.26 0.26 EX league – players from the Polish basketball Extraleague, Americans – American players from the Polish basketball Extraleague SD – standard deviation orientation in competitive sports has been under considerable criticism, including the use of practically all research tools that are used in measuring these spheres [18]. The literature on the subject is considerably more indicative of the presence of higher anxiety or concentration disruptions in ego-oriented individuals or those who perceive their climate as ego-related when compared to task-oriented individuals or those who perceive their climate as task-oriented. Such results are frequently found in studies on young students or individuals participating in youth sports, such as fencers (mean age 12.7 years) [19], athletically active students [17], or athletes engaged in various recreational sports (mean age 14.08 years) [6]. However, not all of these results confirmed the need of developing and maintaining task-oriented goals for such individuals. Instead, these results, similar to those in the present study, did not show the preventive “positive” influence of task orientation and task climate nor did they display the supposed negative influence of ego orien tation and ego climate. Newton and Duda [20] tested the relationship between motivational orientation and multi-dimensional anxiety as well as expectations of success or failure. Studying a group of tennis players (mean age 20.2 years), these researchers demonstrated that ego orientation negatively correlated with self-confidence with the use of Martens’ Completive State Anxiety Inventory (CSAI-2) [21]. The remaining anxiety components, including cognitive anxiety, which is an important constituent from the point of view of the final makeup of anxiety, did not correlate with motivational orientation. Hall et al. [22] examined neurotic and normal perfectionism in group of young 14-year-old runners. They used the notion of motivational orientation by checking its relationship with perfectionism as well as with anxiety levels and self-confidence. The hypothesis that “a dispositional task orientation would be a strong predictor of confidence while a dispositional ego endorsement would predict cognitive anxiety” [22, p. 213] was found to be without merit. 134 Similar results were found by Duda et al. [15] while studying volleyball and basketball players (mean age 21.1 years) and tennis players (mean age 20.0 years). Task orientation positively correlated with lower levels of anxiety only among male volleyball players, while ego orientation positively correlated only with the group of tennis players. The remaining results were statistically insignificant, except for one unexpected result, where female volleyball players with higher task motivational orientation claimed to feel higher levels of anxiety, tension, and pressure than ego-oriented players. The results obtained by ardent advocates and supporters of goal perspective theory, such as Newton and Duda [23], are important in leading credence to the results of present study, as they also did not find an anticipated correlation between multidimensional anxiety and motivational orientation. Martin and Gill [24] carried out an examination on the relationship between motivational orientation and self-confidence in mediumand long-distance runners aged 14–18 years. The results did not confirm the belief that victory-oriented athletes (which is a construct theoretically similar to ego orientation) had smaller values of self-confidence. On the contrary, it was found that the runners who were more oriented towards winning displayed greater self-confidence, although this correlation was insignificant. The results obtained by these authors are consisted with those presented in this study, where self-confidence, in line with Martens et al.’s assumptions [21], is negatively correlated with cognitive anxiety, where the more self-confidence an individual has, the less cognitive anxiety. One of the few experimental studies that showed the influence of strong ego orientation and climate on the frequency of dropping out of sports was found in judokas, where those quitting the sport did not perceive the climate as more ego-oriented than those who kept up the sport [25]. This is important since task orientation and task climate were hypothesized as preventing individuals from making such decisions too early in their sports career. HUMAN MOVEMENT P. Kuczek, Motivational orientation theory and sports Motivational orientation theory was originally developed in the field of education, hence the reason why most empirical data on the subject is based on individuals at a young age. The findings of the present study as well as assumptions made by other researchers demonstrated that the strength of motivational orientation tends to decrease with age [3, 26]. In other words, what may affect adolescent and child athletes does not necessarily imply the same for adults. Moreover, the strength of various motivational correlations was indeed different depending on skill level of the participants, as was seen with the “Concentration disruption” variable. In the professional league (Extraleague), concentration disruption was negatively correlated with ego orientation, whereas in the amateur league it was task orientation. This further substantiates the belief that professional sports operate under a completely different set of principles than amateur sports, and that results of research one do not apply to the other. Serious doubts as to the role of “task orientation” and “ego orientation” have also been put forward by Harwood and Swain [27]. In their opinion, the concept of “motivational orientation” cannot be applied in the same way to sports and to education, asserting that “the overall message here is that we cannot afford to simply assume that task and ego involvement mean exactly the same thing in the sport domain as they do in the education domain” [27, p. 245]. Harwood and Swain found that a distinction between task and ego orientations in the realm of competitive sports to be totally groundless. For example, an athlete who states that he feels satisfied in sport if he really works hard does not necessarily have to be task-oriented. Harwood and Swain provided an example of an athlete who, on account of his high ego and low task motivational orientation, derived satisfaction from defeating others in competition, but who – in order to achieve this goal – had to perform in a way that is characteristic of task orientation, including working hard, placing large emphasis on effort, and the willingness to personally improve. Harwood and Swain postulated on extending the two orientations to include a third one. According to their proposal, the currently existing notion of task orientation should pertain only to recreational sports, while ego orientation should be defined either according to one’s own standards or be based upon general standards and consist of comparing oneself to others. The addition of one or even more orientation constituents has also been postulated by Elliot and Conroy [28]. They pointed out that ego orientation in itself is not unhelpful. Instead, what is important is the recognition of whether an athlete is driven by the need to win or by the need to avoid failure. The former was termed performance-approach orientation, the latter performanceavoidance orientation. They suggested that task orientation should also give rise to two additional constituents, mastery-approach orientation and mastery-avoidance orientation. According to this theory, both orientations are designed for achievement, regardless of whether it is normative success or success gained from individual progress. However, both orientations, guided by the need to avoid failure or the loss of already acquired skills, are also associated with negative expectations and may therefore have an adverse effect on an athlete’s emotional processes. Hardy et al. [9] drew attention to the fact that task and ego orientations are of an independent character, stating that the same athlete can be simultaneously strongly task-oriented and ego-oriented. Despite being confirmed in another study [8], this issue has rarely appeared in the literature on the subject. While comparisons between athletes with high task and high ego orientations are frequent, no comparative studies on athletes with high ego and low task orientation or high task and low ego orientation have been noted. Following Hardy et al.’s description [9], comparisons between task orientation and ego orientation are said to be similar to choosing between an apple and an orange and, therefore, of low theoretical value. After all, both motivations can bring about the desired effects. Many studies credit effective athletes with taking advantage of all possible motivational attitudes in order to raise their motivation and improve efficiency. When it comes to competitive sports, Hardy et al. [9] object to regarding task orientation as more desirable or better. They assert that “ego orientations are often denigrated by goal orientation researchers, a position that is certainly not in accordance with the view received from coaches and performers that: «you don’t get to be a world champion by not wanting to beat other individuals». Indeed, if goals really do motivate one’s behavior (…), then it is difficult to see how one could become a genuinely elite performer without having a strong ego orientation” [9, p. 78]. In a similar vein, Weinberg et al. [10] also spoke on this issue in a discussion on attitude and the choice of goals: “In essence, we have recently begun to question whether sport’s pervasive preoccupation with winning may actually be responsible for many athletes’ anxiety, motivation and self-confidence problems. It is not that winning is unimportant; it is just that, for many athletes and coaches, it has seemingly become the only goal worth pursuing” [10, p. 284]. Weinberg et al. also questioned the need for changing motivational orientation from being ego-oriented to task-oriented, as Ames [5] had promoted, although in the field of education. Weinberg et al. [10] claimed that “(…) in a sports environment, athletes may not need to change their focus. Rather, for some athletes, a winning orientation might produce the best performance and greatest persistence. As noted earlier, it may be the interaction of winning, performance, and fun orientations that is critical, rather than simply saying that an athlete who has a winning orientation should change to performance orientation.” [10, p. 285] 135 HUMAN MOVEMENT P. Kuczek, Motivational orientation theory and sports Many studies and theoretical constructs have emphasized the correlation between motivational climate and motivational orientation [29, 30]. The results obtained in the present study also confirm this relationship. It is by no means certain, though, whether motivational climate affects orientation or whether it is the other way round; that is, motivational orientation affects the perception of motivational climate [8, p. 46]. For Nicholls [3], climate has an objective value, for Ames [5] it maintains a subjective one, signifying that in this case what is more important is what impressions an individual has rather than an analysis of the actual climate they perform in. Ames labeled this as “perceived motivational climate”, emphasizing that the perception of the climate in which an individual acts depends on his/her attitudes and expectations.. The classical theory of motivational climate’s influence upon orientation believes that every athlete performs better in a task climate environment, and it also has a positive effect on the development of an individual’s internal, or autonomous, motivation. This belief has been confirmed by the results of one study [30]. However, according to matching theory, it is more important for athletes to perform in a climate that is compatible with their orientation than for the climate to be taskoriented. If a student is task-oriented, they will find better opportunity to be satisfied when working in a similar climate. If, however, the same individual is placed in an ego-oriented climate, then the goals stipulated in such an environment are dissimilar to their own and can have the student feel that their autonomy is threatened. It is not the very process of the ego climate but the incompatibility with a student’s attitude that poses a problem [32, 33]. Since the present study did not demonstrate the beneficial influence of task attitude or a task climate per se, the statement that it is more beneficial or desirable cannot be confirmed. The question stands whether this implies that coaches and instructors should forgo developing and maintaining a higher proportion of task attitude among athletes. The literature on the subject leads to the conclusion that in the course of training youth, coaches should first maintain task orientation and a task climate and only with the passage of time augment other motivational orientations, e.g. ego orientation. A more mature athlete, engaged in competitive sports, must realize that fans and sponsors expect him/her to win, and lead to the realization by both the coach and athlete to expect the same. This also introduces the idea that coaches could introduce slightly different training methods at various times in the training process. A task motivational climate may be advisable in the off-season so as to help the athlete with the arduous training process and, as the season approaches, switch to a more personal, egooriented form of motivation. The justification of this method requires more detailed analysis and should be taken under consideration in future research. 136 Conclusions The psychometric tests translated into Polish were found to be reliable. The obtained results confirm the doubts of certain researchers on the application of achievement goal theory in competitive sports. Neither task orientation nor task climate was found to significantly lower the level of sports anxiety among basketball players regardless of their performance level. In addition, the hypothesis that high ego orientation in athletes is reflected by a poorer emotional state was not confirmed. References 1. Lepper M.R., Greene D., Nisbett R.E., Undermining children`s intrinsic interest with extrinsic rewards: A test of „overjustification” hypothesis. J Pers Soc Psychol, 1973, 28 (1), 129–137, doi: 10.1037/h0035519. 2. Ryan R.M., Control and information in the intrapersonal sphere: An extension of cognitive evaluation theory. J Pers Soc Psychol, 1982, 43 (3), 450–461, doi: 10.1037/00223514.43.3.450. 3. Nicholls J.G., Achievement motivation: Conception of ability, subjective experience, task choice, and performance. Psychol Rev, 1984, 91 (3), 328–346, doi: 10.1037/ 0033-295X.91.3.328. 4. Dweck C.S., Leggett E.L., A social-cognitive approach to motivation and personality. Psychol Rev, 1988, 95 (2), 256–273, doi: 10.1037/0033-295X.95.2.256. 5. Ames C., Classrooms: Goals, structures, and student motivation. J Educ Psychol, 1992, 84 (3), 261–271, doi: 10.1037/ 0022-0663.84.3.261. 6. 6. Vazou S., Ntoumanis N., Duda J.L., Predicting young athletes’ motivational indices as a function of their perceptions of the coach and peer-created climate. Psychol Sport Exerc, 2006, 7 (2), 215–233, doi: 10.1016/j.psychsport.2005.08.007. 7. Duda J.L., Nicholls J.G, Dimensions of achievement motivation in schoolwork and sport. J Educ Psychol, 1992, 84 (3), 290–299, doi: 10.1037/0022-0663.84.3.290. 8. Roberts G.W., Understanding the dynamics of motivation in physical activity: The influence of achievement goals on motivational processes. In: Roberts. G.W. (ed.), Advances in Motivation in Sport and Exercise. Human Kinetics, Champaign 2001, 1–50. 9. Hardy L., Jones G., Gould D., Understanding Psycholo gical Preparation for Sport. Theory and Practice of Elite Performers. Wiley, Chichester 1996. 10. Weinberg R.S., Burton D., Yukelson D., Weigand D.A., Goal setting in competitive sport: An exploratory inves tigation of practices of collegiate athletes. Sport Psychol, 1993, 7 (3), 275–289. 11. Escarti A., Roberts G.C., Cervello E.M., Guzman J.F., Adolescent goal orientations and the perception of criteria of success used by significant others. Int J Sport Psychol, 1999, 30 (3), 309–324. 12. Smith R.E., Smoll F.L., Schulz R.W., Measurement and correlates of sport-specific cognitive and somatictrait anxiety: The sport anxiety scale. Anxiety Res, 1990, 2, 263–280. 13. Roberts G.C., Treasure D.C., Balague G., Achievement goals in sport: The development and validation of the Perception HUMAN MOVEMENT P. Kuczek, Motivational orientation theory and sports of Success Questionnaire. J Sports Sci, 1998, 16 (4), 337–347, doi: 10.1080/02640419808559362. 14. Kavussanu M., Roberts G.C., Motivation in physical activity contexts: The relationship of perceived motivational climate to intrinsic motivation and self-efficacy. J Sport Exerc Psychol, 1996, 18 (3), 264–280. 15. Duda J.L., Chi L., Newton M.L., Walling M.D., Catley D., Task and ego orientation and intrinsic motivation in sport. Int J Sport Psychol, 1995, 26 (1), 40–63. 16. White S.A., Zellmer S.R., The Relationship Between Goal Orientation, Beliefs About the Sport Success, and Trait Anxiety Among High School, Intercollegiate, and Recreational Sport Participants. Sport Psychol, 1996, 10 (1), 58–72. 17. Sarrazin P., Roberts G., Cury F., Biddle S., Famose J-P., Exerted effort and performance in climbing among boys: The influence of achievement goals, perceived ability, and task difficulty. Res Q Exerc Sport, 2002, 73 (4), 425–436, doi: 10.1080/02701367.2002.10609042. 18. Fogarty G.J., Tenenbaum G., Norrow K., Psychometric Evaluation of Goal Orientation Measures in Sport. In: Katsikitis M. (eds.), Proceedings of the 2006 Joint Conference of the APS and NZPsS. Auckland, 26–30 September, 2006, 120–124. 19. Hall. H.K., Kerr A.W., Motivational antecedents of precompetitive anxiety in youth sport. Sport Psychol, 1997, 11 (1), 24–42. 20. Newton M.L., Duda J.L., The interaction of motivational climate, dispositional goal orientation, and perceived ability in predicting indices of motivation. Int J Sport Psychol, 1999, 30, 63–82. 21. Martens R., Vealey R.S., Burton D., Competitive Anxiety in Sport. Human Kinetics, Champaign 1990. 22. Hall H.K., Kerr W.A., Matthews J., Precompetitive anxiety in sport: The contribution of achievement goals and perfectionism. J Sport Exerc Psychol, 1998, 20 (2), 194–217. 23. Newton M.L., Duda J.L., Relations of goal orientations and expectations on multidimensional state anxiety. Percept Mot Skills, 1995, 81 (3f), 1107–1112, doi: 10.2466/ pms.1995.81.3f.1107. 24. Martin J.J., Gill D.L., The relationship among competitive orientation, sport-confidence, self-efficacy, anxiety, and performance. J Sport Exerc Psychol, 1991, 13 (2), 149–159. 25. Le Bars H., Gernigon C., Ninot G., Personal and contextual determinants of elite young athletes’ persistence or dropping out over time. Scand J Med Sci Sports, 2009, 19 (2), 274–285, doi: 10.1111/j.1600-0838.2008.00786.x. 26. Chin N.S., Khoo S., Low W.Y, Sex, age group and locality differences in adolescent athletes’ beliefs, values and goal orientation in track and field. J Exerc Sci Fitness, 2009, 7 (2), 112–121, doi: 10.1016/S1728-869X(09)60014-9. 27. Harwood C.G., Swain A., Achievement goals in sport: A critique of conceptual and measurement issues. J Sport Exerc Psychol, 2000, 22 (3), 235–255. 28. Elliot A.J., Conroy D.E., Beyond the dichotomous model of achievement goals in sport and exercise psychology. Sport Exerc Psychol Rev, 2005, 1 (1), 17–26. 29. Ntoumanis N., Biddle S.J.H., Haddock G., The mediating role of coping strategies on the relationship between achievement motivation and affect in sport. Anxiety Stress Coping, 1999, 12 (3), 299–327, doi: 10.1080/1061580 9908250480. 30. Moreno J.A., Gimeno E.C., Coll D., Relationships among goal orientations, motivational climate and flow in adolescent athletes: Differences by gender. Span J Psychol, 2008, 11, 181–191. 31. Brunel P.C., Relationship between achievement goal orientations and perceived motivational climate on intrinsic motivation. Scand J Med Sci Sports, 1999, 9 (6), 365–374, doi: 10.1111/j.1600-0838.1999.tb00258.x. 32. Ntoumanis N., Biddle S., The Relationship Between Competitive Anxiety, Achievement Goals, and Motivational Climates. Res Q Exerc Sport, 1998, 69 (2), 176–187, doi: 10.1080/02701367.1998.10607682. 33. Duda J.L., Achievement goal research in sport: Pushing the boundaries and clarifying some misunderstanding. In: Roberts G.W. (ed.), Advances in motivation in sport and Exercise. Human Kinetics, Champaign 2001, 129–182. Paper received by the Editors: January 31, 2012 Paper accepted for publication: April 30, 2013 Correspondence address Piotr Kuczek Zakład Wychowania Fizycznego Państwowa Wyższa Szkoła Zawodowa ul. Mickiewicza 8 33-100 Tarnów, Poland e-mail: [email protected] 137 HUMAN MOVEMENT 2013, vol. 14 (2), 138– 143 GAIT ASYMMETRY DURING DUAL-TASK OBSTACLE CROSSING IN THE YOUNG AND ELDERLY doi: 10.2478/humo-2013-0016 Emmanuel S. da Rocha 1, Álvaro S. Machado 1, Pedro S. Franco 1, Eliane C. Guadagnin 2 , Felipe P. Carpes 1, 2 * 1 2 Applied Neuromechanics Group, Laboratory of Neuromechanics, Federal University of Pampa, Uruguaiana, Brazil Laboratory of Biomechanics, Federal University of Santa Maria, Santa Maria, Brazil Abstract Purpose. To evaluate gait asymmetry during obstacle crossing by young and elderly adults performing normal and dual-task gait. Methods. Ten healthy young adults and ten elderly adults with mild cognitive impairment performed a gait protocol by stepping over a foam obstacle during normal gait and while performing a secondary task (Stroop task). Sagittal kinematics of the lead and trail limbs were analyzed. Statistical procedures involved analysis of variance and t tests at a significance of 0.05. Results. Many of the kinematic variables presented a main effect for group (young adults vs. elderly adults), where the elderly featured poorer gait performance. It was observed that gait velocity during obstacle crossing in normal and dual-task gait was similar between the preferred and non-preferred limbs in both the young and elderly. However, the elderly were slower during normal and dual-task gait. A main effect for the dual-task condition was observed. Kinematic asymmetries for obstacle crossing were more frequent in the elderly and especially during the dual-task condition. Conclusions. The results suggest that the elderly may require more compensatory adjustments after crossing an obstacle. The asymmetries observed among the elderly may contribute to higher risk of falling during perturbed gait. Key words: obstacle negotiation, ageing, functional lateralization, walking, secondary task, perturbed gait Introduction The difficulties that arise when stepping over an obstacle have been used to study locomotion in the elderly [1]. Previous studies have suggested that obstacles encountered on a walking pathway may increase the risk for tripping or slipping in the elderly [2, 3], as they require the adaptation of new gait strategies [4], more precise swing control, and higher levels of inter-joint coordination [5]. Additionally, protocols that combine gait with a secondary task were used to address the relationship between cognitive performance and gait ability in a context more similar to that experienced in daily life. When submitted to a dual-task condition, the elderly presented poorer gait performance than younger subjects [1]. Additionally, the negative effects of a secondary task are more pronounced in the elderly with dementia [6], even in cases with mild cognitive impairment [7]. Assessing gait when stepping over obstacles in a dualtask situation has been suggested as a potential tool for screening fall risk in the elderly [8]. However, there is very little research addressing the presence of gait asymmetry when elderly engage in dual-task walking. “Split-belt” experiments have suggested that gait asymmetries lead to more failures in obstacle avoidance and require more attention to be paid by the elderly [9]. The limitation in performing executive functions during * Corresponding author. 138 walking may increase asymmetry, which could affect dynamic stability [10]. As the elderly require adequate time to adapt foot placement strategies in relation to the obstacle as to avoid contact, dual-task gait would have similar effects on time constraints and might put the elderly in greater risk of contacting the obstacle [2]. Moreover, the elderly with strength asymmetry have greater gait asymmetries and gait variability than those without strength asymmetry [11]. The aim of this study was to address the presence of gait asymmetry in the elderly during obstacle crossing in normal and dual-task gait conditions and compare them with a population of young adults. It was believed that kinematic asymmetries during obstacle crossing in dual-task conditions would be more frequently observed in the elderly. This may suggest that while asymmetry may be part of regular gait performance, its impact on the risk of falling might differ between young and elderly subjects. Material and methods Subjects Ten adult university students (six males, four females), aged 24.1 ± 3.6 years with a height of 1.69 ± 0.12 m and body mass of 68 ± 14.5 kg, and ten elderly community-dwelling volunteers (four males, six females), aged 74.4 ± 5.2 years with a height of 1.57 ± 0.05 m and body mass of 66 ± 9 kg, participated in our study. Subjects HUMAN MOVEMENT E.S. da Rocha et al., Gait asymmetries during obstacle crossing with neurological diseases (e.g., Parkinson’s or Huntington’s disease or who had suffered a stroke), vestibular or visual problems (clinically detectable), or with lower limb prosthesis were excluded. All subjects signed a written informed consent form approved by the local ethics committee (IRB no. #0102011). Neuropsychological and mobility assessment Cognitive status was assessed using the Mini-mental State Examination (MMSE) [12]. Mental status was assessed using the Geriatric Depression Scale [13]. The Instrumental Activities of Daily Living Scale (IADL) [14] was used to quantity the independence of the subjects. Leg preference was verified using the “Waterloo inventory” [15]. Gait assessment Participants performed a gait protocol with obstacles that had been previously used in other studies [3]. They performed the task while wearing their habitual shoes (flat, rubber-soled walking shoes) and clothes at self-selected comfortable speed along a 6 m walkway that had a foam obstacle positioned at the halfway point (height 15 cm, width 34 cm, length 11 cm). A familiarization trial with and without the obstacle was permitted. Two valid trials were considered for each condition. Movement was recorded in the sagittal plane with a digital video camera (S2000HD, FUJI, Japan) at a resolution of 12.2 megapixels using a 1/2.3 inch CCD sensor, with the video later analyzed at 60 Hz. Spherical reflexive markers were placed as anatomical references at the hallux, the fifth metatarsal head, and calcaneous tuberosity on both feet. A motion analysis tool (SkillSpector ver. 1.2.4, Video4coach, Denmark) was used to digitalize and track the markers providing position data. The camera was calibrated using a calibration frame with known dimensions. Estimated tracking error was 4 mm, therefore gait motion was filmed in both directions, with the right limb and the left limb alternating in front of the camera, in order to minimize the influence of recording error. Toe clearance was calculated as the vertical dis- tance between the toe marker and the obstacle when the hallux marker of the swing limb was just crossing above the obstacle [16]. A Butterworth filter with a low-pass cut-off frequency of 6 Hz was applied to filter the data. The kinematics parameters monitored were: pre-obstacle trail limb step length, pre-obstacle trail limb distance, lead limb toe clearance, post-obstacle lead limb distance, lead limb stride length, and trail limb toe clearance (Fig. 1). Step variables were normalized for each subject’s height and average velocity was computed for each trial. The participants were requested to step over the obstacle during normal gait and while performing a variation of the Stroop task. In the dual-task condition, subjects were asked to verbally reply “yes” when the examiner said “blue” and “no” when the examiner said “red”. For any other color that was named, the participants had to repeat the color (for example, if the examiner said “yellow”, subject repeated “yellow”). For a trial to be considered valid, the dual-task condition was to be performed without stopping. Two valid trials were considered for analysis. Statistical analysis Data normality was verified using the Shapiro-Wilk test. Statistical comparisons were performed using analysis of variance in a 2 × 2 × 2 mixed model by analyzing group (elderly and adult), leg (preferred and non-preferred), and condition (normal and dual-task gait) with Bonferroni corrections for multiple comparisons. When main effects or interactions were observed, kinematic data were compared by applying paired t tests. Non-parametric data were compared using the Wilcoxon test. The level of significance was set at 0.05. Results Neuropsychological and mobility The cognitive status of the young adults, assessed using the MMSE, was higher than 26 points indicating cognitively normal status. The elderly were found to (1) pre-obstacle trail limb step length (4) lead limb stride length (2) pre-obstacle trail limb distance (5) trail limb toe clearance (3) lead limb toe clearance (6) post-obstacle lead limb distance; black arrow denotes the movement direction Figure 1. Lower limb movements during the obstacle crossing task, where LL represents the lead limb (the first limb to step over the obstacle) and TL the trail limb (the contralateral limb to step over the obstacle) 139 HUMAN MOVEMENT E.S. da Rocha et al., Gait asymmetries during obstacle crossing was observed for dual-task gait performance while crossing the obstacle with the preferred [Z = –2.524; p = 0.012] and non-preferred limbs [Z = –2.193; p = 0.028]. Gait velocity was similar when crossing the obstacle with the preferred or non-preferred limb. An effect for group in pre-obstacle trail limb step length, post-obstacle lead limb distance, and lead limb stride length was found, which were lower in the elderly (Fig. 2). An effect for leg was observed in pre-obstacle trail limb distance (greater in the preferred leg for both groups) and post-obstacle lead limb distance (lower in the preferred leg for both groups). An effect for condition was observed in both groups for pre-obstacle trail limb step length and pre-obstacle trail limb distance, which was greater in the dual-task condition. Significant interactions were observed between group and leg for trail limb toe clearance, group and condition interaction for post-obstacle lead limb distance, and leg and condition interaction for lead limb toe clearance. The corresponding F and p values are presented in Tables 1 and 2. While symmetry was observed in normal gait, the dual-task condition elicited greater pre-obstacle trail limb step length in the preferred leg in the elderly [t(9) = –4.212; p = 0.002] and in the non-preferred leg in the young adults [t(9) = –2.659; p = 0.026]. Pre-obstacle trail limb distance was found to be asymmetric among the young adults during normal gait [t(9) = 3.22; p = 0.01] and for the elderly in the dual- present mild cognitive impairment as based on MMSE scores between 20 and 26 points [15, 16]. The results from the Geriatric Depression Scale excluded the risk of depression, and all subjects were classified as independent in regard to daily life tasks. Gait analysis When performing normal gait during obstacle crossing with the non-preferred limb, average gait velocity was 0.91 ± 0.26 m/s for the elderly and 1.11 ± 0.13 m/s for the young adults. When comparing the groups, it was observed that gait velocity when crossing the obstacle during normal [Z = –0.105; p = 0.917] and dual-task gait [Z = –1.402; p = 0.161] was similar between the preferred and non-preferred limbs among the young adults. The same was observed for the elderly in normal [Z = –0.663; p = 0.508] and dual-task gait [Z = –1.126; p = 0.260]. During the dual-task condition while crossing an obstacle with the preferred limb, average velocity was 0.71 ± 0.15 m/s for the elderly and 0.97 ± 0.16 m/s for the young adults. When performing the dual-task condition while crossing an obstacle with the non-preferred limb, average gait velocity was 0.78 ± 0.26 m/s for the elderly and 1.04 ± 0.16 m/s for the young adults. The elderly were slower than the young adults during normal gait performance under obstacle-crossing conditions with the preferred [Z = –2.016; p = 0.044] and non-preferred limbs [Z = –2.191; p = 0.028]. The same Table 1. Statistical outcomes considering the effects of group, leg, and condition by analysis of variance (F and p values) Group Variable Pre-obstacle trail limb step length Pre-obstacle trail limb distance Lead limb toe clearance Post-obstacle lead limb distance Lead limb stride length Trail limb toe clearance Leg Condition F p F p F P 6.45 2.59 1.81 47.14 9.68 3.76 0.032* 0.14 0.21 > 0.001* 0.01* 0.08 0.09 17.75 0.79 10.24 4.64 1.95 0.76 0.002* 0.39 0.011* 0.06 0.19 6.05 5.85 3.10 0.08 0.29 0.21 0.03* 0.03* 0.11 0.77 0.60 0.65 * statistically significant at p < 0.05 Table 2. Statistical outcomes considering the interactions of group × leg; group × condition; leg × condition; and group × leg × condition (F and p values) Variable Group × leg F Pre-obstacle trail limb step length Pre-obstacle trail limb distance Lead limb toe clearance Post-obstacle lead limb distance Lead limb stride length Trail limb toe clearance * statistically significant at p < 0.05 140 1.42 0.07 0.003 0.21 3.91 15.73 p 0.26 0.79 0.96 0.65 0.07 0.003* Group × condition Leg × condition Group × leg × condition F p F p F p 0.56 0.002 3.12 10.1 2.18 1.55 0.47 0.96 0.11 0.01* 0.17 0.24 0.09 0.41 14.31 0.001 0.35 0.25 0.76 0.53 0.004* 0.97 0.56 0.62 2.74 3.44 0.98 0.06 0.04 0.19 0.13 0.09* 0.34 0.80 0.83 0.67 HUMAN MOVEMENT E.S. da Rocha et al., Gait asymmetries during obstacle crossing Values normalized for subjects’ height except for toe clearance N – normal gait DT – dual-task condition * indicates statistically significant asymmetry (p < 0.05) # indicates a difference between the groups (p < 0.05) † indicates differences between normal and dual-task gait (p < 0.05) Figure 2. Kinematic data for lead and trail limbs, where the white bars represent data from the preferred leg (P) and black bars represent data from the non-preferred leg (NP) task condition [t(9) = 3.42; p = 0.008]. For both groups, the values were greater in the preferred leg. In the dualtask condition, the elderly increased the pre-obstacle trail limb distance of the preferred leg [t(9) = –3.174; p = 0.011], although this was not observed in the young adults. The elderly presented asymmetry in the post-obstacle lead limb distance in both normal [t(9) = –4.26; p = 0.002] and dual-task conditions [t(9) = –3.51; p = 0.007]. Moreover, a condition effect was observed for this variable in the elderly group, with lower values in the dual-task condition than during normal gait for both the preferred [t(9) = 2.93; p = 0.017] and non-preferred legs [t(9) = 3.47; p = 0.007]. Increased lead limb toe clearance was observed in the elderly performing the dual-task condition with the non-preferred limb when compared with the young adults [t(9) = –2.803; p = 0.021], but no asymmetry was detected. The elderly in the dual-task condition presented asymmetry in trail limb toe clearance, which was greater with the preferred leg [t(9) = 2.39; p = 0.04]. Despite this asymmetry, during the dual-task condition there were no significant changes in the magnitude of trail limb toe clearance in the elderly during the normal and dual-tasking conditions (Fig. 2). Discussion Dual-task conditions are often observed in daily life, such as when walking while talking to other individuals. When crossing obstacles, the elderly are known to require 141 HUMAN MOVEMENT E.S. da Rocha et al., Gait asymmetries during obstacle crossing a longer period of time for stepping over an obstacle [17]. Previous studies on the elderly have suggested an increased risk of tripping or falling when attention is divided during walking in the presence of expected [18, 19] or unexpected obstacles [1]. However, little attention has been paid to the issue of asymmetry in locomotion. Here, the asymmetry in the kinematics of gait over obstacles during normal and dual-task conditions for young adults and the elderly were studied. In general, our data suggest that gait during obstacle-crossing situations in a dual-task condition elicits asymmetries primarily in the elderly. Additionally, the results on the elderly suggest that the non-preferred leg seems to be more affected in a dual-task condition than the preferred leg. Lower extremity asymmetries may increase the risk of falling in the elderly, as had been suggested in a study about asymmetry in leg extension strength and power in individuals with and without a history of falls [20, 21]. Additionally, lower extremity strength asymmetry was recently correlated with gait asymmetry and variability in the elderly, which was reinforced when they were performing near maximal capability [11]. The findings of our study demonstrate that the obstacle-approaching phase differs between the young and elderly. The elderly presented asymmetry in the trail limb kinematics with effects found for both groups and the dual-task condition. The differences, asymmetries, and effects of a dual-task condition in the studied groups suggest that the elderly may require more compensatory adjustment after crossing an obstacle, since the trail limb presented effects for both groups and the dual-task condition, with asymmetric toe clearance in the dualtask condition. Based on these observations, it can be assumed that the elderly may prefer a more consistent gait pattern by shortening step and stride length [22]. However, this did not result in them producing similar movements for the preferred and non-preferred leg. The asymmetry presented by the elderly during obstacle crossing is consistent with the asymmetric propulsion pattern found in the muscle moments and power patterns of the elderly [23]. In the group of elderly, asymmetry was observed in the toe clearance of the trail limb but not in the lead limb. This suggests that the elderly may place greater attention on the first limb when crossing an obstacle, but feature impaired control of gait symmetry when the trail limb crosses. Asymmetry in foot clearance was observed among the elderly with a high risk of falling [10] and may reflect functional asymmetries that are needed for gait stability [24]. Indeed, most of studies on gait asymmetry in the elderly considered the measure of toe or foot clearance [25]. The influence of the dualtask condition on lead limb toe clearance may suggest that the elderly place more attention on the lead limb as it is the first leg to cross an obstacle, but then pay less attention during the second crossing with the trail 142 limb, which was noted to feature significant asymmetry in the dual-task condition. When considering the foot-ground clearance presented by older adults, a recent study reported asymmetries regardless of whether they performed treadmill and overground walking [25]. In both cases, minimum toe clearance was greater with the non-preferred foot. The authors suggested that the non-preferred limb works primarily in the stabilization of gait [25]. Our data on step and stride kinematics suggest that obstacle crossing may induce significant asymmetries in the elderly. Even considering this study’s small sample size, this could generally indicate that gait performed over obstacles may rely on specific responses depending on which leg is first used by the elderly. The protocol presented here suggests that a bilateral assessment of gait during obstacle crossing requires further attention. One of the limitations of this study was the use of a single camera for recording movement, although it may be useful for clinics and hospitals when addressing elderly mobility without the possibility of using several cameras simultaneously. Conclusions The results suggest that the elderly feature kinematic asymmetries during obstacle crossing especially in a dualtask condition. The group differences, asymmetries, and effects of dual-task gait suggest that the elderly may use additional compensatory adjustment after crossing an obstacle. Acknowledgments This study was funded by the Brazilian National Counsel of Technological and Scientific Development (CNPq) by grant No. 476163/2010-2. The authors would like to thank Dr. Jacques Duysens for his comments in preparing the manuscript. References 1. Hegeman J., Weerdesteyn V., van den Bemt B., Nienhuis B., van Limbeek J., Duysens J., Dual-tasking interferes with obstacle avoidance reactions in healthy seniors. Gait Posture, 2012, 36 (2), 236–240, doi: 10.1016/j.gaitpost.2012.02.024. 2. Galna B., Peters A., Murphy A.T., Morris M.E., Obstacle crossing deficits in older adults: A systematic review. Gait Posture, 2009, 30 (3), 270–275, doi: 10.1016/j.gaitpost. 2009.05.022. 3. Chen H.L., Lu T.W., Wanga T.M., Huang S.C., Biomechanical strategies for successful obstacle crossing with the trailing limb in older adults with medial compartment knee osteoarthritis. J Biomech, 2008, 41 (4), 753–761, doi: 10.1016/j.jbiomech.2007.11.017. 4. Zhang C., Mao D., Riskowski J.L., Song Q., Strategies of stepping over obstacles: The effects of long-term exercise in older adults. Gait Posture, 2011, 34 (2), 191–196, doi: 10.1016/j.gaitpost.2011.04.008. 5. Wang T.M., Yen H.C., Lu T.W., Chen H.L., Chang C.F., Liu Y.H. et al., Bilateral knee osteoarthritis does not affect inter-joint coordination in older adults with gait HUMAN MOVEMENT E.S. da Rocha et al., Gait asymmetries during obstacle crossing deviations during obstacle-crossing. J Biomech, 2009, 42 (14), 2349–2356. doi: 10.1016/j.jbiomech.2009.06.029. 6. Beauchet O., Allali G., Berrut G., Hommet C., Dubost V., Assal F., Gait analysis in demented subjects: Interests and perspectives. Neuropsychiatr Dis Treat, 2008, 4 (1), 155–160. 7. Ijmker T., Lamoth C.J.C., Gait and cognition: The relationship between gait stability and variability with executive function in persons with and without dementia. Gait Posture, 2012, 35 (1), 126–130, doi: 10.1016/j.gaitpost.2011.08.022. 8. Beauchet O., Annweiler C., Dubost V., Allali G., Kressig R.W., Bridenbaugh S. et al., Stops walking when talking: a predictor of falls in older adults? Eur J Neurol, 2009, 16 (7), 786–795, doi: 10.1111/j.1468-1331.2009.02612.x. 9. McFadyen B.J., Hegeman J., Duysens J., Dual task effects for asymmetric stepping on a split-belt treadmill. Gait Posture, 2009, 30 (3), 340–344, doi: 10.1016/j.gaitpost. 2009.06.004. 10. Di Fabio R.P., Kurszewski W.M., Jorgenson E.E., Kunz R.C., Footlift asymmetry during obstacle avoidance in highrisk elderly. J Am Geriatr Soc, 2004, 52 (12), 2088–2093, doi: 10.1111/j.1532-5415.2004.52569.x. 11. Laroche D.P., Cook S.B., Mackala K., Strength asymmetry increases gait Asymmetry and variability in older women. Med Sci Sports Exerc, 2012, 44 (11), 2172–2181, doi: 10.1249/MSS.0b013e31825e1d31. 12. Folstein M.F., Folstein S.E., McHugh P.R., “Mini-mental state”. A practical method for grading the cognitive state of patients for the clinician. J Psychiatr Res, 1975, 12 (3), 189–198, doi: 10.1016/0022-3956(75)90026-6. 13. Yesavage J.A., Brink T.L., Rose T.L., Lum O., Huang V., Adey M. et al., Development and validation of a geriatric depression screening scale: a preliminary report. J Psychiatr Res, 1982, 17 (1), 37–49, doi: 10.1016/0022-3956 (82)90033-4. 14. Lawton M.P., Brody E.M., Assessment of older people: self-maintaining and instrumental activities of daily living. Gerontologist, 1969, 9 (3 Part 1), 179–186, doi: 10. 1093/geront/9.3_Part_1.179. 15. Elias L.J., Bryden M.P., Bulman-Fleming M.B., Footedness is a better predictor than is handedness of emotional lateralization. Neuropsychologia, 1998, 36 (1), 37–43, doi: 10.1016/S0028-3932(97)00107-3. 16. Liu M.W., Hsu W.C., Lu T.W., Chen H.L., Liu H.C., Patients with type II diabetes mellitus display reduced toe-obstacle clearance with altered gait patterns during obstaclecrossing. Gait Posture, 2010, 31, 93–99, doi: 10.1016/j. gaitpost.2009.09.005. 17. Uchiyama M., Demura, S., Sugiura, H. The mobility performance of the elderly before, during and after cross- ing over an obstacle. Hum Mov, 2012, 13 (4), 297–302, doi: 10.2478/v10038-012-0034-1. 18. Muir S.W., Speechley M., Wells J., Borrie M., Gopaul K., Montero-Odasso M., Gait assessment in mild cognitive impairment and Alzheimer’s disease: The effect of dualtask challenges across the cognitive spectrum. Gait Posture, 2012, 35 (1), 96–100, doi: 10.1016/j.gaitpost.2011.08.014. 19. Harley C., Wilkie R.M., Wann J.P., Stepping over obstacles: Attention demands and aging. Gait Posture, 2009, 29 (3), 428–432, doi: 10.1016/j.gaitpost.2008.10.063. 20. Perry M.C., Carville S.F., Smith I.C., Rutherford O.M., Newham D.J., Strength, power output and symmetry of leg muscles: effect of age and history of falling. Eur J Appl Physiol, 2007, 100 (5), 553–561, doi: 10.1007/s00421006-0247-0. 21. Skelton D.A., Kennedy J., Rutherford O.M., Explosive power and asymmetry in leg muscle function in frequent fallers and non-fallers aged over 65. Age Ageing, 2002, 31 (2), 119–125, doi: 10.1093/ageing/31.2.119. 22. Chen H.C ., Ashton-M iller J.A., A lexander N.B., Schultz A.B., Stepping over obstacles: gait patterns of healthy young and old adults. J Gerontol, 1991, 46 (6), M196–203, doi: 10.1093/geronj/46.6.M196. 23. Sadeghi H., Prince F., Zabjek K.F., Labelle H., Simultaneous, bilateral, and three-dimensional gait analysis of elderly people without impairments. Am J Phys Med Rehabil, 2004, 83 (2), 112–123, doi: 10.1097/01.PHM.0000107484. 41639.2C. 24. Nagano H., Begg R.K., Sparrow W.A., Taylor S., Ageing and limb dominance effects on foot-ground clearance during treadmill and overground walking. Clin Biomech (Bristol, Avon), 2011, 26 (9), 962–968, doi: 10.1016/j. clinbiomech.2011.05.013. 25. Barrett R.S., Mills P.M., Begg R.K., A systematic review of the effect of ageing and falls history on minimum foot clearance characteristics during level walking. Gait Posture, 2010, 32 (4), 429–435, doi: 10.1016/j.gaitpost.2010. 07.010. Paper received by the Editors: October 2, 2012 Paper accepted for publication: April 16, 2013 Correspondence address Felipe P. Carpes Federal University of Pampa Laboratory of Neuromechanics BR 472 km 592 Po box 118 - ZIP 97500-970 Uruguaiana, RS, Brazil e-mail: [email protected] 143 HUMAN MOVEMENT 2013, vol. 14 (2), 144– 147 Effects of vertical and horizontal plyometric exercises on running speed doi: 10.2478/humo-2013-0017 Dalwinder Singh 1 *, Sukhwinder Singh 2 1 2 Panjab University, Chandigarh, India University College, Dhilwan, India Abstract Purpose. The aim of the present study was to compare the effects of vertical, horizontal and a combination of both vertical and horizontal plyometric exercises (depth jumping) on running speed. Methods. A purposively selected sample of 80 male students were randomly assigned into either a control group or groups training the vertical depth jump, horizontal depth jump or a combination of both. The experimental groups trained twice weekly for 10 weeks, performing 6 sets of 10 repetitions per session. Drop height was increased from 20 to 40 cm according to the step method. Running speed was measured by a 45.72 m dash test before and after the 10-week period. Results. Analysis of covariance was applied to compare scores. A pair-wise comparison was performed using Scheffe’s post-hoc test at a 0.05 level of confidence. The results showed significant improvements among the three experimental groups as compared with the control group, whereas a comparison between the three experimental groups was found to be insignificant. The percentage of performance increase from pre-test to post-test running speed was 2.23%, 2.96% and 3.57% for the groups training vertical, horizontal and both vertical and horizontal depth jumps, respectively. Conclusions. A combination of both vertical and horizontal depth jumping, with a slightly larger emphasis on horizontal plyometric training, can aid sprinters’ performance. Key words: amortization phase, stretch reflex, vertical depth jump, horizontal depth jump, step progression Introduction The term “plyometrics” first made its appearance in sports methodology literature in V.M. Zaciorskij’s 1966 work “Fiziceskie Kacestva Sportsmena”. Zaciorskij used this term to indicate the greater tension present in a group of muscles when an exercise involved a quick stretching phase followed by an equally quick concentric contraction. In this process, the tension expressed by working muscle (metron) measured externally is found to be higher (plio) than the tension expressed using any other exercise (isometric, isotonic, auxotonic) [1]. An American track and field coach named Fred Wilt offered an explanation of the term in 1975, where, based on its Latin origins, plyometrics was interpreted as “measurable increases”. Plyometrics rapidly became known to coaches and athletes as exercises or drills aimed at linking strength with speed of movement in order to produce more power. Plyometric training became essential to athletes who jumped, lifted, or threw. During the late 1970s and into the 1980s, athletes in other sports also began to see the applicability of this concept in their own movement activities. Throughout the 1980s, coaches in sports such as volleyball, football and weightlifting began to use plyometric exercises and drills to enhance their training programmes. If there was any drawback to this enthusiasm, it lay with the lack of expertise that American * Corresponding author. 144 coaches and athletes had in administering plyometric programmes and a faulty belief that more must be better. Since these early years, however, practitioners have learned through applied research as well as trial and error to establish realistic procedures and expectations [2]. The term “plyometrics” remains to be known as a specific group of exercises that encompass a rapid stretching of a muscle that is undergoing eccentric stress followed by a concentric, rapid contraction of that muscle for the purpose of developing a forceful movement over a short period of time [3]. For example, as an athlete lands on the ground during a plyometric exercise, a stretch occurs in the involved muscle fibres. Proprioceptors within the muscle tissue immediately sense this stretch and send a message to the spinal cord through an afferent or sensory neuron. The spinal cord sends a message immedia tely back to the muscle fibre via an efferent or motor neuron, telling it to contract to keep it from overstretching. This is known as the “stretch reflex” and is one of the body’s built-in protection mechanisms for preventing muscle tissue injuries. Plyometric drills can be used to train the body to emit these sensor signals in a shorter period of time, causing the affected muscle to react ever more quickly [4]. Researchers have focused on using depth jumping as a form of plyometric training [5]. Two types of depth jumping in particular were described by Chu [2]. The first is the vertical depth jump, performed by stepping off a box and landing on both feet all the while trying to anticipate the landing. As soon as contact is made, HUMAN MOVEMENT D. Singh, S. Singh, Vertical and horizontal plyometrics for speed it is necessary to spring up as quickly as possible so as to keep the body from “settling” on the landing, keeping ground contact to a minimum. The second is termed as the horizontal depth jump, also performed by taking a step off a box and landing on both feet. However, upon landing, the participant jumps immediately as far forward as possible, again landing on both feet. The aim of this study was to investigate the influence of both vertical and horizontal depth jump training, as well as a combination of both vertical and horizontal depth jumping, on running speed, by calculating an optimal drop height and applying a depth jumping training programme. Material and methods Purposive sampling was used to select eighty (n = 80) male physical education students aged between 18 to 21 years. All participants were full time students attending classes according to their college curriculum. All were deemed medically fit to undergo the study’s training programme and signed an informed consent form prior to participation. The Joint Research Board of the university approved all procedures for the study. The eighty participants were randomly assigned into three experimental groups and one control group. Group VP (n = 20) performed only the vertical depth jump twice a week, Group HP (n = 20) performed only horizontal depth jumping twice a week, Group CP (n = 20) trained with vertical depth jumping on one day and horizontal depth jumping on another day, while Group CG (n = 20) served as the control group. Those participating in the training sessions attended an instruction session before the first test to ensure proper technique and an understanding of the testing process. A demonstration was also provided by a trained athlete. The participants were tested for proper execution of the vertical depth jump from a drop height of 45 cm (44.3 ± 5.13 cm). To ensure data uniformity, the subjects were always tested in the morning by the same group of examiners. A pilot study was conducted to determine training intensity and load progression. Ten participants were randomly selected from the original sample and performed first a standing vertical jump and then the depth jump from a height of 10, 20, 30, 40, 50 and 60 cm. Mean maximum vertical jump height was measured at 46.25 cm. Mean maximum depth jump height was found to be 48.64 cm taken from a step height of 20 cm, with depth jump performance remaining above the initial vertical jump height up to a step height of 40 cm (Fig. 1). Therefore, a drop height of 20 cm, where depth jump performance was at a maximum and higher than vertical jump performance, was taken to be the initial training intensity [2]. Drop height was then increased across the training sessions according to the step method from a height of 20 cm up to 40 cm (Tab. 1). Figure 1. Mean vertical and depth jump performance in the pilot study Table 1. Progression of drop height during the experiment Week Drop Height (cm) I II III IV V VI VII VIII IX X 20 25 30 25 30 35 30 35 40 35 Each of the experimental groups trained twice a week for 10 weeks at identical intensities and volumes. The training sessions were administered by dividing each group into four smaller subgroups. After a brief warm-up, the group was trained simultaneously on four stations, with the five participants of each subgroup performing in rotation one by one at a station. Each of the participants performed 6 sets of 10 repetitions per session [6]. Fifteen seconds of rest was provided as recovery between repetitions by performing a short walk to a cone placed 11 m in front of the station when training the vertical depth jump, or 12.1 m when training the horizontal depth jump [7, 8]. Rest between sets was completed by a 1.5–2 min slow jog to a cone placed 220 meters from the first cone [9]. After training, the participants engaged in a cool down. The running speed of each participant was measured before and after the 10-week period according to the recommendations by the American Alliance for Health, Physical Education and Recreation [10]. Two lines were marked 45.72 m apart and parallel to each other on an area that included enough room for stopping after crossing the finish line. Two subjects ran at the same time, both starting from a standing position. The commands “Are you ready?” and “Go!” were given. At “Go!” the starter dropped his arm so that the time keepers at the finish line could begin timing. The elapsed time from the starting signal until the runner crossed the finish line was recorded to the nearest hundredth of a second. Analysis of covariance was applied to find a significant difference among the groups. Pre-test scores were used as the covariate and post-test scores, adjusted for covariance, were the dependent measures. When a sig145 HUMAN MOVEMENT D. Singh, S. Singh, Vertical and horizontal plyometrics for speed nificant F-value was found, a pair-wise comparison was performed using Scheffe’s post-hoc test to identify significant differences between groups. The alpha level was set at 0.05. Results Discussion The mean pre-test and post-test running speeds of the three experimental groups and control group are presented in Figure 2. The significant differences among the various groups at an F-value of 113.29 was found to be greater than the tabulated value of 2.73 for degrees of freedom (3, 75) at the 0.05 level of confidence (Tab. 2). Furthermore, Scheffe’s post-hoc test was employed to study the direction and significance of differences between the paired adjusted final means. Significant imgroups VP – vertical depth jump group, HP – horizontal depth jump group, CP – vertical and horizontal depth jump group, CG – control group Figure 2. Pre-test and post-test running speed means (s) of the experimental and control Table 2. Analysis of covariance for the experimental groups and control groups Source of variation Between-group Within-group provements in the three experimental groups as compared to control group were found (Tab. 3). However, the differences for the remaining paired means were found to be insignificant. Mean Sum of Degrees sum of squares of freedom squares 0.578 0.127 3 75 0.1927 0.0017 F-value 113.29* * Significant at the 0.05 level F0.05 (3, 75) = 2.73 Analysis of the data revealed that vertical and horizontal plyometric training, as well a combination of both jumps, is effective in bringing about a significant increase in running speed. Similar findings pertaining to running speed performance have been reported by Gemer [11], Tamrakar and Singh [12] and Polhemus and Osina [13]. Luhtanen and Komi [14] recognized the effects of eccentric-concentric coupling on running speed. They partitioned the total contact time of the feet on the ground as either negative contact time or positive contact time, where, assuming that the initial foot plant is at a position with the lowest centre of gravity, the contact leg’s extensor muscles contract eccentrically and perform negative work. The later portion of contact time consists of concentric contractions with a rise in the centre of gravity, making the work being performed positive [14]. This was further supported by Lundin and Berg [15], who attributed improved efficiency of running at higher speeds to the effects of the stretch reflex and use of elastic energy. In the light of above descriptions by Luhtanen and Komi [14] and Lundin and Berg [15], the findings of the present study are in line with the observations presented by Chu [2], who explained that plyometric depth jumping is an activity that acts to increase the neuromuscular system’s ability to more effectively perform concentric contraction, as the forces encountered in plyometric exercises lead to greater motor unit synchronous activity and earlier recruitment of larger motor units via the myotatic reflex [2]. Furthermore, Miller et al. [16] concluded that six weeks of plyometric training reduced the time spent on the ground when compared with a control group. In another study, six weeks’ plyometric training significantly reduced the rebound time in the depth jump [17]. According to Pettitt [18], plyometric training leads to physiological adaptations such as a reduction Table 3. Significance of differences of paired adjusted final means for the experimental and control groups Means (s) Group VP# Group HP# 6.674 6.674 6.674 6.6113 Group CP# Group CG# 6.5784 6.8009 6.6113 6.6113 6.5784 6.5784 6.8009 6.8009 Difference between means 0.0627 0.0956 0.1269* 0.0329 0.1896* 0.2225* * Significant at 0.05; VP# – vertical depth jump group, HP# – horizontal depth jump group, CP# – vertical and horizontal depth jump group, CG# – control group 146 Scheffe’s critical differences 0.1177 0.1177 0.1177 0.1177 0.1177 0.1177 HUMAN MOVEMENT D. Singh, S. Singh, Vertical and horizontal plyometrics for speed of the amortization phase and greater cross-sectional recruitment and threshold elevation for the inverse stretch reflex. Analyses of the differences between the paired adjusted final means of three experimental groups showed no statistically significant result. However, the percentage of performance increase from pre-test to post-test running speed was 2.23%, 2.96% and 3.57% for the groups training vertical (VP), horizontal (HP) and both vertical and horizontal (CP) depth jumps, respectively. Thus, the results are in favour of the CP group, which Chu [2] had originally posited that training involving a horizontal and vertical component could be the most successful in contributing to an improvement in running performance. This is further supported by Dintiman et al. [19], who evaluated the stride length and stride rate of athletes. These authors recommend drills emphasizing vertical displacement for athletes who present a weakness in stride rate or in the vertical jump and, conversely, drills with a larger horizontal displacement component for athletes who present a larger weakness in stride length or in tests such as the standing long jump. Furthermore, a comparison of groups VP and HP showed a trend in favour of group HP, which is in conformity with results of Mach et al. [20], who believe that stretch-shortening drills performed horizontally can improve the speed component of athletes’ speed-power properties. Conclusions A combination of both vertical and horizontal depth jumping can aid running performance, especially in the case of sprinters in training. However, horizontal plyo metric training in itself was more effective in improving running speed performance than solely vertical plyometric training. Thus, while planning a plyometric training programme for sprinters, coaches and physical education teachers should provide slightly more emphasis on horizontal plyometric training. Acknowledgements We express our gratitude to Bhagoo Majra of the S.K.R. College of Physical Education in Punjab, India for his permission to conduct the study and for providing encouragement throughout its course. We are also thankful to the students who volunteered to participate in this study. References 1. Zanon S., Plyometrics: past and present. New studies in athletics, 1989, 1 (4), 7–17. 2. Chu D.A., Jumping into plyometrics. Human Kinetics, Champaign 1998. 3. Chu D., Plyometrics: The link between strength and speed. NSCA Journal, 1983, 5, 20–21. 4. Freeman W., Freeman E., Plyometrics: complete training for all sports. Championship books, Ames 1984. 5. Zanon S., Plieometry in jumping. Die lehre der leichtathletik, 1974, 16, 1–13. 6. de Villarreal E.S.S., González-Badillo J.J., Izquierdo M., Low and moderate Plyometric training frequency produces greater jumping and sprinting gains compared with high frequency. J Strength Cond Res, 2008, 22 (3), 715–725, doi: 10.1519/JSC.0b013e318163eade. 7. Lima J.C., Marin D.P., Barquilha G., da Silva L.O., Puggina E.F., Pithon-Curi T.C., Hirabara S.M., Acute effects of drop jump potentiation protocol on sprint and countermovement vertical jump performance. Hum Mov, 2011, 12 (4), 324–330, doi: 10.2478/v10038-011-0036-4. 8. Read M.M., Cisar C., The influence of varied rest interval lengths on depth jump performance. J Strength Cond Res, 2001, 15 (3), 279–283. 9. Verkhoshansky Y., Perspectives in the improvement of speed-strength preparation of jumpers. Yessis Review of Soviet Physical Education and Sports, 1969, 4, 28–34. 10. American Alliance for Health, Physical Education and Recreation, Youth Fitness Test Manual. AAHPER Publication, Reston 1976. 11. Gemar J.A., The effects of weight training and Plyometric training on vertical jump, standing long jump and forty-meter sprint. J Phys Educ Sports, 1988, 12 (2), 22–26. 12. Tamrakar A., Singh K., Effects of weight training, plyometric training and their combination on selected motor components. J Sports Sports Sci, 2001, 24 (4), 5–14. 13. Polhemus R., Osina M., The effects of plyometric training with ankle and vest weights on conventional weight training programme for men. Track Field Q Rev, 1984, 80 (4), 59–61. 14. Luhtanen P., Komi P.V., Mechanical factors influencing running speed. In: Asmussen E., Jorgensen K. (eds.), Biomechanics VI. University Park Press, Baltimore 1978, 23–29. 15. Lundin P., Berg W., A review of plyometric training. National Strength and Conditioning Association Journal, 1991, 13 (6), 22–30. 16. Miller M.G., Herniman J.J., Ricard M.D., Cheatham C.C., Michael T.J., The effects of a 6-week plyometric training program on agility. J Sports Sci Med, 2006, 5, 459–465. 17. Makaruk H., Sacewicz T., Effects of plyometric training on maximal power output and jumping ability. Hum Mov, 2010, 11 (1), 17–22, doi: 10.2478/v10038-010-0007-1. 18. Pettitt R., The role of Plyometrics in the scope of a periodized training model. J Perform Enhan, 1999, 1 (1), 11–20. 19. Dintiman G., Ward R., Tellez T., Sports speed (2nd edn.). Human Kinetics, Champaign 1997. 20. Mach G., Tschiene P., McNab T., McWatt B., Lydiard A., Ocean coaches clinic. Auckland, New Zealand, January 4–12, 1979. Paper received by the Editors: July 11, 2012 Paper accepted for publication: April 16, 2013 Corresponding address Dalwinder Singh Department of Physical Education Panjab University Chandigarh, India e-mail: [email protected] 147 HUMAN MOVEMENT 2013, vol. 14 (2), 148– 153 THE EFFECTIVENESS OF DIFFERENT TYPES OF VERBAL FEEDBACK ON LEARNING COMPLEX MOVEMENT TASKS doi: 10.2478/humo-2013-0009 Tomasz Niznikowski *, Jerzy Sadowski, Andrzej Mastalerz Faculty of Physical Education and Sport in Biala Podlaska, Józef Piłsudski University of Physical Education, Warsaw, Poland Abstract Purpose. The purpose of the study was to assess the effectiveness of different types of verbal feedback in the learning of a complex movement task. Methods. Twenty university students took part in a six-week training course learning how to correctly execute the vertical jump. The participants were randomly assigned to one of three groups: Group E&P received verbal feedback on errors made during movement execution and on how to improve, Group P obtained verbal feedback only when they correctly performed the task, and Group E was provided with verbal feedback only when an error was made. Performance was measured on three separate occasions, before the training course (pre-training), one day after (post-training) and seven days after completing the course (retention) by executing the vertical jump in front of three gymnastic judges who scored their performance on a scale of 1 to 10. Jump kinematics were also measured pre-training and post-training by recording landing force and flight time on a force platform. Results. Post-hoc comparison indicated that a significant improvement in performance was observed only in the group receiving verbal feedback on errors (E). Judges’ scores received in post-training were significantly higher than those measured pre-training (10.3 %; p < 0.0003) and further increased to 14.4 % in the retention test (p < 0.0001). Judges’ scores for the groups receiving verbal feedback on errors and correctness (E&P) and only correctness (P) improved insignificantly. Conclusions. Providing too much verbal feedback when learning the vertical jump turned out to be less effective than providing limited verbal feedback only when errors were made. Key words: training sessions, verbal feedback, vertical jump, complex task Introduction One of the most important factors in the motorlearning process is the feedback provided to a learner attempting to acquire a new motor skill. Many researchers have attempted to find the most appropriate methods of providing information through feedback to aid the learning and refinement of motor skills or body position control [1–5]. Supplementary information on how a task was completed, when coming from a source external to the performer, e.g. a teacher or a coach, is known as extrinsic or augmented feedback. There is a bulk of research providing experimental evidence on such factors as the frequency of feedback, organization of feedback, types of augmented feedback, forms of knowledge of result (KR), or knowledge of performance (KP) [6, 7]. Because augmented feedback is such an important part of motor skill learning, teachers and coaches should understand what types of information as well as how often and how precise it should be provided to facilitate the process of learning new skills. Feedback that is too precise is as useless as that which is too vague [8]. Some researchers [9] postulated that the amount and precision of KR are often too overwhelming, with the learner unable to correct a certain response due to the fact that individuals can effectively process only a limited amount * Corresponding author. 148 of information at a time. Hence, it has been argued that coaches should develop the form and content of how augmented feedback would be presented ahead of time. Furthermore, the complexity of a motor task is believed to determine which learning method or feedback strategy would be most successful, where, for example, numerous sources of task-related information are considered to be beneficial for learning complex tasks [10, 11]. As many studies have revealed, learning principles derived from the study of simple skills are not transferable to that of learning more complex skills [12]. Schmidt and Lee [13] claim that further research is required to establish relationships between the level of motor task complexity and forms and types of feedback. Currently there is a lack of data on how different types of feedback affect the effectiveness of completing tasks at varying levels of complexity [2, 11, 14–16]. However, some researchers have highlighted the fact that it may be extremely difficult to establish the influence of different types of content and form of feedback on task performance, due in part to the numerous intricate mechanisms that occur during this process [14, 17]. Others stress the necessity of such research in order to develop guidelines for learning motor tasks at different levels of complexity [11, 18–20]. Therefore, in order to contribute to the literature on the subject, the purpose of this study was to assess the effectiveness of different types of verbal feedback in the learning of a complex movement task. HUMAN MOVEMENT T. Niznikowski, J. Sadowski, A. Mastalerz, The effectiveness of verbal feedback Material and methods Twenty students were recruited and randomly assigned to one of three groups. Each of the groups differed in terms of the feedback they were to receive when executing a motor task. The groups were as follows: group E&P obtained information on the errors they made and on how to correct them (n = 7, height 177 cm ± 5.0 cm, body mass 81.2 kg ± 3.8 kg, age 20.3 ± 1.1 years), group P received feedback only when they correctly executed the task (n = 6, height 177 cm ± 5.0 cm, body mass 81.2 kg ± 3.8 kg, age 20.3 ± 1.3 years), and group E obtained information only on the errors they made (n = 7, height 178 cm ± 4.0 cm, body mass 79.4 kg ± 3.6 kg, age 20.4 ± 1.2 years) (Tab. 1). A six-week experiment was conducted, with 60-min training sessions held three times per week (on Mondays, Wednesdays, and Fridays), with each subject participating in a total of 16 sessions. The subjects learned how to correctly execute the vertical jump by swinging the arms forward and upward, pulling the knees up to the chest while grabbing the shins followed by a half-squat landing with the arms extended sidewards. All of the subjects were unfamiliar with this type of task. The pro- gressive-part method was applied to the training process, i.e., the task was divided into parts. The subjects mastered the preparatory phase during training sessions 1–4; sessions 5–8 were devoted to acquiring the main phase, while sessions 9–12 focused on learning how to perform the final phase. Sessions 13–16 were devoted to performing the entire movement. Each training session involved performing 20 sets of 5 repetitions each of the aspect being taught. After each set the subjects received feedback (knowledge of results). Performance was measured on three separate occasions, before beginning the training course (pre-training), after (post-training) and seven days after completing the course (retention). The assessment tests began with a standard warm-up followed by the participants perform a single execution of the movement task. Three gymnastic judges rated their performance on a scale of 1 to 10 based on the criteria of the International Gymnastics Federation (FIG). Each minor error received a deduction 0–0.3 pts., for a medium error 0.4–0.6 pts. were deducted, while a major error cost the participant 0.7–1 pts. The inter-rater reliability of the experts’ scores was confirmed by the concordance correlation coefficient (= 0.94). Table 1. Examples of feedback: Group E&P – verbal feedback on errors and on how to improve, Group P – verbal feedback only on correct movement execution, and Group E – verbal feedback only on errors (Group E&P) – you performed the jump learning too far forward, jump straight up – you performed the jump leaning too far backwards, jump straight up – you did not perform the jump while simultaneously swinging the arms up, try it again with arms swinging up at the same time – you drew the knees up to your chest too early, pull your knees at the end of the rising phase – you drew your knees up to your chest too late, pull your knees at the end of the rising phase – you did not grab your shins with your hands, hold your shins next time – tucking done too early, do it during the ascending flight phase – tucking done too late, do it during the ascending flight phase – untucking done too early, do it during the beginning of the descending phase – untucking done too late, do it during the beginning of the descending phase – landing without bending the knee and hip joints, do it by cushioning the landing at the knee and hip joints – you did not keep your arms in front of you out to the side, hold your arms out next time (Group P) – good vertical jump while simulta neously swinging the arms up – you drew knees at the right time – hands correctly grabbed the shins – correct body tuck during the rising flight phase – correct body tuck during the beginning of the descending flight phase – correct landing by absorbing impact with the ankles, knees, and hips – direction of the arms to the side and up in front was correct (Group E) – jump was performed leaning too far forward – jump was performed leaning too far backwards – you did not simultaneously swing your arms up – you drew your knees to your chest too early – you drew your knees to your chest too late – hands grabbed the shins too early – hands grabbed the shins too late – tucking done too early – tucking done too late – untucking done too early – untucking done too late – landing done without bending the knee and hip joints – you kept your arms to the side 149 HUMAN MOVEMENT T. Niznikowski, J. Sadowski, A. Mastalerz, The effectiveness of verbal feedback Results ANOVA with repeated measures for the judges’ scores revealed a significant effect of Test Time (F(2,32) = 8.30; p = 0.001). There were no interaction effects of Group (F(2,16) = 2.15; p = 0.809) as well as Group x Time of Measurement (F(4, 32) = 1.91, p = 0.133). Means and standard deviations are presented in Table 2. The rate of how the scores improved is displayed in Figure 2. Fisher’s LSD test (p < 0.05) was performed for posthoc pairwise comparison, indicating that a significant improvement in performance was observed only in the group that received verbal feedback about errors (E). Table 2. Means (± SD) of judges’ scores at pre-training, post-training, and retention for Groups: E&P – verbal feedback on errors and how to improve, P – verbal feedback on correctness, and E – verbal feedback on errors Figure 1. Example of ground reaction vertical force (GRVF) measure with flight time and landing force marked A jumping and landing assessment was performed at pre-training and post-training by quantifying jump performance by flight time and recording vertical ground reaction force (VGRF). The participants performed two maximal height jumps, a countermovement jump (Test A) and a vertical jump by pulling the knees up to the chest (Test B). Kinematic data were measured on a Type 2812A1-3 Force Plate System with BioWare software v. 3.23 (Kistler, Switzerland) at a sampling rate of 400 Hz. Body mass was also measured on the force plate, which was calibrated prior to each measurement. Participants were instructed to begin from a standing position and jump as high as they could. No other specific instructions were provided during the test as to not influence performance. Three jumps were completed for each test, with ample rest provided between each trial. Only the jump attaining the greatest height was selected for analy sis, with landing force and flight time (Fig. 1) evaluated to estimate jumping and landing effectiveness. Statistical significance was assessed with ANOVA. Normality of distribution and homogeneity of variances were tested with the Shapiro-Wilk test. If normal distribution was verified, the studied variables were then analyzed by two-way mixed-factor analysis of variance, Group (3) x Time of Measurement (3) for the judged jumps and Group (3) x Time of Measurement (2) for the force measurements, with the three experimental groups representing a between-subjects factor and the three testing periods representing a within-subjects factor. Statistical significance was set at p < 0.05. Posthoc Fisher’s LSD test was used for pairwise comparison. The results were analyzed using Statistica v. 7.1 software (StatSoft, USA). 150 E&P P E Pre-training Post-training Retention 7.15 ± 0.16 7.19 ± 0.15 6.8 ± 0.16 7.27 ± 0.22 7.47 ± 0.2 7.5 ± 0.22 7.35 ± 0.22 7.5 ± 0.2 7.78 ± 0.22 Figure. 2. Percent increase in judges’ scores at pre-training, post-training, and retention by Groups: E&P – verbal feedback on errors and how to improve, P – verbal feedback on correctness, and E – verbal feedback on errors Scores received in post-training were significantly higher than in pre-training (10.3 %; p < 0.0003) and further increased to 14.4 % in the retention test (p < 0.0001), pointing to an improvement in task performance. Judges’ scores observed in the group with verbal feedback on errors and correctness (E&P) and correctness (P) improved insignificantly. ANOVA on the groups’ jumping performance revealed significant interaction effects of Group x Time of Measurement for landing force (VGRF) in Test A (F(4, 32) = 3.24, p = 0.066). There were no effects of Group (F(2, 16) = 2.0101, p = 0.16642) as well as Time of Measurement (F(1, 16) = 0.00551, p = 0.94174). There were no interaction effects of Group, Time of Measurement, and Group x Time of Measurement for flight time (T) in Tests A and B as well as for landing force in Test B. Means and standard deviations are presented in Table 3. HUMAN MOVEMENT T. Niznikowski, J. Sadowski, A. Mastalerz, The effectiveness of verbal feedback Table. 3. Means (± SD) of flight time (T) and landing force (LF) recorded during Tests A (countermovement jump) and B (vertical jump) across test times (pre-training and post-training) for the groups receiving verbal feedback on errors and how to improve (E&P), verbal feedback only on correctness (P), and verbal feedback on errors (E) Pre-training E&P Post-training E&P Pre-training P Post-training P Pre-training E Post-training E T [s] A B 0.49 ± 0.02 0.54 ± 0.02 0.49 ± 0.02 0.57 ± 0.02 0.49 ± 0.02 0.54 ± 0.02 0.51 ± 0.02 0.57 ± 0.02 0.52 ± 0.02 0.55 ± 0.02 0.52 ± 0.02 0.59 ± 0.02 LF [N/kg] A B 31.4 ± 6.1 28.5 ± 3.9 37.4 ± 5.7 35.9 ± 4.0 26.4 ± 6.4 32.8 ± 4.1 33.7 ± 6.1 31.9 ± 4.2 45.1 ± 5.9 30.8 ± 3.8 33.6 ± 5.6 30.9 ± 3.9 The highest flight time was recorded for the group receiving verbal feedback on errors (E), although the results were very similar among all three groups. Post-hoc comparisons indicated a significant decrease in landing force in Test A only for Group E. Landing force in posttraining was significantly higher than in pre-training (25.5 %; p < 0.06) for the other two groups, although the increase in landing force was statistically insignificant for Group E&P for both Tests A and B in post-training. A decrease in landing force was only observed in Group P for Test B, although this result was statistically insignificant (2.74%, p > 0.05). Discussion The purpose of the study was to assess the effectiveness of different types of verbal feedback in the learning of a complex movement task, finding that the effectiveness of learning the task was different among the groups receiving different feedback. Providing verbal information on what errors were made and what should be improved (E&P) as well as feedback only when the task was correctly performed (P) turned out to be the least effective strategies. Instead, participants from Group E, who received feedback only when they made an error, obtained the best results. This may stem from the fact that too much verbal feedback particularly at the initial stage of learning a complex movement task is not beneficial. Some researchers believe that providing too much feedback is too overwhelming for learners, making them unable to effectively process new information. Moreover, it is believed that providing too much information causes learners to become overdependent on extrinsic sources of information. As a result, the use of intrinsic information becomes more limited, which leads to difficulties in performing a task once the amount of extrinsic information is reduced [4]. In line with the above assumptions, although the subjects from Group E received 22% and 15% less feedback than those from Group E&P and Group P, they exhibited better learning effects. Similar results were obtained by Sadowski et al. [21], who noted that providing feedback both on errors and how to improve performance was not as effective as providing feedback only on the correctness of performing a complex movement task. Conversely, Kernodle et al. [18] claim that when a task is complex and difficult, it is advisable to provide feedback both on errors and on how to improve. Williams and Hodges [20], Tzetzis et al. [10], and Wulf et al. [15] also maintain that the simultaneous employment of prescriptive and descriptive feedback brings about better learning results. It appears that it is still hard to state unequivocally which type of feedback is the most effective in learning complex movement tasks. Our findings, however, are in line with those of Wulf and Shea [12], and Williams and Hodges [20], who found that learning effects depended, inter alia, on types of feedback on knowledge of result (KR) or knowledge of performance (KP). In our opinion, learning effects depend not only on the content of feedback but also on the complexity of the movement skills needed to perform a task. Similar observations were made by Tzetzis et al. [16], Tzetzis and Votsis [19], and Tzetzis et al. [10], who investigated correlations between the correctness of task performance and feedback quality as well as the complexity of a skill. Tzetzis et al. [10] found that in the process of learning the difficult backhand-clear in badminton (a high return stroke on the non-dominant side of the body that carries the shuttlecock deep into the backcourt), the group receiving positive feedback, correction cues, and feedback on errors performed better than the group receiving only correction cues and positive feedback or the group that received only feedback on errors. It ought to be emphasized that Tzetzis et al. [10] conducted their study on badminton players with already some form of experience, whereas our investigation involved students with no prior experience of the task. This may indicate that, in the learning of movement tasks, the learning effect is determined not only by the content of feedback and task complexity but also by athletes’ experience. Therefore, the findings of the above-mentioned researcher are not generalizable to athletes other than badminton players. Similarly, our findings refer to the learning of movement tasks that were new and unfamiliar and this may account for the fact that different types of feedback were found to be more effective than others. The training method employed in our study may also account for the differences between our results 151 HUMAN MOVEMENT T. Niznikowski, J. Sadowski, A. Mastalerz, The effectiveness of verbal feedback and the findings of the aforementioned researchers. The progressive-part method was used, where task learning is divided into consecutive parts. This allows for a relatively complex task to be simplified and, in the present study, did not require the use of extremely extensive or very precise feedback. Winstein and Schmidt [7] proved that too much feedback was no more effective than little feedback, while Janelle et al. [22] showed that, in learning an overhead throw, only 11% of total feedback provided was utilized by learners. Guadagnoli et al. [23] stated that longer summaries are better in the learning of simple movement tasks, while shorter summaries are more appropriate in complex tasks. Magill and Schoen felder-Zohdi [24] claimed that multiple sources of taskrelated information are redundant for simple tasks as single sources already provide enough adequate information for the development of cognitive representations and overt performance. In turn, Laguna [11] proved that during the observational learning process the performance of a complex task benefited from a combination of task-related information (model demonstration and knowledge of performance). However, it should be noted that the task adopted in Laguna’s study used arm movement only, while the present study applied a task using the whole body. Also of interest was the fact that Group E finished their jumps in a better landing position, with landing force generated by Group E being lower than in Groups P and E&P. Other researchers observed a decrease in landing force after physical [25, 26] and technical training [27] as well as after being provided with specific instructions. Prapavessis and McNair [28] noted a decrease in landing force (19%) immediately upon providing technical guidelines regarding the kinematics of the lower limbs. These researchers drew similar conclusions when applying imagery-based feedback. In other studies, providing augmented feedback during landings decreased landing force by 13% to 19% already after one session [29, 30]. Our results confirmed that applying verbal feedback on errors not only determines better learning effects than verbal feedback on task error and improvement cues and only on execution correctness, but that it may help in the prevention of injuries by decreasing landing force. Therefore, the results of such verbal feedback may aid in developing appropriate guidelines and principles when learning complex motor skills. One of the limitations of this study that need attention is the fact that the participants demonstrated similar levels of general physical fitness and development and did not reveal any significant differences regarding maximal vertical jump performance. As a result, the findings should not be directly compared to athletes for example, as these individuals feature high levels of physical fitness and motor skill development. Moreover, the force-velocity potential of athletes is much higher than in less active people. To further clarify the 152 most appropriate methods in learning complex tasks, future investigations should be carried out on subjects having different motor competences and testing carried out with the use of various motor tasks and types of feedback. Conclusions The learning effects of new complex movement tasks depend on the content of providing feedback on task performance (KP). Providing too much verbal feedback when learning the vertical jump turned out to be less efficient than limited verbal feedback focused only on the errors being made when performing the task. The learning effects depend on the type of feedback, its amount and the content of information as well as the complexity of the task. The progressive-part method is recommended in the motor learning of new complex tasks, providing short cues on what errors are made. Further research is needed to determine the principles behind learning complex motor skills. It is advisable to carry out studies on complex motor tasks with varying degrees of freedom. The complexity of the task should be estimated using a clear task-characteristic scale to avoid ambiguous results. References 1. Adams J.A., Historical review and appraisal of research on the learning, retention, and transfer of human motor skills. Psychol Bull, 1987, 101, 41–74, doi: 10.1037/00332909.101.1.41. 2. Salmoni A.W., Schmidt R.A., Walter C.B., Knowledge of results and motor learning: a review and critical reappraisal. Psychol Bull, 1984, 95, 355–386, doi: 10.1037/00332909.95.3.355. 3. Swinnen, S.P., Information feedback for motor skill learning: A review. In: Zelaznik H.N. (ed.), Advances in motor learning and control. Human Kinetics, Champaign 1996, 37–66. 4. Wulf G., Shea C.H., Understanding the role of augmented feedback: The good, the bad and the ugly. In: Williams A.M., Hodges N.J. (eds.), Skill acquisition in sport: Research theory and practice. Routledge, London 2004, 121–144. 5. Zemková E., Hamar D., The effect of task-oriented sensorimotor exercise on visual feedback control of body position and body balance. Hum Mov, 2010, 11 (2), 119–123, doi: 10.2478/v100038-010-0013-3. 6. Schmidt R.A., Lee T.D., Motor Control and Learning. A Behavioral Emphasis. Human Kinetics, Champaign 1999. 7. Winstein C.J., Schmidt R.A., Reduced frequency of knowledge of results enhances motor skill learning. J Exp Psychol Learn Mem Cognit, 1990, 16, 677–691, doi: 10.1037/02787393.16.4.677. 8. Wright D.L., Smith-Munyon L., Sidaway B., How close is too close for precise knowledge of results? Res Q Exerc Sport, 1997, 68 (2), 172–176 9. Lee T.D., Carnahan H., When to provide knowledge of results during motor learning: Scheduling effects. Hum Perform,1990,3,87–105,doi:0.1207/s15327043hup0302_2. HUMAN MOVEMENT T. Niznikowski, J. Sadowski, A. Mastalerz, The effectiveness of verbal feedback 10. Tzetzis G., Votsis E., Kourtessis T., The effect of different corrective feedback methods on the outcome and self-confidence of young athletes. J Sports Sci Med, 2008, 7 (3), 371–378. 11. Laguna P., Task complexity and sources of task-related information during the observational learning process. J Sports Sci, 2008, 26, 1097–1113, doi: 10.1080/026404 10801956569. 12. Wulf G., Shea C.H., Principles derived from study of simple skills do not generalize to complex skill learning. Psychonomic Bull Rev, 2002, 9, 185–211, doi: 10.3758/ BF03196276. 13. Schmidt R.A., Lee T.D., Motor Control and Learning: A Behavioural Emphasis. 3rd edition. Human Kinetics, Champaign 1998. 14. Franks I.M., The use of feedback by coaches and players. In: Reilly T., Bangsbo J., Hughes M. (eds.), Science and football III. E & FN Spon, London 1997, 267–278. 15. Wulf G., Shea C.H., Matschiner S., Frequent feedback enhances complex motor skill learning. J Mot Behav, 1998, 30 (2), 180–192, doi: 10.1080/00222899809601335. 16. Tzetzis G., Kioumourtzoglou E., Laios A., Stergiou N., The effect of different feedback models on acquisition and retention of technique in basketball. J Hum Mov Stud, 1999, 37, 163–181. 17. Kernodle M.W., Carlton L.G., Information feedback and the learning of multiple-degree-of-freedom activities. J Mot Behav, 1992, 24 (2),187–196,doi:10.1080/00222895.1992. 9941614. 18. Kernodle M.W., Johnson R., Arnold D.R., Verbal instruction for correcting errors versus such instructions plus videotape replay on learning the overhead throw. Percept Mot Skills, 2001, 92, 1039–1051, doi: 10.2466/ pms.2001.92.3c.1039. 19. Tzetzis G., Votsis E., Three feedback methods in acquisition and retention of badminton skills. Percept Mot Skills, 2006, 102, 275–284, doi: 10.2466/pms.102.1.275-284. 20. Williams A.M., Hodges J.N., Practice, instruction and skill acquisition in soccer: Challenging tradition. J Sports Sci, 2005, 23 (6), 637–650, doi: 10.1080/026404104000 21328. 21. Sadowski J., Mastalerz A., Niźnikowski T., Wiśniowski W., Biegajło M., Kulik M., The effects of different types of verbal feedback on learning a complex movement task. Pol J Sport Tourism, 2011, 18, 4, 308–310, doi: 10.2478/ v10197-011-0026-2. 22. Janelle C.M., Barba D.A., Frehlich S.G., Tennant L.K., Cauraugh J.H., Maximizing performance feedback effectiveness through videotape replay and a self-controlled learning environment. Res Q Exerc Sport, 1997, 68 (4), 269–279. 23. Guadagnoli M.A., Dornier L.A., Tandy R., Optimal length for summary of results: the influence of task related experience and complexity. Res Q Exerc Sport, 1996, 65, 250–257. 24. Magill R.A., Schoenfelder-Zohdi B., A visual model and knowledge of performance as sources of information for learning a rhythmic gymnastic skill. Int J Sport Psychol, 1996, 27, 7–22. 25. Hewett T.E., Stroupe A.L., Nance T.A., Noyes F.R., Plyometric training in female athletes. Decreased impact forces and increased hamstring torques. Am J Sports Med, 1996, 24, 765–773, doi: 10.1177/036354659602400611. 26. Irmischer B.S., Harris C., Pfeiffer R.P., DeBeliso M.A., Adams K.J., Shea K.G., Effects of a knee ligament injury prevention exercise program on impact forces in women. J Strength Cond Res, 2004, 18 (4), 703–707. 27. Dufek J.S, Bates B.T., The evaluation and prediction of impact forces during landings. Med Sci Sports Exerc, 1990, 22, 370–377 28. Prapavessis H., McNair P.J., Effects of instruction in jumping technique and experience jumping on ground reaction forces. J Orthop Sports Phys Ther, 1999, 29, 352–356. 29. McNair P.J., Prapavessis H., Callender K., Decreasing landing forces: Effect of instruction. Br J Sports Med, 2000, 34, 293–296, doi:10.1136/bjsm.34.4.293. 30. Onate J.A., Guskiewicz K.M., Sullivan R.J., Augmented feedback reduces jump landing forces. J Orthop Sports Phys Ther, 2001, 31, 511–517. Paper received by the Editor: August 16, 2012 Paper accepted for publication: February 19, 2013 Correspondence address Tomasz Niźnikowski Wydział Wychowania Fizycznego i Sportu w Białej Podlaskiej ul. Akademicka 2 21-500 Biała Podlaska, Poland e-mail: [email protected] 153 HUMAN MOVEMENT 2013, vol. 14 (2), 154 – 160 DIFFERENCES IN THE DIRECTION OF EFFORT ADAPTATION BETWEEN MOUNTAIN BIKERS AND ROAD CYCLISTS doi: 10.2478/humo-2013-0018 Marek Zatoń, Dariusz Dąbrowski * University School of Physical Education, Wrocław, Poland Abstract Purpose. Different forms of cycling require the use of different abilities and skills. The aim of this paper was to attempt to identify differences in the directions and dynamics of the body’s adaption to training in road (ROAD) and mountain (MTB) cyclists. Methods. Research was performed on a group of competitive road (n = 25) and mountain (n = 25) cyclists, mean age 16.96 ± 0.78 years presenting maximal oxygen uptake values of 4.45 ± 0.47 L/min –1. Body composition and physiological and biochemical parameters at rest, during exercise, and during restitution (cool down) were determined. Exercise was performed on a cycle ergometer in the form of a progressive load test. Analysis of the results included cluster analysis and basic statistical methods. Results. Cluster analysis indicated that the amount of work performed during the progressive load test was a universal indicator of physical fitness. The level of base excess (BE) in the 3rd min of restitution had a large influence on the remaining parameters in both groups. Training adaptation in MTB were manifested through increased values of maximum heart rate, blood oxygen saturation, oxygen partial pressure, and lactate and BE levels in the blood, as well as a reduction in blood pH and body mass. Conversely, in ROAD, adaptation to effort was evidenced by increased maximum values of oxygen uptake, minute ventilation, cardiac output and the rate of carbon dioxide elimination as well as an increase in hematocrit count and lean body mass. Conclusions. Adaptation to training by road cyclists is primarily evident in the development of aerobic capacity. Mountain biking induces adaptive changes in the development of anaerobic capacity by increasing the buffer capacity of the blood and muscles, as well as the development of the oxygen transportation system. Key words: road cycling, mountain biking (MTB), effort adaptation, physical ability Introduction Road cycling competitions are commonly held as single or multi-stage races. Examples of the latter include the Tour de France, which lasts 21 days (~100 hours of exercise) and is performed over a distance of over 3500 km [1]. Road cycling competition demands prolonged effort while forcing competitors to perform at high intensity levels – upwards of 90% of maximum oxygen uptake ( O2max) – well above the anaerobic threshold [1]. This finds road cyclists to be characterised by impressive aerobic capacity, reaching maximum aerobic power levels of 370–570 W, maximal oxygen uptake of 4.4–6.4 L min–1 and aerobic power at the onset of blood lactate accumulation (OBLA) at 300–500 W [2]. As a result, training in road cycling is based mainly on the development of power and aerobic capacity. In order to develop oxygen capacity, the continuous training is commonly used. It employs exercise performed at average intensity ( 60% O2max) for long duration (up to 6 h). Although a road race is mostly performed at constant speed, cyclists often perform 20–70 accele rations during a race at levels above maximum aerobic power [3] whose energy cost is covered via the glyco- * Corresponding author. 154 lytic and phosphogenic pathways. Hence, road cycling training also integrates interval and variable training to further improve aerobic capacity and glycolytic capacity as well as develop anaerobic performance. Mountain bike races are usually performed on natural terrain and rely on overcoming obstacles [4]. This form of cycling competition is performed at high intensity for the majority of a race, some of which last up to two hours. Impellizzeri et al. [5] analysed the work intensity during a race, finding mean heart rate (HR) values of 171 beats min–1 ( 90% HRmax). Frequent uphill runs and accelerations also require high anaerobic fitness, with the glycolytic and phosphogenic pathways used to meet the required energy demand, causing significant concentrations of lactate in the blood (10–11 mmol L –1 during the first 45 minutes of a race) [6]. This makes the buffer capacity of muscle and blood an important determinant in mountain biking performance. Furthermore, mountain bikers are also characterised by high levels of aerobic capacity, with O2max values of 72.1 ± 7.4 mL kg–1 min–1 [7] and aerobic power at OBLA at 366–417 W [8]. However, mountain biking training is much more diverse than that in road cycling, where repetitive training, among others, is used to develop the ability to perform in conditions of alternating phosphogenic and glycolytic pathway use [4]. However, in order to develop glycolytic power and capacity, variable and interval training is also used (as in road cycling). HUMAN MOVEMENT M. Zatoń, D. Dąbrowski, Adaptation differences in cyclists In order to better understand the differences between road and mountain cyclists’ conditioning, the aim of the present study was to determine the directions and dynamics of adaptation to training by analysing differences in body composition and physiological and biochemical parameters at rest, during exercise (progressive load test) and during restitution (cool down). Material and methods The study involved fifty men (N = 50) engaged in road (n = 25) and mountain cycling (n = 25) with 2–5 years of competitive riding experience (championship winners and national team members in their respective categories). The age of participants was between 16–18 years (mean age 16.96 ± 0.78 years). Mean body mass was 68.21 ± 6.71 kg, mean body height 178.44 ± 6.41 cm. Later testing found the participants to present maximum oxygen uptake values of 4.45 ± 0.47 L min–1, or 65.88 ± 6.56 mL kg-1 min-1 relative to body mass, indicating the high physical fitness of the participants. The study was approved by the Human Research Ethics Committee at the University of Physical Education in Wrocław, Poland. The participants (or guardian, in the case of minors) signed an informed consent form which outlined the study’s aims and procedure. The subjects were asked to refrain from heavy exercise 24 hours before measurement taking as well as to not eat earlier than 3–4 hours before the actual test. At rest, the participants were measured for body mass (m) by a WPT-200 (Radwag, Poland) medical scale, body height (h) with an anthropometer (GPM, Switzerland) and resting blood pressure (RRsp); blood pressure over 150/90 mmHg resulted in exclusion from further participation in the study. Body composition was assessed by a 6100/XL analyser (Futrex, England), measuring body water (Water%) and fat percentage (Fat%), body fat (Fatkg) and fat free body mass (FFMkg) expressed in kilograms, and body water content expressed in litres (WaterL). Acid-base balance was measured by collecting 80 µl of arterial blood from the fingertip into heparin tubes and immediately examined in a blood gas analyser (model 248, Bayer, USA), determining -log [H+] (pHsp), partial oxygen pressure (pO2sp), base excess (BEsp) and blood oxygen saturation (O2SATsp). Peripheral blood morphology was determined by drawing capillary blood into EDTA tubes and stirring the sample for 2 min. The samples were then entered into an ABX Micros 16 OT (Horiba, USA) haematological analyser for hematocrit (HCTsp) count. A hematocrit count over 50% disqualified a participant from the study. In addition, blood lactate (LAsp) levels were determined by taking 10 µl samples of capillary blood from the fingertip with Dr. Lange LKM 140 test vials (Hach-Lange, Germany) and analysed on a LP 400 spectrophotometer (Hach-Lange, Germany). An exercise test with progressive load was then administered to the participants on an Excalibur Sport cycle ergometer (Lode, Netherlands). The ergometer was calibrated before each test as well as individually adjusted for each participant. The test began with a load of 50 W, increased by 50 W every 3 min. The subjects were instructed to maintain a cadence of no less than 60 rpm. The test was performed until exhaustion or when an increase in load did not result in increased oxygen consumption, after which the participants continued to pedal with no load for 5 min as restitution (cool down). The cycle ergometer was connected to a computer that recorded power output, heart rate, time and speed allowing the total work (Wz) done during the test to be calculated. Heart rate (HR) was measured with a S810 heart rate monitor (Polar, Finland). Respiratory variables were assessed with a Quark metabolic cart (Cosmed, Italy). Measurement of exhaled air began 2 min before the start of the progressive load test and continued for 5 min after it was completed. The metabolic cart was calibrated with atmospheric air and reference gases before each trial. Variables that were recorded included: maximal oxygen uptake ( O2max) and maximum oxygen uptake relative to body mass ( O2max kg-1), maximum rate of carbon dioxide elimination ( CO2max), maximum oxygen content (FeO2max) and carbon dioxide (FeCO2max) in exhaled air, maximum ventilation per minute ( Emax), maximum respiratory rate (RQmax) and maximum cardiac output (Qmax). The recorded values were averaged over 30-s periods and cardiac output was then estimated [9]. At the 3rd min of restitution, systolic (RRs3min) and diastolic (RRr3min) blood pressure was measured in addition to the abovementioned parameters of acid-base balance and blood morphology (a suffix of 3min denotes that they were measured during restitution). In total, 26 physiological parameters and five somatic variables were analysed. Basic statistics of the parameters, including arithmetic means, standard deviations and minimum and maximum values, were calculated. The Student’s t test for independent groups was used to calculate the significance of differences between the mean values of the parameters of the road and mountain cyclists. An additional step included cluster analysis in order to classify the tested parameters and better indicate the differences between the two groups. This method groups a set of variables into subsets (clusters), where parameters located in one cluster are more closely related, in a certain sense, to each other than to those in other clusters or located further away. The clusters are plotted on a dendogram, creating a hierarchy of clusters that merge with each other at certain distances. The larger the Euclidean distance (abscissa) of a cluster or individual parameter, the greater the influence the pa155 HUMAN MOVEMENT M. Zatoń, D. Dąbrowski, Adaptation differences in cyclists The road cyclists were characterised by higher values of all the analysed physiological parameters than the mountain bikers except for O2max kg–1. However, most of the differences were not statistically significant except for O2max, Wz, Emax, CO2max, and Qmax (Tab. 1). Biochemical parameters were found to be very similar in both groups, although there was a slight trend of exhibiting higher values was observed among the mountain bikers. However, most differences were also found to be statistically insignificant. Significant differences between the groups were found only among pH3min, BE3min and LA3min (Tab. 2). Analysis of the somatic parameters found mountain bikers characterised by lower mass and body height and, consequently, less lean body mass and body fat as well as lower total water content. Significant differences were recorded for FFMkg and Fatkg as well as WaterL (Tab. 3). Cluster analysis of the two groups’ physiological and somatic characteristics found that three parameters in the mountain bike cyclist group (MTB) and four in the road cyclist group (ROAD) deserved attention (Figs. 1 and 2). However, in both groups, the last or one of the last clusters containing all the other parameters was the amount of work done in the progressive load test (Wz). Among mountain bikers, maximum heart rate was found to be at a greater Euclidean distance than in road cyclists. The obvious relationship between maximum heart rate (HRmax), maximum lung ventilation ( Emax) and systolic blood pressure (RRs3min) in both groups bound these parameters into a single cluster. However, less clear is the relationship among diastolic blood pressure (RRr3min) and two other clusters it is connected with containing additional biochemical, physiological and constitutional parameters. O2max, expressed both in relative and absolute terms, had no decisive influence on the other parameters (small Euclidean distance). However, in MTB, maximal oxygen uptake relative to body mass ( O2max kg–1) is farther on the abscissa when compared with road cyclists. Furthermore, BE3min was clustered in both groups, underpinning the importance of this parameter. Figure 2. Cluster analysis of the measured variables in the group of road cyclists (ROAD); dendogram depicting the weighted connections by their Euclidean distances Figure 1. Cluster analysis of the measured variables in the group of mountain bike cyclists (MTB); dendogram depicting the weighted connections by their Euclidean distances rameter or parameters have on the others. All statistical calculations were performed using Statistica v. 10.0 software (Statsoft, USA). Results 156 HUMAN MOVEMENT M. Zatoń, D. Dąbrowski, Adaptation differences in cyclists Table 1. The significance of differences among the analysed physiological parameters of mountain bike (MTB) and road (ROAD) cyclists Parameter MTB Wz [kJ] O2max [L min–1] O2max kg–1 [mL kg–1 min–1] Emax [L min–1] CO2max [L min–1] HRmax [bpm min–1] Qmax [L min–1] RQmax FeO2max [%] FeCO2max [%] RRssp [mmHg] RRrsp [mmHg] RRs3min [mmHg] RRr3min [mmHg] *p 0.05, ** p 249.92 ± 50.39 4.26 ± 0.49 66.03 ± 7.53 154.32 ± 18.44 4.73 ± 0.52 194.24 ± 9.29 26.5 ± 3.12 1.64 ± 0.16 18.3 ± 0.71 5.38 ± 0.48 125.8 ± 13.05 77.0 ± 9.35 147.4 ± 18.04 70.8 ± 14.41 ROAD 354.88 ± 25.1 4.64 ± 0.38 65.73 ± 5.58 181.32 ± 16.32 5.45 ± 0.44 196.8 ± 7.04 28.9 ± 2.05 1.66 ± 0.13 18.44 ± 0.44 5.49 ± 0.49 132.6 ± 11.38 81.0 ± 7.64 154.4 ± 15.02 68.0 ± 13.23 t –9.32** –3.10* 0.16 –5.48** –5.28** –1.10 –3.21* –0.61 –0.83 –0.78 –1.96 –1.66 –1.49 0.72 0.001 Table 2. The significance of differences among acid-base balance, lactate concentration and hematocrit count of mountain bike (MTB) and road (ROAD) cyclists Parameter pHsp pH3min pO2sp [mmHg] pO23min [mmHg] O2SATsp [%] O2SAT3min [%] BEsp [mmol L –1] BE3min [mmol L –1] HCTsp [%] HCT3min [%] LAsp [mmol L –1] LA3min [mmol L –1] *p 0.05, ** p MTB ROAD t 7.41 ± 0.02 7.2 ± 0.05 70.02 ± 5.42 95.67 ± 4.27 94.0 ± 1.35 95.78 ± 0.72 –0.04 ± 1.28 –14.4 ± 2.39 46.05 ± 2.52 48.57 ± 2.67 0.63 ± 0.29 12.09 ± 2.36 7.41 ± 0.02 7.16 ± 0.04 70.05 ± 5.55 95.52 ± 4.85 93.97 ± 1.52 95.38 ± 0.75 0.37 ± 1.53 –16.41 ± 1.76 45.92 ± 1.83 48.51 ± 2.27 0.75 ± 0.3 13.5 ± 1.43 0.10 3.00* –0.02 0.11 0.06 1.92 –1.03 3.38* 0.21 0.09 –1.43 –2.56* 0.001 Table 3. The significance of differences among the somatic variables of mountain bike (MTB) and road (ROAD) cyclists Parameter m [kg] h [cm] Fat% [%] Fatkg [kg] FFMkg [kg] WaterL [L] Water% [%] *p 0.05, ** p MTB ROAD 64.84 ± 5.79 175.6 ± 6.1 8.66 ± 2.14 5.67 ± 1.71 59.16 ± 4.68 43.43 ± 3.46 67.03 ± 1.48 71.58 ± 5.89 181.28 ± 5.5 9.41 ± 2.66 6.86 ± 2.33 65.15 ± 4.26 47.86 ± 3.18 66.53 ± 1.78 t –4.08** –3.47* –1.09 –2.06* –4.74** –4.71** 1.07 0.001 In the ROAD group, HCT, Water% and Qmax were found to have a significant impact on the other parameters (large Euclidean distance). In MTB, cluster analysis indicated that blood oxygen saturation (O2SATsp) and its partial pressure in the 3rd minute of restitution (pO23min) have a significant impact on the other parameters. Discussion Cluster analysis found that the amount of work done during the progressive load test was the last or one of the last clusters containing all the other parameters. This indicates that the work performed during an ergo157 HUMAN MOVEMENT M. Zatoń, D. Dąbrowski, Adaptation differences in cyclists metric test can be used as a universal measure of exercise capacity and a key indicator of performance in mountain biking and road cycling. This can also make it a worthwhile tool in objectively assessing training by measuring improved work efficiency, understood as a reduction in energy cost and physiological work (evidenced by a decrease in submaximal values of O2, HR, E and postexercise lactate concentration), as performance in cycling is largely determined by the cost-effectiveness of work performed at a submaximal intensity [10–11]. Another parameter that was found to play an important role in mountain biking was maximum heart rate, as evidenced by its greater influence on other variables than in the road group. Its increase is evident of adaptation to anaerobic effort, which is especially dominate in cross-country racing [5]. Road cyclists, on the other hand, feature lower maximum heart rate values, primarily through the use of long-duration training, stimulating the parasympathetic branch of the autonomic nervous system [12]. Additional training effects in both road and MTB cyclists were observed during the exercise test, where increased oxygen demand and an increased rate of carbon dioxide elimination produced during the oxidation of energy substrates were found to provoke increased minute ventilation, heart rate (via decreased parasympathetic nervous system activity and increased sympathetic activity) and systolic blood pressure [13], as was evidenced by the linking of these parameters into a single cluster in both groups. In both research groups, diastolic blood pressure decreased relative to resting values (6.2 mmHg in the MTB group and 13 mmHg in the road group). Although diastolic blood pressure during exercise may show a slight increase, no change or even a decrease, Cornelissen and Fagard [14], after a meta-analysis of the available literature, indicated that endurance training reduces average resting blood pressure. Therefore, the post-workout reduction in diastolic blood pressure found in the present study is believed to be largely the effect of cycling training. Furthermore, diastolic blood pressure was found to combine two clusters of various biochemical, physiological and constitutional variables into one. In the group of MTB riders, diastolic blood pressure (both at rest and at the 3rd minute of restitution) was combined with HCTsp, HCT3min, WaterL (one group of variables) and pO2sp, Water%, FFMkg and O2max kg–1 (the second group of variables). The cause of these parameters being clustered together may stem from the fact that water content and blood cell count are known to affect blood pressure through changes in the quantity of plasma and blood viscosity [15]. The MTB cyclists had less body mass and were shorter than road cyclists. They also had featured significantly less lean body mass (MTB: 59.16 ± 4.68 kg versus ROAD: 65.15 ± 4.26 kg, p 0.05) and fatty tissue (MTB: 5.67 ± 1.71 kg versus ROAD: 6.86 ± 2.33 kg, 158 p 0.001) and less total body water content (MTB: 43.43 ± 3.46 L versus ROAD: 47.86 ± 3.18 L, p 0.001). These results are in line with those by other authors such as Penteado et al. [16]. Furthermore, Lee et al. [17] also confirmed mountain bikers are characterised by lower body mass (65.3 ± 6.5 kg, p = 0.01) and fatty tissue (sum of seven skin-folds: 33.9 ± 5.7 mm, p = 0.01) than road cyclists (74.7 ± 3.8 kg and 44.5 ± 10.8 mm, p = 0.01, respectively). Furthermore, Lucía et al. [1] confirmed that competitors specializing in individual time trials on flat terrain are generally taller and heavier than those who specialize in mountain riding. However, they indicated no statistically significant differences in the percentage of body fat in MTB or road cyclists. These differences in the somatic features of cyclists specializing in different types of riding can be explained by the specificity of the sport and the body’s adaptation to training. Success in road cycling is known to be determined mainly by aerobic fitness and the ability to generate and maintain high performance throughout an entire race [2]. Training programmes designed to develop maximum power during cycling result in increased muscle mass, although the development of aerobic metabolism favours a shift toward oxidation of free fatty acids [4] and can cause an increase in muscle triglyceride levels [18]. In contrast, performance in mountain biking requires both strong aerobic and anaerobic fitness, as frequent uphill biking and accelerations rely on energy from the glycolytic and phosphogenic pathways and can lead to significant concentrations of lactate in the blood [6]. As a result, repetition, interval and variable training methods are used by this group in order to maximize aerobic and anaerobic abilities. These forms of training lead to further reductions in body mass, which can also contribute to a reduction of aerodynamic drag and rolling resistance, thus having a major impact on competitive success [19–20]. Other parameters of interest in the MTB group were blood oxygen saturation (both at rest and during restitution) and partial oxygen pressure in the 3rd min of restitution, which were both grouped over a large Euclidean distance. Mean blood oxygen saturation in the 3rd minute of restitution and partial oxygen pressure in the blood were higher in the MTB group (95.78% and 95.67 mmHg, respectively) than in the group of road cyclists (95.38% and 95.52 mmHg, respectively). This may have come about due to increased oxygen saturation and energy without significant increases in haemoglobin concentration and red blood cell count (possibly with changes in erythrocytic indices, although this parameter was not tested). This notion was confirmed by Mørkeber et al. [21], who demonstrated that haemoglobin concentration (Hb) and hematocrit count (HCT) decrease under the influence of aerobic training. They found that, during the off-season, Hb and HCT in elite cyclists were 15 g dL–1 and 43.2%, respectively, while during the competitive season they fell to 14.1 g dL –1 (Hb) and 40.9% (HCT). HUMAN MOVEMENT M. Zatoń, D. Dąbrowski, Adaptation differences in cyclists This was attributed to an increase in plasma, where, during exercise, blood volume decreases due to a loss of water as a result of thermoregulation function, and to maintain blood oxygen capacity by reducing glycogen levels. A reduction of plasma volume during exercise has also been linked to intercellular and extracellular fluid shifts [4, 15]. The importance of developing aerobic capacity among road cyclists was seen by the large Euclidean distances of maximum cardiac output, hematocrit count and total body water content, indicating a number of cardiovascular adaptations in this group. The first of these being, namely, an increase in blood density combined with an increase in the amount of the morphological elements of the blood. This factor is believed to contribute to achieving high performance in endurance sports [15]. Secondly, endurance efforts cause an increase in stroke volume and, consequently, an increase in cardiac output, which together with the morphological changes in the blood, further improve aerobic capacity [1, 2, 22]. It is interesting that O2max, expressed in both relative and absolute terms, was not influenced as strongly by the other parameters (based on the small Euclidean distance), even though it is traditionally considered to be one of the most important determinants of cycling performance. This may be explained by the fact that while maximal oxygen uptake efficiency improves the supply of oxygen to the mitochondria, it does not address the efficiency of cellular metabolism [8]. This indicates that this is just one of many parameters that can be used for evaluating performance in cycling and may in fact better serve in the selection of athletes who already are successfully competitive by predicting their development, and not by strictly assessing the effectiveness of a training programme [4]. Also worthy of attention is the use of absolute or relative O2max values when selecting cyclists to perform in various cycling competitions. Researchers have noted that O2max relative to body mass is more useful in assessing the fitness of MTB cyclists [6, 11, 23]. In the present study, average absolute maximum oxygen uptake was higher among road cyclists than mountain bikers (4.64 ± 0.38 L min–1 versus 4.26 ± 0.49 L min–1, respectively). However, after calculating oxygen consumption relative to body mass, the opposite was found, with MTB cyclists showing higher values (MTB: 66.03 ± 7.53 mL kg–1 min–1 versus ROAD: 65.73 ± 5.58 mL kg–1 min–1). Tolerance to acidity is the ability of muscles to perform contractions with high concentrations of lactate and hydrogen ions [10]. In mountain biking, this parameter is of particular interest as riders are provided with rest when going downhill after intensive uphill climbs [11], underpinning the interval nature of this kind of effort. The adaptation of the body to increased metabolic acidosis occurs through increased buffer capacity of blood and muscle [24–26] and, as post-exertion BE partially describes the buffering capacity of the blood, explains the link of these two factors in both groups and indicating their importance (higher in MTB group). Furthermore, the road cyclists were characterised by higher values of Wz, Emax, CO2max (p 0.001), O2max and Qmax (p 0.05) than MTB. This suggests that training adaptation in road cycling primarily occurs in the respiratory tract (increased Emax, CO2max and O2max) and the circulatory system (increase in Qmax), as other authors also reported an increase in maximal respiratory values under the influence of training in a group of elite cyclists [1, 8, 22]. Among the statistically significant (p 0.05) differences in the biochemical parameters between both MTB and ROAD, higher concentrations of lactate and consequently a higher base excess along with lower blood pH values were found in road cyclists. Contradictory results were obtained by Lucía et al. [23], who compared riders specialising in individual time trials (ITT) with those specialising in mountain stages (C). They found that the C riders featured higher average pH values, maximum concentration of lactate and bicarbonate concentration in venous blood, while the ITT group achieved greater absolute power output. Furthermore, other researchers have also noted the significant impact of mountain biking training on the buffer capacity of the blood and muscles and anaerobic capacity, which include LAmax and post-exercise BE and pH values in the blood and muscle [4, 6, 11]. The differences in these test results may stem from differences in training, diet, motivation to perform at maximum effort during an exercise test or a combination of all these variables. These aspects, which were not analysed in the present study, should be included in future research on training adaptation. Conclusions Adaptation to training among road cyclists is expressed through increased aerobic capacity and an increase in lean body mass. Mountain biking induces adaptive changes in the direction of development of anaerobic capacity by increasing the buffer capacity of the blood and muscles, as well as the development of the system transporting oxygen from the lungs to the tissues. This discipline also promotes changes in body composition leaning towards lower body mass and reduced body fat. The amount of work done in a progressive exercise test and the concentration of base excess in the blood in the third minute of restitution after maximum effort are useful indicators in monitoring changes in physical fitness of road cyclists and mountain bikers. References 1. Lucía A., Hoyos J., Chicharro J.L., Physiology of Professional Road Cycling. Sports Med, 2001, 31 (5), 325–337. 159 HUMAN MOVEMENT M. Zatoń, D. Dąbrowski, Adaptation differences in cyclists 2. Mujika I., Padilla S., Physiological and performance characteristics of male professional road cyclists. Sports Med, 2001, 31 (7), 479–487. 3. Ebert T.R., Martin D.T., Stephens B., Withers R.T., Power output during a professional men’s road-cycling tour. Int J Sports Physiol Perform, 2006, 1 (4), 324–335. 4. Zatoń M., Hebisz R., Hebisz P., Physiological basis of mountain biking training [in Polish]. AWF, Wrocław 2011. 5. Impellizzeri F., Sassi A., Rodriguez-Alonso M., Mognoni P., Marcora S., Exercise intensity during off-road cycling competitions. Med Sci Sports Exerc, 2002, 34 (11), 1808–1813. 6. Impellizzeri F.M., Marcora S.M., The Physiology of Mountain Biking. Sports Med, 2007, 37 (1), 59–71. 7. Impellizzeri F., Marcora S., Rampinini E., Mognoni P., Sassi A., Correlations between physiological variables and performance in high level cross country off road cyclists. Br J Sports Med, 2005, 39 (10), 747–751. 8. Faria E.W., Parker D.L., Faria I.E., The Science of Cycling Physiology and Training – Part 1. Sports Med, 2005, 35 (4), 285–312. 9. Stringer W.W., Hansen J.E., Wasserman K., Cardiac output estimated noninvasively from oxygen uptake during exercise. J Appl Physiol, 1997, 82 (3), 908–912. 10. Joyner M.J., Coyle E.F., Endurance exercise performance: the physiology of champions. J Physiol, 2008, 586 (1), 35–44, doi:10.1113/jphysiol.2007.143834. 11. Costa V., De-Oliveira F., Physiological variables to predict performance in cross-country mountain bike races. J Exerc Physiol Online, 2008, 11 (6), 14–24. 12. Leicht A.S., Allen G.D., Hoey A.J., Influence of intensive cycling training on heart rate variability during rest and exercise. Can J Appl Physiol, 2003, 28 (6), 898–909, doi: 10.1139/h03-064. 13. Hu M., Finni T., Zou L., Perhonen M., Sedliak M., Alen M. et al., Effects of strength training on work capacity and parasympathetic heart rate modulation during exercise in physically inactive men. Int J Sports Med, 2009, 30 (10), 719–724, doi: 10.1055/s-0029-1225329. 14. Cornelissen V.A., Fagard R.H., Effects of endurance training on blood pressure, blood pressure-regulating mecha nisms, and cardiovascular risk factors. Hypertension, 2005, 46(4),667–675,doi:10.1161/01.HYP.0000184225.05629.51. 15. Wirnitzer K.C., Faulhaber M. Hemoglobin and hematocrit during an 8 day mountainbike race: A field study. J Sports Sci Med, 2007, 6 (2), 265–266. 16. Penteado V.S.R, Castro C.H.M., Pinheiro M.M., Santana M., Bertolino S., Mello M.T. et al., Diet, body composition, and bone mass in well-trained cyclists. J Clin Densitom, 2010, 13 (1), 43–50, doi:10.1016/j.jocd.2009. 09.002. 17. Lee H., Martin D.T., Anson J.M., Grundy D., Hahn A.G., Physiological characteristics of successful mountain bikers 160 and professional road cyclists. J Sports Sci, 2002, 20 (12), 1001–1008, doi: 10.1080/026404102321011760. 18. Dobrzyn P., Pyrkowska A., Jazurek M., Szymanski K., Langfort J., Dobrzyn A., Endurance training-induced accumulation of muscle triglycerides is coupled to upregulation of stearoyl-CoA desaturase 1. J Appl Physiol, 2010, 109 (6), 1653–1661, doi: 10.1152/japplphysiol.00598.2010. 19. García-López J., Rodríguez-Marroyo J.A., Juneau C.E., Peleteiro J., Martínez A.C., Villa J.G., Reference values and improvement of aerodynamic drag in professional cyclists. J Sports Sci, 2008, 26 (3), 277–286, doi: 10.1080/0264041 0701501697. 20. Kyle C.R., The effect of crosswinds upon time trials. Cycling Sci, 1991, 3(3-4), 51-56. 21. Mørkeberg J.S., Belhage B., Damsgaard R., Changes in blood values in elite cyclist. Int J Sports Med, 2009, 30 (2), 130–138, doi: 10.1055/s-2008-1038842. 22. Abbiss C.R., Laursen P.B., Models to explain fatigue during prolonged endurance cycling. Sports Med, 2005, 35 (10), 865–898. 23. Lucía A., Joyos H., Chicharro J.L., Physiological response to professional road cycling: climbers vs. time trialists. Int J Sports Med, 2000, 21 (7), 505–512, doi: 10.1055/s2000-7420. 24. Weston A.R., Myburgh K.H., Lindsay F.H., Dennis S.C., Noakes T.D., Hawley J.A., Skeletal muscle buffering capacity and endurance performance after high-intensity interval training by well-trained cyclists. Eur J Appl Physiol Occup Physiol, 1997, 75 (1), 7–13, doi: 10.1007/s00421 0050119. 25. Böning D., Klarholz C., Himmelsbach B., Hütler M., Ma assen N., Extracellular bicarbonate and non-bicarbonate buffering against lactic acid during and after exercise. Eur J Appl Physiol, 2007, 100 (4), 457–467, doi: 10.1007/ s00421-007-0453-4. 26. Böning D., Rojas J., Serrato M., Reyes O., Coy L., Mora M., Extracellular pH defense against lactic acid in untrained and trained altitude residents. Eur J Appl Physiol, 2008, 103 (2), 127–137, 10.1007/s00421-008-0675-0. Paper received by the Editors: January 3, 2013 Paper accepted for publication: February 19, 2013 Correspondence address Dariusz Dąbrowski Katedra Fizjologii i Biochemii Akademia Wychowania Fizycznego al. Paderewskiego 35 51-612 Wrocław, Poland e-mail: [email protected] HUMAN MOVEMENT 2013, vol. 14 (2), 161– 167 COMPARISON OF ACCURACY OF VARIOUS NON-CALORIMETRIC METHODS MEASURING ENERGY EXPENDITURE AT DIFFERENT INTENSITIES doi: 10.2478/humo-2013-0019 KRZYSZTOF DURKALEC-MICHALSKI *, MAŁGORZATA WOŹNIEWICZ, JOANNA BAJERSKA, JAN JESZKA Poznań University of Life Sciences, Poznań, Poland Abstract Purpose. The purpose of the study was to evaluate the accuracy of three non-calorimetric methods’ measurements of energy expenditure (EE) in laboratory conditions and to compare the results obtained by each method in free-living condition in a group of adult subjects. Methods. Measurement was performed on 20 individuals aged 19–39 years. An assessment of EE at different intensities of physical activity was conducted by: monitoring heart rate with a S-610 Polar Sport Tester (HRM), measuring body movement by an ActiGraph GT1M accelerometer (AM), and recording METs (MR) by a physical activity questionnaire, for different activities (leisure and exercise) at various intensities in laboratory and free-living conditions. Indirect calorimetry (Cosmed K4b2 respirometer) was used as a reference standard. Results. The most reliable tool for EE assessment was HRM (100% accurate). AM overestimated EE (about 60%) for activity at moderate-intensity and underestimated EE (about 40%) at vigorous-intensity. MR overestimated the results, with measurement errors increasing with an increase in physical activity intensity (about 40–120%). Conclusions. Although AM and MR provided less accurate results than HRM in laboratory conditions, there were no significant differences between the three methods (HRM, AM and MR) when total daily energy expenditure was calculated for the participants in free-living condition. Key words: energy expenditure, method accuracy, exercise, energy metabolism/physiology Introduction Research indicates that 50% of health is determined by lifestyle, including making healthy diet choices and performing enough physical exercise [1, 2]. Unfortunately, irregular lifestyles, low physical activity levels, and poor nutrition are observed ever more frequently among today’s youth, placing this generation at a greater risk for developing adverse health effects in the future [3–5]. In order to better screen and identify at-risk individuals, some preventive medicine strategies include measuring daily energy expenditure (EE) and physical activity levels (PAL) [6, 7]. Such methods can quickly assess whether one’s energy supply is properly balanced, preventing excess weight gain and obesity as well as other lifestyle diseases [8]. However, an accurate assessment of energy expenditure and physical activity level requires the use of measurement tools that need to take into account a wide variety of human activities, functions, and lifestyles. Furthermore, the various methods available for calculating daily energy expenditure possess a number of limitations. Although direct calorimetry is considered to be the gold standard in EE measurement, it is a costly technique and requires the use of special calorimetry chambers that prevent analysis in natural conditions, such as during normal activities of daily living [9, 10]. * Corresponding author. Similarly, methods using doubly labeled water are also quite expensive, and these techniques are also unable to determine energy expenditure during various life activities and forms of physical activity [9, 11]. Advances in technology have made it possible to construct portable respirometers that continuously measure oxygen consumption and exhaled carbon dioxide (a form of indirect calorimetry), allowing energy expenditure to be precisely determined in a wider range of daily activities [9, 10, 12, 13]. However, this method also features a number of drawbacks, such as the high cost of the measuring apparatus and the need to always breathe through a special mask or mouthpiece, making it difficult to conduct research over longer periods of time. Nonetheless, the high accuracy coupled with the relatively low cost of indirect calorimetry has allowed it to be used as a new reference standard in evaluating simpler, non-calometric methods that can measure energy expenditure and physical activity. Some of the most commonly used non-calometric methods include monitoring heart rate and body movement (heart rate monitors and accelerometers). Questionnaires and physical activity logs are also used, paired with tables that can estimate the energy cost of various activities. The greatest advantage of the above methods is their low cost and noninvasiveness. In addition, these measurement tools are designed to be easy to use and allow participants to go about their natural lives with no restrictions on the type of activity, its duration or inten161 HUMAN MOVEMENT K. Durkalec-Michalski et al., Accuracy of energy expenditure assessing sity [12, 14]. However, the accuracy of such instruments is of critical importance, as they may provide incorrect results or be unsuitable for various research purposes. In addition, the various non-calometric methods available for estimating energy expenditure have been frequently evaluated only by comparing one of them against a reference method [13, 15, 16], with few studies having conducted a simultaneous assessment of several measurement methods at the same time. This is unfortunate, as analysis performed under similar research conditions could help eliminate factors that may distort the results, especially when comparing similar measurements. Moreover, in order to obtain results of a practical nature it is important to validate measurements performed both in laboratory and “free-living” conditions. Assah et al. [17] believe that the measuring procedures used in laboratory testing do not fully reflect the physical activity patterns observed in uncontrolled, natural conditions. The authors also added that testing performed in “free-living” conditions allows for observation of a wider range of differentiated forms of physical activity. With the above in mind, the purpose of this study was to assess and compare the energy expenditure values measured by various non-calometric methods with those attained by indirect calorimetry when performing different forms of physical activity in laboratory conditions, and to also compare the results of the noncalorimetric methods in more natural, “free-living” conditions. Material and methods Twenty individuals participated in the study, 11 women, aged 26.0 ± 4.5 years, and 9 men, aged 26.5 ± 5.0 years, all of whom led normal life activities. Before the start of the study, the participants’ body mass and height were measured to calculate their body mass index (BMI) and metabolic body weight (body mass raised to the power of 0.73). Basal metabolic rate (BMR) was calculated after fasting and in stress-free conditions by indirect calorimetry using the K4b2 portable gas respiro meter (Cosmed, Italy). The participants were found to be in good health with none showing signs of obesity (BMI 30 kg/m2). Three non-calometric methods used to measure energy expenditure were assessed in laboratory conditions: by monitoring heart rate (HR) with a S-610 Polar Sport Tester heart rate monitor (Polar Electro Oy, Finland), by measuring body movement with a GT1M triaxial accelerometer (ActiGraph, USA), and by recording physical activity in the form of questionnaire used to calculate the metabolic cost (MET, Metabolic Equivalent of Task) of the performed activities. Indirect calorimetry was assessed with the previously-mentioned K4b2, continuously analyzing (breath-by-breath) the volume of inhaled and exhaled air as well as changes in gas concentration between oxygen uptake and expiration. The port162 able gas analyzer was calibrated each time before use with a reference gas mixture of: CO2 – 5%, O2 – 16%. The taking of measurements by the three non-calorimetric methods and indirect calorimetry as a reference were performed in laboratory conditions, beginning each time in the morning after the participants had consumed an easy to digest breakfast (average energy value of 600 kcal, composed of 13% protein, 57% carbohydrates, and 30% fat) and continued for five hours in successive stages reflecting an average breakdown of the participants’ normal daily routine, which had been previously recorded during a pilot study. The breakdown came to: sleep, lasting 94 min and 30 s, which accounted for 31.5% of the day; light-intensity activity (i.e. reading, writing, working at a computer, or watching TV) performed in a seated position, lasting 133 min and 30 s, which accounted for 44.5% of the day; moderate-intensity activity (simulated by walking, various laboratory exercises, preparing meals, or washing dishes), lasting 69 min, accounting for 23.0% of the day; and vigorousintensity activity (performed on a CX1 cycle ergometer [Kettler, Germany] at an intensity of 70% VO2max at 150 W so as to reach heart rate values of 170–180 bpm), lasting 3 min, which accounted for 1.0% of the day. The first 15 min of the test were treated as an adaptation period and were omitted from the final results. In addition, 10-min pauses were introduced between each activity phase and also not recorded. The calibration techniques recommended by Livingstone et al. were adhered to during measurement taking [18]. The obtained data were than proportionally calculated and presented as total daily energy expenditure. Energy expenditure measured with monitoring heart rate is based on the physiological relationship between heart rate and metabolic rate, which is a result of the body’s need to deliver sufficient levels of oxygen and energy substrates. The heart rate monitor (S-610 Polar Sport Tester) used in this method consisted of a cardiac pulse transmitter placed on the chest around the area of the heart by a rubber strap and a wrist monitor that recorded the amount of beats per minute. A correct estimate of EE was preceded by first performing regression analysis between oxygen uptake (VO2) and heart rate (HR) – VO2/HR – for each individual. This assessment was aided by the values recorded during indirect calorimetry at various intensity levels (lying, sitting, standing, walking, and riding the ergometer). In accordance with the procedure recommended by Bradfield et al. [19] and Livingstone et al. [18], the HR values obtained from earlier VO2/HR calculations were used to delineate threshold heart rate, or HR-FLEX (as the average between the highest heart rate at rest and the lowest exercising heart rate), creating a individually established threshold between activities performed at light intensity and those of at least moderate physical activity. After HR-FLEX was calculated for each participant, the heart rate recorded throughout the measurement period was cate- HUMAN MOVEMENT K. Durkalec-Michalski et al., Accuracy of energy expenditure assessing Table 1. Estimating individual total daily energy expenditure based on heart rate measurement Type of activity Equation Legend EE during sleep EE = ST/1400 × BMR ST – Sleep time BMR – Basal metabolic rate EE at light-intensity activity (HR < HR-FLEX) EE = BMR/1440×DEp × 1.4 DE p – duration of effort at light intensity (min) EEmin = (ax + b) × 4.9 EE min – energy expenditure (kcal/min) a – linear regression slope coefficient (VO2/HR) x – HR (bpm) b – linear regression intercept coefficient (VO2/HR) 4.9 – energy equivalent for oxygen (kcal/dm3) EE at moderate- and vigorous-intensity activity (HR HR-FLEX) BMR calculated by indirect calorimetry using the K4b2 respirometer. ogrized into four types of activity depending on their intensity [18], with energy expenditure calculated using the procedure described in Table 1. The second non-calometric method for measuring energy expenditure (EE) was performed with a accelero meter, which provides an objective assessment of all phy sical activity performed over a period of time as well as its duration and intensity [20]. The accelerometer is a lightweight, waterproof, and noninvasive tool, and it can record body movement in the vertical, lateral, and longitudinal directions. With this method, energy expen diture (EE) associated with physical activity is calculated by the use of an intrasystemic algorithm, composed of two equations [21]. For light-intensity activity (counts < 1952, i.e., < 3.0 METs; with 1 count equal to 16.6 mg/s at 0.75 Hz), the Work-Energy Theorem is used: EE (kcal/min) = counts/min × 0.0000191 × body mass (kg). For moderateand vigorous-intensity activity (counts 1952, i.e. 3.0 METs), Freedson’s equation is used: EE (kcal/min) = 0.00094 × counts/min + 0.1346 × body mass (kg) – 7.37418. Total daily energy expenditure (kcal) at different intensities of physical activity is then calculated by: EE = EEpa + BMR × Dpa, where EEpa– energy expenditure associated with physical activity, Dpa – duration of physical activity at a given intensity. Energy expenditure during sleep was calculated the same way as in the method monitoring heart rate (Tab. 1). The third non-calometric method used for measuring energy expenditure involved a physical activity questionnaire used to register the type and duration of all activity the participants performed. The activities were crossindexed to compute their MET values (kcal/h/kg BM), where one MET represents 1 kcal burned per 1 kg of body mass (BM) in 1 h at complete rest, and it is equivalent to oxygen uptake of about 3.5 ml/kg of body mass. The three non-calorimetric methods were also assessed in “free-living” conditions, with the participants leading their normal life activities over two 24-h periods over three days (two weekdays and one day off from work), excluding the time spent sleeping. All three methods were used at the same time, meaning the participants wore the Polar Sport Tester heart rate monitor and the ActiGraph accelerometer and logged their physical activity by use of the questionnaire. The data collected were used to calculate total daily energy expenditure Statistical analysis of the collected data was performed using Statistica v. 7.1 (Statsoft, USA), which included checking for straight-line correlations, one-way analysis of variance (ANOVA) post hoc Tukey’s test if the results were statistically different; the level of significant was set at = 0.05. Results The anthropometric characteristics of the group are presented in Table 2. An assessment of the participants’ nutritional status whith BMI index found that both the males and females generally featured adequate BMI levels (24.4 ± 3.7 kg/m2 and 21.9 ± 3.4 kg/m2 , respectively), although the results were largely dispersed with a number of individuals who were underweight (BMI < 18.4 kg/m2) or overweight (BMI > 25 kg/m2). Large differences among the group were also found after calculating the physical activity level (PAL) for each participant, based on the ratio of total metabolic rate to basal metabolic rate, and ranged from 1.02 to 2.42. Table 3 contains the energy expenditure values of physical activity performed at different intensities from using the three non-calorimetric methods and indirect calorimetry. Significant differences (p < 0.05) in measured energy expenditure were found between the physical activity questionnaire (measuring METs) and the accelerometer (ActiGraph GT1M) at rest; between indirect calorimetry (K4b2 gas analyzer) or heart rate (S-610 Polar Sport Tester) and the accelerometer at moderate-intensity activity; between indirect calorimetry or heart rate measurement or the physical activity questionnaire and the accelerometer at vigorous-intensity activity. Although the total daily energy expenditure (TDEE) values measured by the various methods in laboratory conditions did not significantly differ, the discrepancy in TDEE 163 HUMAN MOVEMENT K. Durkalec-Michalski et al., Accuracy of energy expenditure assessing Table 2. Anthropometric characteristics and basal metabolic rate (BMR) of the participants Women n = 11 Parameter ± SD Age [years] Basal metabolic rate (BMR)1 [kcal/day] Body mass [kg] Body height [cm] BMI [kg/m2] Metabolic body weight [kg0.73] Physical activity level (PAL)2 26.0 ± 4.5 1135.2 ± 192.6 60.1 ± 9.1 165.9 ± 5.4 21.9 ± 3.4 19.9 ± 2.2 1.61 ± 0.42 Men n = 9 Min – max ± SD 19.0 – 36.0 960.2 – 1441.5 65.0 – 100.0 166.0 – 191.0 18.2 – 29.9 21.1 – 28.8 1.07 – 2.42 1 BMR calculated by indirect calorimetry, 2 PAL during “free-living” conditions: 1.55–1.6 – moderately active lifestyle; 1.75 – vigorously active lifestyle [22] 26.5 ± 5.0 1240.1 ± 87.1 77.7 ± 14.0 178.0 ± 8.4 24.4 ± 3.7 23.9 ± 3.1 1.52 ± 0.39 Min – max 23.0 – 39.0 1114.4 – 1458.6 47.0 – 83.0 152.0 – 173.0 17.7 – 29.4 16.6 – 25.2 1.02 – 2.07 1.4 –sedentary lifestyle; Table 3. Assessment of energy expenditure measured by the three non-calorimetric methods versus indirect calorimetry at different physical activity levels Activity intensity level Method Indirect calorimetry (K4b2) Questionnaire (METs) Accelerometer (ActiGraph) Heart rate (Polar Sport Tester) Sleep [kcal/kg BM/ duration]* Light intensity [kcal/kg BM/ duration] Moderate intensity Vigorous intensity Total daily energy [kcal/kg BM/ [kcal/kg BM/ expenditure duration] duration] [kcal/kg BM/day] 7.7 ± 1.7a 14.6 ± 3.5a 14.0 ± 4.3a 1.0 ± 0.3a 37.3 ± 8.3a 6.8 ± 0.5a 17.9 ± 7.5b 18.3 ± 5.2ab 2.2 ± 0.8b 45.2 ± 10.9a 7.5 ± 0.6a 12.5 ± 2.8c 22.5 ± 14.6b 0.6 ± 0.3c 43.1 ± 17.4a 7.5 ± 0.6a 14.1 ± 3.6a 13.3 ± 4.0 a 1.0 ± 0.3a 36.0 ± 6.7a a, b, c – inscriptions denote statistically significant differences ( = 0.05) of the values in the columns * time spent at each physical activity level, including: sleep – 454 min (7.6 h) = 31.5% of the day (the resting metabolic rate was adopted as the energy expenditure of sleep for the accelerometer and heart rate methods) light-intensity activity: 641 min (10.68 h) = 44.5% of the day; moderate-intensity activity: 329 min (5.48 h) = 23.0% of the day vigorous-intensity activity: 16 min (0.27 h) = 1.0% of the day values assessed by the K4b2 portable gas analyzer or by monitoring heart rate, and the physical activity questionnaire or the accelerometer, was between 15–20%. An assessment of EE measurement accuracy by the three non-calometric methods and compared against those recorded by indirect calorimetry are presented in Figure 1. On the basis of the results, it was found that monitoring heart rate with the Polar Sport Tester was 260 Mets - Questionnaire Actigraph - Accelerometer Polar-Sport - HR monitor 240 220 b 200 Accuracy [%] 180 160 b b b 140 120 a a a 100 a a 80 60 40 20 Light intensity Moderate intensity Vigorous intensity a, b – inscriptions denote statistically significant differences ( = 0.05) of the values Figure 1. Accuracy of energy expenditure measurements by three different non-calorimetric methods 164 the most reliable tool in measuring EE at rest as well as at moderate and vigorous physical activity (accuracy of 95%–100%). The method using the accelerometer (ActiGraph) overestimated EE at moderate intensity by 60% and underestimated EE by 40% at vigorous intensity (the exercise test on the cycle ergometer). However, the accelerometer was 86% accurate in measuring EE at light intensity in relation to the values measured by indirect calorimetry. Out of all the methods used to measure energy expenditure, the least accurate was that using the physical activity questionnaire and correlating the answers with MET values. This method overestimated energy expenditure with ever larger measurement errors as the physical activity intensity increased: being 20%–30% off for activity at light intensity to 120% off for vigorous intensity. Statistical analysis of the results confirmed that the physical activity questionnaire (calculating METs) was significantly less accurate (p < 0.05) than the other measurement methods by overestimating energy expenditure at light and vigorous intensity levels. Furthermore, energy expenditure assessed by the accelerometer (ActiGraph) HUMAN MOVEMENT K. Durkalec-Michalski et al., Accuracy of energy expenditure assessing 2200 a TDEE [kcal/day] 2100 a a 2000 1900 1800 1700 1600 1500 Mets - Questionnaire Actigraph - Accelerometer Polar-Sport - HR monitor Figure 2. Comparison of total daily energy expenditure values recorded in “free-living” conditions by the three different non-calorimetric methods and physical activity questionnaire (METs) at moderate intensity were significantly less accurate (p < 0.05) than by monitoring heart rate. Figure 2 provides a comparison of total daily energy expenditure by the three non-calorimetric methods in “free-living” conditions. In comparison with EE based on monitoring heart rate (Polar Sport Tester), whose measurement accuracy in laboratory conditions was confirmed by indirect calorimetry, both the accelerometer and questionnaire methods overestimated total daily energy expenditure by 5%. However, no statistically significant differences in total daily energy expenditure were found among the three non-calorimetric methods. Discussion The present study estimated energy expenditure by monitoring heart rate, using a accelerometer, and recording physical activity on questionnaire to calculate METs, and compared the results with those attained by indirect calorimetry using a K4b2 respirometer. The most accurate of the non-calometric methods was monitoring heart rate using the S-610 Polar Sport Tester heart rate monitor, with an accuracy close to 100%. These results are in line with previous observations on the reliability of this method by other researchers. Goodie et al. [23] found a high correlation (r = 0.98, p < 0.001) between heart rate measurements using a Polar Vantage XL heart rate monitor and those obtained using electrocardio graphy (ECG). In turn, Maffeis et al. [16] validated this measurement technique and its accuracy in non-obese children by comparing it with energy expenditure measured using doubly labeled water. Garet et al. [24] conducted a study on verifying measurement of energy expenditure by heart rate with the gold standard of EE assessment, direct calorimetry. They found that measurement of physical activity levels and energy expenditure by heart rate was quite accurate and did not differ with respect to the data obtained using the reference method. An assessment of the accuracy of the ActiGraph accelerometer found it overestimated energy expenditure up to 60% during moderate-intensity effort when com- pared to the reference values from indirect calorimetry, and that the obtained results showed the highest intragroup variability. This may be explained by the findings of Hustvedt et al. [25], who claimed that some accelero meters can wrongly interpret even small variations in walking gait (from 2 to 3 km/h), classifying it as mode rate-vigorous instead of light intensity. Furthermore, Le Masurier et al. [26] noted that accelerometers may incorrectly record non-walking movement as walking, overestimating energy expenditure especially among individuals who often travel by car. What was also of interest was that the accelerometer used in this study underestimated energy expenditure during vigorous-intensity activity by 40% in comparison with EE obtained by indirect calorimetry. This could be linked to this study’s use of the cycle ergometer to simulate vigorous exercise, as a accelerometer works primarily by measuring torso movement, and its placement on the waist may have only recorded movement made by the upper body and not the cyclical work performed by the lower limbs. A more correct measure of this type of effort may require the use of additional sensors in accelero meters, or the development of even more accurate intrasystemic algorithms in order to correctly estimate energy expenditure during cycling. Therefore, the conclusions set forth by Trost et al. [27] seem to be corroborated, they stated that the algorithms used in accelerometers to assess energy expenditure do not take into account all the various types of physical activity humans perform. However, it is worth mentioning that the predictive accuracy of the most commonly used methods to calculate energy expenditure on the basis of various physiological parameters was highest by measurements taken by an ActiGraph accelerometer with Freedson’s equation (73% accurate) [28]. In the present study, the least accurate data on energy expenditure at different exercise intensities in laboratory conditions were collected by the use of the physical activity questionnaire that calculated METs. This may be due to the need, among other factors, of maintaining a very detailed log of the duration and type of physical activity performed as well as problems connected with properly classifying and interpreting their impact on energy expenditure. Sergi et al. [29], in a study on an elderly population, found that this method underestimated the values of activity performed at light- or moderateintensity in comparison with the results attained by indirect calorimetry. It is believed that changes in body composition and the functioning of the cardiovascular system may explain for these differences. Seale et al. [30] found that the use of a physical activity questionnaire to calculate METs (4.60 MJ/d for men and 3.42 MJ/d for women) significantly overestimated total daily energy expenditure when compared with the doubly labeled water method. Similarly, Milani et al. [31] performed a study on patients after coronary events, finding that energy expenditure estimated by a questionnaire was 165 HUMAN MOVEMENT K. Durkalec-Michalski et al., Accuracy of energy expenditure assessing far less reliable than a reference method (indirect calorimetry). They found that this method overestimated the results of an exercise test both before and after a 12-week cardiac rehabilitation program. Similar measurement errors were found in the present study, and, more interestingly, the magnitude of error increased with higher exercise intensity, indicating this is a systemic error. Thus, due to their low accuracy, both the physical activity questionnaire calculating MET values as well as the accelerometer methods should be limited to general population studies attempting to obtain only indicative total daily energy expenditure and physical activity levels. As was mentioned, the physical activity questionnaire and accelerometer methods overestimated total daily energy expenditure at different activity intensities by 15% and 20%, respectively, than those recorded using the reference method. Although these results were found to be statistically insignificant, the size of this error may have a number of physiological repercussions, as the use of these methods to assess total daily energy expenditure may lead to erroneous assumptions on individuals’ daily energy requirements. In light of the results attained in laboratory settings, the data obtained in “free-living” conditions showed a surprisingly high convergence among the non-calometric methods. As monitoring heart rate in laboratory conditions deviated to a considerably lesser extent from the indirect calorimetry method in comparison with the other methods, it was expected that a similar variation would have been observed in natural conditions. However, the differences between the mean values of the three non-calorimetric methods amounted to only 5%, which corresponds to a deviation of approximately 100 kcal/d (0.4 MJ/d) between the evaluated methods. This is likely to be attributable to the fact that there was a greater range of different forms of physical activity being performed and at more varied intensities, hence the measurement errors could have mutually compensated each other [17]. As a result, it can be assumed that in many cases the practical application of any of the three methods can provide relatively close assessment of total daily energy expenditure, although attention needs to be paid to the questionnaire and accelerometer methods from overestimating the results even in “free-living” conditions. However, the results of this study should be used with some caution in regard to the population being studied, where in this case it comprised of individuals who were sedentary or moderately physically active. Conclusions Monitoring heart rate is a reliable method for assessing energy expenditure at different intensity levels. Energy expenditure measurements based on a accelero meter and in particular with the use of a physical activity questionnaire calculating MET values are less accurate, 166 where the questionnaire method showing a tendency towards measurement overestimation, with error increasing with activity intensity. On the other hand, the accelerometer both overestimated or underestimated results depending on the intensity or type of physical effort being performed. Nonetheless, each of the evaluated non-calometric methods can be successfully used to meaningfully assess total daily energy expenditure in more natural, “free-living” conditions, especially in a young sample group with low to average physical activity levels. References 1. Wojtyniak B., Goryński P., Health Status of the Polish Population and the National Health Program 2006–2015 [in Polish]. Reumatologia, 2007, 45 (1), supl.1, S5-S17. 2. POL-HEALTH. Ministry of Health, Department of Health Policy. National program of overweight and obesity prevention and chronic noncommunicable diseases by improving nutrition and physical activity for 2007–2011 [in Polish]. Warszawa 2009. Available from: http://www. mz.gov.pl/w w wfiles/ma_ struktura/docs/ot ylosc_ 06012010.pdf. 3. Durkalec-Michalski K., Suliburska J., Jeszka J., The evaluation of eating habits and nutritional status in young men according to their physical activity [in Polish]. Standardy medyczne/Pediatria, 2011, 8, 100–106. 4. Czeczelewski J., Raczyński G., Food intake, somatic traits and physical activity of adolescents. Hum Mov, 2006, 7 (1), 58–64. 5. Howe C.A., Freedson P.S., Feldman H.A., Osganian S.K., Energy expenditure and enjoyment of common children’s games in a simulated free-play environment. J Pediatr, 2010, 157 (6), 936–942, doi: 10.1016/j.jpeds.2010.06.041. 6. Speck R.M., Schmitz K.H., Energy expenditure comparison: a pilot study of standing instead of sitting at work for obesity prevention. Prev Med, 2011, 52 (3–4), 283–284, doi: 10.1016/j.ypmed.2011.02.002. 7. Norton K., Norton L., Sadgrove D., Position statement on physical activity and exercise intensity terminology. J Sci Med Sport, 2010, 13 (5), 496–502, doi: 10.1016/j. jsams.2009.09.008. 8. Allender S., Scarborough P., Peto V., Rayner M., Leal J., Luengo-Fernandez R. et al., European cardiovascular disease statistics edition 2008. Available from: http:// www.ehnheart.org/publications/annual-reports.html. 9. Hageman P.A., Norman J.F., Pfefferkorn K.L., Reiss N.J., Riesberg K.A., Comparison of two physical activity monitors during a 1-mile walking field test. J Exerc Physiol, 2004, 7 (3), 102–110. 10. Seale J.L., Rumpler W.V., Conway J.M., Miles C.W., Comparison of doubly labeled water, intake-balance, and directand indirect-calorimetry methods for measuring energy expenditure in adult men. Am J Clin Nutr, 1990, 52 (1), 66–71. 11. Rising R., Harper I.T., Fontvielle A.M., Ferraro R.T., Spraul M., Ravussin E., Determinants of total daily energy expenditure: variability in physical activity. Am J Clin Nutr, 1994, 59 (4), 800–804. 12. White K., Schofield G., Kilding A.E., Energy expended by boys playing active video games. J Sci Med Sport, 2011, 14 (2), 130–134, doi:10.1016/j.jsams.2010.07.005. HUMAN MOVEMENT K. Durkalec-Michalski et al., Accuracy of energy expenditure assessing 13. Nieman D.C., Trone G.A., Austin M.D., A new handheld device for measuring resting metabolic rate and oxygen consumption. J Am Diet Assoc, 2003, 103 (5), 588–592, doi: 10.1053/jada.2003.50116. 14. Bourrilhon C., Philippe M., Chennaoui M., Van Beers P., Lepers R., Dussault C. et al., Energy expenditure during an ultraendurance alpine climbing race. Wilderness Environ Med, 2009, 20 (3), 225–233, doi: 10.1580/08-WEMEOR-217R3.1. 15. Campbell K.L., Crocker P.R., McKenzie D.C., Field evaluation of energy expenditure in women using Tritrac accelerometers. Med Sci Sports Exerc, 2002, 34 (10), 1667–1674 16. Maffeis C., Pinelli L., Zaffanello M., Schena F., Iacumin P., Schutz Y., Daily energy expenditure in free-living conditions in obese and non-obese children: comparison of doubly labelled water (2H2(18)O) method and heart-rate monitoring. Int J Obes Relat Metab Disord, 1995, 19 (9), 671–677. 17. Assah F.K., Ekelund U., Brage S., Wright A., Mbanya J.C., Wareham N.J., Accuracy and validity of a combined heart rate and motion sensor for the measurement of free-living physical activity energy expenditure in adults in Cameroon. Int J Epidemiol, 2011, 40 (1), 112–120, doi: 10.1093/ ije/dyq098. 18. Livingstone M.B., Robson P.J., Totton M., Energy expenditure by heart rate in children: an evaluation of calibration techniques. Med Sci Sports Exerc, 2000, 32 (8), 1513–1539. 19. Bradfield R.B., Chan H., Bradfield N.E., Payne P.R., Energy expenditures and heart rates of Cambridge boys at school. Am J Clin Nutr, 1971, 24 (12), 1461–1466. 20. Tryon W.W., Williams R., Fully proportional actigraphy: a new instrument. Behav Res Meth Instr Comp, 1996, 28 (3) 392–403, doi: 10.3758/BF03200519. 21. Rothney M.P., Neumann M., Béziat A., Chen K.Y., An artificial neural network model of energy expenditure using nonintegrated acceleration signals. J Appl Physiol, 2007, 103 (4), 1419–1427, doi: 10.1152/japplphysiol.00429.2007. 22. World Health Organization, Obesity: Preventing and managing the global epidemic. report of WHO consultation. Technical report series 894. WHO, Geneva 2000, 1–253. 23. Goodie J.L., Larkin K.T., Schauss S., Validation of the Polar Heart Rate Monitor for Assessing Heart Rate During Physical and Mental Stress. J Psychophysiol, 2000, 14 (3), 159–164, doi: 10.1027/0269-8803.14.3.159. 24. Garet M., Boudet G., Montaurier C., Vermorel M., Coudert J., Chamoux A., Estimating relative physical workload using heart rate monitoring: a validation by wholebody indirect calorimetry. Eur J Appl Physiol, 2005, 94 (1–2), 46–53, doi: 10.1007/s00421-004-1228-9. 25. Hustvedt B.E., Christophersen A., Johnsen L.R., Tom ten H., McNeill G., Haggarty P. et al., Description and validation of the ActiReg: a novel instrument to measure physical activity and energy expenditure. Br J Nutr, 2004, 92 (6), 1001–1008, doi: 10.1079/BJN20041272. 26. Le Masurier G.C., Tudor-Locke C., Comparison of pedometer and accelerometer accuracy under controlled conditions. Med Sci Sports Exerc, 2003, 35 (5), 867–871. 27. Trost S., Way R., Okely A., Predictive validity of accelero meter prediction equations for energy expenditure (EE) during overland walking and running in children and adolescents. Med Sci Sports Exerc, 2004, 36 (5), S197. 28. Trost S.G., Way R., Okely A.D., Predictive validity of three ActiGraph energy expenditure equations for children. Med Sci Sports Exerc, 2006, 38 (2), 380–387. 29. Sergi G., Coin A., Sarti S., Perissinotto E., Peloso M., Mulone S. et al., Resting VO2, maximal VO2 and metabolic equivalents in free-living healthy elderly women. Clin Nutr, 2010, 29 (1), 84–88, doi: 10.1016/j.clnu.2009.07.010. 30. Seale J.L., Klein G., Friedmann J., Jansen G.L., Mitchell D.C., Smiciklas-Wright H., Energy expenditure measured by doubly labeled water, activity recall, and diet records in the rural elderly. Nutrition, 2002, 18, 568–573, doi: 10. 1016/S0899-9007(02)00804-3. 31. Milani R.V., Lavie C.J., Spiva H., Limitations of estimating metabolic equivalents in exercise assessment in patients with coronary artery disease. Am J Cardiol, 1995, 75 (1), 940–942, doi: 10.1016/S0002-9149(99)80693-6. Paper received by the Editor: September 27, 2011 Paper accepted for publication: April 25, 2013 Correspondence address Krzysztof Durkalec-Michalski Zakład Dietetyki Katedra Higieny Żywienia Człowieka Uniwersytet Przyrodniczy ul. Wojska Polskiego 31 60-624 Poznań, Poland e-mail: [email protected] 167 HUMAN MOVEMENT 2013, vol. 14 (2), 168– 174 Exercise or relaxation? Which is more effective in improving the emotional state of pregnant women? doi: 10.2478/humo-2013-0020 Monika Guszkowska*, Katarzyna Sempolska, Agnieszka Zaremba, Marta Langwald Józef Piłsudski University of Physical Education, Warszawa, Poland Abstract Purpose. The aim of this study was to compare the changes in emotional states in pregnant women after completing a relaxation session and a one-off physical exercise class. Methods. The study included 139 pregnant women between the ages of 22 to 34 years (28.59 ± 2.99 years) in their second and third trimesters of pregnancy who were participating in one of three programs: a progressive relaxation course, a physical exercise program, or a traditional childbirth education program (control group). Emotional states were assessed by McNair, Lorr, and Droppleman’s Profile of Mood States immediately before (pre-test) attending their seventh respective class and then immediately after finishing it (post-test) Results. The pre-test emotional state of participants in all three groups was similar. Post-test, both the exercise and relaxation groups featured significantly improved emotional states, with the changes greater than those of women who attended the prenatal class. Pregnant women who participated in physical exercise were less troubled and tense and characterized by a higher level of vigor than the control group. Conclusions. Physical exercise may be especially helpful in coping with fatigue and feeling tired, while relaxation training is more beneficial for women with elevated levels of anxiety and depression. Key words: exercise, relaxation, pregnancy, emotions Introduction Research shows that performing physical exercise at a moderate intensity by healthy pregnant women not only poses no threat to the mother or fetus, but actually contains a number of important health and physical benefits for both the mother and child [1–4]. As explained by Melzer et al. [5] in a recent literature review on this subject, regardless of the physiological changes that occur during pregnancy, pregnant women benefit the same from regular physical activity as non-pregnant women. Physical activity is therefore an important component of a healthy pregnancy, with today’s health recommendations advising expectant mothers without pregnancy-related risks or complications to perform at least 30 minutes of moderately intensive, preferably aerobic, physical exercise as often as possible, even every day [1–2, 6]. Unfortunately, research has shown that the amount of physical activity performed either during work or for leisure significantly decreases during pregnancy [7–9]. The proportion of pregnant women participating in moderate to vigorous intensity physical exercise or sport falls steadily as the pregnancy advances, where significantly more moderate to high intensity physical exercise is performed in the first and second trimester than in the third. Moreover, the duration and intensity of the * Corresponding author. 168 exercise performed during pregnancy is significantly reduced. Although the number of women who are lightly active remains stable during pregnancy, the proportion of women leading a sedentary lifestyle increases significantly. Studies conducted on pregnant women in the United States found that most spent more than half their day engaged in sedentary behavior and did not follow minimum physical activity recommendations [10]. The positive effects of performing proper amounts of exercise during pregnancy not only have a major impact on physical health but are also known to have a number of potential benefits on mental health. The mental well-being of expectant mothers is known to have a significant impact on pregnancy, childbirth, motherhood, and the newborn and its later development in life. Pregnant women under large amounts of stress are more at risk for miscarriages or premature birth as well as perinatal complications [11, 12]. Stress during pregnancy is linked to giving birth to small for gestational age babies in poorer psychophysical states and found to increase their risk of developmental disorders in later life [12–14]. Since prenatal stress may significantly contribute to pregnancy complications and developmental disorders, particular importance has been placed on reducing the stress levels of pregnant women. One such solution is physical exercise, at least for those women whose pregnancy is progressing normally. Numerous studies conducted on a general population have repeatedly confirmed the positive emotional changes experienced after a one-off workout. Therefore, instead of reviewing the results of individual studies, attention was focused on HUMAN MOVEMENT M. Guszkowska et al., Exercise and relaxation for pregnant women analyzing meta-analyses of the available literature. It was found that the majority of studies focused on the possibility of using physical exercise in lowering negative emotional states, such as fear and depression. Starting from 1981, more than 40 systematic reviews have been published, all of which confirmed that physical exercise reduces anxiety and depression levels [15–17]. One of the first studies of this type was performed by Yeung [18], who noted that the majority of the results show an improvement in mood after a one-off workout, regardless of gender or age or even disability. Positive effects were observed after both aerobic and anaerobic exercise of varying duration and intensity, and were usually felt up to 3–4 hours after completion. Interestingly, among the studies analyzed by Yeung [18], the one group which featured a deterioration in mood after exercise were pregnant women. Another aspect that needs to be considered is the approach proposed by positive psychology, which places emphasis on the determinants of mental well-being. By adopting this perspective, it needs to be asked whether one-off exercise can in fact improve the indicators of positive mood such as positive affect, vigor, energy level, joy, and euphoria. Reed and Ones [19] completed a metaanalysis on this issue, addressing over 158 studies conducted between 1979 and 2005, although only two involved pregnant women. The results of their metaanalysis found significant increases in the indicators of positive arousal immediately after aerobic exercise, particularly when the levels of pre-exercise were below average. Furthermore, the positives effects of exercise at low intensity, lasting up to 35 minutes, and performed from a low to moderate frequency (intensity × duration) were unilaterally confirmed. Unfortunately, few of the analyzed studies investigated the effect of one-off exercise on the emotional states of pregnant women. The few did observed a decrease in the psychological indicators of depression and anxiety after a one-off aerobic workout [20]. Similar decreases in anxiety and depression levels were observed in postpartum women after participating in a 60-minute aerobic training session at moderate intensity; in addition, they also exhibited an improvement in mood and an increase in vigor [21]. A study performed on pregnant women participating in aqua-aerobics classes indicated that this type of exercise causes increases in positive mood, better well-being, a decrease in negative emotions, and a reduction in feeling tired or fatigued [22]. Similarly, after a one-off workout from the 9 Months Active program, a group of pregnant women featured beneficial emotional changes, particularly with noted decreases in anxiety and tension levels [23]. Nonetheless, relaxation techniques are by far the most commonly applied methods for alleviating stress and anxiety. A meta-analysis by Manzoni et al. [24] found that such techniques are moderately to highly effective in reducing anxiety. Particularly effective in reducing anxiety was meditation, although a number of other techniques (autogenic training, progressive relaxation, and mixed techniques) were also helpful. However, none of the studies covered by this meta-analysis involved pregnant women and so far little is known about the effectiveness of relaxation therapy in this population. Outside of the available meta-analyses on this subject, of some interest were the findings of Urech et al. [25], who compared the acute effects (i.e., the effect of a oneoff class) of three relaxation techniques (progressive relaxation, imagery relaxation, and passive relaxation), on pregnant women. In all cases, a significant reduction in cortisol, noradrenaline, and ACTH levels was observed, with progressive and imagery relaxation also found to decrease the expectant mothers’ heart rates. After further analysis, this study concluded that imagery relaxation was more effective than the other two methods in reducing cardiovascular activity as well as inducing a subjectively perceived state of relaxation. Another study [26] on pregnant women found that an active relaxation session helped decrease anxiety levels and heart rate better than a passive relaxation method. However, passive relaxation was found to cause more significant decreases in noradrenaline levels, which did not occur in the group of pregnant women who performed active relaxation. No change in the level of adrenaline was observed in either group, although both groups featured a significant decrease in the level of cortisol. In light of the relatively few studies that have addressed this issue, the aim of the present study was to compare the changes in the emotional states of expectant mothers who were attending an exercise training program or a relaxation course against a control group attending a traditional childbirth education course immediately before attending one of their classes and after it was completed. Material and methods The study included 139 pregnant women between the ages of 22 to 34 years (mean 28.59 ± 2.99 years) in their second (n = 54) or third trimester (n = 85), or between 20–34 weeks of gestation (27.96 ± 4.01 weeks). All of the participants had completed higher education and lived in a capital city; 78.4% (n = 109) were married, the remaining 21.6% (n = 30) were unmarried. All of the participants were professionally active before becoming pregnant, although at the time of the study 56.1% (n = 78) had stopped working. The study was approved by the Senate Ethics Committee at the Józef Piłsudski Univeristy of Physical Education in Warsaw, Poland. The participants were recruited from women who had signed up to attend a traditional childbirth education program in two different hospitals. Those who met the initial entrance requirements (being in good health 169 HUMAN MOVEMENT M. Guszkowska et al., Exercise and relaxation for pregnant women and that this was their first single pregnancy) were allowed to choose whether they wanted to participate in a prenatal program that included relaxation sessions or a completely independent program focused solely on physical exercise. An additional condition to participate in either of these courses was medical approval declaring no contraindications for participation. Those who met the original study prerequisites but did not want to voluntarily participate in either of the research groups were used to create a control group. Additional exclusion criteria included individuals who trained systematically at home or who were already participating in organized exercise or relaxation classes as well as women with multiple pregnancies or with any pregnancy complications. The relaxation group involved 42 women attending prenatal classes with an emphasis on practical relaxation techniques. The course lasted six weeks, with relaxation exercises held twice a week. The participants in this course performed various relaxation techniques which included breathing technique, autogenic training, imagery relaxation, and relaxation methods performed in pairs (often with their partner). The duration of each course varied depending on the subject, but ranged between 30 to 50 minutes. The second group consisted of 56 women who completed an aerobic-strength physical exercise course based on the eight-week 9 Months Active program. The course was conducted by qualified instructors and held twice a week, with each class lasting 50 minutes. The program focused on general fitness by increasing strength, muscle elasticity, and joint mobility with elements taken from Pilates, yoga, and exercise-ball training. The last group was a control group, composed of 41 women participating in traditional childbirth education classes held twice a week for a period of six weeks. This program focused on educating future parents on issues surrounding pregnancy, the postpartum period, childbirth, and postnatal care. The duration of each class varied depending on the subject, but ranged between 45 to 60 minutes. The emotional state of the participants was measured immediately before attending one of their respective classes (pre-test) and then again upon its completion (post-test) by the Profile of Mood States (POMS) by McNair, Lorr, and Droppleman, [27], used to assess five negative affective states (anger, tension, confusion, depression, and fatigue) and vigor. This tool was originally developed to monitor the effects of psychotherapy due to its sensitivity to mood changes, but has often been used to study the effects of physical exercise on emotional states. A Polish version of this assessment tool was used, which met all basic psychometric requirements. A one-off measurement was performed during the seventh class the participants were attending. In the relaxation group, the class on that day focused on Jocobson’s progressive relaxation technique, while the exercise group performed typical exercise activities as 170 part of the 9 Months Active program. The control group attended a typical prenatal class that had no physical fitness, breathing, or relaxation exercises. Furthermore, none of the class content that day involved issues surrounding childbirth, as such a topic could lead to the participants experiencing anxiety and contribute to a worse emotional state. Only pregnant women were allowed to attend the exercise and relaxation classes that day, while those in the prenatal classes were allowed to attend the class with their partners. All of the classes lasted 50 minutes, an analysis was only performed on those participants who had attended all of the preceding six classes in their respective programs. A self-designed questionnaire was also administered, collecting data on each participants (age, marital status, education, and employment status before and during pregnancy) and their pregnancy history as well as a selfassessed health and physical fitness survey (items rated on a 5-point scale, from 1 – very bad to 5 – very good). As the selection of the participants was not randomized, the participants were compared by the use of socio-demographic variables by one-dimensional analysis of variance (ANOVA) and the chi-square test ( 2). A priori analysis found significant differences among the groups in terms of the stage of pregnancy (F = 10.31, p < 0.001), with a post hoc Bonferroni correction finding that the participants in the exercise group were at a significantly earlier stage (26.12 ± 4.58 weeks) than the control group (29.27 ± 3.20 weeks, p < 0.001) or those participating in the relaxation class (29.14 ± 3.60 weeks, p = 0.001); the last two groups did not significantly differ from each other (p > 0.1). Differences were also noted in the proportion of women in their second or third trimester in each group ( 2 = 9.25, p = 0.010). The number of women in their second or third trimester participating in the physical exercise class was similar (53.6% and 46.2%, respectively), while women in their third trimester formed the majority in the relaxation group (n = 28, 66.7%) and control group (n = 31, 75.6%). No statistically significant differences were found between the groups in terms of age (F = 0.677, p > 0.1), marital status ( 2 = 3.831, p > 0.1), being employed while pregnant ( 2 = 2.270, p > 0.1), or self-assessed physical fitness levels (F = 1.035, p > 0.1). However, self-assessed health levels were found to differ (F = 3.070, p = 0.055), with pregnant women who signed up to participate in the exercise course evaluated their health slightly better (4.27 ± 0.59 points) than the control group (3.95 ± 0.67 points, p = 0.054), although they did not differ from those that were to participate in the relaxation group (4.05 ± 0.58). No other statistically significant differences were found between the groups (p > 0.1). Results Means and standard deviations of the participants’ pre-test and post-test results from all three groups are HUMAN MOVEMENT M. Guszkowska et al., Exercise and relaxation for pregnant women Table 1. Pre- and post-test scores measuring emotional states of the relaxation group, exercise group, and the control group Relaxation group (n = 42) Variables Anger Confusion Depression Fatigue Tension Vigor Exercise group (n = 56) Control group (n = 41) Pre-test M (SD) Post-test M (SD) Pre-test M (SD) Post-test M (SD) Pre-test M (SD) Post-test M (SD) 4.43 (5.32) 6.83 (3.93) 5.24 (5.78) 6.07 (4.78) 6.48 (4.62) 17.74 (5.55) 2.64 (4.15) 4.90 (3.56) 3.14 (4.68) 4.24 (4.54) 3.10 (3.37) 18.60 (5.95) 4.68 (5.10) 6.16 (3.72) 5.46 (7.74) 5.11 (4.19) 5.59 (4.91) 18.55 (4.54) 1.79 (3.04) 3.89 (2.56) 2.45 (5.48) 3.50 (3.38) 3.38 (3.54) 20.32 (4.42) 4.46 (4.69) 6.90 (4.19) 4.46 (5.42) 4.66 (3.38) 6.49 (5.40) 17.68 (3.83) 3.56 (4.94) 6.27 (4.21) 3.80 (4.81) 4.39 (3.88) 5.54 (5.27) 18.39 (4.84) presented in Table 1. Analysis of the pre-test POMSmeasured emotional states of the participants found no significant differences in the levels of anger (F(2,136) = 0.036, p < 0.1), confusion (F(2,136) = 0.545, p > 0.1), depression (F(2,136) = 0.289, p < 0.1), fatigue (F(2,136) = 1,261, p > 0.1), tension (F(2,136) = 0.538, p > 0.1), and vigor (F(2,136) = 0.543, p > 0.1), pointing to a similar emotional state among the three groups. This allowed further analysis to be performed without control of the baseline outcome measures. Repeated measures analysis of variance (Group × Time of measurement) was performed to determine the changes in emotional state and how they differed depending on the type of course that was attended. Since the groups significantly differed in terms of the stage of pregnancy, this variable was treated as a covariate. The post-test results were also compared using onedimensional analysis of variance. Here, it was found that the level of anger in the entire study group significantly decreased (F(1,136) = 5.080, p = 0.026, 2 = 0.036) and did not depend on the type of group (effect of Group was insignificant F(2,136) = 0.329, p > 0.1). There was, however, a significant interaction between the groups and time of measurement (F(2,136) = 3.342, p = 0.038, 2 = 0.047). Within-group repeated measures analysis of variance found that all participants experienced a significant reduction in anger, although the effect was stronger in the exercise group (F(1,55) = 28.533, p < 0.001, 2 = 0.342) and relaxation group (F(1,41) = 16.586, p < 0.001, 2 = 0.288) than in the control group (F(1,40) = 5.308, p = 0.026, 2 = 0.117). No significant effect of trimester was found (F(1,136) = 0.046, p > 0.1). In the post-test, significant intergroup differences were found (F(2,136) = 2.328, p = 0.101). The level of confusion of the entire group did not change significantly (F(1,136) = 2.091, p > 0.1) and did not vary depending on the group (F(2,136) = 1.523, p > 0.1). However, a significant interaction between the groups and time of measurement was observed (F(2,136) = 3.832, p = 0.024, 2 = 0.054). Significant decreases in confusion were noted for the relaxation group (F(1,41) = 25.95, p < 0.001, 2 = 0.388) and exercise group (F(1,55) = 31.123, p < 0.001, 2 = 0.361), with no statistically significant changes found in the con- trol group (F(1,41) = 2.429, p > 0.1). A trend was observed with the effect of trimester (F(1,136) = 2.946, p = 0.088, 2 = 0.024), where confusion increased at more advanced stages of pregnancy. The groups were significantly differentiated in the post-test (F(2,146) = 5.709, p = 0.004), with the level of confusion significantly higher in the control group than the pregnant women who were exercising (p = 0.003). A similar case was found for depression, with no significant main effect found (F(1,136) = 0.359, p > 0.1). Participation in any of the groups did not determine its level (main effect of group was insignificant F(2,136) = 0.016, p > 0.1). However, a significant interaction between group and time of measurement was observed (F(2,136) = 3.805, p = 0.025, 2 = 0.053), stemming from the fact that a significant decrease in the level of depression occurred in the relaxation group (F(1,41) = 22.391, p < 0.001, 2 = 0.353) and exercise group (F(1,55) = 17.810, p < 0.0001, 2 = 0.245), with no statistically significant changes in the control group (F(1,40) = 1.619, p > 0.1). The effect of trimester was also statistically insignificant (F(1,41) = 22.391, p < 0.001, 2 = 0.353). In the post-test no significant intergroup differences were found (F(2,136) = 0.863, p > 0.1). The level of fatigue did not significantly change among the entire group (F(1,136) = 0.080, p > 0.1). Analysis performed on each of the individual groups confirmed a significant decrease in fatigue again for the exercise group (F(1,55) = 8.009, p = 0.016, 2 = 0.127) and relaxation group (F(1,41) = 5.234, p = 0.027, 2 = 0.113), with insignificant changes in the control group (F(1,40) = 0.072, p > 0.1). Neither was the main effect of group (F(2,136) = 0.579, p > 0.1) or the interaction between group and time of measurement (F(2,136) = 1.671, p > 0.1) found to be statistically significant. However, a significant effect of trimester was found (F(1,136) = 4.572, p = 0.034, 2 = 0.033), with women at a more advanced stage of pregnancy featuring higher levels of fatigue. The groups did not differ significantly in the post-test measurement (F = 0.740, p > 0.1). The entire study sample exhibited a significant decrease in tension (F(1,136) = 5.899, p = 0.016, 2 = 0.042). Within-group analysis pointed to a significant decrease in tension in the relaxation group (F(1,41) = 29.036, p < 171 HUMAN MOVEMENT M. Guszkowska et al., Exercise and relaxation for pregnant women 0.001, 2 = 0.415) and exercise group (F(1,55) = 18.890, p < 0.001, 2 = 0.256) with no significant changes in the control group (F(1,40) = 2.215, p > 0.1). The mean tension level did not vary depending on the group (F(2,136) = 1.42, p > 0.1), although the interaction between group and time of measurement was statistically significant (F(2,136) = 3.670, p = 0.028, 2 = 0.052). The effect of trimester was also statistically insignificant (F(1,136) = 0.094, p > 0.1). In the post-test, significant intergroup differences were noted (F(2,136) = 4.566, p = 0.012); the tension level was higher in the control group than the relaxation group (p = 0.022) and exercise group (p = 0.033), with neither of the last two groups differing significantly from each another. Among the last studied parameter, the level of vigor did not significantly change in the entire group (F(1,136) = 1.233, p > 0.1). Analysis on each of the individual groups confirmed a significant increase in vigor only in the participants in exercise program (F(1,55) = 17.190, p < 0.001, 2 = 0.238). No statistically significant changes were found in the relaxation group (F(1,41) = 1.023, p > 0.1) or control group (F(1,40) = 1.582, p > 0.1). Neither was the main effect of group (F(2,136) = 0.639, p > 0.1) or the interaction between group and time of measurement (F(1,136) = 0.718, p > 0.1) found to be statistically significant. A significant effect of trimester was found (F(1,136) = 5.744, p = 0.018, 2 = 0.041), with vigor higher in women in the second trimester. No statistically significant differences between the groups were found in the post-test measurements (F(2,136) = 2.209, p > 0.1). Discussion The results of the mood assessment scale found that pregnant women who participated in an exercise or relaxation session improved their emotional state. These improvements in both groups were larger than for women participating solely in traditional prenatal classes. In this last group, only a significant decrease in anger was observed. For pregnant women participating in physical exercise, an improvement in mood was seen in all indicators of emotional state, with the same seen for women in the relaxation group except in the case of vigor. As of yet, few comparisons have been made on the effectiveness of physical exercise and relaxation as two concurrent effects on emotional well-being. The few studies that do exist compared the anti-anxiety effects of different forms of physical exercise and relaxation techniques, finding relatively minor differences between these two methods in terms of a decrease in anxiety and tension [28–30]. This study found that the emotional benefits of relaxation and physical exercise to be slightly different from each other, as evidenced when comparing the size of the effects. The levels of tension, anger, confusion, and depression were found to be smaller, albeit minimally, after completing the exercise session than the 172 relaxation class, although a larger decrease was noted in fatigue. Furthermore, only the exercise group presented a significant increase in vigor. On the other hand, relaxation resulted in a profound drop in negative emotional states, although the positive state of vigor did not change. Similar results were obtained by Saklofske et al. [31] when comparing the effects of walking and relaxation on the affective sphere. Both conditions caused a significant drop in tension, although only the physically active group featured increased energy levels. It seems that physical activity is at least no less effective than relaxation techniques in reducing negative emotional states, while being more effective in inducing positive states. The results of the present study were found to be in line with those presented earlier, in which it was concluded that one-off workouts improve the emotional well-being of different groups [15–19], including pregnant women [20, 22, 23]. The effectiveness of physical exercise appears to be particularly high in bringing about those states associated with arousal, where, in the present study, only the exercise group presented a significant increase in the amount of vigor while at the same time featuring the largest decrease in fatigue. However, the effectiveness of various relaxation methods in reducing anxiety levels has also been confirmed in the meta-analysis carried out by Manzoni et al. [24]. Additionally, a study focused on pregnant women also confirmed that participation in relaxation classes lowered anxiety levels [32]. In the present study, the relaxation class on the day of measurement was based on progressive relaxation, which had been proven to be particular effective in both the general population [24] as well as pregnant women [25, 32]. Although the effectiveness of relaxation methods in reducing negative emotional states was slightly greater than by physical exercise, no significant change was noted in vigor. This cause and effect relationship seems to be quite logical. Relaxation in itself is based on reducing overall arousal levels. This results in a decrease in the intensity of negative emotions, but it may also be the cause of the decrease in vigor and increase in lethargy. The obtained results seem to confirm Russell’s circumplex model of affect [33]. According to this author, there exist two independent dimensions of affect, one related to valence (pleasure–displeasure) and the other to arousal (alertness–somnolence). This allows four categories of affect to be distinguished: positive arousal (a pleasant state, feeling joyful excitement, energy, and vigor), positive low arousal (associated with feelings of inner peace and contentedness), negative arousal (suffering), and negative low arousal (sadness and depression). Relaxation leads to positive low arousal, causing a decrease in anxiety and tension since these states are associated with negative stimulation (or at least stabilizes their levels, as was found in the present study), and also caused a decrease in overall arousal, and, conse- HUMAN MOVEMENT M. Guszkowska et al., Exercise and relaxation for pregnant women quently, an increase in feelings of pleasure. Physical exercise also led to increase in hedonistic feelings but in different way, primarily by increasing the general level of arousal that is felt as a rise in vitality, vigor, and vital energy. None of the three analyzed groups differed from one another in terms of their emotional well-being before beginning their respective classes (pre-test). Upon finishing, however, certain intergroup differences were noted especially between those participating in the childbirth education program and the 9 Months Active exercise program. The pregnant women taking part in physical exercise revealed lower levels of confusion and tension. No significant differences were found between the exercise and relaxation groups, however. One of the more interesting results of the present study was the decrease in the level of anger in the control group. Prenatal classes held in traditional childbirth schools provide expectant mothers with various information and help them prepare for childbirth. This may have contributed to their improvement in mood due to not only the subject matter (infant care) but also that the fathers/partners of the child were also allowed to attend, providing an important source of support. It should also be remembered that simply being in a peaceful environment is enough to improve one’s emotional state [18]. The study did have a number of limitations, beginning with the fact that the sample population was rather homogeneous: all of the participants were welleducated, living in a capital city, had a steady job before pregnancy, and had above-average incomes, all of which limits the generalization of the results. Secondly, the selection process was not randomized, as the participants chose which class they would like to take based on their own personal preferences. As a result, women in less advanced stages of pregnancy and slightly better assessing their own health naturally gravitated towards the course focusing on physical exercise. However, the effect of trimester, or how advanced the pregnancy was, was statistically controlled. The week of gestation significantly differentiated the levels of fatigue and vigor, with women in their third trimester having lower energy levels and felt more tired. This effect was not found among the other negative states (anger, confusion, depression, or tension), which is in contrast to previous studies that suggest more advanced pregnancies have increased feelings of anxiety and depression [34, 35]. Thirdly, as fathers were allowed to attend the traditional prenatal class (control group), this may have also significantly affected the emotional states of the expectant mothers. Conclusions Despite these limitations, the results are suggestive that a one-off exercise and relaxation session can in- crease levels of emotional comfort in pregnant women more effectively than attending a traditional prenatal class. Physical exercise can cause an increase in energy levels, while progressive relaxation techniques can help reduce the level of negative affect. Physical exercise may be particular useful when dealing with fatigue and feeling tired, which are often experienced during pregnancy, while relaxation techniques are likely to bring greater benefits to pregnant women with elevated levels of anxiety or depression. Acknowledgements The research was financed under project no. NN 404 017838, “The influence of pregnant women’s physical activity on their mental and physical health, the course of pregnancy, and childbirth,” by the Ministry of Science and Higher Education in Poland. References 1. Davies G.A., Wolfe L.A., Mottola M.F., MacKinnon C., Arsenault M.Y., Bartellas E. et al., Exercise in pregnancy and postpartum periods. J Obstet Gynecol Can, 2003, 25 (6), 516–529. 2. Royal College of Obstetricians and Gynaecologists, Exercise in pregnancy (RCOG Statement 4), 2006. Available from: URL: http://www.rcog.org.uk/index.asp/PageID=1366. 3. Reimann M.K., Kanstrup Hansen I-L., Effects on the foetus of exercise in pregnancy. Scand J Med Sci Sports, 2000,10(1),12–19,10.1034/j.1600-0838.2000.010001012.x. 4. Weissgerber T.L., Wolfe L.A., Davies G.A.L., Mottola M.F., Exercise in the prevention and treatment of maternal– fetal disease: a review of the literature. Appl Physiol Nutr Metab, 2006, 31 (6), 661–674, doi: 10.1139/h06-060. 5. Melzer K., Schutz Y., Boulvain M., Kayser B., Physical activity and pregnancy. Cardiovascular adaptations, recommendations, and pregnancy outcomes. Sports Med, 2010, 40 (6), 493–507, doi: 10.2165/11532290-00000000000000. 6. Artal M., O’Toole M., Guidelines of the American College of Obstetricians and Gynecologists for exercise during pregnancy and the postpartum period. Brit J Sports Med, 2003, 37 (1), 6–12, doi: 10.1136/bjsm.37.1.6. 7. Evenson K.R., Savitz D.A., Huston S.L., Leisure-time physical activity among pregnant women in the US. Paediatr Perinat Epidemiol, 2004, 18 (6), 400–407, doi: 10.1111/ j.1365-3016.2004.00595.x. 8. Poudevigne M.S., O’Connor P.J., A review of physical activity patterns in pregnant women and their relationship to psychological health. Sports Med, 2006, 36 (1), 19–38, doi: 10.2165/00007256-200636010-00003. 9. Rousham E.K., Clarke P.E., Gross H., Significant changes in physical activity among pregnant women in the UK as assessed by accelerometry and self-reported activity. Eur J Clin Nutr, 2006, 60 (3), 393–400, doi: 10.1038/ sj.ejcn.1602329. 10. Evenson K.R., Wen F., Prevalence and correlates of objectively measured physical activity and sedentary behavior among US pregnant women. Prev Med, 2011, 53 (1–2), 39–43 doi: 10.1016/j.ypmed.2011.04.014. 11. Andersson L., Sundstrom-Poromaa I., Wulff M., Astrom M., Bixo M., Implications of antenatal depression and 173 HUMAN MOVEMENT M. Guszkowska et al., Exercise and relaxation for pregnant women anxiety for obstetric outcome. Obstet Gynecol, 2004, 104 (3), 467–476, doi: 10.1097/01.AOG.0000135277.04565.e9. 12. Martini J., Knappe S., Beesdo-Baum K., Lieb R., Wittchen H-U., Anxiety disorders before birth and self-perceived distress during pregnancy: Associations with maternal depression and obstetric, neonatal and early childhood outcomes. Early Hum Dev, 2010, 86 (5), 305–310, doi: 10.1016/j.earlhumdev.2010.04.004. 13. Parcells D.A., Women’s mental health nursing: depression, anxiety and stress during pregnancy. J Psychiatr Ment Health Nurs, 2010, 17 (9), 813–820, doi: 10111/j.1365-2850. 2010.01588.x. 14. Field T., Diego M., Hernandez-Reif M., Figueiredo B., Deeds O., Ascencio A. et al., Comorbid depression and anxiety effects on pregnancy and neonatal outcome. Infant Behav Dev, 2010, 33 (1), 23–39, doi: 10.1016/j.infbeh. 2009.10.004. 15. Biddle S.J.H., Emotion, mood and physical activity. In: Biddle S.J.H., Fox K.R., Boutcher S.H. (eds.), Physical activity and psychological well-being. Routledge, London 2000, 63–87. 16. Biddle S.J.H., Mutrie N., Psychology of physical activity. Determinants, well-being and interventions. 2d ed. Routledge, London 2008. 17. Landers D.M., Arent S.M., Physical activity and mental health. In: Singer R.N., Hausenblas H.A., Janelle C.M. (eds.), Handbook of sport psychology. Wiley, New York 2001, 740–765. 18. Yeung R.R., The acute effect of exercise on mood state. J Psychosom Res, 1996, 40 (2), 123–141. 19. Reed J., Ones D.S., The effect of acute aerobic exercise on positive activated affect: A meta analysis. Psychol Sport Exerc, 2006, 7 (5), 477–514, doi: 10.1016/j.psychsport.2005. 11.003. 20. Koltyn K.F., Mood changes in pregnant women following an exercise session and a prenatal information session. Women’s Health Issue, 1994, 4 (4), 191–195. 21. Koltyn K.F., Schultes S.S., Psychological effects of an aerobic exercise session and a rest session following pregnancy. J Sport Med Phys Fitness, 1997, 37 (4), 287–291. 22. Lox C.L., Treasure D.C., Changes in feeling states following aquatic exercise during pregnancy. J Appl Soc Psychol, 2000, 30 (3), 518–527, 10.1111/j.1559-1816.2000. tb02494.x. 23. Guszkowska M., Bernatek P., Changes in emotional states inpregnant women after one-time physical exercise [in Polish]. Polskie Forum Psychologiczne, 2010, 15, 14–24. 24. Manzoni G.M., Pagnini F., Castelnuovo G., Molinari E., Relaxation training for anxiety: a ten-years systematic review with meta-analysis. BMC Psychiatry, 2008, 8 (6), 41, doi: 10.1186/1471-244X-8-41. 25. Urech C., Fink N.S., Hoesli I., Wilhelm FH, Bitzer J., Alder J., Effects of relaxation on psychobiological wellbeing during pregnancy: A randomized controlled trial. 174 Psychoneuroendocrinology, 2010, 35 (9), 1348–1355, doi: 10.1016/j.psyneuen.2010.03.008. 26. Teixeira J., Martin D., Prendiville O., Glover V., The effect of acute relaxation on indices of anxiety during pregnancy. J Psychosom Obstet Gynecol, 2005, 26 (4), 271–276, doi: 10.1080/01674820500139922. 27. Dudek B., Koniarek J., Adaptation of Profile of Mood States (POMS) by D.M. McNair, M. Lorr and L.F. Droppleman [in Polish]. Przegląd Psychologiczny, 1987, 3, 753–762. 28. Crocker P.R.E., Grozelle C., Reducing induced state anxiety: effect of acute aerobic exercise and autogenic relaxation. J Sports Med Phys Fitness, 1991, 31 (2), 277–282. 29. Glazer A.R., O’Connor P.J., Mood improvements following exercise and quiet rest in bulimic women. Scand J Med Sci Sports, 1993, 3 (1), 73–79, doi: 10.1111/j.1600-0838. 1993.tb00365.x. 30. Brown D.R., Morgan W.P., Raglin J.S., Effects of exercise and rest on the state anxiety and blood pressure of physically challenged college students. J Sports Med Phys Fitness, 1993, 33 (3), 300–305. 31. Saklofske D.H., Blomme G.C., Kelly I.W., The effect of exercise and relaxation on energetic and tense arousal. Personality and Individual Differences, 1992, 13 (5), 623– 625, doi: 10.1016/0191-8869(92)90204-3. 32. Newham J.J., Westwood M., Aplin J.D., Wittkowski N., State-trait anxiety inventory (STAI) scores during pregnancy following intervention with complementary therapies. J Affect Disord, 2012, 142 (1), 22–30, doi: 1016/j. jad.2012.04.027. 33. Russell J.A., A Circumplex model of affect. J Pers Soc Psychol, 1980, 39 (6), 1161–1178, doi: 10.1037/h0077714. 34. DiPietro J.A., Mendelson T., Williams E.L., Costigan K.A., Physiological blunting during pregnancy extends to induced relaxation. Biol Psychol, 2012, 89 (1), 14–20, doi: 10.1016/j.biopsycho.2011.07.005. 35. Hoffman S., Hatch M., Depressive symptomatology during pregnancy: Evidence for an association with decreased fetal growth in pregnancies of lower social class women. Health Psychol, 2000, 19 (6), 535–543. Paper received by the Editors: September 20, 2012 Paper accepted for publication: April 24, 2013 Correspondence address Monika Guszkowska Zakład Podstaw Społeczno-Kulturowych w Turystyce Wydział Turystyki i Rekreacji Akademia Wychowania Fizycznego ul. Marymoncka 34 00-968 Warszawa, Poland e-mail: [email protected] HUMAN MOVEMENT 2013, vol. 14 (2), 175– 184 Analogy vs. technical learning in a golf putting task: an analysis of performance outcomes and attentional processes under pressure doi: 10.2478/humo-2013-0021 Linda Schücker 1 *, Norbert Hagemann 2 , Bernd Strauss 1 1 2 Institute of Sport and Exercise Sciences, University of Muenster, Muenster, Germany Institute of Sports and Sport Science, University of Kassel, Kassel, Germany Abstract Purpose. It is assumed that analogy learning helps prevent individuals from choking under pressure by limiting the conscious control of movements when performing in high-pressure situations. The aim of the study was to extend the application of analogy learning to golf putting and include an assessment on the proposed mechanisms of analogy learning and performance under pressure. Methods. Golf novices learned a putting task either by technical instructions or with analogy. After the learning phase, the participants were tested under low- and high-pressure conditions. Attentional focus was measured using a dual-task paradigm based on a skill and an externally focused task. Results. Both groups showed an increase in putting accuracy under pressure while performance in both dual-tasks decreased under pressure. Despite a difference in verbal knowledge, no group differences were found in putting or dual-task performance. Conclusions. The results suggest that it does not matter if the skill is learned technically or by analogy with regard to performance under pressure. Key words: motor learning, implicit learning, attentional mechanisms Introduction The phenomenon of choking under pressure has been frequently studied over the past several decades. Besides its underlying mechanisms, strategies to prevent choking under pressure are of considerable interest to researchers. Choking under pressure has been defined as performing more poorly than expected given one’s skill level in situations with high performance pressure [1, 2]. Cases of choking have occurred across a wide range of sports and even those performed by highly skilled athletes. Missing a seemingly easy putt in an important golf tournament is just one famous example where choking can be observed among professional athletes. However, it is important to keep in mind that not every performance failure can be equated with choking. Random fluctuations in skill level are common; only significantly less than optimal performance as a response to a high pressure situation can be considered as choking [2, 3]. Furthermore, according to Baumeister [1], an additional definition of choking under pressure is where the individual desire to perform in an optimal way is the highest, yet, despite this optimal motivation and the athletes’ strive to perform at their best, their performance drops to a suboptimal level. Researchers attempting to study this phenomenon are required to induce pressure experimentally, which poses one of the challenges in this field of research. * Corresponding author. Pressure is defined as the presence of a situation in which the incentive for optimal performance is highest and subjectively perceived as such [4]. Furthermore, pressure relies on the contingency of rewards or punishment on performance outcome, it can include the presence of an evaluative audience and other competitors, is dependent on how personally important a performance outcome really is, and in situations when the event is thought to be unrepeatable [4]. Besides individual differences in susceptibility to choking, such as dispositional reinvestment, two different attentional theories have been proposed to explain the paradoxical performance effects in high pressure situations. Distraction theories assume that pressure creates a distracting environment that impairs attentional resources necessary to successfully execute the task [e.g., 2, 5, 6]. Distractions can include concentrating on taskirrelevant stimuli or being apprehensive about a given situation [4, 6–8]. A specific distraction theory currently being discussed is attentional control theory (ACT), which has been proposed by Eysenck et al. [6]. It assumes that under pressure processing resources are disturbed by task-irrelevant stimuli culminating in poorer processing efficiency. Eysenck et al. further assumed that efficiency is disturbed more than effectiveness (performance outcome). Therefore, while performance quality might be stable, more resources are needed to attain a given performance level, or, in other words, one has to invest more effort for the same performance outcome while under pressure. Studies on distraction theories have confirmed it in tasks that require high demands on working memory [9, 10]. 175 HUMAN MOVEMENT L. Schücker, N. Hagemann, B. Strauss, Analogy learning in golf putting On the other hand, self-focus theories (also termed explicit monitoring theories) have gained support when accounting for the phenomenon of choking during sensorimotor tasks [1, 11]. In this case, it is assumed that pressure causes a redirection of attention to the actual execution of movement, leading to conscious control of usually automated processes and consequently to a breakdown in performance [e.g., 1, 11, 12]. Explicit monitoring theories Many studies have been designed using explicit monitoring theories as a theoretical guideline. There is ample evidence showing that directing attention to the execution of well-learned motor tasks leads to performance decrements. The detrimental effect of internally focused attention has been studied in a number of different sports. In many of these studies, attentional focus was treated as the independent variable whereas pressure was taken out of the equation. Beilock, Carr, MacMahon, and Starkes [13] conducted two experiments manipulating attentional focus by including an internal skill-focus condition and an external dual-task condition during movement execution. In two different sports, golf putting and soccer dribbling, they found better performance in the external rather than the internal focus of attention in a group of experienced players. However, novice performers as well as experts performing a less familiar task (dribbling with the non-dominant foot in soccer) profited from monitoring the step-by-step execution of the movement, which indicated the importance of skill level for the attentional focus effect. These results were replicated in field hockey, with the slowest performance found when participants monitored the position of their hand while the fastest under dual-task conditions [14]. Similar effects were also found in baseball [15], again in soccer [16], and in golf pitching performance [17]. In running, as a cyclic endurance task, an external focus was superior to two internal focus conditions in terms of movement economy [18]. Wulf et al. conducted a series of experiments on the effects of attentional focus [see 19 for a review]. They explained the detrimental effects of an internal focus of attention by constraining the motor system and interfering with automatic control processes. EMG studies lend support to this constrained action hypothesis [20, 21]. According to the reinvestment theory [22], an inward focus of attention implies conscious control over the movement with explicit knowledge. This, in turn, leads to a deterioration in performance as the skill no longer functions automatically [23]. Reinvestment of declarative knowledge of how a skill works [22] as well as explicitly monitoring a skill [11] and constrained action [19] all consistently conclude that focusing on the execution of well-learned motor tasks has a negative effect on performance by interfering with automatic movement control. 176 It is assumed that the consistently reported negative effect of an internal focus of attention mirrors the attentional processes induced by pressure [2]. Indirect evidence was found in training studies, which showed that practice with dealing with an internal focus of attention reduced choking under pressure by letting participants adapt to the attentional focus they experience under pressure [see 7, 11]. More direct evidence about the attentional mechanisms involved in choking was presented by Gray [12]. Using a simulated baseball batting task, he assessed attentional focus by using a dual-task paradigm. A short tone was presented during movement execution. Skill-focused attention was measured by judging the direction of bat movement upon hearing the tone while externally-focused attention was measured by judging the pitch of the tone. When placed under pressure, participants demonstrated a higher level of skill-focused attention (better performance in the skill-focused dual task, meaning higher accuracy in judging bat movement) compared with a control group without pressure. The tone-judgment task was found not to be affected by pressure. Also important was the fact that an increase in skill-focused attention was related to a deterioration in batting performance and changes in batting kinematics. This frequently cited study was the first to directly demonstrate that pressure does induce an inward shift of attentional focus as Baumeister [1] had proposed 20 years earlier. Results from an experimental study that included measurement of the “quiet eye” go in line with strengthening the importance of attentional focus under pressure [24]. This study showed that individuals who did not choke under pressure were able to direct visual attention externally, as was indicated by a longer quiet eye period. Further support for the explicit monitoring theory was demonstrated in an experiment by Gucciardi and Dimmock [25], where they directly compared self-focus to distraction theories on a group of experienced golfers. They showed degraded performance under pressure when they relied on explicit knowledge, while focusing on task-irrelevant cues as well as the swing thought condition did not cause choking. Attempts to prevent choking under pressure Different kinds of strategies to prevent choking have been reported in the literature on the subject. One approach is to let participants adapt to the kind of focus they experience under pressure. Studies have found that training under self-focus conditions reduces a deterioration of performance when under pressure [7, 11]. In a recent study, Oudejans and Pijpers [26] demonstrated that training under mild levels of anxiety reduced performance decrements under subsequently higher levels of anxiety. It has to be noted, however, that anxiety (induced in this case by different heights on a climbing wall) is not the same as pressure. Pre-performance routines have also been discussed as a way to alleviate HUMAN MOVEMENT L. Schücker, N. Hagemann, B. Strauss, Analogy learning in golf putting choking. It was assumed that they enable the motor response to run automatically without conscious control [27, 28]. Another approach involved participants thinking of a global cue rather than detailed explicit instructions when performing under pressure [29]. Choking was reduced in this swing thought condition, and similar results were shown by Gucciardi and Dimmock [25]. Opposed to the aforementioned strategies is the approach promoted by Masters [23]. He assumes that explicit knowledge about movement execution is reinvested under pressure and causes detrimental performance effects. It follows that the avoidance of the buildup of explicit knowledge is a way to prevent choking. So, rather than implementing a strategy to help athletes deal with the pressure situation, Masters [23] favors an intervention during the skill acquisition phase. In his experiment, he showed that participants who had only acquired a small amount of explicit knowledge (through implicit learning) were less susceptible to choking under pressure [23]. However, implicit motor learning incorporates several problems (such as it being a lengthy process) that makes it difficult to implement in sports training contexts outside a laboratory setting. As an alternative, Masters [30] suggested analogy learning as it operates with biomechanical metaphors instead of declarative knowledge and technical know-how. Here, he proposed that only one rule which consists of a general analogy ought to be provided and should include all the technical aspects necessary to execute the skill successfully [30]. Liao and Masters [31] designed an experiment to test whether analogy learning shows similar characteristics as implicit learning. Table tennis novices were instructed to learn the topspin forehand either implicitly, explicitly, or by analogy (drawing a right-angled triangle with a table tennis paddle). The results confirmed the implicit characteristics of analogy learning with less explicit knowledge and its robustness when performing under dual-task conditions. In a second experiment, Liao and Masters [31] showed that analogy learners’ performance was not negatively affected by pressure as opposed to that of the explicit learning group. Using the same analogy learning paradigm, Law et al. [32] showed that supportive audiences (under the notion that supportive audiences induce stress) brought about performance decrements only in the explicit learning group. It was believed that analogy learners acquire less explicit knowledge about a movement, which leads to less consciously controlled movement execution under stress. Contrasting results were shown in another study using analogy learning in the table tennis forehand [33]. In this study, a large number of repetitions (10,000) were implemented during the learning phase in an analogy and explicit learning group. Performance was assessed after 1,400 and 10,000 repetitions under pressure conditions. Despite the fact that the explicit learning group accumulated more explicit rules, neither of the groups showed performance decrements when under pressure. These findings did not confirm the fact that the amount of explicit knowledge is related to performance decrements under pressure. As table tennis had been predominantly used in analogy learning, Lam, Masters and Maxwell [34, 35] conducted two studies using a new motor task that involved taking basketball shots from a seated position. In one study, it was shown that performance did not degrade for the analogy condition in a dual-task transfer test but did for both explicit and control conditions [35]. The other study involved a pressure manipulation to test Masters’ [23] theory of explicit knowledge reinvestment under pressure [34]. After two days of learning with a total of 480 trials, the third day consisted of a test phase in an A–B–A (low-pressure, highpressure, low-pressure) design. Probe reaction times (PRT) to assess allocation of attention and shooting performance were treated as the dependent variables. No difference in performance was found for the analogy group, while the explicit learning group displayed a significant drop in performance in the high-pressure condition. PRT did not show any differences, suggesting an equal attentional load in both groups. As the analogy learners reported less explicit rules about their movement, the results were interpreted as evidence for the presence of conscious processing. However, as the authors noted in their discussion, this evidence was rather incidental, where a direct measure of cognitive processes under different pressure conditions would be more helpful in finding better evidence on how level analogy learning actually operates. Schücker, Ebbing, and Hagemann [36] conducted a study incorporating two kinds of learning instructions (analogy vs. technical) and linked them to a measure of skill-focused attention under low- and highpressure. The results revealed higher amounts of skillfocused attention for the technical learning group compared with the analogy learning group during the high-pressure condition. However, these differences were not related to differences in performance and a manipulation check for pressure was missing. Furthermore, the method of analogy learning differed considerably from that of Masters [30], as it worked with a whole set of analogies instead of using a single metaphor encompassing all technical aspects of the movement. The present study To this day, explanations for the positive effect of analogy learning in preventing choking under pressure have mostly been deduced rather indirectly. Differences in the amount of explicit knowledge between learning groups are taken as evidence for the conscious processing hypothesis [34]. This study aims to relate different learning methods to an assessment of attentional processes under pressure by means of a dual-task para digm. Several studies proved that analogy learning is helpful in avoiding performance decrements when under pressure compared with classic learning paradigms based 177 HUMAN MOVEMENT L. Schücker, N. Hagemann, B. Strauss, Analogy learning in golf putting on technical instructions [e.g., 31, 32, 34]. Gray [12] successfully used a dual-task paradigm and showed an increase in skill-focused attention under pressure. The aim of this study was to combine these two approaches to show the efficacy of analogy learning in alleviating choking under pressure, on the one hand, and to assess its functioning by implementing a skill-focused dual task on the other hand. As analogy learning has not yet been implemented in studying different movement skills, it was decided to test this method on a golf putting task. As the movement in putting has been commonly represented through a pendulum analogy [e.g., 37], it was decided to use this analogy as it incorporates the essential aspects of the movement. In line with previous research, it was expected that analogy and technical learning groups would improve performance equally in the learning phase, but that only the analogy learning group would retain performance under pressure while the technical learning group would show the choking effect. Performance in a skill-focused dual task was used as an indicator for the amount of skillfocused attention. It was assumed that the technical learning group would show an increase in skill-focused attention under pressure when compared with the analogy learning group. Material and methods Participants Apparatus The putting task was performed on an artificial grass putting mat 4 m in length and 1.5 m in width. Standard golf balls were placed 2 m from the target, which was indicated by a red circle with a diameter of 10 cm. A grid with 5 cm squares was plotted on the mat around the target to allow for quick assessment of putting performance by scoring vertical and horizontal error. All participants used the same standard putter. A Casio EX-F1 digital camera (Casio, Japan) was used to record the putting movement at a rate of 30 frames per second. To assess focus of attention, a dual-task design similar to the one in Gray’s [12] experiments was used. A single 100 ms auditory tone (produced at 800 or 1000 Hz) was presented while the participants performed the putt. After completing the putt the participants were randomly asked to either judge the pitch of the tone or at what movement phase the tone was sounded (“Which tone was it?” or “Which picture was it?”). The movement phase was judged by pictures showing the whole putting movement, the participants were asked to indicate which picture best corresponded to the point in time when the tone was heard during the movement (Fig. 1). The tone was linked to a light signal so the actual point in time when the tone was heard could be identified later during video analysis. Procedure Forty-one undergraduate students (23 males, 18 females) volunteered to take part in this study. Their mean age was 21.44 years (SD = 2.98). None had any previous golf experience nor had received any kind of formal instruction before. Participants were randomly assigned to either an analogy (n = 20, 9 females and 11 males) or a technical (n = 21, 9 females and 12 males) learning group. Three participants in each group were lefthanded. Written informed consent was obtained before the beginning of the experiment. The study was conducted according to the ethical guidelines of the American Psychological Association (APA). Participants were tested individually by performing a series of 300 putts during the learning phase followed by another but shorter series of putts in the test phase. They were instructed to try to place the ball as close as possible to the middle of a red circle from a distance of 2 m. The participants were given an information sheet either with the analogy instructions or a set of six technical instructions according to their group. Both groups also received a picture demonstrating the starting position. The analogy group’s instructions included the metaphor of performing the movement like a pendulum, which was visually demonstrated to Figure 1. Pictures used for the skill-focused dual task showing the whole putting movement 178 HUMAN MOVEMENT L. Schücker, N. Hagemann, B. Strauss, Analogy learning in golf putting Table 1. Technical instructions for putting, adapted from Poolton, Maxwell, Masters, and Raab [38] Technical instructions 1. Move your arms and the club back a short distance 2.Swing your arms and the club forward with a smooth action along a straight line 3. Allow your arms and the club to continue swinging a short distance after contact with the ball 4. Adjust the speed of your arms and the club so that the correct amount of force is applied 5. Adjust the angle of your arms and the club to attain the correct direction 6. Focus on the ground for a few seconds after hitting the ball them (swinging a weight on a cord). The technical instructions were based on those by Poolton et al. [38]. However, in this study, we did not differentiate between an internal and an external focus of attention as this was not the focus of our experiment (Tab. 1). After each set of 50 putts the participants rested for a period of 1–2mins. During the break they were reminded of their specific learning instructions. After completing 300 putts both learning groups were asked to write down the rules they had actually used during the learning phase. After the learning phase was completed, the participants had to complete four blocks of 20 trials under dual-task conditions. The first series of 20 putts was used for familiarization with the dual-task procedure followed by an A–B–A (low-pressure, high-pressure, low-pressure) design. The second set of 20 putts was used as the first low-pressure baseline and appeared to the participants as just another series of putts. The third series of putts formed the high-pressure condition followed by a second low-pressure baseline. A scenario that has been frequently used before [e.g., 11, 12] was introduced to increase pressure. After completing the first baseline, participants were told that the putting performance of their last 20 putts was to be calculated. They were then told that during the following series of 20 putts they had a chance of winning an additional 10€ (apart from the 5€ participation fee) by improving their putting performance by 20%. They were also given a team scenario where they were paired with another participant of the experiment and both had to improve their performance to win the extra money. They were then told that their partner had successfully completed their portion of the trial. After giving this pressure scenario, the experimenter calculated the actual putting performance (total distance from target) of the last 20 putts and told the participant by how many centimeters they had to improve in the next series to reach the 20% criterion. Participants were reminded that they still had to provide answers for the dual-task condition. At the end of the experiment putting performance in the high pres- sure condition was calculated and those who actually reached the 20% criterion received the extra reward money. After data collection was completed, all participants were fully debriefed. To assess whether the introduction of pressure manipulation was successful, a German version of the cognitive and somatic anxiety subscales of the CSAI-2R [39] was administered before each series of 20 putts in the low- and high-pressure situations. A pressure rating scale from 1 (no pressure) to 7 (extreme pressure) was admini stered after each pressure condition [see 40]. Data Analysis Putting performance in the learning phase was recorded as the horizontal and vertical distance from target in 5 cm increments. This allowed for a quick assessment during the 300 putts. Total distance from the target was calculated at a later time. In the test phase, the horizontal and vertical distance from target was measured more precisely at 1 cm increments, with total distance also calculated a later time. Video recordings of each participant were analyzed frame by frame with Premiere CS3 Pro (Adobe, USA) to determine the actual point in time at which the tone was sounded during the movement. To assess inter-rater reliability, 10% of the video sample were analyzed by a second independent rater. Intraclass correlation revealed an inter-rater reliability of r = 0.99 at p < 0.001. As was mentioned previously, the difference between the picture which actually corresponded with the tone signal and the picture the participants selected was used as an indicator for measuring performance of judging the movement phase. Tone pitch judgments were calculated as a percentage of the amount of correct judgments. To analyze the verbal protocol, two independent raters who were blind to the learning conditions of the participants counted the number of explicit rules. Statements were only counted as explicit rules if they referred to the technical or mechanical aspects of the movement (e.g., swing with little acceleration/force). They were excluded if they were irrelevant to movement execution (an example of one is “don’t make the concentration phase too short”). Inter-rater reliability was deemed sufficient at r = 0.84, p < 0.001. Average scores were computed to show the number of rules reported by each participant. Statistical Analysis All data analyses were computed with PASW Statistics 18 (SPSS, USA) software. The significance level was set at p < 0.05. For effect sizes, ŋ 2p or d were calculated. Analysis of variance (ANOVA) was used for the main analysis and violation of the assumption of sphericity was corrected by Greenhouse-Geißer adjustments. 179 HUMAN MOVEMENT L. Schücker, N. Hagemann, B. Strauss, Analogy learning in golf putting Results Manipulation check To assess whether pressure was induced successfully, a two factor ANOVA with the within-subject factor pressure and the between-subject factor group was computed for the somatic and cognitive anxiety subscales of the CSAI-2R [39] and the pressure scale. There was no difference between pressure conditions for the somatic anxiety subscale. However, the cognitive anxiety subscale showed significantly higher values under pressure than under the two low-pressure conditions, F (2, 78) = 25.73, p < 0.001, ŋ 2p = 0.40 (first low-pressure M = 16.00, SD = 4.82, high-pressure M = 20.88, SD = 5.73, second low-pressure M = 15.95, SD = 6.30). The pressure scale showed a large effect for pressure as well, F (2, 78) = 91.91, p < 0.001, ŋ 2p= 0.70 (first low-pressure M = 2.68, SD = 1.08, high-pressure M = 4.29, SD = 1.23, second low-pressure M = 2.22, SD = 0.99). There was no significant effect of group and no significant interaction effect of group × pressure. The results of the manipulation check lead to the conclusion that pressure was induced successfully by the cover story. Figure 2. Mean distance from target of technical and analogy learning groups throughout the learning and test phases Learning phase The 300 putts in the learning phase were split into fifteen blocks of 20 putts in order to examine learning progress. For these blocks the mean and within-subject variation (as a measure of putting performance consistency) of total distance (cm) from the target were calculated. To determine whether initial putting performance was equal in the analogy and technical learning group, a one-way ANOVA was computed for the first block of 20 putts. No group differences were found for mean distance from target at F (1, 39) = 1.62, p = 0.69 and withinsubject variation in the first block F (1, 39) = 0.00, p = 0.98. Distance from target was found to be far (M = 48.82, SD = 10.15) and within-subject variation high (M = 35.28, SD = 5.67), indicating that the participants were unfamiliar with the task. A 2 × 15 ANOVA (group × block) with repeated measures for the factor block was calculated for the two dependent measures to assess performance throughout the learning phase. For distance-totarget, a significant effect of block was found, F (8.7, 339.25) = 45.65, p < 0.000, ŋ 2p = 0.54, but not of group, F (1, 39) = 0.13, p = 0.72, and no interaction effect, F (8.7, 339.25) = 0.76, p = 0.65. The results for withinsubject variation revealed the same pattern, a significant effect of block, F (14, 546) = 39.64, p < 0.000, ŋ 2p = 0.5, no effect of group, F (1, 39) = 0.02, p = 0.88, and no interaction effect, F (14, 546) = 0.47, p = 0.95. This shows that both groups improved their putting performance equally throughout the learning phase (see Fig. 2 – mean distance, Fig. 3 – within-subject variation). 180 Figure 3. Within-subject variation in distance from target of the technical and analogy learning groups throughout the learning and test phases Test phase: Putting performance A 2 × 3 (group × pressure condition) ANOVA with repeated measures on pressure condition was computed to analyze for differences between the three pressure conditions. For mean distance-to-target, the effect of pressure was significant at F (2, 78) = 3.72, p = 0.03, ŋ 2p = 0.09. Post-hoc paired sampled t tests with Bonferroni adjustments revealed that performance was significantly improved from the first low-pressure to highpressure condition (p = 0.02, see Fig. 2). There was no effect of group, F (1, 39) = 0.00, p = 0.97, and no interaction effect, F (2, 78) = 0.05, p = 0.95. The same pattern was found for within-subject variation. There was a significant effect of pressure, F (2, 78) = 6.56, p = 0.002, ŋ 2p = 0.14. Post-hoc tests showed that performance was significantly improved from the first low-pressure to HUMAN MOVEMENT L. Schücker, N. Hagemann, B. Strauss, Analogy learning in golf putting high-pressure condition (p = 0.005), and also from first low-pressure to second low-pressure (p = 0.03, see Fig. 3). There was no effect of group, F (1, 39) = 0.04, p = 0.84, and no interaction effect, F (2, 78) = 0.19, p = 0.83. Test phase: secondary task performance Tone pitch judgments To analyze performance in the tone pitch judgment task, 2 × 3 (group × pressure condition) ANOVA with repeated measures on pressure condition was computed with the dependent measure of correct tone judgments measured as a percentage. Analysis revealed a significant effect of pressure, F (2, 78) = 4.11, p = 0.02, ŋ 2p = 0.1. Post-hoc paired sampled t tests with Bonferroni adjustments showed that tone recognition under high-pressure was significantly worse than in the first low-pressure condition (p = 0.03, see Fig. 4). There was no effect of group, F (1, 39) = 0.1, p = 0.76, and no interaction effect, F (2, 78) = 0.23, p = 0.80. Movement phase judgments Performance in movement phase recognition was calculated by the difference between the picture which actually corresponded to when the tone was sounded and the picture the participants selected. The mean spread to the correct picture was analyzed by 2 × 3 ANOVA to look at differences in the pressure conditions and the learning groups. The effect of pressure was found to be significant, F (2, 78) = 11.54, p < 0.001, ŋ 2p = 0.23. As Figure 5 shows, the post-hoc test revealed that performance in picture recognition degraded from the first low-pressure to high-pressure condition (p < 0.01). There was a trend for improvement in picture recognition from high-pressure to second low-pressure (p = 0.06). As for the tone judgment task, there was no effect of group, F (1, 39) = 1.32, p = 0.26, and no interaction effect, F (2, 78) = 0.98, p = 0.38. Verbal knowledge An independent samples t test revealed that the number of explicit rules was significantly higher for the technical learning group (M = 3.38, SD = 1.23) than for the analogy learning group (M = 2.0, SD = 1.01), t (39) = 3.9, p < 0.001, d = 1.6. Discussion Figure 4. Tone judgments in the externally-focused dual task Figure 5. Picture recognition in the internally-focused dual task In this study, we examined two methods of learning a golf putting task (analogy vs. technical) with regard to the stability of performance under pressure and the attentional processes that were involved. In line with our expectations, both learning groups improved performance equally throughout the learning phase, indicating that the pendulum analogy for golf putting is as effective in learning as receiving traditional technical instructions. As shown in other studies, the analogy learning group reported fewer technical instructions than the technical learning group. However, our assumptions about performance under pressure were not supported by the results. Firstly, despite a significant increase in pressure as evidenced in both manipulation checks (CSAI-2R and pressure scale), there were no performance decrements for either of the two learning groups. On the contrary, both groups showed an increase in performance from the low-pressure to high-pressure conditions. This finding goes in line with a recent study conducted by Ehrlenspiel, Wei, and Sternad [41], where participants in the stressed group did not choke either but instead improved task performance in a rhythmic ball bouncing task. In Koedijker et al.’s longitudinal study [33] on analogy learning in table tennis, both learning groups did not show any decrements in performance, however, 181 HUMAN MOVEMENT L. Schücker, N. Hagemann, B. Strauss, Analogy learning in golf putting there were no increases in performance either. Our study did not show an advantage of analogy compared to technical learning, and therefore is not consistent with studies that did find a positive effect of analogy learning in preventing choking under pressure when compared with traditional learning [e.g. 31, 34]. However, it is important to keep in mind that choking under pressure did not occur in either group. The results of the two dual-tasks are not consistent with the previously-stated assumptions either. Firstly, contrary to Schücker et al.’s findings [36], the dual-task designed to measure the amount of skill-focused attention did not reveal any differences between the two learning groups. In all pressure conditions, both groups showed an equal response to the two dual tasks despite a different amount of technical verbal knowledge. We would have expected a higher amount of skill-focused attention in the explicit learning group when under pressure. In the dual task, both groups showed similar results in the external focus of attention as well. Secondly, the skilled focus as well as the external focus of the dual task showed decreased accuracy under pressure, which could signify that the amount of attention devoted to the secondary task decreased in general under pressure. Lam et al.’s [34] findings of probe reaction time results under pressure for analogy and explicit learning groups did not reveal any differences between them either, despite a difference in performance under pressure. Allocation of attentional resources during movement execution was equal in all conditions in Lam et al.’s study [34]. In our study, both groups increased putting performance and decreased accuracy in both dual tasks. The participants in our study did not show any form of performance decrement under high pressure, thus no evidence of choking under pressure was found. It seems that the significant increases in CSAI-2R scores were not powerful enough to produce performance deficits. The scores of the cognitive anxiety subscale and pressure scale were similar to those reported previously by other researchers [e.g., 40]. However, despite the expected decrease in performance, both groups showed increases in performance under pressure, which was not expected at all. One theory that has been discussed with regard to increases in performance is the social facilitation theory originally postulated by Zajonc [42]. Performance in simple motor tasks might actually improve under pressure as induced by social evaluative audiences [5]. The question then stands: is golf putting a simple motor task? Golf putting is a complex movement which needs to be performed very accurately in order to lead to good performance outcomes. It is doubtful that it had been so well learned by the groups that social facilitation effects could explain for their increase in performance. This is also intersecting considering the fact that researchers looking at the choking phenomenon have previously used the golf putting task [e.g., 11, 23]. There 182 were no evident differences between the analogy and technical learning group under pressure, where even though the skill had been instructed differently in the learning phase, both groups showed the same putting and dual-task performance under pressure. This means that the same mechanisms are applied when the skill is executed under stress. However, as participants knew they had a fifty percent chance of being asked about their movement execution in the secondary task, the participants of both groups might have directed their attention to movement execution because of the nature of the dual-task. An explanation of the results (increase in putting performance and decrease in dual-task performance under pressure) can also be considered from the perspective of the attentional control theory [6]. It is possible that the participants invested extra effort so as to improve their performance in the golf-putting task (primary task) and neglected the dual-task portion to some degree as it was not part of the pressure manipulation. In general, the findings of our study do not lend credence to the assumptions made in the reinvestment theory and the usefulness of analogy learning in preventing choking under pressure. Despite a difference in verbal knowledge, no differences were found in performance (both groups did not show decreases in performance) nor in attentional processes under pressure. The results do not go in line with explicit monitoring theories, as these would have predicted an increase in skill-focused attention under pressure as per Gray [12]. The results of this study lead to the conclusion that it does not matter how a skill was learned (either by analogy or by technical instructions) when it comes to performance under pressure and limits the conclusions on performance after a short learning interval. However, Koedijker et al. [33] found similar results in a longterm learning interval but different results in table tennis after a short learning interval [43]. Both studies conducted by Koedijker et al. did not include an online measure of attentional focus and included a fast externally paced task in contrast to the slower and self-paced task of golf putting. Some limitations weaken the conclusion of this study and need to be discussed. First, the issue of pressure manipulation requires further discussion. The results of the manipulation check showed that pressure was induced successfully albeit the observed changes were relatively small. In a laboratory setting, it is very difficult to induce pressure similar to that in real competition. The ecological validity of these types of studies is limited to producing generally smaller levels of stress. However, our results showed that participants did feel more under pressure in the high-pressure condition, allowing comparisons between the pressure conditions to be valid. Nonetheless, it should be considered whether the small changes found in some studies’ performance levels should be interpreted as signs of choking. HUMAN MOVEMENT L. Schücker, N. Hagemann, B. Strauss, Analogy learning in golf putting Apart from the discussed attentional explanation for the observed pattern of performance outcomes, the role of motivation should also be considered. A greater amount of motivation in the high-pressure condition could explain for the participants’ better putting performance. According to Baumeister [1] only extremely motivated people choke when under pressure; it may be that the participants were motivated just enough to perform well. Future studies on choking should include an assessment of motivation in addition to measures of anxiety and pressure. Another issue that is of importance is the length of the learning interval, which was relatively short in this study with only 300 repetitions. In this early stage of skill acquisition, focusing on the skill might not be detrimental to performance as movement execution is far from being completely automated. The inclusion of a dualtask at so early of a stage could have caused performance decrements of the primary task. Our results are limited as they are based on a short learning interval. A similar study but implementing a longer learning interval as in Koedijker et al. [33] should be conducted in the future. Finally, a critical assessment of the secondary task as a measure of internal and external focus of attention is needed. The aim was to design a task to measure the amount of internal and external focus of attention. The question is whether the dual-task approach is a valid measure for focus of attention. As had been shown before [see 12], designing secondary tasks relating to movement execution and external stimuli is a valid measure. However, it should be questioned whether there are variables that might overlay the results of this measure. Secondary tasks do require at least some allocation of attentional resources. If a secondary task on skill execution is not answered correctly this may not only be due to the fact that attention was not focused on the skill but also that attention was not allocated to the secondary task itself. Therefore, the decrease in secondary task performance under pressure as was observed in this study could also signify that more attention was allocated to do well in the primary task under pressure and that the amount of skill and externally focused attention was not measured precisely by the dual task. In the future, the design of valid measures of attentional focus should be emphasized. References 1. Baumeister R.F., Choking under pressure: Self-consciousness and paradoxical effects of incentives on skillful performance. J Pers Soc Psychol, 1984, 46 (3), 610–620, doi: 10.1037/0022-3514.46.3.610. 2. Beilock S.L., Gray R., Why do athletes choke under pressure? In: Tenenbaum G., Eklund R.C. (eds.), Handbook of Sport Psychology. John Wiley & Sons, New Jersey 2007, 425–444. 3. Strauss B., Choking under pressure: positive public expectations and decreases in performance [in German]. Zeit schrift für experimentelle Psychologie, 1997, 44, 636–655. 4. Baumeister R.F., Showers C.J., A review of paradoxical performance effects: Choking under pressure in sports and mental tests. Eur J Soc Psychol, 1986, 16 (4), 361–383, doi: 10.1002/ejsp.2420160405. 5. Strauss B., Social facilitation in motor tasks: a review of research and theory. Psychol Sport Exerc, 2002, 3 (3), 237–256, doi: 10.1016/S1469-0292(01)00019-X. 6. Eysenck M.W., Derakshan N., Santos R., Calvo M.G., Anxiety and cognitive performance: Attentional control theory. Emotion, 2007, 7 (2), 336–353, doi: 10.1037/1528 -3542.7.2.336. 7. Lewis B.P., Linder D.E., Thinking about choking? Attentional processes and paradoxical performance. Pers Soc Psychol Bull, 1997, 23 (9), 937–944, doi: 10.1177/014616 7297239003. 8. Wine J., Test anxiety and direction of attention. Psychol Bull, 1971, 76 (2), 92–104, doi: 10.1037/h0031332. 9. Beilock S.L., Carr T.H., When high-powered people fail: Working memory and “Choking under pressure” in math. Psychol Sci, 2005, 16 (2), 101–105, doi: 10.1111/j.09567976.2005.00789.x. 10. Beilock S.L., Kulp C.A., Holt L.E., Carr T.H., More on the fragility of performance: Choking under pressure in mathematical problem solving. J Exp Psychol: Gen, 2004, 133 (4), 584–600, doi: 10.1037/0096-3445.133.4.584. 11. Beilock S.L., Carr T.H., On the fragility of skilled performance: What governs choking under pressure? J Exp Psychol: Gen, 2001, 130 (4), 701–725, doi: 10.1037/00963445.130.4.701. 12. Gray R., Attending to the execution of a complex sensorimotor skill: Expertise differences, choking, and slumps. J Exp Psychol: Appl, 2004, 10 (1), 42–54, doi: 10.1037/ 1076-898X.10.1.42. 13. Beilock S.L., Carr T.H., MacMahon C., Starkes J.L., When paying attention becomes counterproductive: Impact of divided versus skill-focused attention on novice and experienced performance of sensorimotor skills. J Exp Psychol: Appl, 2002, 8 (1), 6–16, doi: 10.1037/1076-898 X.8.1.6. 14. Jackson R.C., Ashford K.J., Norsworthy G., Attentional focus, dispositional reinvestment, and skilled motor performance under pressure. J Sport Exerc Psychol, 2006, 28 (1), 40–68. 15. Castaneda B., Gray R., Effects of focus of attention on baseball batting performance in players of differing skill levels. J Sport Exerc Psychol, 2007, 29 (1), 60–77. 16. Ford P., Hodges N.J., Williams A.M., Online attentionalfocus manipulations in a soccer-dribbling task: Implications for the proceduralization of motor skills. J Mot Behav, 2005, 37 (5), 386–394, doi: 10.3200/JMBR.37.5. 386-394. 17. Bell J.J., Hardy J., Effects of attentional focus on skilled performance in golf. J Appl Sport Psychol, 2009, 21 (2), 163–177, doi: 10.1080/10413200902795323. 18. Schücker L., Hagemann N., Strauss B., Völker K., The effect of attentional focus on running economy. J Sports Sci, 2009,27(12),1241–1248,doi:10.1080/02640410903150467. 19. Wulf G., Attentional focus and motor learning: A review of 10 years of research. E-Journal Bewegung und Training, 2007, 1, 1–64. 20. Vance J., Wulf G., Töllner T., McNevin N., Mercer J., EMG activity as a function of the performer’s focus of attention. J Mot Behav, 2004, 36 (4), 450–459, doi: 10.3200/ JMBR.36.4.450-459. 183 HUMAN MOVEMENT L. Schücker, N. Hagemann, B. Strauss, Analogy learning in golf putting 21. Zachry T., Wulf G., Mercer J., Bezodis N., Increased movement accuracy and reduced EMG activity as the result of adopting an external focus of attention. Brain Res Bull, 2005, 67 (4), 304–309, doi: 10.1016/j.brainresbull.2005. 06.035. 22. Masters R.S.W., Maxwell J.P., The theory of reinvestment. Int Rev Sport Exerc Psychol, 2008, 1 (2), 160–183, doi: 10.1080/17509840802287218. 23. Masters R.S.W., Knowledge, knerves and know-how: The role of explicit versus implicit knowledge in the breakdown of a complex motor skill under pressure. Br J Psychol, 1992, 83 (3), 343–358, doi: 10.1111/j.2044-8295.1992. tb02446.x. 24. Vickers J.N., Williams A.M., Performing under pressure: The effects of physiological arousal, cognitive anxiety, and gaze control in biathlon. J Mot Behav, 2007, 39 (5), 381–394, doi: 10.3200/JMBR.39.5.381-394. 25. Gucciardi D.F., Dimmock J.A., Choking under pressure in sensorimotor skills: Conscious processing or depleted attentional resources? Psychol Sport Exerc, 2008, 9 (1), 45–59, doi: 10.1016/j.psychsport.2006.10.007. 26. Oudejans R.R.D., Pijpers J.R., Training with mild anxiety may prevent choking under higher levels of anxiety. Psychol Sport Exerc, 2010, 11 (1), 44–50, doi: 10.1016/j. psychsport.2009.05.002. 27. Cohn P.J., Preperformance Routines in Sport: Theoretical Support and Practical Applications. Sport Psychol, 1990, 4 (3), 301–312. 28. Lonsdale C., Tam J.T.M., On the temporal and behavioural consistency of pre-performance routines: An intra-individual analysis of elite basketball players’ free throw shooting accuracy. J Sports Sci, 2008, 26 (3), 259–266, doi: 10.1080/02640410701473962. 29. Jackson R.C., Willson R.J., Using ‘swing thoughts’ to prevent paradoxical performance effects in golf putting. In: Farrally M.R., Cochran A.J. (eds.), Science and golf III: Proceedings of the 1998 world scientific congress of golf. Human Kinetics, Leeds 1999, 166–173. 30. Masters R.S.W., Theoretical aspects of implicit learning in sport. Int J Sport Psychol, 2000, 31 (4), 530–541. 31. Liao C., Masters R.S.W., Analogy learning: A means to implicit motor learning. J Sports Sci, 2001, 19 (5), 307–319, doi: 10.1080/02640410152006081. 32. Law J., Masters R., Bray S.R., Eves F.F., Bardswell I., Motor performance as a function of audience affability and metaknowledge. J Sport Exerc Psychol, 2003, 25 (4), 484–500. 33. Koedijker J.M., Oudejans R.R.D., Beek P.J., Table tennis performance following explicit and analogy learning 184 over 10.000 repetitions. Int J Sport Psychol, 2008, 39 (3), 237–256. 34. Lam W.K., Maxwell J.P., Masters R., Analogy learning and the performance of motor skills under pressure. J Sport Exerc Psychol, 2009, 31 (3), 337–357. 35. Lam W.K., Maxwell J.P., Masters R.S.W., Analogy versus explicit learning of a modified basketball shooting task: Performance and kinematic outcomes. J Sports Sci, 2009, 27 (2), 179–191, doi: 10.1080/02640410802448764. 36. Schücker L., Ebbing L., Hagemann N., Learning by Analogies: Implications for performance and attentional processes under pressure. Hum Mov, 2010, 11 (2), 191–199, doi:10.2478/v10038-010-0025-z. 37. Letzelter H., Letzelter M., Golftechniken: Wieso, weshalb, warum? [in German]. Philippka, Münster 2002. 38. Poolton J.M., Maxwell J.P., Masters R.S.W., Raab M., Benefits of an external focus of attention: Common coding or conscious processing? J Sports Sci, 2006, 24 (1), 89–99, doi: 10.1080/02640410500130854. 39. Cox R.H., Martens M.P., Russell W.D., Measuring anxiety in athletics: The Revised Competitive State Anxiety Inventory-2. J Sport Exerc Psychol, 2003, 25 (4), 519–533. 40. Kinrade N.P., Jackson R.C., Ashford K.J., Dispositional reinvestment and skill failure in cognitive and motor tasks. Psychol Sport Exerc, 2010, 11 (4), 312–319, doi: 10.1016/j.psychsport.2010.02.005. 41. Ehrlenspiel F., Wei K., Sternad D., Open-loop, closed-loop and compensatory control: performance improvement under pressure in a rhythmic task. Exp Brain Res, 2010, 201 (4), 729–741, doi: 10.1007/s00221-009-2087-8. 42. Zajonc R.B., Social facilitation. Science, 1965, 149 (3681), 269–274, doi: 10.1126/science.149.3681.269 . 43. Koedijker J.M., Oudejans R.R.D., Beek P.J., Explicit rules and direction of attention in learning and performing the table tennis forehand. Int J Sport Psychol, 2007, 38 (2), 227–244. Paper received by the Editor: February 22, 2013 Paper accepted for publication: April 25, 2013 Correspondence address Linda Schücker Institute of Sport and Exercise Sciences University of Muenster Horstmarer Landweg 62b 48149 Münster, Germany e-mail: [email protected] HUMAN MOVEMENT PUBLISHING GUIDELINES – Regulamin publikowania prac The Editorial Office of Human Movement accepts original empirical as well as comparative research papers on sport science from sports medicine, exercise physiology, biomechanics, kinesiology, sociology, psychology. The Journal also invites such contributions as letters to the Editor, reports from scientific conferences and book reviews. The publication of submitted contributions to Human Movement is free of charge. The original version of the journal is offered in print form. All proposals should be prepared using the guidelines set forth below and sent electronically to: [email protected] The author is also obliged to submit a signed declaration (downloadable from our website) that the submitted work has not been and will not be published in any other publications without the consent of the Editorial Office and that they agree for their work to be published in Human Movement. Articles with more than one author need only one declaration, signed by the principal author on behalf of all the co-authors. The Editorial Office will not accept articles that were “ghostwritten” or feature “guest authorship”, and any irregularities will be reported and disclosed by the Editorial Office. Articles submitted for publication in the quarterly Human Movement are peer-reviewed. The peer-review procedure used at Human Movement is in accordance with the guidelines set out by the Polish Ministry of Science and Higher Education. The author may provide the names of potential reviewers, but the Editorial Office reserves the right in their selection of reviewers. Reviewers will not know the author’s name nor will the authors know the reviewer’s name. Based on the reviewers’ assessment of the submitted work, the Editorial Office will decide whether an article is to be published or not. The Editorial Office’s decision is final. Authors are not remunerated for published works. Redakcja kwartalnika Human Movement przyjmuje do publikacji oryginalne prace empiryczne oraz przeglądowe z nauk o kulturze fizycznej ograniczone do problematyki medycyny sportu, fizjologii wysiłku fizycznego, biomechaniki, antropomotoryki, psychologii. Przyjmowane są również listy do Redakcji, sprawozdania z konferencji naukowych i recenzje książek. Publikowanie prac w Human Movement jest bezpłatne. Wersją pierwotną czasopisma jest wersja papierowa. Wszystkie prace powinny być przygotowane wg opisanych niżej zasad i przesłane w wersji elektronicznej na adres: [email protected]. Autor jest zobowiązany ponadto do przesłania podpisa nego oświadczenia (formularz do pobrania ze strony inter netowej), że treść artykułu nie była i nie będzie publiko wana w tej formie w innych wydawnictwach bez zgody Redakcji czasopisma Human Movement oraz że zgadza się na ogłoszenie jej w tym kwartalniku. Przy pracach zespo łowych oświadczenie w imieniu wszystkich współautorów składa główny autor. Redakcja nie przyjmie artykułu, w którym występują zja wiska „ghostwritting” i „quest authorship”, a wszelkie nie prawidłowości będą ujawniane przez Redakcję. Artykuły zamieszczane w kwartalniku Human Movement są recenzowane. Procedury recenzowania są zgodne z wytycznymi Ministerstwa Nauki i Szkolnictwa Wyższego, umieszczonymi na stronie: http://pbn.nauka.gov.pl. Autor może podać nazwiska potencjalnych recenzentów, lecz Redakcja zastrzega sobie prawo ich doboru. Recenzenci nie znają nazwisk autorów ani autorzy nie znają nazwisk recenzentów. W zależności od oceny recenzentów Redakcja podejmuje decyzję, czy artykuł zostanie opublikowany czy nie. Decyzja Redakcji jest ostateczna. Autorzy nie otrzymują honorarium za opublikowanie pracy. Detailed guidelines for submitting articles to Human Movement Szczegółowe zasady przygotowania artykułu do Human Movement 1. The article should be written in English. 2.Empirical research articles, together with their summary and any tables, figures or graphs, should not exceed 20 pages in length; comparative articles are limited to 30 pages. Page format is A4 (about 1800 characters with spaces per page). Pages should be numbered. 3. Articles should be written using Microsoft Word with the following formats: – Font: Times New Roman, 12 point – Line spacing: 1.5 – Text alignment: Justified – Title: Bold typeface, centered 4. The main title page should contain the following: – The article’s title – A shortened title of the article (up to 40 characters in length including spaces), which will be placed in the running head 1. Redakcja publikuje prace w języku angielskim. Jedynie autorzy zatrudnieni na uczelniach wydających czasopismo mogą nadsyłać prace w języku polskim. 2. Tekst prac empirycznych wraz ze streszczeniem, rycinami i tabelami nie powinien przekraczać 20, a prac przeglądowych – 30 stron znormalizowanych formatu A4 (ok. 1800 znaków ze spacjami na stronie). Strony powinny być ponumerowane. 3. Artykuł należy przygotować w edytorze tekstu Microsoft Word według następujących zasad: – krój pisma: Times New Roman, 12 pkt; – interlinia: 1,5; – tekst wyjustowany; – tytuł zapisany pogrubionym krojem pisma, wyśrodkowany. 4.Strona tytułowa powinna zawierać: – tytuł pracy; 185 HUMAN MOVEMENT Publishing guidelines – Regulamin publikowania prac – The name and surname of the author(s) with their affiliations written in the following way: the name of the university, city name, country name. For example: The University of Physical Education, Wrocław, Poland – Address for correspondence (author’s name, address, e-mail address and phone number) 5. The second page should contain: – The title of the article –An abstract of approximately 250 words divided into the following sections: Purpose, Methods, Results, Con clusions – Three to six keywords to be used as MeSH descriptors (terms) 6. The third page should contain: – The title of the article – The main text 7. The main body of text in empirical research articles should be divided into the following sections: –skrócony tytuł artykułu (do 40 znaków ze spacjami), który zostanie umieszczony w żywej paginie; – imię i nazwisko autora (autorów) z afiliacją zapisaną wg następującego schematu: nazwa uczelni, nazwa miejscowości, nazwa kraju, np. Akademia Wychowania Fizycznego, Wrocław, Polska; – adres do korespondencji (imię i nazwisko autora, jego adres, e-mail oraz numer telefonu). 5. Następna strona powinna zawierać: – tytuł artykułu; – streszczenie (około 200 wyrazów) składające się z następujących części: Purpose, Methods, Results, Conclusions; – słowa kluczowe (3–6) – ze słownika i w stylu MeSH. 6. Trzecia strona powinna zawierać: – tytuł artykułu; – tekst główny. 7. Tekst główny pracy empirycznej należy podzielić na następujące części: Introduction The introduction prefaces the reader on the article’s subject, describes its purpose, states a hypothesis, and mentions any existing research (literature review) Wstęp We wstępie należy wprowadzić czytelnika w tematykę artykułu, opisać cel pracy oraz podać hipotezy, stan badań (przegląd literatury). Material and methods This section is to clearly describe the research material (if human subjects took part in the experiment, include their number, age, gender and other necessary information), discuss the conditions, time and methods of the research as well identifying any equipment used (providing the manufacturer’s name and address). Measurements and procedures need to be provided in sufficient detail in order to allow for their reproducibility. If a method is being used for the first time, it needs to be described in detail to show its validity and reliability (reproducibility). If modifying existing methods, describe what was changed as well as justify the need for the modifications. All experiments using human subjects must obtain the approval of an appropriate ethnical committee by the author in any undertaken research (the manuscript must include a copy of the approval document). Statistical methods should be described in such a way that they can be easily determined if they are correct. Authors of comparative research articles should also include their methods for finding materials, selection methods, etc. Materiał i metody W tej części należy dokładnie przedstawić materiał badawczy (jeśli w eksperymencie biorą udział ludzie, należy podać ich liczbę, wiek, płeć oraz inne charakterystyczne cechy), omówić warunki, czas i metody prowadzenia badań oraz opisać wykorzystaną aparaturę (z podaniem nazwy wytwórni i jej adresu). Sposób wykonywania pomiarów musi być przedstawiony na tyle dokładnie, aby inne osoby mogły je powtórzyć. Jeżeli metoda jest zastosowana pierwszy raz, należy ją opisać szczególnie precyzyjnie, przedstawiając jej trafność i rzetelność (powtarzalność). Modyfikując uznane już metody, trzeba omówić, na czym polegają zmiany, oraz uzasadnić konieczność ich wprowadzenia. Gdy w eksperymencie biorą udział ludzie, konieczne jest uzyskanie zgody komisji etycznej na wykorzystanie w nim zaproponowanych przez autora metod (do maszynopisu należy dołączyć kopię odpowiedniego dokumentu). Metody statystyczne powinny być tak opisane, aby można było bez problemu stwierdzić, czy są one poprawne. Autor pracy przeglądowej powinien również podać metody poszukiwania materiałów, metody selekcji itp. Results The results should be presented both logically and consistently, as well as be closely tied with the data found in tables and figures. Wyniki Przedstawienie wyników powinno być logiczne i spójne oraz ściśle powiązane z danymi zamieszczonymi w tabelach i na rycinach. Discussion Here the author should create a discussion of the obtained results, referring to the results found in other literature (besides those mentioned in the introduction), as well as emphasizing new and important aspects of their work. Dyskusja W tym punkcie, stanowiącym omówienie wyników, autor powinien odnieść uzyskane wyniki do danych z literatury (innych niż omówione we wstępie), podkreślając nowe i znaczące aspekty swojej pracy. Conclusions In presenting any conclusions, it is important to remember the original purpose of the research and the stated hypotheses, and avoid any vague statements or those not based on the results of their research. If new hypotheses are put forward, they must be clearly stated. Wnioski Przedstawiając wnioski, należy pamiętać o celu pracy oraz postawionych hipotezach, a także unikać stwierdzeń ogólnikowych i niepopartych wynikami własnych badań. Stawiając nowe hipotezy, trzeba to wyraźnie zaznaczyć. 186 HUMAN MOVEMENT Publishing guidelines – Regulamin publikowania prac Acknowledgements The author may mention any people or institutions that helped the author in preparing the manuscript, or that provided support through financial or technical means. Podziękowania Należy wymienić osoby lub instytucje, które pomogły autorowi w przygotowaniu pracy bądź wsparły go finansowo lub technicznie. Bibliography The bibliography should be composed of the article’s citations and be arranged and numbered in the order in which they appear in the text, not alphabetically. Referenced sources from literature should indicate the page number and enclose it in square brackets, e.g., Bouchard et al. [23]. The total number of bibliographic references (those found only in research databases such as SPORTDiscus, Medline) should not exceed 30 for empirical research papers (citing a maximum of two books); there is no limit for comparative research papers. There are no restrictions in referencing unpublished work. Bibliografia Bibliografię należy uporządkować i ponumerować według kolejności cytowania publikacji w tekście, a nie alfabetycznie. Odwołanie do piśmiennictwa należy oznaczyć w tekście numerem i ująć go w nawias kwadratowy, np. Bouchard et al. [23]. Bibliografia (powołania zawarte tylko w bazach danych, np. SPORTDiscus, Medline) powinna się składać najwyżej z 30 pozycji (dopuszcza się powołanie na 2 publikacje książ kowe), z wyjątkiem prac przeglądowych. Niewskazane jest cytowanie prac nieopublikowanych. Citing journal articles Bibliographic citations of journal articles should include: the author’s (or authors’) surname, first name initial, article title, abbreviated journal title, year, volume or number, page number, doi, for example: Opis bibliograficzny artykułu z czasopisma Opis bibliograficzny artykułu powinien zawierać: naz wisko autora (autorów), inicjał imienia, tytuł artykułu, tytuł czasopisma w przyjętym skrócie, rok wydania, tom lub numer, strony, numer doi, np. Tchórzewski D., Jaworski J., Bujas P., Influence of long-lasting balancing on unstable surface on changes in balance. Hum Mov, 2010, 11 (2), 144–152, doi: 10.2478/v10038-0100022-2. Tchórzewski D., Jaworski J., Bujas P., Influence of long-lasting balancing on unstable surface on changes in balance. Hum Mov, 2010, 11 (2), 144–152, doi: 10.2478/v10038-0100022-2. If there are six or less authors, all the names should be mentioned; if there are seven or more, give the first six and then use the abbreviation “et al.” If the title of the article is in a language other than English, the author should translate the title into English, and then in square brackets indicate the original language; the journal title should be left in its native name, for example: Gdy autorami artykułu jest sześć lub mniej osób, należy wymienić wszystkie nazwiska, jeżeli jest ich siedem i więcej, należy podać sześć pierwszych i zastosować skrót „et al.”. Tytuł artykułu w języku innym niż angielski autor powinien przetłumaczyć na język angielski, a w nawiasie kwadratowym podać język oryginału, tytuł czasopisma należy zostawić w oryginalnym brzmieniu, np. Jaskólska A., Bogucka M., Świstak R., Jaskólski A., Mechanisms, symptoms and after-effects of delayed muscle soreness (DOMS) [in Polish]. Med Sport, 2002, 4, 189–201. Jaskólska A., Bogucka M., Świstak R., Jaskólski A., Mechanisms, symptoms and after-effects of delayed muscle soreness (DOMS) [in Polish]. Med Sport, 2002, 4, 189–201. The author’s research should only take into consideration articles published in English. W pracy powinny być uwzględnianie tylko artykuły publikowane ze streszczeniem angielskim. Citing books Bibliographic citations of books should include: the author (or authors’) or editor’s (or editors’) surname, first name initial, book title translated into English, publisher, place and year of publication, for example: Opis bibliograficzny książki Opis bibliograficzny książki powinien zawierać: nazwisko autora (autorów) lub redaktora (redaktorów), inicjał imienia, tytuł pracy przetłumaczony na język angielski, wydawcę, miejsce i rok wydania, np. Osiński W., Anthropomotoric [in Polish]. AWF, Poznań 2001. Osiński W., Anthropomotoric [in Polish]. AWF, Poznań 2001. Heinemann K. (ed.), Sport clubs in various European countries. Karl Hofmann, Schorndorf 1999. Heinemann K. (ed.), Sport clubs in various European countries. Karl Hofmann, Schorndorf 1999. Bibliographic citations of an article within a book should include: the author’s (or authors’) surname, first name initial, article title, book author (or authors’) or editor’s (or editors’) surname, first name initial, book title, publisher, place and year of publication, paga number, for example: Opis bibliograficzny rozdziału w książce powinien zawie rać: nazwisko autora (autorów), inicjał imienia, tytuł roz działu, nazwisko autora (autorów) lub redaktora (redaktorów), inicjał imienia, tytuł pracy, wydawcę, miejsce i rok wydania, strony, np. McKirnan M.D., Froelicher V.F., General principles of exercise testing. In: Skinner J.S. (ed.), Exercise testing and exercise prescription for special cases. Lea & Febiger, Philadelphia 1993, 3–28. McKirnan M.D., Froelicher V.F., General principles of exercise testing. In: Skinner J.S. (ed.), Exercise testing and exercise prescription for special cases. Lea & Febiger, Philadelphia 1993, 3–28. 187 HUMAN MOVEMENT Publishing guidelines – Regulamin publikowania prac Citing conference materials Citing conference materials (found only in international research databases such as SPORTDiscus) should include: the author’s (or authors’) surname, first name initial, article title, conference author’s (or authors’) or editor’s (or editor’s) surname, first name initial, conference title, publisher, place and year of publication, page number, for example: Opis bibliograficzny materiałów zjazdowych Opis bibliograficzny materiałów zjazdowych (umieszczanych tylko w międzynarodowych bazach danych, np. SPORTDiscus) powinien zawierać: nazwisko autora (autorów), inicjał imienia, tytuł, nazwisko autora (autorów) lub redaktora (redaktorów), tytuł pracy, wydawcę, miejsce i rok wydania, strony, np. Rodriguez F.A., Moreno D., Keskinen K.L., Validity of a twodistance simplified testing method for determining critical swimming velocity. In: Chatard J.C. (ed.), Biomechanics and Medicine in Swimming IX, Proceedings of the IXth World Symposium on Biomechanics and Medicine in Swimming. Université de St. Etienne, St. Etienne 2003, 385–390. Rodriguez F.A., Moreno D., Keskinen K.L., Validity of a twodistance simplified testing method for determining critical swimming velocity. In: Chatard J.C. (ed.), Biomechanics and Medicine in Swimming IX, Proceedings of the IXth World Symposium on Biomechanics and Medicine in Swimming. Université de St. Etienne, St. Etienne 2003, 385–390. Citing articles in electronic format Citing articles in electronic format should include: author’s (or authors’) surname, first name initial, article title, abbreviated journal title, year of publication, journal volume and number, website address where it is available, doi number, for example: Opis bibliograficzny artykułu w formie elektronicznej Opis bibliograficzny artykułu w formie elektronicznej powinien zawierać: nazwisko autora (autorów), inicjał imienia, tytuł artykułu, tytuł czasopisma w przyjętym skrócie, rok wydania, tom i numer, adres strony, na której jest dostępny, numer doi, np. Donsmark M., Langfort J., Ploug T., Holm C., Enevoldsen L.H., Stallknech B. et al., Hormone-sensitive lipase (HSL) expression and regulation by epinephrine and exercise in skeletal muscle. Eur J Sport Sci, 2 (6), 2002. Available from: URL: http://www.humankinetics.com/ejss/bissues. cfm/, doi: 10.1080/17461391.2002.10142575. Donsmark M., Langfort J., Ploug T., Holm C., Enevoldsen L.H., Stallknech B. et al., Hormone-sensitive lipase (HSL) expression and regulation by epinephrine and exercise in skeletal muscle. Eur J Sport Sci, 2 (6), 2002. Available from: URL: http://www.humankinetics.com/ejss/bissues. cfm/, doi: 10.1080/17461391.2002.10142575. 8. The main text of any other articles submitted for consideration should maintain a logical continuity and that the titles assigned to any sections must reflect the issues discussed within. 8. Tekst główny w pracach innego typu powinien zachować logiczną ciągłość, a tytuły poszczególnych części muszą odzwierciedlać omawiane w nich zagadnienia. 9. Footnotes/Endnotes (explanatory or supplementary to the text). Footnotes should be numbered consecutively throughout the work and placed at the end of the main text. 9.Przypisy (objaśniające lub uzupełniające tekst) powinny być numerowane z zachowaniem ciągłości w całej pracy i umieszczone na końcu tekstu głównego. 10. Tables, figures and photographs – Must be numbered consecutively in the order in which they appear in the text and provide captions –Should be placed within the text – Additionally, figures or photographs must be attached as separate files in .jpg or .pdf format (minimum resolution of 300 dpi) – May not include the same information/data in tables and also figures – Illustrative materials should be prepared in black and white or in shades of gray (Human Movement is published in such a fashion and cannot accept color) –Symbols such as arrows, stars, or abbreviations used in tables or figures should be clearly defined using a legend. 10. Tabele, ryciny i fotografie – należy opatrzyć numerami i podpisami; – należy umieścić w tekście artykułu; –dodatkowo ryciny i fotografie trzeba dołączyć w postaci osobnych plików zapisanych w formacie *.jpg lub *.pdf (gęstość co najmniej 300 dpi); –nie można powtarzać tych samych wyników w tabelach i na rycinach; –materiał ilustracyjny powinien zostać przygotowany w wersji czarno-białej lub w odcieniach szarości (w taki sposób jest drukowane czasopismo Human Movement); – symbole, np. strzałki, gwiazdki, lub skróty użyte w tabelach czy na rycinach należy dokładnie objaśnić w legendzie. Manuscripts not prepared as per the requirements set forth in “Publishing Guidelines” will be returned to the author for correction. The Editorial Office reserves the right to make any language corrections or remove abbreviations found in the manuscript. Once the Editorial Office accepts an article for publication, a proof will be sent to the author for approval. It is the author’s responsibility to accept any changes or submit any corrections within one week of receiving the proof. Praca przygotowana niezgodnie z wymogami „Regulaminu publikowania prac” zostanie odesłana autorowi do poprawy. Redakcja zastrzega sobie prawo usuwania usterek językowych oraz dokonywania skrótów. Artykuł po opracowaniu redakcyjnym zostanie przekazany autorowi do akceptacji. Obowiązkiem autora jest przesłanie ewentualnych uwag i poprawek w ciągu jednego tygodnia. Prior to printing, the author will receive their article in .pdf format. It is the author’s responsibility to immediately inform the Editorial Office if they accept the article for publication. At such a point in time, only minor corrections can be accepted from the author. 188 Przed drukiem autor otrzyma swój artykuł do akceptacji w formie pliku pdf. Obowiązkiem autora jest niezwłoczne przesłanie do Redakcji Human Movement informacji o akceptacji artykułu do druku. Na tym etapie będą przyjmowane tylko drobne poprawki autorskie. HUMAN MOVEMENT Publishing guidelines – Regulamin publikowania prac The Journal is subject to copyright as per the Berne Convention and the International Copyright Convention, except where not applicable pursuant to a country’s domestic law. The Editorial Office accepts advertising in Human Movement, which may be located on the second or third page of the cover or as additional separate pages. Ad rates are negotiated separately. Authors should contact the Editorial Office of Human Movement only by email. Publikacje podlegają prawu autorskiemu wynikającemu z Konwencji Berneńskiej i z Międzynarodowej Konwencji Praw Autorskich, poza wyjątkami dopuszczanymi przez prawo krajowe. Redakcja przyjmuje zamówienia na reklamy, które mogą być umieszczane na 2. i 3. stronie okładki lub na dodatkowych kartach sąsiadujących z okładką. Ceny reklam będą negocjowane indywidualnie. Autorzy powinni się kontaktować z Redakcją Human Move ment wyłącznie za pośrednictwem poczty elektronicznej. SUBSCRIBING to THE HUMAN MOVEMENT JOURNAL ZASADY PRENUMERATY CZASOPISMA HUMAN MOVEMENT The price of annual subscription (four issues) for individual subscribers is PLN 54 and PLN 110 for institutions. All subscriptions are payable in advance. Subscribers are requested to send payment with their order whenever possible. The orders should be sent to the Editorial Office: e-mail: [email protected] or Human Movement Editorial Office University School of Physical Education al. I.J. Paderewskiego 35 51-612 Wrocław, Poland Cena rocznej prenumeraty (cztery numery) dla odbiorców indyw idualnych w kraju wynosi 54 zł brutto, dla instytucji 110 zł brutto. Zamówienie wraz z potwierdzeniem dokonania wpłaty należy przesłać na adres mailowy: [email protected] lub The issues of the journal are sent by post after receiving the appropriate transfer to the account: Numery czasopisma wysyłamy pocztą po otrzymaniu od pow iedniej wpłaty na konto: BPH PBK S.A. O/Wrocław 42 1060 0076 0000 3210 0014 7743 Akademia Wychowania Fizycznego al. Paderewskiego 35, 51-612 Wrocław, Poland with the note: Human Movement subscription. BPH PBK S.A. O/Wrocław 42 1060 0076 0000 3210 0014 7743 Akademia Wychowania Fizycznego al. Paderewskiego 35, 51-612 Wrocław z dopiskiem: Prenumerata Human Movement. We ask the subscribers to give correct and clearly written addresses to which the journal is to be sent. Prosimy zamawiających o bardzo wyraźne podawanie adresów, pod które należy wysyłać zamawiane egzemplarze czasopisma. Pojedyncze egzemplarze można zamówić w ten sam sposób, wpłacając 16 zł brutto (odbiorca indywidualny) i 30 zł brutto (instytucja) na podane konto. Single copies can be ordered in the same way, by transferring PLN 16 (individual subscribers) and PLN 30 (institutions) to the above mentioned account. Redakcja czasopisma Human Movement Akademia Wychowania Fizycznego al. I.J. Paderewskiego 35 51-612 Wrocław 189
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