East Tennessee State University Digital Commons @ East Tennessee State University Electronic Theses and Dissertations 8-2016 Positional and Match Action Profiles of Elite Women’s Field Hockey Players in Relationship to the 2015 FIH Rule Changes Heather A. Abbott East Tennessee State University Follow this and additional works at: http://dc.etsu.edu/etd Part of the Exercise Science Commons, and the Other Kinesiology Commons Recommended Citation Abbott, Heather A., "Positional and Match Action Profiles of Elite Women’s Field Hockey Players in Relationship to the 2015 FIH Rule Changes" (2016). Electronic Theses and Dissertations. Paper 3092. http://dc.etsu.edu/etd/3092 This Dissertation - Open Access is brought to you for free and open access by Digital Commons @ East Tennessee State University. It has been accepted for inclusion in Electronic Theses and Dissertations by an authorized administrator of Digital Commons @ East Tennessee State University. For more information, please contact [email protected]. Positional and Match Action Profiles of Elite Women’s Field Hockey Players in Relationship to the 2015 FIH Rule Changes _______________ A dissertation presented to the faculty of the Department of Exercise and Sport Sciences East Tennessee State University In partial fulfillment of the requirements for the degree Doctor of Physiology in Sport Physiology and Performance _______________ by Heather Anne Abbott August 2016 _______________ Kimitake Sato, Ph.D., Chair Michael H. Stone, Ph.D. Satoshi Mizuguchi, Ph.D. Dave Hamilton, MS. Keywords: Global Positioning System, Time Motion Analysis, Team Sport, Substitutions, Field Sports, Time on Pitch 1 ABSTRACT Positional and Match Action Profiles of Elite Women’s Field Hockey Players in Relationship to the 2015 FIH Rule Changes by Heather A. Abbott The objective of this dissertation was to examine the action profiles of elite field hockey players in relationship to the 2015 FIH rule change. The following are major findings of the dissertation: Study 1 – Relative action profiles before the rule change revealed that defenders work at a lower meter per minute (m/min) when compared with all other positions, and that forwards, midfielders, and screens perform similar m/min during a game. Examination of pre rule change difference from the 1st to the 2nd half play showed that elite level field hockey players are able maintain high-intensity actions in zone 6 throughout the game by increasing actions in zones 1 and 2, and decreasing actions in zones 4 and 5. Study 2 – Action profiles after the rule formatting change revealed the team was unable to match the percent of distance covered in zones 4 and 5 during the 1st quarter all in subsequent quarters. The low intensity actions in zone 1 and 2 gradually increased, while m/min gradually declined. However the percent of distance covered in zone 6 showed no statistically significant change. When positional differences were examined forwards covered the greatest percent of distance in zones 5 and 6, followed by midfielders, 2 screens, and defenders. This pattern varies for zone 4, within which the midfielders possesses the greatest percent distance covered. Study 3 – Relative action profile comparisons for the team, pre to post the 2015 rule change did not indicate a significant change in zones 2, 3, 4, 5, and 6. However zone 1 experience a statistically significant decrease. Positional analysis showed statistically significant changes for midfielders only. The changes were a decrease in zone 1, and increase in zone 5 and 6 during the first half of the game, and decrease in zone 1 and m/min during the second half of the game. A major focus of the US Women’s National Team is to develop the athletes’ physical capacity to maintain and repeat high intensity actions. The combination of physical preparation and tactical strategies allow the team to express high m/min and numerous high intensity actions throughout a match. 3 Copyright 2016 by Heather A. Abbott All Rights Reserved 4 DEDICATION This dissertation is dedicated to my family. This journey would not have been possible without your love, support and encouragement. 5 ACKNOWLEDGEMENTS Dr. Kimi Sato - for his advice and endless patience throughout this project. It would not have been possible without his support and assistance in the analysis and subsequent write-ups. Dr. Michael Stone – for his willingness to share his knowledge and experience, I am forever grateful. Dr. Satoshi Mizuguchi – for his constructive criticism, and for tell me what I needed to hear instead of what I wanted to hear. Dave Hamilton - for allowing me the opportunity to work with the US Women’s National Field Hockey Team, and providing me with endless advice on GPS match analysis. The US Women’s National Field Hockey Team – for volunteering to participate in this research. Without their participation, none of this would have been possible. My colleagues at East Tennessee State University – for motivating me during my educational pursuits. Thank you 6 TABLE OF CONTENTS Page ABSTRACT...............................................................................................................2 DEDICATION ...........................................................................................................5 ACKNOWLEDGEMNTS .........................................................................................6 LIST OF TABLES .....................................................................................................11 LIST OF FIGURES ...................................................................................................13 Chapters 1. INTRODUCTION ................................................................................................14 Rational for Research/Statement of Problem .....................................................17 Objective of Research ........................................................................................17 Significance........................................................................................................18 Operational Definitions ......................................................................................20 2. COMPREHENSIVE LITATURE REVIEW .........................................................21 Introduction ........................................................................................................21 Existing Literature .............................................................................................21 Field Hockey Rules ............................................................................................22 Time Motion Analysis History ..........................................................................24 Global Positioning System History....................................................................25 Global Positioning System Validity and Reliability ..........................................26 Field Hockey Specific Global Positioning System Validation ..........................30 Global Positioning System and Micro Technology Metrics .............................34 Distance......................................................................................................34 7 Velocity ......................................................................................................35 Inertial Movement Analysis .......................................................................38 Player Load and Metabolic Power .............................................................39 Global Positioning System Action Profiles in Field Hockey.............................40 Action Profile Comparison ........................................................................41 Monitoring .................................................................................................42 Game vs. Practice.......................................................................................43 Fatigue........................................................................................................45 Problems/Considerations/Match Variability ..............................................47 Summary ............................................................................................................47 3. STUDY 1: Positional and Match Action Profiles of Elite Women’s Field Hockey Players ........................................................................................................................49 Abstract ..............................................................................................................50 Introduction ........................................................................................................51 Methods..............................................................................................................53 Experimental Approach to the Problem .....................................................53 Athletes ......................................................................................................53 Procedures ..................................................................................................................54 Statistical Analysis .....................................................................................................55 Terms/Definitions .....................................................................................56 Results ................................................................................................................57 Descriptors .................................................................................................57 Position Differences ...................................................................................61 8 1st vs. 2nd Half ............................................................................................64 Discussion ..........................................................................................................66 Practical Application ..........................................................................................68 References ..........................................................................................................69 4. STUDY 2 International Women’s Field Hockey Action Profiles Post 2015 Rule Change .......................................................................................................................75 Abstract ..............................................................................................................76 Introduction ........................................................................................................77 Methods..............................................................................................................78 Athletes Subjects........................................................................................78 Data Collection ..........................................................................................78 Data Analysis .............................................................................................81 Statistical Analysis .............................................................................................82 Results ................................................................................................................83 Descriptive .................................................................................................83 Team Quarter Comparison .........................................................................85 Quarter Comparison by Position................................................................89 Discussion ..........................................................................................................99 Conclusion .........................................................................................................100 References ..........................................................................................................101 5. STUDY 3 – Changes in Elite Field Hockey Player Action Profile due to 2015 Rule Change ...............................................................................................................104 Abstract ..............................................................................................................105 9 Introduction ........................................................................................................106 Methods..............................................................................................................107 Athletes Subjects........................................................................................107 Data Collection ..........................................................................................107 Data Analysis .............................................................................................110 Statistical Analysis .............................................................................................111 Results ................................................................................................................112 Team Full Game Pre vs. Post Rule Change ...............................................112 Team Pre 1st vs. Post 1st and Pre 2nd vs. Post 2nd ...........................................................112 Position Pre 1st vs. Post 1st and Pre 2nd vs. Post 2nd ....................................................112 Discussion ..........................................................................................................121 Conclusion .........................................................................................................122 References ..........................................................................................................123 6. SUMMARY AND FUTURE INVESTIGATIONS ..............................................127 REFERENCES ..........................................................................................................147 APPENDIX:ETSU Institutional Review Board Approval Form...............................148 VITA ........................................................................................................................149 10 LIST OF TABLES Table Page 2.1 Validation GPS: devices, sampling frequency, and criterion measures ..............33 2.2 GPS Velocity Zones.............................................................................................37 3.1 Tournament Schedule and Outcome ....................................................................58 3.2 Positional Playing Time .......................................................................................58 3.3 Champions Challenge and World Cup Player and Position Action Profiles .......69 3.4 Absolute Number of efforts, Maximum and Average Distance Covered in Top nkl3 Velocity Zones ...................................................................................................60 3.5 Descriptive Data for Relative Velocity Zones .....................................................62 3.6 ANOVA Main Effect for Position .......................................................................62 3.7 Relative Percent Distance covered in Velocity Zones Between Positions ..........63 3.8 Team Changes Relative Percent Distance covered from 1st to 2nd half ...............65 4.1 Tournament Schedule and Outcome ....................................................................78 4.2 Absolute Positional Action Profiles for the Full Game .......................................82 4.3 Relative Action Profiles for the Full Game .........................................................82 4.4 Team Relative Action Profiles by Quarter...........................................................84 4.5 Team Relative Action Profiles Between Quarters ...............................................84 4.6a Forwards Relative Action Profiles by Quarter ...................................................89 4.6b Midfielder Relative Action Profiles by Quarter.................................................89 4.6c Screens Relative Action Profiles by Quarter .....................................................90 4.6d Defenders Relative Action Profiles by Quarter .................................................90 4.7a. Forwards effect size across Quarter ..................................................................91 11 4.7b. Midfielders effect size across Quarter ..............................................................91 4.7c. Screens effect size across Quarter .....................................................................92 4.7d. Defenders effect size across Quarter.................................................................92 5.1 Tournament Schedule ..........................................................................................106 5.2 Paired t-test for Team Full Game Action Profiles Pre vs. Post ..........................111 5.3a Paired t-test for Team Full Game Action Profiles Pre1 vs. Post 1 .....................112 5.3b Paired t-test for Team Full Game Action Profiles Pre 2 vs. Post 2 ...................113 5.4a Forwards Pre 1 vs. Post 1 & Pre 2 vs. Post 2 Wilcoxon Signed Rank Tests ....114 5.4b Midfielders Pre 1 vs. Post 1 & Pre 2 vs. Post 2 Wilcoxon Signed Rank Tests .115 5.4c Screens Pre 1 vs. Post 1 & Pre 2 vs. Post 2 Wilcoxon Signed Rank Tests ........116 5.4d Defenders Pre 1 vs. Post 1 & Pre 2 vs. Post 2 Wilcoxon Signed Rank Tests ....117 12 LIST OF FIGURES Figure Page 4.1 Team m/min by quarter ........................................................................................85 4.2 Team Relative Percent Distance ..........................................................................86 4.3a Forwards Relative Percent Distance ..................................................................93 4.3b Midfielders Relative Percent Distance...............................................................94 4.3c Screens Relative Percent Distance .....................................................................95 4.3d Defenders Relative Percent Distance .................................................................96 13 CHAPTER 1 INTRODUCTION Field hockey is an international sport played by both men and women, which has undergone rapid and radical change within the past ten years. The arrival of synthetic playing surface (Malhotra, Ghosh, & Khanna, 1983), modernized sticks (Allen, Foster, Carré, & Choppin, 2012), and rule alterations such as the self-start (Tromp & Holmes, 2011), have changed the physiological requirements of the game. Most recently the match formatting has been changed from two thirty-five minute halves with a ten minute half time, into four fifteen minute quarters with two, two minute rest periods, and one ten minute half time (FIH, 2014). The sporting actions in field hockey consist of multiple interspersed high intensity activities, which are multi directional in nature. It requires significant levels of aerobic and anaerobic capacity, strength and power (Reilly & Borrie, 1992). In field hockey the number of players on the field at one time is eleven. Normally a team plays with ten field players, and one goalie (Mitchell-Taverner, 2005). Seven players are available on the bench for rolling substitutions; expect for the Olympics and Pan American games, in which only five players are allowed on the bench. The interchanging of players can occur at any moment, creating the opportunity to maintain high levels of intensity throughout the game. Various factors such as player position (Gabbett, 2010) (Field Hockey), style of play (Bradley et al., 2011) (Soccer), level of play (Jennings, Cormack, Coutts, & Aughey, 2012b) (Field Hockey), age of players (Vescovi, 2014) (Field Hockey), gender of the athletes (Bradley, Dellal, Mohr, Castellano, & Wilkie, 2014) (Soccer), level of 14 opposition (Lago, 2009) (Soccer), and match status (Lago-Penas, 2012) (Soccer) can have an impact on the action profiles of players. Time motion analysis (TMA) techniques have provided valuable information regarding the action profiles of field players, in numerous sports including field hockey (Jennings, Cormack, Coutts, & Aughey, 2012a; Jennings et al., 2012b; MacLeod, Bussell, & Sunderland, 2007; Macutkiewicz & Sunderland, 2011; Spencer, Lawrence, et al., 2004; Spencer, Rechichi, et al., 2005; Vescovi & Frayne, 2015; White & MacFarlane, 2014; Wyldea, Yonga, Azizb, Mukherjeec, & Chiac, 2014). It has proved to be a useful tool to quantify the physical output of players during matches (Bloomfield, Polman, & O'Donoghue, 2007) through either the manual or computer analysis of film. However, the use of time motion analysis systems has been restricted from most teams due to its expensive and time intensive nature. The recent introduction of sport specific Global Positioning System (GPS) technology for TMA has allowed the monitoring of action profiles by a greater number of field sport teams due to its less expensive nature, and computerized analysis programs. The evolution of the sports GPS technology allowed coaches and sports scientist to determine and compare player’s movements during the games or training. The newer higher sampling rate has created a more valid tool for measuring distance and velocity (Castellano, Casamichana, Calleja-Gonzalez, Roman, & Ostojic, 2011; Johnston, Watsford, Kelly, Pine, & Spurrs, 2014; Portas, Harley, Barnes, & Rush, 2010). However, using inappropriate analysis procedures can alter the perceived action profiles of field hockey players (Wehbe, Hartwig, & Duncan, 2014). It has been previously noted that discrepancies exist when reporting locomotor activities (e.g. walking, jogging, running) 15 with TMA (Gabbett, 2010), and making a comparison between studies is difficult. Inconsistencies in data processing also create discrepancies in reported measures, specifically when comparing full game time to the time on pitch. Furthermore, different GPS analysis procedures can also influence the time-dependent measures reported by GPS. The current practice for GPS analysis has essentially been driven by soccer literature. Normally soccer players are on the pitch for a full game or do not reenter the game after substitution. However, in field hockey a high number of substitutions are allowed. Unlimited substitutions allow for offensive and defensive pressure to be applied throughout the match. With this understanding it is important to acknowledge the need for different analysis strategies, and the difficulty to generalize women’s soccer data to field hockey. Full game versus time on pitch analysis alters the description of the work to rest ratio and physical demands of elite field hockey players (White & MacFarlane, 2013). It is also important to note that TMA system such as GPS do not measure the demands of competition rather the outputs of players. Data from GPS systems can be easily misinterpreted. For example, total distance expressed without the minutes of match play can be misleading, because total distance covered in related to time on pitch. The expression of distance per minute of match time is important in sports with unlimited substitutions like field hockey. However, even the use of distance per minute can be misleading high-intensity movements are lumped together with low-intensity movements. Therefore it has led to the implementation of distances being measured in varying velocity zones. This allows practitioners to locate intense action during matches. 16 However velocity zones can be arbitrarily set leading to the misrepresentation of data. Regardless, GPS has provided coaches, trainers and sports scientist with a better understanding of the action profiles of athletes during games and training. This has led to the ability to tailor and adapt training and recovery programs to individual athlete profiles. Rationale for Research/Statement of Problem New match formatting and clock stoppages during corners and after goals, implemented by the International Hockey Federation (FIH), are believed to provide teams the ability to maintain and produce more high intensity actions. The new rule reads: “…Match Periods (4 x 15 Minute Quarters and time stoppages for the award of Penalty Corners and Goals), the Penalty Corner Countdown Clock and Video Umpire, which will only be used at FIH World level Tournaments…” (FIH, 2014). The author suspects that the implementation of these rules has affected the action profiles of field hockey players, by allowing for more high-intensity actions, resulting from the additional rest periods. The available action profiles for women’s field hockey in relationship to rule changes is scarce. For example only one study exists examining the effect of the 2009, free-hit rule on the game (Tromp & Holmes, 2011). To the authors knowledge no data exists on the effects of the 2015 rule changes on women’s field hockey. Objective of Research The primary objective of this dissertation was to establish the changes in GPS game action profiles for the relative variables, m/min, and percent of the total distance 17 covered in zones 1 through 6 from the US Women’s National Field Hockey team players, for the team and by position, caused by the evolution of game formatting, specifically the rules adapting play at World level tournaments by the FIH (FIH, 2014). The secondary objectives of this dissertation included: 1. Reporting the absolute action profiles including total distance, and total distance covered in zones 1, 2, 3, 4, 5, 6, pre 2015 rule change for team, player, and position, and post the 2015 rule change for team, and position. 2. Determine the changes in team, and positional relative action profiles before the 2015 rule change from the 1st to 2nd half of the game. 3. Determine the team and positional relative action profiles after the 2015 rule change in across the four quarters of a game. Significance This type of research is not novel; GPS research has provided useful information in many field sports such as field hockey (Gabbett, 2010), soccer (Wehbe et al., 2014), rugby (Sirotic, Knowles, Catterick, & Coutts, 2011), and Australian football (Varley, Gabbett, & Aughey, 2014), and various studies have investigated the changes in rules on different sports such as Rugby League (Eaves, Lamb, & Hughes, 2008; Meir, Colla, & Milligan, 2001), Rugby Union (Williams, Hughes, & O'Donoghue, 2005), Beach Volleyball (Giatsis, 2003; Ronglan & Grydeland, 2006), and Netball (O'Donoghue, 2012). However, for this dissertation the population, sample size, consistency of team members, and investigation of the 2015 rule change are innovative. This dissertation uses 18 the US women’s national team, who currently represent an elite standard of women’s field hockey. The team finished with a World Ranking of 8th in December 2014, and 7th in December 2015. The data included in this dissertation span a period of four international tournaments: the Champions Challenge 2014, Rabobank Hockey World Cup 2014, World League 3 Semi Finals, and 2015 Pan American Games. Two international tournaments were played before to the rule change, and two international tournaments were played after the rule change. The significance of this research is also strengthened by the high percentage of returning players allowing for a comparison in almost same sample. The team members remained constant between the Champions Challenge 2014 and Rabobank Hockey World Cup 2014. Two player changes were made for World League 3 in comparison to the 2015 roster, and one player change was made for the Pan American Games compare to the 2015 roster. In addition to the retention of players across games, the large number of files, and the evaluation of multiple tournaments is uncommon. Analysis with many observations of the same players are more likely to reduce discrepancies between matches due to different opponents and tactics and to reveal underlying commonalities. To the author’s knowledge the effects of 2015 rule change on games action profiles has never been studied. It is important to define the new match play action profiles of the team and of each position in order to better prepare players. This will allow for the continued development of attributes specific to the new style of play. Knowledge of the progression of the game, and the ongoing changes in physiological demands will be beneficial for strength and conditioning practitioners when designing training programs for the development of athletes. 19 Operational Definitions FIH International Hockey Federation – is the international governing body of field hockey. GPS Global position system – is a satellite based navigation system, that provided location and time information TMA Time-Motion Analysis – varying techniques used to quantify the action profiles of players during competitions. 20 CHAPTER 2 COMPREHENSIVE LITERATURE REVIEW Introduction The purpose of this review is to examine the current literature surrounding the methods used to determine GPS action profiles for team sports. The primary focus is field hockey. However other team-based sports are discussed in the literature review. Existing Literature The existing literature on field hockey is sparse. Podgórski and Pawlak (2011) published “A Half Century of Scientific Research in Field Hockey” with the goal of illuminating the status of research field hockey publications from 1960 to 2010. The number of citations for field hockey (7,459) pales in comparison to other field based team sports such as lacrosse (22,700), cricket (182,759), soccer (258,943), and football (1,025,038). The research publications were obtained from PubMed and EBSCO host databases, and www.scholar.google.pl, by entering the term “FIELD HOCKEY”. Upon further analysis the authors deduced that only 208 of the 7,459 citations directly related to field hockey, with the majority of the peer-reviewed research examining: the injuries occurring during training and games, skill development, tactics and match play, as well as the anthropometric and physical characteristics of players. There is a lack of research examining the specific game and practice demands of field hockey from elite population. Several studies claim to involve elite populations, but the use of the word elite can be often be misrepresented (Dwyer & Gabbett, 2012; Wassmer & Mookerjee, 2002). The minuscule amount of research involving elite field 21 hockey players presents with methodological limitations. Issues include lack of information on the reliability of the analysis method, low sample size, generalizing one players action profile for a whole positional group, and varying team rosters. Podgórski and Pawlak (2011) showed an increasing trend in the number of field hockey related publications. However the numbers of papers are still inferior to other field sports. Field Hockey Rules Field hockey is an internationally played sport, with the two largest tournaments based competitions being the Olympics and the World Cup. It is played between two teams of eleven players, normally ten field players, and a goalkeeper (Mitchell-Taverner, 2005). The objective of the game is to score a spherical ball, with a circumference between 224 and 235 mm, and a weight between 156 and 163 grams in into the opponents 3.66 meters wide by 2.14 meters high goal (FIH, 2014). The game is played at the international level on 91.4 meters by 55 meters’ artificial water based turf. Field hockey shares similar tactical and structural concepts with soccer. However aspects of field hockey are unique to the sport, and must be taken into consideration when analyzing field hockey specific research (Hodun, Clarke, De Ste Croix, & Hughes, 2016). The unique aspect of field hockey includes: body positions due to the use of sticks (Reilly & Borrie, 1992; Wdowski & Gittoes, 2013), rolling substitutions (Tromp & Holmes, 2011), penalty corners (Vinson et al., 2013), and the drag flick (de Subijana, Juarez, Mallo, & Navarro, 2011; Laird & Sutherland, 2003). Historically field hockey has been an intermittent high intensity sport consisting of two 35 minute halves (FIH, 2012). Numerous rule changes, implemented by the 22 International Hockey Federation (FIH) over the years have transformed the game of field hockey with some having more impact than others. Some rules have had more noticeable effects on the game. In 1975 when the FIH developed a common set of rules for men and women, in 1992 unlimited substitutions were allowed, in 1998 the off sides rule was removed from the game, in 2009 self-pass rule was implemented, and most recently in 2015 the time parameters of the game were changed (FIH, 2014). The action demands of the sport are in transition due to the most recent rule change with international matches being played in four 15 minute quarters. In addition to decreasing the game time from 70 minutes to 60 minutes, clock stoppages have been introduced. The game clock is stopped during corners, and a countdown clock, independent from the game clock, of 40 seconds is started. The offensive team has 40 seconds to complete the awarded corner. The game clock is also stopped after a goal is scored. The clock is stopped, and a 40 second countdown clock independent of the game clock is started, this gives the team scoring team time to celebrate. The rule change effects the official game time, but with the ability to stop the clock, the actual length of a game can vary. For example, if three corners occurred in the first quarter of a game the official game time maybe 15 minute. However, the length of play would be 17 minutes. International players, coaches, and sport scientists have recognized the impact of the game formatting rule change on substitution tactics, and game intensity. However to the author’s knowledge no empirical evidence of the effect of the 2015 game formatting rule change has been presented. Time motion analysis is commonly used in team sports to track player movements, and create player action profiles (Gabbett, 2010; Jennings et al., 2012a; Macutkiewicz & Sunderland, 2011; Vescovi & Frayne, 2015; White & MacFarlane, 23 2014; Wyldea et al., 2014). Global positioning systems specifically allow for the movement patterns such as total distance, distances covered at various speeds, and time on pitch. With the ever-evolving rules in field sports, performance analysis, and player action profiles provided by GPS can be a helpful tool in assessing the effects of different rules. Time Motion Analysis History Time motion analysis is a method used for quantifying the action profiles performed by athletes. It involves tracking the movements of athletes, through either the manual or computer analysis of film, or GPS. Video based TMA has proved to be a useful tool to quantify the physical output of players during field based sporting events (Bloomfield et al., 2007; Rienzi, Drust, Reilly, Carter, & Martin, 2000). Early research involving TMA utilized video cameras, and could only captured the data of a single player (Carling, Bloomfield, Nelsen, & Reilly, 2008). The nature of time and labor intensive analysis made it difficult for use in the team environment. However, it was shown to be reliable for examining movements of individual players (Duthie, Pyne, & Hooper, 2003). The introductions of sophisticated computer analysis systems have reduced the time-intensive nature of video analysis (Carling et al., 2008; Gray & Jenkins, 2010). However, the systems are expensive, require costly stadium based instillation, and require intensive calibrations. Recently sporting GPS technology and combined GPS and accelerometer systems have become popular in training and match quantification. The relatively inexpensive, and portable GPS technology has allowed performance tracking to be used by a greater number of field sports. 24 Global Position Systems History Current GPS technology uses satellites to construct the geographical location and movements of a receiver, which allows for the tracking of individual players. However, until the 1980s GPS technology was restricted for military use only. When the technology was finally made available for civilian use, the system was created with deliberate error. This made precision measurement impossible. In 2000, the US Department of Defense reduced the deliberate error in the system allowing for an increase in accuracy of nondifferential GPS technology (Terrier, Ladetto, Merminod, & Schutz, 2000). This change allowed for lighter, smaller and cheaper units to become available to the general public. Specific sports units were then developed to withstand heat, moisture, and sporting collisions. Current units are light and compact enough to wear under an athletic jersey in specially designed harnesses. Specialized GPS units and associated computer analysis provided the ability to both collect and analyze data relevant to the performance of athletes. The growth of the sports focused GPS industry resulted in GPS technology integrated with accelerometers and gyroscopes to allow for the collection of physical performance markers by individual athletes (Coutts & Duffield, 2010; D. Jennings, S. Cormack, A. J. Coutts, L. J. Boyd, & R. J. Aughey, 2010b; Rampinini et al., 2007; Varley, Fairweather, & Aughey, 2012). The application of GPS technology in the context of team sport has overcome many of the limitations of video-based TMA. The evolution manual video analysis to GPS allows coaches and sports scientist to determine and compare player’s movements during real time games or training. The low cost of GPS technology and portability of the system allow for data to be collected in many outdoor settings. 25 Global Positioning System Validity and Reliability The validity and reliability of GPS systems when assessing movement demands of team sports are influenced by several factors: GPS sampling frequency, speed, distance, and path of movements. The current trend in team sports is 10 Hz nondifferential GPS unit integrated with a 100 Hz tri-axial accelerometer, gyroscope, and magnetometer. However the above mention measures must be considered when using any GPS units, and especially when examining previous publications. Sampling frequency also known as sampling rate is the number of samples obtained during one second of collection. The sampling frequency of the technology influences the accuracy, reliability, and validity of data. Early GPS units operated at 1 Hz, while newer GPS units sample at frequencies of 5, 10, and even 15 Hz (Cummins, Orr, O'Connor, & West, 2013). As the sampling rates of GPS signals have increased, the accuracy of the measuring has also increased. Studies that compared units operating at 5 Hz to older units operating at 1 Hz found that the increased sampling frequency increased the accuracy of measurements (Coutts & Duffield, 2010; Jennings, Cormack, Coutts, Boyd, & Aughey, 2010a; MacLeod, Morris, Nevill, & Sunderland, 2009; Petersen, Pyne, Portus, & Dawson, 2009; Portas et al., 2010; Randers et al., 2010). Jennings et al. (2010a) assessed the validity and reliability of distance data measured by GPS units sampling at 1 Hz and 5 Hz during movement patterns common to team sports. They found that the accuracy decreased as speed of locomotion increased in straight line and the change of direction (COD) running. When comparing the accuracy of distance collected between a 1 Hz and a 5 Hz GPS, the standard error of estimate was calculated as the percent differences between the know distance and the GPS measured 26 distance. For a standing start, 10-m sprint was the percent difference between the known and GOPS measured was 32.4 % for units collecting at 1 Hz and 30.9 % for units collecting at 5 Hz. The increased sampling rate improved the GPS devices standard error. However, the 5 Hz systems were still limited in its ability to assess short, high speed, linear and COD running. Given that the most common sprint distance in team sports such as soccer, rugby, and field hockey are between 10-20 meters (Spencer, Bishop, Dawson, & Goodman, 2005), using 5 Hz GPS to measure distance traveled at very high velocities may be inappropriate, especially if older units that sample at low frequencies are used for data collection. Studies comparing GPS units sampling at 5 Hz and 10 Hz found superior accuracy for units sampling at 10 Hz when measuring velocity during straight-line running, accelerations, and decelerations, when compared to a tripod mounted laserbased criterion measure (Rampinini et al., 2015; Varley et al., 2012). The superiority of 10 Hz units over a linear distance of 15 and 30 meters is shown by Castellano et al. (2011). The researchers used video and timing gates to show accurate distance measurements taken by a unit sampling at 10 Hz. They noted an increase in accuracy as the distances increased. The intra-device reliability was greater over 30 meters than 15 meters. The inter-device reliability showed CV = 1.3%for 15 meters 30 meters and CV = 0.7% 30 meters. They found that the accuracy of the units improved with increased distance, and the standard error of measure between the known distance and distance measured by the GPS units was 10.9% when running 15 meters, but it was only 5.1% for the 30 meters trails. Regardless of the sampling frequency used, accuracy is reduced as movement velocity increases and distances covered decrease. Portas et al. (2010) 27 reported measurement error between the know distance and GPS estimated distance to be lowest during walking, which was measured at 1.8 meters per seconds, and produced of 0.7 % and highest during running at 5.6 %. Jennings et al. (2010a) showed that the measurement accuracy of both 1 Hz and 5 Hz GPS systems improved as distances covered increases during straight-line movements, COD, and a team sport running simulation circuit. The difference between criterion and GPS measured distance ranged from 9.0% to 32.4%. Total distance over the simulated running circuit exhibited the lowest variation (CV 3.6%) while sprinting over 10 meters demonstrated the highest (CV 77.2% at 1 Hz). These studies provide justification for the use of newer, higher frequency, GPS units in intermittent high intensity team sports. In addition to sampling frequency the movements used during validity and reliability testing must be considered. A study by Rampinini et al. (2015) examined a team sport specific running courses varying intensities. The courses required the participants to perform acceleration and deceleration movements. The authors examined two GPS units, sampling at 5 Hz and 10 Hz. The authors found that when compared to radar gun sampling at 32 Hz the 10 Hz GPS unit showed a 1.9% error for total distance and a 4.7% error for high speed running. Steps have even been taken to examine specific field sport conditioning. For example, the convergent validity and the test–retest reliability of GPS devices for measuring repeated sprint ability was studied by Barbero-Álvarez, Coutts, Granda, Barbero-Álvarez, and Castagna (2010). Results showed a strong correlation between peak speed measures with the GPS device and repeated sprint ability test performance measured against timing gates (r=0.87 for 15 meters, and r= 0.94 for 30 meters) These 28 data supports the use of 1Hz GPS for measuring repeated sprint ability performance testing in field sports, suggesting that GPS can be used in place of timing gates for RSA performance testing. When examining the validity and reliability of GPS units it is also import to consider the unit’s manufacture, and model. In a study by Randers et al. (2010) the authors compared four different TMA systems, a video-based time-motion analysis system, a semi-automatic multiple-camera system, and two GPS systems, one sampling a 5 Hz and one sampling at 1 Hz. The total distance covered during a soccer match was different between a semi-automatic multiple-camera system (10.8 ± 0.8 km), a videobased time–motion analysis system (9.5 ± 0.7 km), a 5 Hz GPS device (10.7 ± 0.7 km) and a 1 Hz GPS device (9.5 ± 0.9 km). The distance covered in high-intensity running was 2.7 ± 0.5, 1.6 ± 0.4, 2.0 ± 0.6 and 1.7 ± 0.4 km for the semi-automatic multiplecamera system, video-based system, 5 Hz GPS and 1 Hz GPS, respectively. Sprinting distance during the match was different between the four systems, with recorded values of 0.4 ± 0.2, 0.4 ± 0.2, 0.4 ± 0.2 and 0.2 ± 0.2 km for the semi-automatic multiplecamera system, video-based system, 5 Hz GPS and 1 Hz GPS, respectively. These results suggest that absolute distances taken from different time-motion analysis technologies should not be used interchangeably. When examining the previously presented information it is difficult to compare the validation studies due to the multiple criterion measures used to validate the GPS units. Therefore, the validation of GPS has methodological limitations that must be taken into account when assessing results. Criterion measures ranged from: electronic timing gates (Barbero-Álvarez et al., 2010; Castellano et al., 2011; Coutts & Duffield, 2010; 29 Jennings et al., 2010a; MacLeod et al., 2009; Petersen et al., 2009; Portas et al., 2010), radar gun (Rampinini et al., 2015), Tripod-mounted laser (Varley et al., 2012), VICON (Duffield, Reid, Baker, & Spratford, 2010),Theodolite (Gray & Jenkins, 2010) and videobased time-motion analysis system, and a semi-automatic multiple-camera system (Randers et al., 2010). The use of trundle wheel or tape measure, and timing gates can introduce error. For example, there is error in the ability of a trundle wheel to accurately measure distance, and in the timing gates to accurately measure time (Barbero-Álvarez et al., 2010; Castellano et al., 2011; Coutts & Duffield, 2010; Jennings et al., 2010a; MacLeod et al., 2009; Petersen et al., 2009; Portas et al., 2010). The methodological limitations of the trundle wheel or tape measure, and timing gates are most apparent when the research by Duffield et al. (2010) is examined. They used VICON to validate two 1 Hz GPS units and two 5Hz GPS units for total distance and speed. Both devices showed statically significant differences to the VICON for distance and speed. The interunit reliability ranged from r=0.10-0.70, and CV was 4% for 1 Hz units, and 25% for 5 Hz units. When a precision system was used to examine GPS validity it showed that both devices underestimate distance and speed. It also showed inter-unit error exist, establishing the need for player to wear the same units across data collection. Field Hockey Specific Global Positioning System Validation Various research has been done to validate GPS for general field sports, including field hockey (MacLeod et al., 2009). MacLeod et al. (2009) examined the validity of nondifferential GPS specifically for movement patterns used during field hockey. They conducted a TMA of international field hockey players to determine the movement 30 patterns expressed during games. With the TMA information, the authors created a circuit including a T-shaped shuttle, a straight-line shuttle, a straight sprint, and a zigzag shuttle to replicated players’ game movements. Each shuttle was measured against timing gates for mean speed and total distance was measured with a trundle wheel. All participants completed 14 laps with the intent of the total distance covered in an international match. A limitation of the validation is in the available equipment; the GPS units only collected at 1 Hz, and the accelerometer at 100 Hz. The Pearson correlation for the mean speed recorded by the timing gates and the GPS for the shuttle movements is r = 0.99. However the GPS overestimated distances for the T-shuttle, straight-line shuttle and straight-line shuttle sprint by 0.1 meters, 0.2 meters and 0.1 meters respectively. The mean distance covered reported by the GPS was 6820.5 meters, whereas, the actual distance covered was 6818 meters reported by the trundle wheel. The authors concluded that the nondifferential GPS system used in the study provided a valid measurement tool for assessing player movement patterns typically seen in field hockey. However the previously noted practical limitations of sampling frequency affect the potential precision of the data. With all of the previously mentioned validation studies the inherent error of the criterion measure must be taken into consideration. There is human error in the ability of the trundle wheel to actually measure the distance covered, and determining the exact starting point with GPS software can be difficult. In addition to this the timing gates are not a gold standard of measurement and carry inherent error. A summary of the GPS devices, sampling frequency, and criterion measure used for validation can be found in Table 2.1. 31 With the current information we know that the velocity and distance of a task directly influence the validity of the GPS measurements, and that GPS units with a higher sampling rate enhance the validity of the data. While the addition of high intensity short duration, and COD movement patterns decrease the validity of GPS results. The validity of GPS units is task and time dependent, and must be considered when presenting the results of data collection. With all the above taken into consideration we can then assume that studies conducted with 1 Hz GPS units and even 5 Hz GPS units provide a poor representation of sport action profiles, especially high intensity interval sports, in which short distances are covered at high intensities 32 Table 2.1 Validation GPS: devices, sampling frequency, and criterion measures Study MacLeod, Morris, Nevill, & Sunderland, 2009 GPS Device Frequency Task Measure Parameter 1 HZ Field Hockey SC ETT, TW Distance, Speed Petersen, Pyne, Portus, & Dawson, 2009 SPI Elite MinimaxX, SPI-10, SPIPro 5 Hz, 1 Hz Cricket SC ETG Distance, Speed Barbero-Álvarez, Coutts, Granda, BarberoÁlvarez, & Castagna, 2010 SpiElite 1 Hz LR ETG Coutts & Duffield, 2010 SPI-10, SpieElite WiSPI 1 Hz Team Sport SC ETG Peak Velocity Distance, Peak Velocity Jennings, S. Cormack, Coutts,Boyd, & Aughey, 2010 MinimaxX 1 Hz, 5 Hz LR, COD, Team Sport SC ETG Distance, Speed Jennings, Cormack, Coutts, Boyd, & Aughey, 2010 Duffield, Reid, Baker, & Spratford, 2010 MinimaxX v2.5 5 Hz LR, COD, Team Sport SC GPS Unit Between Unit MinimaxX v2.0, SpiElite 1 Hz, 5 Hz Tennis SC VICON Distance, Velocity Portas, Harley, Barnes, & Rush, 2010 MinimaxX Version 2.5, 1 Hz, 5Hz LR, COD, Soccer SC TW Distance Gray, Jenkins, Andrews, Taaffe, & Glover, 2010 SpiElite 1 HZ LR Theodolite Distance Randers et al., 2010 MinimaxX v2.0, SpiElite 1 Hz, 5Hz Soccer Match Running Video Distance Castellano, Casamichana, CallejaGonzalez, Roman, & Ostojic, 2011 MinimaxX v4.0 10 Hz LR ETG, Video Varley, Fairweather, & Aughey, 2012 V2.0 vs. MinimaxX 5 Hz, 10 Hz LR Acc, Dec ETG Waldron, Worsfold, Twist, & Lamb, 2011 SPI-Pro 5 Hz LR ETG Johnston et al., 2012 MinimaxX 5 Hz Team Sport SC Rader Distance Instantaneous Velocity Distance, Peak Velocity Distance, Peak Velocity Rampinini et al., 2015 SPI-Pro and MinimaxX 5 Hz, 10 Hz LR, Acc, Dec Radar Distance, Speed, Metabolic Power Johnston, Watsford, Kelly, Pine, & Spurrs, 2014 MinimaxX S4 vs. SPIProX 10 Hz, 15 Hz Team Sport SC ETG Distance, Speed Notes: LR=Linear Runs, SC=Simulation Circuit, Acc=Acceleration, Dec=Deceleration, ETG= Electronic Timing Gates, TW=Trundle Wheel 33 Global Positioning System and Micro Technology Metrics It is important to note that GPS does not measure the physical demands of a competition; rather it measures the output of a player. Therefor action profile should be used when refereeing to the metrics reported by GPS. There is extensive information on the action profiles of athletes from GPS, accelerometer, gyroscope, and magnetometer combined systems. The information produced by these systems includes total distance, distance per minute, distance and time in velocity zones, time on pitch, COD, acceleration, and deceleration. These metrics have been applied to detect fatigue in matches, identify periods of most intense play, and differentiate action profiles by position, competition level, and sport. Distance Total distance covered is a useful metric in steady state scenarios, but team sports are intermittent in nature. In team sports with unlimited substitutions reporting total distance travel can be especially misleading. The expression of distance per minute of match time is more useful for individual athletes, because it provides a reference to the time the athlete spent in game. Total distance can be misleading when examining athlete profiles because high-intensity movements are lumped together with low-intensity movements. The logical progression of total distance measures is to break movement into distance per minute and then further into minutes spent in different velocity zones. 34 Velocity Velocity zones measure the distances covered at a velocity. The velocity zones can be manipulated within the analysis systems of the GPS. Therefore the definition of the velocity band for standing, walking, jogging, running and sprinting often differs between researchers. Recent research suggests the number of high-intensity activities performed, and the time spent in each high-intensity zone, and the total distances covered in each high-intensity zone are important metrics (Cummins et al., 2013). It has been recommended that sport scientist use velocity ranges and sprint definition previously published in the literature, but large variations in the definitions and inability to agree on set definitions have resulted in confusion among researchers. Although recommendations for reporting GPS data for field hockey have been presented there is generally a wide range of reporting methods employed in the literature (Dwyer & Gabbett, 2012) (Table 2.2) A recent trend in the field hockey literature has been to simplify the velocity zones into low, moderate, high, and very high intensity running classifications (Vescovi & Frayne, 2015; White & MacFarlane, 2014) or into low and high intensity classifications (Jennings et al., 2012a, 2012b), but these classifications also vary greatly. Regardless it seems that the existing velocity ranges used in publications have been arbitrarily determined. Several prominent field hockey specific publication (Lythe & Kilding, 2011; White & MacFarlane, 2013) derive their velocity zones from Men’s International Soccer Video based time motion analysis (Di Salvo et al., 2007). For the purpose of this dissertation velocity zones from previously published international women’s field hockey will be used (Macutkiewicz & Sunderland, 2011). The velocity zones used will be: zone 1 standing (0-.16 m/s), zone 2 walking (.19-1.6 35 m/s), zone 3 jogging (1.69-3.05 m/s), zone 4 running (3.08-4.16 m/s), zone 5 fast running (4.19-5.27 m/s), zone 6 sprinting (>5.27 m/s). The velocity zones, designating the action profiles were originally adapted from definitions provided by Bangsbo and Lindquist (1992) and Lothian and Farrally (1992). These studies were performed on soccer and field hockey populations, respectively (Table 2.2). 36 Table 2.2 GPS Velocity Zones Study Gender Type Population Australian FH League National and International FH Velocity Zones (m/s) Zone 1 Zone 2 Zone 3 Low 0 - 1 Mod 1 - 5 High 5 - 7 Low .1 - 4.17 High > 4.17 W GPS Jennings, Cormack, Coutts, & Aughey, 2012 M GPS Jennings, Cormack, Coutts, & Aughey, 2012 M GPS Australian FH Low .1 - 4.17 High > 4.17 W GPS DI FH Low 0-2.22 Mod 2.254.44 High 4.475.55 M GPS Stand 0-0.16 Walk .19-1.6 Jog 1.69-3.05 M TMA Stand 0-0.16 Walk .19-1.6 Jog 1.69-3.05 W GPS Stand 0-.1 Walk .2-1.7 Jog 1.8-3.6 W GPS Stand 0-0.16 Walk .19-1.6 Jog 1.69-3.05 M GPS Low 2.77 4.16 Mod 4.165.27 High Speed 5.27- 6.38 M GPS U-18 Asia Cup FH Low > 4.17 High < 4.17 M TMA Australian FH NA M GPS Australian FH NA M&W TMA Non-elite FH NA W TMA National League FH NA TMA International Soccer NA Gabbett, 2010 Vescovi & Frayne, 2015 Lythe & Kilding, 2011 Di Salvo et al., 2007) Dwyer & Gabbett, 2012 Macutkiewicz & Sunderland, 2011 White & MacFarlane, 2014 Wyldea, Yonga, Azizb, Mukherjeec, & Chiac, 2014 Spencer et al., 2005 Polglaze, Dawson, Hiscock, & Peeling, 2014 McManus & Stevenson, 2007 Lothian & Farrally, 1992 Bangsbo & Lindquist, 1992 National New Zealand International Soccer Australian State league FH International FH Scottish National FH Notes: FH=Field Hockey M=Male W=Female 37 Zone 4 Zone 5 Max 5.588.88 Run 3.084.16 Run 3.084.16 Fast Run 4.19-5.27 Fast Run 4.19-5.27 Run 3.7-5.3 Sprint >5.4 Run 3.084.16 Sprint > 6.38 Fast Run 4.19-5.27 Zone 6 Sprint >5.27 Sprint >5.27 Sprint >5.27 Inertial Movement Analysis Some research suggests that distances covered, whether total or at varying velocities, neglects to consider stresses imposed through acceleration, deceleration, and impact forces (McLellan, Lovell, & Gass, 2011; Varley et al., 2012). The addition of inertial sensors, sometimes referred to as micro technology, in GPS units has allowed for the measuring of jumps, accelerations, deceleration, COD, and levels of impact. Due to the high number of changes of direction involved in team sports it has been suggested that these forces be included when analyzing and compiling the action profiles of field sport athletes. The integration GPS with accelerometer, gyroscopes and magnetometers has made the estimation of COD effects possible. Accelerometers are motion sensors that detect linear acceleration, while gyroscopes are motion sensors that detect angular velocity. Accelerometers and gyroscopes are often used together because they complement each other’s ability to provide precise acceleration, deceleration, and COD data. Magnetometers have a sensor that detects the Earth’s magnetic field and measure the orientation relative to magnetic North. The combination of these micro sensors allows for the inertial movement analysis metrics. Cummins et al. (2013) suggests that in addition to reporting distances traveled at various velocities and user-defined velocity zones the total number of accelerations and decelerations of the athletes should be reported. However this information can also be misleading because uses can set the threshold for what constitutes as an acceleration and deceleration. Similar to the velocity zones, practitioners are able to set thresholds for low, medium, high, and very high accelerations and decelerations. The lack of universal definitions must be taken into consideration when reviewing research. 38 Player Load and Metabolic Power In addition to the breakdown of IMA data, several GPS analysis companies have created algorithms that combine accelerometer and gyroscopic data into a single value. Catapult Sports has named their instantaneous sum of the three axes of acceleration derived from the combination of accelerometer and gyroscopic data “Player Load”. Player Load is derived from a mathematical formula that accounts for accelerations and decelerations in all three dimensions. Player Load has demonstrated a strong relationship to heart rate, blood lactate levels and rating of perceived exertion (Casamichana, Castellano, Calleja-Gonzalez, San Roman, & Castagna, 2013; Scott, Lockie, Knight, Clark, & Janse de Jonge, 2013). Metabolic Power is calculated by an algorithm using known measured oxygen uptake and accelerometer data to describe energy expenditure of whole body movements (Walker, McAinch, Sweeting, & Aughey, 2016). The reliability of metabolic power estimated from GPS based algorithms in field sports is poor with the typical error of the estimate between GPS derived metabolic power and a VO2 portable gas analyzer was 19.8% (Buchheit, Manouvrier, Cassirame, & Morin, 2015). Previously, energy expenditure estimations in soccer have been done by video match analysis, but more research is needed for GPS applications (Osgnach, Poser, Bernardini, Rinaldo, & di Prampero, 2010). More research is needed to improve the algorithms used for Player Load and Metabolic Power. For the purpose of this dissertation, Player Load and Metabolic Power are dependent on individual player attributes, and therefore not generalizable to position profiling. 39 Global Positioning System Action Profiles in Field Hockey The GPS and micro technology derived metrics presented above have been used to quantify the physical output of players during matches (Bloomfield et al., 2007). This technology has been utilized in team sports to advance the understanding of a variety of field sports demands including: Soccer (Buchheit, Mendez-Villanueva, Simpson, & Bourdon, 2010; Wehbe et al., 2014), Rugby Union (Cunniffe, Proctor, Baker, & Davies, 2009), Rugby League (Gabbett, Jenkins, & Abernethy, 2012; McLellan & Lovell, 2013; McLellan et al., 2011; Sirotic et al., 2011), Rugby Sevens (Granatelli et al., 2014), Australian Football (Coutts, Quinn, Hocking, Castagna, & Rampinini, 2010; Gray & Jenkins, 2010; Young, Hepner, & Robbins, 2012), and Field Hockey (Jennings et al., 2012a; Lythe & Kilding, 2011; Macutkiewicz & Sunderland, 2011; Vescovi & Frayne, 2015; White & MacFarlane, 2014). GPS application through the analyses of action profiles has enhanced our understanding of the intermittent nature that characterizes team sports (Spencer, Bishop, et al., 2005). GPS has been used to compare athletes between positions, age groups and levels of performance. It has also been used to monitor loads acquired during games and training, in addition to monitoring, comparing games to practices, and examining the time course of games and tournaments. Before examining the extensive uses of GPS in field hockey a standard for data collection and analysis must be defined. The current practice for GPS analysis has essentially been driven by soccer literature. Normally soccer players are on the pitch for a full game or do not reenter the game after substitution. However, in field hockey a high number of substitutions are allowed. This tactic allows for offensive and defensive pressure to be applied throughout 40 the match, and is used at the elite levels because the strategy relies on an even distribution of talent throughout team. Rolling substitutions allow players additional ability to recover off the field, before returning to play. Full game versus time on pitch analysis alters the description of the work to rest ratio and other time demands of elite field hockey players (White & MacFarlane, 2013). It has been suggested that elite field hockey is played at a higher intensity than other team sports with the same relative distances (Aughey, 2011a), and all previously reported data represents field hockey as an intermittent high intensity sport (Boyle, Mahoney, & Wallace, 1994; Gabbett, 2010; Jennings et al., 2012b; Lythe & Kilding, 2011; Polglaze, Dawson, Hiscock, & Peeling, 2014; Spencer, Lawrence, et al., 2004; Spencer, Rechichi, et al., 2005; White & MacFarlane, 2014). With this understanding it is important to acknowledge the need for different analysis strategies, and the inability to generalize women’s soccer data to field hockey. Action Profile Comparisons The production of different profiles within sports has drawn attention to the different running patterns observed at varying levels of the same sport (Jennings et al., 2012b), throughout a competitive season (Spencer, Bishop, & Lawrence, 2004), through a tournament scenario (Higham, Pyne, Anson, & Eddy, 2012) and between genders (Bradley et al., 2014). This information has led to a better understating of long-term athlete development, and the action profile traits need to perform at a high level within the sport. To the authors knowledge only one study has compared different levels of field hockey player’s specifically male national-level Australian player to their international 41 counterparts (Jennings et al., 2012b). The authors determined that international players cover 13.9% more total distance and 42.0% more distance at high speed running (>15 km/hr) then national players. Within the international population the midfielders performed the greatest total distance, and achieve the greatest high intensity running distance when compared to forwards and defenders. The authors also noted a decrease in total distances from the first to second half of the game for both national and international players. Macutkiewicz and Sunderland (2011) reported the action profiles of 25 female field hockey players over 13 international matches, in respect to positional demands. They attributed the differences in demands to the substitution tactics used by the team. Macutkiewicz and Sunderland (2011), Spencer, Lawrence, et al. (2004) and MacLeod et al. (2007) all reported that defender spend more time in low-intensity actions then midfielder, and forwards. However the exact distances covered are hard to define between the studies due to the variability in methods used, and the differences in movement classifications. Comparisons between studies are difficult due to the varying definitions. Monitoring Perhaps the most common, and daily use for GPS within teams sports is for monitoring purposes. Results from studies using GPS devices to monitor team sport players during competitions have provided clearer guidelines for training practices, and the monitoring of practices has led to a better understanding of player movement needs. The GPS devices also allow for team (Gabbett et al., 2012) and positional (Bloomfield et al., 2007) based monitoring during competition and practice. The ability to monitor 42 individuals allows sport scientists to examine the influence of training volume, intensity, and frequency on athletic performance, specifically as an external marker. Generally performance abilities improve as training volume, intensity, and frequency increase, but negative adaptations to exercise training are dose related. High incidence of illness and injury occurring when training loads is too high, resulting in overtraining. GPS monitoring can be used to assist in proper training prescriptions (Casamichana et al., 2013; Scott et al., 2013). The use of GPS as a monitoring tool has provided insight into weekly or day- by-day external load management (Scott et al., 2013). This information can then be used to improved periodization, and optimize the performance in training and games, and may help the detection of injury, fatigue and overtraining (Cummins et al., 2013). Game vs. Practice Monitoring procedures have developed into comparing action profiles of games, practices, and drills within practices. Gabbett et al. (2012) examined the demands of rugby league competitions and compared those demands to tradition rugby league practices. They found that the high intensity physical demands of competition were not well matched by those observed in traditional conditioning, repeated high-intensity effort exercise, and skills training activities. Individual drills and small-sided games have been examined to provide a better understanding of a player’s actions under different constraints. Gabbett and Mulvey (2008) investigated the movement patterns of smallsided games used in soccer training and compared them to different levels of competition. They found that while small-sided games offer players opportunities to engage in 43 movement patterns similar to those in games they often lack the high-intensity repeated sprints performed in games. Compiling the available drill, and small-sided game research produced by GPS has enabled coaches to design and implement conditioning practices that stress the appropriate physical requirements of the sport. This information provides insight for coaches on the modifications needed for training action’s to better prepare rugby players. Similar small game vs. practice research has been done with men’s and women’s field hockey drills with the intent of providing coaches with a better understanding of the activities occurring during game based training. Gabbett (2010) examined 19 training appearances and 32 games from an elite population of women’s field hockey players, that included or members of the Australia women's national field hockey team. The data were examined for positional profiles during both game based training practices and competitions. Only game based training session that included minimal coaching was included. The researchers found that the time spent in specific velocity zones during the small-sided games training didn’t reflect the action profiles of the matches. With this information the coaches and athletes examined can then modify the training group size, drill design, or drill complexity to better simulate the demands of competition. However without the specific details about the drills performed during the training sessions the time spent in varying velocity zones is limited in its usefulness for other coaches, White and MacFarlane (2014) used GPS data from the men’s Scottish National Team, and 75-competition analysis from 8 games, and 37 training analysis from 4 practice sessions. The practice data ware segmented into four categories: running, technical, tactical, and small-sided games, providing insight into the training sessions 44 themselves. The researchers also stated the purpose of the drills was technical and tactical development in preparation for competition, while running was designated as player conditioning. Similar to Gabbett (2010), White and MacFarlane (2014) attempted to compensate for the start and stop nature of practice, which is believed to decrease the overall intensity. Their GPS data breakdown including omitting breaks in-between drills. They found that even though training duration was longer for practices than matches the sprinting and high intensity distances were not different between games and practices. The authors included descriptions of the practices and training competed, and concluded that training environments can be manipulated to produce similar game action profiles. When compiling game vs. practice research it is easy to appreciate the multiple variables in training that can produce large differences in the reported distances covered and high intensity actions. Without the context of a training plan and the constant monitoring of training load, the nuisances of the specificity of training are lost. It can only therefore be generalized that under the right conditions drills can provide an adaptive stimulus resembling those recorded in games. Fatigue GPS has been used to examine the construct of fatigue in field sports, with the rationale that fatigue manifests as a decrease in performance. Researchers approached the concept of in game fatigue by splitting the data into distinct time frames to establish whether work rate varies with time or different tasks. Segments have been broken down with in games for first and second halves (Bradley & Noakes, 2013; Granatelli et al., 2014), by quarters (Coutts et al., 2010), and into 5 minute (Bradley & Noakes, 2013), and 45 1 minute (Granatelli et al., 2014) segments. Researchers have also examined the changes in action profiles across tournaments (Higham et al., 2012; Spencer, Rechichi, et al., 2005). The premises are based on the comparison of the overall work rate under different time constraints and the correlations of work rate with indices of the fatigue. However data with different teams have shown confounding results. Individual teams and players pace differently (Black & Gabbett, 2014), while substitution strategies (Bradley & Noakes, 2013), styles of play (Rampinini, Impellizzeri, Castagna, Coutts, & Wisloff, 2009), opposition (Aughey, 2011b; Bradley & Noakes, 2013), match score (Black & Gabbett, 2014; Bradley & Noakes, 2013), and level of player (Rampinini et al., 2009), impact work rate. Assuming fluctuations in work rate are due to fatigue is extremely misleading. It has recently been shown that pacing may occur in prolonged high-intensity intermittent team sports (Duffield, Coutts, & Quinn, 2009). Which could skew the interpretation of GPS-based fatigue. The introduction of substitutions must also be considered, due to the various rules within different sports. The information available on pacing measured by GPS comes from sports with limited substitutions like rugby (Black & Gabbett, 2014) and soccer (Gabbett, Wiig, & Spencer, 2013), and therefore might not be practical to apply to an unlimited substitution sport like field hockey. With the above research taken into consideration this dissertation plans to only report GPS data as athlete profile data, or simply the actions performed by the position or athlete during the game. Spencer, Rechichi, et al. (2005) examined an international men’s tournament consisting of three games player within four days. Across the games the time spent standing increased, and the time spent in the jogging decreased. The authors concluded 46 that the time between games was to short too allow for recovery, and the subsequent games were negativity impacted. The authors used a positional based analysis and accounted for time of pitch. The author note that substitution strategy, playing style of opposition, changes in tactic, and environmental conditions could have influenced the results. It is also important to note that each game was won or lost by a one-point goal differential. Regardless residual fatigue could be a factor in tournament scenarios for international field hockey players, and recovery techniques should be utilized to encourage the dissipation of fatigue. This is in contrast to other studies, which show no changes across a tournament. However direct comparison between studies is difficult. Problems/Considerations/Match Variability It is important to note the match-to-match variability that occurs for action profiles (Gregson, Drust, Atkinson, & Salvo, 2010). There are numerous factors that may contribute to the variations reported within GPS team sport data. Previously mentioned factors include: substitution strategies (Bradley & Noakes, 2013), styles of play and tactics (Rampinini et al., 2009), opposition (Aughey, 2011b; Bradley & Noakes, 2013), match score (Black & Gabbett, 2014; Bradley & Noakes, 2013), and level of player (Rampinini et al., 2009), impact work rate. This is combined with the fact that past studies could be outdated, and lack relevance to the current game. Summary The goal of this chapter was to provide a theoretical basis for the experimental chapters of this dissertation. It provided an overview of the existing TMA literature, 47 specifically GPS. GPS literature conducted on field hockey players in reference to positions, age groups and levels of performance, games and practices were examined. Sport specific GPS units provide coaches and sport scientists with action profiles produced by athletes. The validity and reliability of GPS systems when assessing movement demands of team sports are influenced by several factors: GPS sampling frequency, speed, distance, and path of movements, which must be taken into consideration when examining and conducting research. Information in produced from GPS, accelerometer, gyroscope, and magnetometer combined systems. The information gained from these systems includes total distance, distance per minute, distance and time in velocity zones, time on pitch, COD, acceleration, and deceleration. The intent of this dissertation was to use GPS derived metrics to examine the action profiles produced by elite level field hockey players before and after a game formatting rule change. The purpose was to provide coaches and sport scientist with a depiction of the changes caused by the 2015 FIH game formatting rule change. 48 CHAPTER 3 POSITIONAL AND MATCH ACTION PROFILES OF ELITE WOMEN’S FIELD HOCKEY PLAYERS Authors: Heather A Abbott1, Kimitake Sato1, Satoshi Mizuguchi1, Dave Hamilton2, Michael H. Stone1 Affiliations: Center of Excellence for Sport Science and Coach Education Department of Exercise and Sport Sciences, East Tennessee State University, Johnson City, TN, USA1 USA Field Hockey, Manheim, PA2 Prepared for Submission to Journal of Strength and Conditioning Research 49 ABSTRACT The purpose of this study was to examine the action profiles of the US Women’s National Field Hockey Team recorded with GPS during the 2014 Champions Challenge and World Cup. Eighteen female international field hockey players (age 25.5 ± 0.17 years, body mass 61.1 ± 4.7 kg) were tracked over thirteen international matches, giving a total of 195-player match analysis. The descriptive data (playing time, odometer, absolute distances and relative percent distances covered zone 1 standing (0-.16 m/s), zone 2 walking (.19-1.6 m/s), zone 3 jogging (1.69-3.05 m/s), zone 4 running (3.08-4.16 m/s), zone 5 fast running (4.19-5.27 m/s), zone 6 sprinting (>5.27 m/s), and velocity zone efforts, maximum effort distance, and average effort distance in zones 4,5, and 6) in reference to both player and position are presented as the mean ± standard deviation (SD). A series of ANOVAs were used to compare the relative percent distances covered between positions, and a paired sample t-test was used to compare the relative percent distances for the team between each half. The findings revealed that defenders work at a lower meter per minute (m/min) when compared with all other positions, and that forwards, midfielders, and screens perform similar m/min during a game. It is possible for elite level field hockey players to maintain high-intensity actions in zone 6 from the 1st half to 2nd half of the game by increasing actions in zones 1 and 2, and decreasing actions in zones 4 and 5. KEY WORDS: Global Positioning System, Time Motion Analysis, Team Sports, Substitutions, Field Sports 50 INTRODUCATION Field hockey is a multifactorial team sport, with interspersed high-intensity activities that are multi-directional in nature; it requires significant levels of aerobic and anaerobic power, strength, and power (5, 8, 24). Field Hockey has undergone fairly rapid and radical changes within the past ten years. For example, the arrival of synthetic playing surfaces (19), modernized sticks (1), and new rule alterations such as the self-start (28), have changed the physiological requirements of the game. Time-motion analysis techniques, such as global positioning systems (GPS), have provided valuable information regarding the action profiles of field hockey players (7, 8, 10, 11, 17, 18, 20, 31, 33, 34). It is important to note that GPS does not measure the demands of competition, but rather the outputs of players. GPS units have been shown to be reliable and valid for measuring distance and velocity with the accuracy improving as sampling frequency increases (12, 21, 29). A high sampling frequency is especially important for intermittent high-intensity sports such as field hockey, which involve numerous high-speed and short distance actions. Early field hockey publications might not accurately represent the actions of field players due to the recent rule changes (28), and varying analysis procedures used (32). It has been previously noted that discrepancies exist when reporting locomotor activities (eg. walking, jogging, running) with TMA (8), and making a comparison between studies is difficult. Moreover, inconsistencies in data processing also create discrepancies in reported measures, specifically when comparing full game time to the time on pitch. 51 Different GPS analysis procedures can influence the time-dependent measures reported by GPS. This is specifically evident within sports with rolling substitutions, such as field hockey. The tactic of rolling substitutions creates offensive and defensive pressure throughout the match and is utilized at the elite level. This strategy relies on an even distribution of talent throughout the team. The efficient use of this strategy affects an athlete’s ability to produce repeat high-intensity actions. Previous research that uses full game GPS rather than time on pitch analysis, resulting in a misrepresentation of the time dependent factors provided by GPS. Time on pitch analysis produce higher relative distance results then analysis of full games (124 m/min vs. 78 m/min, p ≤ .0001) (32). However, absolute measures such as distances covered, the number of efforts and distance of efforts are unaffected (32). In addition to varying analysis methods, the level of players (11), level of competition (14), age of players (30), gender of players (6), match status (15), and tactical style (23) utilized by the team has the potential to affect the reported positional profiles. Therefore, it is important to characterize the style of play implemented at the highest level in the US. To the author’s knowledge, the unique and aggressive style of play used by the US Women’s National Team has not been profiled. Therefore, the aim of this study was to assess the action profiles of elite women’s field hockey players in the US by team, player, and position across a game, and to determine if action profiles differed between the 1st and 2nd halves of a match. 52 METHODS EXPERIMENTAL APPROCACH TO THE PROBLEM GPS technology allowed for the measurement of absolute variables (total distance covered, distance covered in zones 1,2,3,4,5, 6, and velocity zone efforts, maximum effort distance, and average effort distance in zones 4,5, and 6), and relative variables (m/min, percent of the total distance covered in zones 1, 2, 3, 4, 5, and 6) from the US Women’s National Field Hockey Team. The relative variables were used to determine the differences in action profiles because not all players received the same amount of playing time. The relative action profiles were analyzed for differences between positions across a game, and between 1st and the 2nd half for the team. ATHLETES Eighteen members of the US Women’s National Field Hockey Team age (25.54 ± .17 years, body mass 61.12 ± 4.66 kg) participated in this study. The team finished with a World Ranking of 8th in December 2014. Goalies were removed from GPS analysis, but included in physical player profiles. GPS recordings were collected from the 2014 Champions Challenge and 2014 World Cup (Table 1). The team members remained constant between the two international tournaments. The US Women’s National Team finished the 2014 Champions Challenge with the 1st ranking, sustaining 5 wins, and 1 loss. During the 2014 World Cup, the team finished with a 4th place ranking, after winning 4, tying 1, and losing 2 games. The East Tennessee State University Institutional review board approved this study and each athlete read and signed a written informed consent document. 53 PROCEDURES All GPS data collection was performed on outdoor water based turf. Data was collected during the 2014 Champion’s Challenge in Glasgow, Scotland and the 2014 Rabobank Hockey World Cup in The Hague, Netherlands, giving a total of 195 player-match files for analyses from thirteen games. All GPS data was acquired using Catapult Minimax X (Catapult Innovations, Melbourne, Australia), which samples at 10 Hz. This device had previously been shown to be valid for distance and velocity during linear and sport specific movements (12, 13, 21, 29). The GPS units were worn within a specifically designed bib with a neoprene pouch. The bibs hold the units between the shoulder blades of the athlete. Each player wore the same device across all matches. All players were acclimated to wearing the GPS units as a result of previous practice, and game monitoring. The GPS data was downloaded using the manufacturer-supplied software (Logan Plus, version 5.1.7). The downloaded data was edited to only include time spent on the field of play, during the regulation game time. The data were exported to Microsoft Excel for further analysis. Individual player action profiles were identified and players were categorized into four positions: forwards, midfielders, screens, and defenders. Similar player categorization for field hockey has only been utilized in one prior study (20). Players were substituted into the same positions; therefore, each play only contributes to one positional group. Time on the substitution bench was not analyzed or included in any calculations of rest or low-intensity exercise. The velocity zones were chosen from previously published international field hockey research (stand 0-.16 m/s, walk .19-1.6 54 m/s, jog 1.69-3.05 m/s, run 3.08-4.16 m/s, fast run 4.19-5.27 m/s, and sprint>5.27 m/s) (17, 18). The velocity zones were originally adapted from definitions provided by Bangsbo and Lindquist (2) and Lothian and Farrally (16). The studies consisted of video based time motion analysis performed on soccer (2) and field hockey (16) populations. STASTICAL ANAYLSIS Each individual athlete’s data files were combined across games, and the mean ± SD was calculated for absolute and relative measures. Absolute data was constructed using two varying methods: a player method, and a positional method. The player absolute data represents the mean ± SD for the total number of players used in that positional group. The absolute position data represents the work performed by the positional group regardless of the number of players substituting into that position. The players were separated into four different positions: forwards, midfielders, screens, and defenders, and player and positional representation were constructed. The benefit of positional reporting is that it negates the substitution strategy used by the US Women’s National Team, and presents the mean ± SD of the position regardless of how many players played in that positional group during the game. Reporting total distances is in the context of player or position is limited in its usefulness because distance covered is directly related to the amount of time a player spent on the pitch. Therefore, relative percent distances covered were used to examine the differences between positions and the team changes across the game. Total distance covered was considered relative to the total number of minutes played for each athlete (meters per minute), and the total distance covered in each velocity zone (1-6) was considered relative to the total distance covered, resulting in the 55 relative percentage distance covered for each velocity zone. The number of efforts, maximum, and average distance covered in velocity zones 4, 5, and 6 are presented as mean ± SD. A paired sample t-test was run to compare 1st vs. 2nd half relative data. The difference between playing positions across a game was analyzed using a series of 1-way ANOVAs, with post hoc Bonferroni tests. All statistical procedures were performed with SPSS (IBM, New York, NY). Statistical significance was set at p - value <0.05, and all data is reported as mean ± SD. The effect size was calculated from the ratio of the mean difference to the SD. Cohen’s d effect sizes (d) were assessed using the following criteria: trivial <. 2, small .2-.6, moderate .61-1.20, large 1.21-2.00 and very large 2.01-4.0 (9). TERMS/DEFINATIONS Player = Absolute action profiles divided by the total number of players (team data were divided by 16, forwards were divided by 4, midfielders were divided by 5, screens were divided by 3, and defenders were divided by 4) Position = Absolute action profiles divided by the number of positions on the field (team data were divided by 10, forwards were divided by 2, midfielders were divided by 3, screens were divided by 2, and defenders were divided by 3) Relative = m/min, Percent of distance covered in velocity zones 1, 2, 3, 4, 5, and 6 relative to the total distance covered. 56 RESULTS DESCRIPTORS Playing time varied based on the player, and position (Table 2). No inferential statistics were applied. However, simple numerical comparisons revealed defenders and screens appear to average the highest playing time per match, followed by the midfielders, and forwards. The absolute action profile characteristics of the games are presented in Table 3. Action profiles were reported in both the context of position and player. Player profiles represent the absolute distances covered by the members of the US Women’s National Team. Player data is specific to the teams’ personnel, tactics, substitution strategy, and opposition. A positional breakdown of the data provides coaches with the absolute total distance covered by each position on the team. This information is still specific to the formation that the US Women’s National Team uses (2 forwards, 3 midfielders, 2 screens, and 3 defenders). 57 Table 1. Tournament Schedule and Outcome Tournament Finish Location Champions 1st Glasgow, Challenge I 2014 Scotland Rabobank Hockey World Cup 2014 4th The Hague, Netherlands Date/Opponent/Score 4/27/2014 4/28/2014 4/30/2014 5/1/2014 5/3/2014 5/4/2015 ESP RSA IRL INDIA ESP IRL 3 to 1 1 to 2 3 to 0 1 to 0 3 to 1 3 to 1 6/1/2014 6/3/2014 6/6/2014 6/8/2014 6/10/2014 6/12/2014 6/14/2014 ENG ARG CHN GER RSA AUS ARG 2 to 1 2 to 2 5 to 0 4 to 1 4 to 2 2 to 2 1 to 2 Table 2. Positional Playing time Position N Average Minutes Forwards 4 38.25 Midfielders 5 41.40 Screens 3 57.00 Defenders 4 57.50 58 SD 1.26 8.26 3.00 11.41 Table 3. Champions Challenge and World Cup Player and Position Action Profiles N Odometer (m) Player 16 3701 Position 10 5921 Forward Player 4 3091 Forward Position 2 6181 Midfielder Player 5 3264 Midfielder Position 3 5441 Screen Player 3 2293 Screen Position 2 3439 Defender Player 4 5912 Defender Position 3 7882 Data Presented as mean ± SD ± ± ± ± ± ± ± ± ± ± 1675 1675 1094 1094 985 985 701 701 1378 1378 Zone 5 Fast Zone 6 Zone 1 StandZone 2 Walk Zone 3 Jog Zone 4 Run Run 4.19- Sprint >5.27 m/ min 0-.16 m/s .19-1.6 m/s 1.69-3.05 m/s 3.08-4.16 m/s 5.27 m/s m/s 36 58 28 57 31 51 21 32 61 82 ± ± ± ± ± ± ± ± ± ± 22 22 12 12 13 13 9 9 26 26 891 1426 716 1431 802 1337 563 844 1425 1901 ± ± ± ± ± ± ± ± ± ± 443 443 258 258 291 291 254 254 467 467 1270 2032 1008 2017 1119 1865 804 1206 2071 2761 59 ± ± ± ± ± ± ± ± ± ± 604 604 350 350 355 355 324 324 511 511 923 1477 782 1565 783 1305 543 814 1523 2031 ± ± ± ± ± ± ± ± ± ± 442 442 238 238 232 232 136 136 390 390 432 691 414 827 378 630 260 389 648 864 ± ± ± ± ± ± ± ± ± ± 191 191 175 175 141 141 27 27 165 165 151 241 151 301 151 252 107 160 183 244 ± ± ± ± ± ± ± ± ± ± 77 77 120 120 83 83 31 31 49 49 117 188 117 234 120 200 118 177 114 152 ± ± ± ± ± ± ± ± ± ± 9 9 11 11 11 11 11 11 9 9 Table 4. Absolute Number of efforts, Maximum and Average Distance covered in Top 3 Velocity Zones Velocity Zone 4 Velocity Zone 5 Velocity Zone 6 Team Forwards Midfielders Screens Defenders Velocity Zone Efforts 104 ± 24 91 ± 4 97 ± 27 132 ± 12 104 ± 30 Max Effort Distance (m) 50 ± 6 49 ± 5 53 ± 8 54 ± 0 46 ± 5 Average Effort Distance (m) 13 ± 1 13 ± 1 14 ± 1 14 ± 0 12 ± 1 Max Velocity Effort Zone Distance Efforts (m) 50 ± 13 37 ± 5 54 ± 3 36 ± 2 52 ± 16 39 ± 4 62 ± 8 44 ± 2 37 ± 11 32 ± 2 60 Average Effort Distance (m) 13 ± 1 12 ± 1 13 ± 1 14 ± 1 12 ± 1 Velocity Zone Efforts 15 ± 5 17 ± 1 16 ± 5 16 ± 4 8 ± 3 Max Effort Distance (m) 38 ± 6 42 ± 4 40 ± 5 40 ± 4 29 ± 2 Average Effort Distance (m) 16 ± 1 17 ± 1 17 ± 1 17 ± 1 15 ± 0 POSITION DIFFERENCE Main effect data is represented in table 6, and the p valve and d for all the interactions is presented in Table 7. Results of the ANOVAs showed statistically significant differences in zones 2, 3, 5, and 6 and m/min (Table 6). The post hoc tests indicated that forwards and midfielders did not had any statistically significant differences in relative percent distance covered in each zone and m/min (Table 7). Screens had only one statistical difference when compared to forwards, in which screens covered statistically less relative percent distance covered in zone 6 than forwards (Tables 5 and 7). On the other hand, defenders covered statistically greater relative distance in zones 3 and 2 than forwards and midfielders, respectively, but statistically shorter relative percent distance covered in zones 5 and 6 and m/min than forwards and midfielders. Defenders also covered shorter relative percent distance in zone 5 and m/min than screens. 61 Table 5. Descriptive Data for Relative Zones Relative Zones Zone 1 0 -.16m/s Zone 2 .17 - 1.68 m/s Zone 3 1.69 - 3.07 m/s Zone 4 3.08 - 4.18 m/s Zone 5 4.19 -5.27 m/s Zone 6 > 5.27 m/s m/min Team 1.06 ± 24.12 ± 33.11 ± 24.89 ± 12.04 ± 4.75 ± 120.58 ± Note: All data is mean +/- SD Forwards Midfielders Screens Defenders 0.31 0.91 ± 0.13 0.96 ± 0.31 1.04 ± 0.15 1.37 ± 0.43 4.83 22.62 ± 2.00 21.39 ± 4.22 22.77 ± 1.43 30.03 ± 4.87 3.61 29.94 ± 1.72 32.36 ± 1.65 32.73 ± 4.99 37.49 ± 1.46 3.23 25.53 ± 1.94 26.12 ± 2.57 26.78 ± 2.35 21.28 ± 3.46 3.04 14.00 ± 0.42 13.68 ± 1.35 12.65 ± 2.33 7.58 ± 1.89 2.04 6.96 ± 0.76 5.47 ± 1.16 3.98 ± 1.42 2.21 ± 0.72 10.25 125.75 ± 3.86 125.20 ± 10.89 123.67 ± 1.53 107.25 ± 5.74 Table 6. ANOVA Main Effect for Position Relative Zones Df F Zone 1 0 -.16m/s (3,12) 2.038 Zone 2 .17 - 1.68 m/s (3,12) 4.832 Zone 3 1.69 - 3.07 m/s (3,12) 6.329 Zone 4 3.08 - 4.18 m/s (3,12) 3.398 Zone 5 4.19 -5.27 m/s (3,12) 14.901 Zone 6 > 5.27 m/s (3,12) 15.691 m/min (3,12) 6.119 sig. 0.162 0.020 0.008 0.054 0.000 0.000 0.009 62 Table 7. Relative Percent Distance covered in Velocity Zones Between Positions Forward vs. Forward vs. Mid Screen Relative Zones P ES P ES Zone 1 0 -.16m/s 1.000 0.214 1.000 -0.921 Zone 2 .17 - 1.68 m/s 1.000 0.372 1.000 -0.084 Zone 3 1.69 - 3.07 m/s 1.000 -1.436 1.000 -0.749 Zone 4 3.08 - 4.18 m/s 1.000 -0.260 1.000 -0.580 Zone 5 4.19 -5.27 m/s 1.000 0.317 1.000 0.807 Zone 6 > 5.27 m/s 0.313 1.516 *0.016 2.610 m/min 1.000 0.067 1.000 0.709 * Significance, ES = Effect Size, P= p-value Forward vs. Midfielder vs. Defender Screen P ES P ES 0.279 -1.450 1.000 -0.320 0.082 -1.991 1.000 -0.436 *0.007 -4.730 1.000 -0.102 0.259 1.514 1.000 -0.267 *0.001 4.697 1.000 0.542 *0.000 6.443 0.424 1.148 *0.021 3.783 1.000 0.197 63 Midfielder vs. Screen vs. Defender Defender P ES P ES 0.356 -1.094 0.983 1.031 *0.024 -1.896 0.135 -2.024 0.062 -3.293 0.175 -1.293 0.133 1.586 0.114 1.857 *0.000 3.717 *0.007 2.390 *0.003 3.391 0.258 1.578 *0.018 2.062 *0.069 3.910 1st VS. 2nd HALF The team differences determined as the relative percent distance cover in each velocity zone were used to determine if the team expressed any changes in action profile from the 1st to the 2nd half of the game. The results showed a moderate increase in the percent of distance cover in zones 1 and 2 and a moderate decrease in the percent distance covered in zones 4 and 5 from the 1st half to the 2nd half (Table 8). Trivial decreases were produced in zones 3 and 6, and a moderate decrease was noted in m/min. However, no relative data showed statistically significance difference between the 1st and 2nd half of the game. 64 Table 8. Team Changes Relative Percent Distance covered form the 1st to 2nd Half Std. Error pRelative Zones Periods N Mean ± SD Mean value Zone 1 0 -.16m/s 1st half 16 0.94 ± 0.20 0.05 0.107 2nd half 16 1.14 ± 0.44 0.11 Zone 2 .17 - 1.68 m/s 1st half 16 22.34 ± 3.48 0.87 0.105 2nd half 16 25.11 ± 5.66 1.42 Zone 3 1.69 - 3.07 m/s 1st half 16 32.54 ± 2.73 0.68 0.848 2nd half 16 32.30 ± 4.08 1.02 Zone 4 3.08 - 4.18 m/s 1st half 16 25.11 ± 2.43 0.61 0.172 2nd half 16 23.51 ± 3.85 0.96 Zone 5 4.19 -5.27 m/s 1st half 16 12.47 ± 2.71 0.68 0.221 2nd half 16 11.14 ± 3.29 0.82 Zone 6 > 5.27 m/s 1st half 16 4.82 ± 2.01 0.50 0.688 2nd half 16 4.52 ± 2.17 0.54 m/min 1st half 16 121.75 ± 11.50 2.87 0.147 2nd half 16 116.06 ± 10.08 2.52 65 Effects Size Qualitative Descriptor -0.59 Moderate -0.59 Moderate 0.07 Trivial 0.49 Moderate 0.44 Moderate 0.14 Trivial 0.53 Moderate DISCUSSION This study investigated the action profiles of US Women’s National Team during the 2014 Champions Challenge and 2014 World Cup. In this study, the defenders appear to have spent greatest time on the pitch (Table 2) and covered the highest absolute distances by player and position (Table 3). Playing time is important in determining the absolute distances covered during a match (20). Defenders tactical position allows them to moderate and control the field. It is the goal of a defender to organize and control space on the pitch. These positional requirements allow the defenders to recover on the field resulting in less substitution and more time spent on the pitch. Forwards appear to have spent the least amount of time on the field (Table 2). This is most likely due to high intensity and repeated runs performed by the forwards resulting in more frequent substitutions. Playing time differences for positions have previously been noted by Macutkiewicz and Sunderland (18). A difference in playing time between positional groups is a product of the unlimited substitution rule. The team action profiles of the US Women’s national team showed that players covered a 16.8% of the total distance in zones 5 and 6. This is higher than previously reported 6.1%, for men’s by Lythe and Kilding (17), and 6.4% for women’s by Macutkiewicz and Sunderland (18) under the same velocity zone definitions. When comparing positional differences for relative data, the results showed that defenders covered less relative percent distance than forwards in zones 3, 5, 6 and m/min. Previous studies reported that defenders cover less distance at higher intensity than forwards, midfielders, and screens (5, 8, 10, 18), which represent the link of action profiles to the tactical demands specific 66 to positional roles. Previous research (8) has suggested position specific conditioning based on the differences reported between positions. However, the percent difference in high intensity velocity zones and variation in significance between zones should be considered to justify the need for position specific conditioning. When examining the mean ± SD for relative percent distance covered in zones 3, 5 and 6 between forwards and midfielders the relative percent distances and m/min are similar. No statistical differences existed between forwards and midfielders. The lack of significance contradicts the suggested need for prescription of additional position-specific highintensity-type training between forwards, midfielders and screens. Examination of the average and maximum effort distance covered by the team in velocity zones 4, 5, 6 suggests that an average effort is between 13 and 16 meters, while a max effort ranges between 40 and 50 meters (Table 4). Short-duration, high-intensity efforts replicating match requirements should be used during training (26). The variation of the percent relative distance covered in the varying velocity zones (Table 5) demonstrates the need for a balanced development of aerobic and anaerobic capacities for field hockey players. This agrees with previous research that concluded field hockey to be an aerobically demanding sport with frequent anaerobic efforts (8, 24). Athletes need to possess the ability to perform intermittent high-intensity actions and recovery, from those activities quickly because sprinting is not evenly distributed throughout a game (26). Increasing an athlete’s top speed can allow them to produce higher relative speeds during a match, while increasing athletes’ aerobic capacity will allow for a higher critical speed to be maintained while recovering between intermitted bouts of high-intensity (3, 4, 30). 67 When comparing the 1st to the 2nd half for team relative percent distances no statistical significance was concluded. More slightly more distance was covered in the second half in zones 1, 2, and 3 (Table 8). This agrees with the increase in lower work intensity (011km/hr) reported by Spencer, Rechichi, Lawrence, Dawson, Bishop and Goodman (27) for men’s field hockey. The results also agree with the decrease in zone 4 from the 1st to 2nd half. It seems that players compensate for the high intensity of the game by decreasing their moderate-intensity actions and increasing their low-intensity actions to allow for the maintenance of high-intensity actions from the 1st to 2nd half. The increase in lowintensity actions may be needed to assist in the ability to recover from high-intensity actions. Optimal utilization of rolling substitutions may cease the increase in low intensity actions from the 1st to 2nd half by allowing players to recover off the pitch. It has been suggested that high-intensity running is a much more important indicator of success than total distances covered (22, 25, 26). It is important to note that the difference in relative percent distance covered across halves is not considered statistically for any relative data, this is likely due to the using a high number of rolling substitutions throughout the match, which is speculated to permit the maintenance of intensity. PRACTICAL APPLICATION High-intensity sprints taking place in zone 6 only make up a small portion of match actions (5-8%) in elite field hockey. Actions performed in zones 4 (12-13%), and 5, (2526%), represent a greater portion of the game then zone 6. Due to the intermittent nature of field hockey, there is a necessity to repeat high-intensity actions throughout a game, and the ability to perform those actions is recognized as a key determinant of success (3). 68 Unfortunately high-intensity actions create fatigue. Positional differences indicate that defenders covered less relative percent distance in zones 5 and 6 when compared to forwards and midfielders. 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WhiteADandMacFarlaneNG.AnalysisofInternationalCompetitionand TraininginMen'sFieldHockeybyGlobalPositioningSystemandInertial SensorTechnology.Journalofstrengthandconditioningresearch/National Strength&ConditioningAssociation,2014. 34. WyldeaM,YongaLC,AzizbAR,MukherjeecS,andChiacM.ApplicationofGPS technologytocreateactivityprofilesofyouthinternationalfieldhockey playersincompetitivematch-play.InternationalJournalofPhysicalEucation, 74 CHAPTER 4 WOMEN’S ELITE FIELD HOCKEY ACTION PROFLIES POST 2015 RULE CHANGE Authors: Heather A Abbott1, Kimitake Sato1, Satoshi Mizuguchi1, Dave Hamilton2, Michael H. Stone1 Affiliations: Center of Excellence for Sport Science and Coach Education Department of Exercise and Sport Sciences, East Tennessee State University, Johnson City, TN, USA1 USA Field Hockey, Manheim, PA2 Prepared for Submission to International Journal of Sport Science and Coaching 75 Abstract The object of this paper was to analyze the action profiles of the US Women’s’ National Field Hockey Team using GPS technology, after the 2015 International Hockey Federation (FIH) game time formatting change. The purposes were to present coaches with an elite level standard of the new game, and to examine action profile changes across the game. Actions were recorded over two international tournaments, during twelve games, resulting in one hundred forty-eight files for sixteen athletes (age 20.5 ± 2.5 years, body weight 60.6 ± 5.2 kg). The descriptive data was presented for playing time, odometer, absolute distances covered zone 1 standing (0-.16 m/s), zone 2 walking (.19-1.6 m/s), zone 3 jogging (1.69-3.05 m/s), zone 4 running (3.08-4.16 m/s), zone 5 fast running (4.19-5.27 m/s), and zone 6 sprinting. Total distance covered was also considered relative to the total number of minutes played for each athlete ((meters per minute (m/min)). A total distance covered in each velocity zone (1-6) was also considered relative to the total distance covered in percentage. A series of repeated measures ANOVAs with post hoc tests revealed statistical significance (p>.05) for team data relative data across quarters. Meters per minute in 1st vs. 3rd and 1st vs. 4th quarters had large effect sizes (1.2-2.0), and 1st vs. 2nd quarters had moderate (0.61-1.2) effects sizes. Statistical significance was also found for velocity zones 4 and 5 when examining 1st vs. 2nd, 1st vs. 3rd, and 1st vs. 4th quarters. Another series of repeated measures ANOVAs on positional data revealed that all positions produce the greatest m/min during quarter 1, and relative distance covered in zones 1 and 2 statistically increased throughout the game. Key Words: Global Positioning System, Time Motion Analysis, Team Sports, Substitutions, Game Formatting 76 Introduction In the United States, women’s field hockey is played from under twelve developmental programs to college level, and an athlete’s career can culminate with the highest level of play on the Women’s National Team. Historically the game has been played during two thirty-five minute halves, with a ten minute half time, and a continually running clock (FIH, 2012). New match duration and clock stoppage for corners and goals have been implemented. The change in the game time requirements and clock management rules has created a new match format at the international level. The new rule reads: “These currently include Match Periods (4 x 15 Minute Quarters and time stoppages for the award of Penalty Corners and Goals), the Penalty Corner Countdown Clock and Video Umpire, which will only be used at FIH World level Tournaments…” (FIH, 2014) Athletes are provided with two minutes of rest between quarters 1st and 2nd, and 3rd and 4th, with a ten minutes half time in-between quarters 2nd and 3rd. The rule changes are expected to impact physiological and tactical demands of the game. Therefore, the purpose of this study was to provide coaches with a descriptive profile of elite field hockey players under the new FIH match formatting. Additional analysis was done to determine the team and positional differences between the four quarters of match play. . Findings of this study are intended to aid in developments of training methods specific to the new match formatting 77 Methods Athletes Seventeen elite level field hockey players (age 20.5 ± 2.5 years, body weight 60.6 ± 5.2 kg) participated in this study. Goalies were not included in this study. The East Tennessee State University Institutional Review Board approved this study. Each athlete read and signed a written informed consent. A total of seventeen field players’ game action profiles were examined. Sixteen field players participated in the 2015 World League 3 Semi Finals while only fifteen field players participated in the 2015 Pan American Games. This was due to the limitation on team size during the Pan American games, because of its designation as an Olympic qualifier, the team carried fifteen field players and one goalie due to the bench limitation of sixteen. In comparison sixteen field players and two goalies were carried during the 2015 World League 3 Semi Finals. Roster changes across the tournaments resulted in the removal of two field player, and one goalie from the 2015 World League 3 Semi Finals roster, and the addition of one new field player to the Pan American games roster. This resulted in seventeen different athletes involvement in data collection. Players’ files were divided into 4 positional groups: forwards, midfielder, screens, and defenders. Data Collection The action profiles of the US Women’s National Field Hockey Team were measured using GPS sporting technology. Action profile data was collected using Optimye S5 GPS units (Catapult Innovations, Team S4, Melbourne, Australia), sampling at 10 Hz. This device has been shown to be valid for distance and velocity during linear and sport 78 specific movements (Johnston, Watsford, Kelly, Pine, & Spurrs, 2014; Rampinini et al., 2015; Varley, Fairweather, & Aughey, 2012). Data was collected during the 2015 World League 3 Semi Finals in Valencia, Spain during 7 matches, and the 2015 Pan American Games in Toronto Canada during six matches (Table 1). The US Women’s National Team finished 5th during the World League 3 Semi Finals, and 1st during the 2015 Pan American Games. The team’s international ranking culminated in a world ranking of 7th during 2015. All matches were played on a water based, synthetic turf, which was in compliance with FIH field of play rules (FIH, 2014). GPS units were positioned between the scapulae in a custom built harness worn under the uniform. Players wore the same units across both tournaments. All players were acclimated to wearing the GPS units as a result of previous practice, and game monitoring. GPS data were downloaded and analyzed using proprietary software (LoganPlus, version 5.1.7). The downloaded data were edited to only include time spent on the field of play, during the regulation game time. The data was then exported to a Microsoft Excel spreadsheet for further analysis. 79 Table 1. Schedule Tournament Finish Location World League 3 Semi Finals 5th Valencia, Spain Pan American Games 1st Toronto, Canada Games/Opponent/Score 6/11/2015 URU 2 to 0 6/13/2015 RSA 4 to 1 6/14/2015 GER 2 to 2 7/13/2015 URU 7/15/2015 CHIL 7/17/2015 CUBA 5 to 0 2 to 0 12 to 0 80 6/16/2015 IRL 0 to 2 7/20/2015 DOM REP 15 to 0 6/18/2015 ARG 0 to 3 6/20/2015 IRL 6 to 1 7/22/2015 CAN 7/24/2015 ARG 3 to 0 2 to 1 6/21/2016 ESP 3 to 1 Data Analysis One hundred and forty-eight game action profiles were collected over twelve matches. The velocity zones were set in relationship to previously published international field hockey research (Macutkiewicz & Sunderland, 2011). The velocity zones used were: zone 1 stand 0-.16 m/s, zone 2 walk .19-1.6 m/s, zone 3 jog 1.69-3.05 m/s, zone 4 run 3.08-4.16 m/s, zone 5 fast run 4.19-5.27 m/s, and zone 6 sprint>5.27 m/s. These specific action profiles were originally adapted from definitions provided by Bangsbo and Lindquist (1992) for Men’s international soccer athletes and Lothian and Farrally (1992) for Women’s National League field hockey athletes. Each individual athlete’s data files were averaged across games to obtain absolute and relative measures. This data processing was chosen to account for several missing files due to a few corrupted data files. The sample size for this study was seventeen, but each athlete had a varying number of full game files to produce their sample. Players were divided into four positional groups: forwards, midfielder, screens, and defenders. Players were substituted into the same positional group, but not always into the same positional role (ex: right midfielder vs. center midfielder). In order to provide an estimate of position’s absolute action profiles , data obtained from all players was average across the number of players playing the particular position at any point in time on the field (e.g. forward position). This provided an evaluation for each field position, not the individual players that play the position. This processing procedure was chosen to account for the variation of the number of players between the tournaments. Team relative action profiles and positional relative action profiles were then determined for each quarter. It is 81 important to note that for these analyses, not all players played an equal number of minutes, and the new match formatting caused variation between quarter lengths. Therefore, a total distance covered was considered relative to the total number of minutes played for each athlete (m/min), and total distance covered in each velocity zone (1-6) was considered relative to the total distance covered in percentage to account for the difference in time on pitch. Analysis of the relative variables allows for comparisons for the team across quarters, and for positions across quarters. Team relative action profiles across the quarters, and positional relative action profiles were determined for each quarter. Statistical Analysis All statistical procedures were performed with SPSS on relative data (IBM, New York, NY). A series of repeated measures ANOVA’s were used to analyze the differences for the team between quarters. For team data ANOVA’s statistical significance was set at p≤0.05, and all data were summarized in mean ± standard deviation (SD) with associated 95% confidence intervals. Cohen’s D effects size were evaluated as trivial <. 2, small .2.6, moderate .61-1.20, large 1.21-2.00, and very large 2.01-4.0 (Hopkins, Marshall, Batterham, & Hanin, 2009). Thesmallsamplesizesforpositionaldatawerenot deemedappropriateforinferentialstatistics.However,visual representation of positional action profiles during all quarters is shown in Graphs 3a (forwards), 3b (midfielders), 3c (screens), and 3d (defenders). 82 Results Descriptive The absolute distances covered by positions follow the same descending pattern for odometers in meters as, the time position time on pitch (Table 2). It has been previously noted that playing time is important in determining the absolute distances covered during a match (Jennings et al., 2012). Examination of the relative variables, which account for the varied playing time, showed that forwards covered the greatest percent distance in zones 5 and 6, followed by midfielders, screens, and defenders (Table 3). This pattern varies for zone 4, within which the midfielders possess the greatest percent distance covered. 83 Table 2. Absolute Player and Positional Action Profiles for the Full Game # Odometer (m) Position 10 8823 Forward Position Midfield Position Screen Position Defender Position 2 3 2 3 11965 7534 8767 8056 ± 1776 ± 314 ± 954 ± 1653 ± 972 Zone 1 Dist Stand 0-.16 m/s 38 46 29 54 32 ± 29 ± 7 ± 12 ± 20 ± 5 Zone 2 Dist Walk .19-1.6 m/s Zone 3 Dist Jog 1.69-3.05 m/s ± 573 ± 163 ± 306 ± 579 ± 493 2883 ± 680 3576 ± 174 2260 ± 374 2765 ± 567 3121 ± 411 2141 2737 1537 2084 2384 Zone 4 Dist Run 3.084.16 m/s 2166 2911 2029 2365 1675 ± 479 ± 66 ± 330 ± 462 ± 199 Zone 5 Dist Fast Run 4.19-5.27 m/s 1134 1797 1201 1105 646 ± ± ± ± ± Zone 6 Dist Sprint >5.27 m/s 272 461 37 198 77 99 898 478 393 199 ± ± ± ± ± All Data are represented as mean ± SD Table 3. Relative Action Profiles for the Full Game Team Forwards Midfielders Screens Defenders Zone 1 0 -.16m/s 0.42 ± 0.44 0.37 ± 0.12 0.37 ± 0.21 0.59 ± 0.21 0.40 ± 0.04 Zone 2 .17 - 1.68 m/s ± ± ± 22.53 8.29 22.67 2.09 20.61 5.71 23.20 ± 4.34 29.45 ± 4.22 Zone 3 1.69 - 3.07 m/s 29.91 ± 9.75 29.79 ± 2.05 29.81 ± 2.08 31.47 ± 1.68 38.64 ± 1.58 Zone 4 3.08 - 4.18 m/s 22.54 ± 7.28 24.48 ± 1.72 26.81 ± 2.10 26.77 ± 0.57 20.78 ± 1.93 Zone 5 4.19 -5.27 m/s ± ± ± 11.91 5.01 15.16 1.50 15.99 2.33 13.10 ± 3.02 8.22 ± 2.33 Zone 6 > 5.27 m/s 4.98 ± 2.79 7.53 ± 1.36 6.42 ± 0.99 4.88 ± 2.00 2.51 ± 0.98 m/min 108.14 ± 33.40 121.56 ± 6.74 125.28 ± 12.37 118.66 ± 8.84 108.34 ± 5.49 All Data are represented as mean ± SD, Velocity zone data is represented as a % of the total distance covered 84 140 65 73 17 64 Team Quarter Comparison The effect of the game quarter on team m/min was statistically significant for 1st vs. 2nd, 1st vs. 3rd, and 1st vs. 4th; decreases were also statistically significant for 2nd vs. 3rd, and 2nd vs. 4th quarters (Table 5). The large effects size produced when comparing 1st vs. 3rd and 1st vs. 4th may represent an opportunity for the implementation of recovery techniques during the 10 minute half time (Table 5). A gradual decrease in m/min is expressed comparative across all quarters in relationship to the 1st quarter. The changes for the 3rd vs. 4th quarters were not statistically significant. The changes in m/min across a game are visually represented in Graph 1. A statistically significant increase in the percent of distance covered in zone 2 was noted from 1st vs. 3rd, 1st vs. 4th, 2nd vs. 3rd and 2nd vs. 4th. Increasing the percent of time spent walking is also indicative of fatigue, but the effect sizes for these changes were small to trivial. The percent of distance covered in zones 4 and 5 decreased when comparing 1st vs. 2nd, 1st vs. 3rd and 1st vs. 4th quarters, but no statistical significance occurred when comparing zone 6 across the game. A visual representation of the team changes across a game for actions in zones 1, 2, 3, 4, 5, and 6 are presented in Graph 2. The cumulative effect of this information illuminates the general increase in low-intensity actions such as walking, and a decrease in running, and fast running in 1st vs. 2nd, 1st vs. 3rd, and 1st vs. 4th quarters. However, a more in-depth examination of positional changes across the game was needed to determine the appropriate corrective actions. 85 Table. 4 Team Relative Action Profiles by Quarter Q1 Q2 Q3 95% CI Mean SD Zone 1 0 -.16m/s Lower Q4 95% CI Upper Mean SD Lower 95% CI Upper Mean SD Lower 95% CI Upper Mean SD Lower Upper 0.31 ± 0.18 0.21 0.41 0.34 ± 0.14 0.27 0.42 0.41 ± 0.22 0.30 0.53 0.47 ± 0.29 0.32 0.62 Zone 2 .17 - 1.68 m/s 19.93 ± 4.21 17.69 22.18 21.26 ± 5.49 18.34 24.19 22.25 ± 4.80 19.69 24.81 22.48 ± 5.13 19.74 25.21 Zone 3 1.69 - 3.07 m/s 30.46 ± 4.70 27.95 32.96 30.36 ± 4.93 27.73 32.99 30.75 ± 4.33 28.44 33.05 30.58 ± 4.43 28.22 32.95 Zone 4 3.08 - 4.18 m/s 25.83 ± 2.25 24.63 27.03 24.20 ± 2.69 22.76 25.63 23.61 ± 2.86 22.09 25.14 23.68 ± 2.76 22.21 25.16 Zone 5 4.19 -5.27 m/s 15.31 ± 3.64 13.37 17.25 13.96 ± 3.74 11.96 15.95 13.23 ± 2.68 11.80 14.66 13.00 ± 3.69 11.03 14.97 6.11 ± 2.36 4.85 7.37 5.70 ± 2.28 4.49 6.92 5.35 ± 2.00 4.29 6.42 5.43 ± 2.01 4.36 6.50 126.87 ± 8.53 122.33 131.42 119.27 ± 11.11 113.35 125.19 113.43 ± 11.10 107.51 119.34 113.18 ± 10.87 107.39 118.97 Zone 6 > 5.27 m/s m/min *Velocity zone data is represented as a % of the total distance covered Table 5. Team Relative Action Profiles Between Quarters 1st vs. 2nd * Zone 1 0 -.16m/s Zone 2 .17 - 1.68 m/s Zone 3 1.69 - 3.07 m/s Zone 4 3.08 - 4.18 m/s Zone 5 4.19 -5.27 m/s Zone 6 > 5.27 m/s m/min 1st vs. 3rd 1st vs. 4th p valu e ES Qual p value ES Qual p value ES 1.00 -0.19 Trivial 0.14 -0.51 Small 0.10 -0.68 0.10 -0.27 Small 1.00 0.03 1.00 0.00 -0.51 Small 1.00 0.02 0.02 0.00 0.66 0.37 0.17 0.77 Moderate Small 0.00 0.00 Trivial 0.12 Moderate 0.00 -0.54 0.86 0.65 0.35 1.36 Moderate Moderate 0.01 0.00 Small 0.18 Large 0.00 0.85 Qual p value ES Qual p value ES Qual Moderate 0.23 -0.39 Small 0.09 -0.58 Small 0.52 -0.24 Small -0.05 Trivial 0.04 Trivial -0.02 Trivial 0.07 Trivial Small 0.03 -0.19 Trivial Moderate 0.44 0.61 Moderate 0.31 Small 1.00 Large 0.00 86 0.05 -0.23 Small 1.00 -0.08 Trivial 0.63 1.40 3rd vs. 4th * ES 1.00 -0.03 Trivial 2nd vs. 4th Qual 1.00 0.02 Trivial 0.00 2nd vs. 3rd * p valu e 1.00 -0.05 Trivial Trivial 1.00 0.21 0.10 0.22 Small 0.16 Trivial 1.00 Small 0.00 0.53 1.00 0.19 Small 1.00 Trivial 1.00 0.26 Small 0.13 Trivial 1.00 -0.04 Trivial Small 1.00 0.02 Trivial 0.55 Graph 1. m/min Teamm/minbyQuarter 140.00 135.00 130.00 125.00 120.00 115.00 110.00 105.00 100.00 m/min Quarter1 Quarter2 Quarter3 Quarter4 Note: n=16 87 Graph 2. PercentofTotalDistance TeamRelativePercentDistancebyQuarter 36.00 34.00 32.00 30.00 28.00 26.00 24.00 22.00 20.00 18.00 16.00 14.00 12.00 10.00 8.00 6.00 4.00 2.00 0.00 Quarter1 Quarter2 Quarter3 Quarter4 Zone10-.16m/s Zone2.17- 1.68 Zone31.69- 3.07 Zone43.08- 4.18 Zone54.19-5.27 Zone6>5.27m/s m/s m/s m/s m/s Note: n=16 88 Quarter Comparison by Position Figure 6a display the relative mean ± SD and 95% confidence interval for all the action profiles variables per quarter. Figure 7a displays the effects size and qualitative descriptors for effect size across quarters. Forwards produced the highest m/min in quarter 1 compared with all other quarters. Forward’s m/min decreased for 1st vs. 2nd, 1st vs. 3rd, and 1st vs. 4th quarters. However, when m/min were examined in reference to the previous quarter the effect sizes gradually decreased, depicting a progressive decline throughout the game. Figure 6b display the relative mean ± SD and 95% confidence interval for all the action profiles variables per quarter. Figure 7b displays the effects size and qualitative descriptors for effect size across quarters. Similar to forwards, midfielders produced the highest m/min in the 1st quarter, and the effects sizes were moderate for 1st vs. 2nd, large for 1st vs. 3rd, and large for 1st vs. 4th. It’s important to note that midfielders showed a moderate to large effect size in zones 4 and 5 for 1st vs. 2nd, 1st vs. 3rd, and 1st vs. 4th. Figure 6c display the relative mean ± SD and 95% confidence interval for all the action profile variables per quarter. Figure 7c displays the effects size and qualitative descriptors for effect size across quarters and showed a progressive decrease across the game. Similar to forwards and midfielders, screens produced the highest m/min in the 1st quarter and the effects sizes were moderate for 1st vs. 2nd, large for 1st vs. 3rd, and large for 1st vs. 4th. They also showed a decline in m/min in subsequent quarters compared to the 1st. Screens maintained their percent distance covered in zones 5 and 6 across quarters. 89 However, they did express a decrease represented as a large effect size in zone 4 when comparing 1st vs. 2nd, 1st vs. 3rd and 1st vs. 4th quarters. Figure 6d displays the relative mean ± SD and 95% confidence interval for all the action profiles variables per quarter. Figure 7d displays the effects size and qualitative descriptors for effect size across quarters. Defenders produced the highest m/min in quarter 1. However, the difference for m/min when comparing the 1st vs. 2nd was trivial. When comparing 1st vs. 3rd and 1st vs. 4th moderate effect sizes very produced. Defenders experience a decline in the amount of time spent running when comparing the 1st vs. 4th quarter. The decrease in running during 1st vs. 4th was accompanied by increases in the amount of time standing in 2nd vs. 3rd and 2nd vs. 4th. 90 Table 6a. Forwards Relative Action Profiles by Quarter Q1 Q2 Q3 95% CI Forwards Zone 1 0 .16m/s Zone 2 .17 1.68 m/s Zone 3 1.69 3.07 m/s Zone 4 3.08 4.18 m/s Zone 5 4.19 5.27 m/s Zone 6 > 5.27 m/s m/min Mean SD Lower Upper Mean SD 95% CI Lower Upper Mean SD 95% CI Lower Upper Mean SD Lower Upper ± 0.15 0.10 0.47 0.37 ± 0.13 0.24 0.50 0.41 ± 0.18 0.19 0.63 0.44 ± 0.23 0.17 0.71 20.00 ± 3.09 16.32 23.68 21.98 ± 4.91 16.92 27.03 22.77 ± 4.36 18.44 27.10 23.13 ± 5.20 18.39 27.88 32.31 ± 3.78 28.26 36.37 31.34 ± 5.11 26.64 36.04 32.34 ± 5.01 27.96 36.73 31.35 ± 4.95 26.95 35.76 26.14 ± 1.83 24.08 28.20 24.60 ± 1.97 22.29 26.91 24.78 ± 2.57 22.32 27.25 24.33 ± 3.24 21.94 26.73 14.78 ± 3.47 11.30 18.27 13.73 ± 3.45 10.29 17.16 12.94 ± 2.25 10.39 15.48 13.61 ± 5.06 9.88 17.33 6.49 ± 2.98 4.09 8.89 6.51 ± 2.83 4.38 8.65 5.23 ± 2.35 3.30 7.15 5.55 ± 2.05 3.46 7.64 129.66 ± 6.04 121.08 138.2 5 121.31 ± 8.71 109.92 132.70 114.76 ± 11.18 103.35 126.16 116.69 ± 12.09 105.5 7 127.81 Q1 Q2 95% CI 95% CI 0.28 Table 6b. Midfielder Relative Action Profiles by Quarter Midfielders Zone 1 0 .16m/s Zone 2 .17 1.68 m/s Zone 3 1.69 3.07 m/s Zone 4 3.08 4.18 m/s Zone 5 4.19 5.27 m/s Zone 6 > 5.27 m/s m/min Q4 Mean SD Lower Upper Mean SD Q3 95% CI Lower Upper Q4 Mean SD 95% CI Lower Upper Mean SD 95% CI Lower Upper 0.41 ± 0.26 0.20 0.61 0.42 ± 0.18 0.28 0.57 0.55 ± 0.31 0.30 0.79 0.71 ± 0.43 0.40 1.01 21.37 ± 4.67 17.26 25.49 23.04 ± 5.47 17.38 28.69 23.78 ± 3.60 18.94 28.62 24.43 ± 4.90 19.12 29.73 28.22 ± 1.37 23.69 32.76 28.59 ± 1.58 23.34 33.85 29.44 ± 2.14 24.54 34.34 28.81 ± 2.53 23.88 33.73 27.40 ± 2.20 25.09 29.70 26.11 ± 2.24 23.53 28.70 25.20 ± 1.63 22.44 27.95 25.11 ± 2.18 22.43 27.78 16.44 ± 3.72 12.54 20.33 14.44 ± 4.04 10.59 18.28 13.31 ± 2.89 10.47 16.16 13.22 ± 3.40 9.06 17.38 6.16 ± 2.24 3.48 8.84 5.33 ± 1.24 2.94 7.72 5.57 ± 1.86 3.42 7.73 5.68 ± 1.51 3.35 8.01 129.51 ± 12.14 119.91 139.10 119.72 ± 17.2 9 106.98 132.46 114.1 3 ± 15.0 5 101.38 126.88 111.08 ± 15.12 98.64 123.51 91 Table 6c. Screens Relative Action Profiles by Quarter Q1 Q2 95% CI Screens Zone 1 0 .16m/s Zone 2 .17 1.68 m/s Zone 3 1.69 3.07 m/s Zone 4 3.08 4.18 m/s Zone 5 4.19 5.27 m/s Zone 6 > 5.27 m/s m/min Mean SD Mean SD Q3 95% CI Q4 Mean SD 95% CI Mean SD 95% CI Lower Upper Lower Upper Lower Upper Lower Upper 0.31 ± 0.13 0.08 0.55 0.33 ± 0.06 0.16 0.50 0.38 ± 0.15 0.10 0.66 0.41 ± 0.12 0.06 0.75 22.98 ± 3.99 18.23 27.73 24.07 ± 6.09 17.54 30.59 25.05 ± 5.55 19.46 30.65 24.67 ± 5.65 18.54 30.80 34.45 ± 7.24 29.21 39.68 34.27 ± 7.33 28.20 40.33 32.20 ± 7.61 26.54 37.86 33.54 ± 7.44 27.85 39.22 25.46 ± 3.37 22.80 28.12 21.28 ± 3.28 18.30 24.26 20.63 ± 4.08 17.45 23.81 20.43 ± 1.26 17.34 23.52 12.33 ± 4.95 7.83 16.83 10.48 ± 4.24 6.04 14.92 11.21 ± 4.05 7.93 14.49 10.26 ± 3.70 5.46 15.07 4.46 ± 3.09 1.36 7.55 3.61 ± 2.86 0.86 6.37 3.77 ± 1.89 1.28 6.26 4.24 ± 3.81 1.54 6.93 124.57 ± 11.95 113.49 135.65 111.91 ± 12.7 9 97.20 126.62 106.2 2 ± 12.5 0 91.50 120.94 107.15 ± 6.71 92.79 121.51 92 Table 6d. Defenders Relative Action Profiles by Quarter Q1 Q2 95% CI Defenders Zone 1 0 .16m/s Zone 2 .17 1.68 m/s Zone 3 1.69 3.07 m/s Zone 4 3.08 4.18 m/s Zone 5 4.19 5.27 m/s Zone 6 > 5.27 m/s m/min Mean SD Upper Mean SD Q4 Mean SD Lower Upper 95% CI Mean SD Lower Upper 95% CI Lower Upper 0.24 ± 0.19 0.04 0.45 0.23 ± 0.12 0.08 0.37 0.31 ± 0.19 0.06 0.55 0.33 ± 0.20 0.03 0.63 16.12 ± 3.43 12.00 20.23 16.49 ± 4.57 10.84 22.15 17.96 ± 4.50 13.12 22.80 18.06 ± 3.69 12.75 23.36 27.37 ± 3.67 22.84 31.91 27.98 ± 4.46 22.72 33.23 28.97 ± 2.09 24.06 33.87 29.19 ± 2.43 24.26 34.11 24.15 ± 1.01 21.85 26.45 23.97 ± 2.26 21.38 26.55 22.81 ± 1.71 20.05 25.56 23.89 ± 2.08 21.22 26.57 17.08 ± 2.21 13.19 20.98 16.37 ± 2.36 12.52 20.21 15.04 ± 1.12 12.19 17.88 14.08 ± 1.87 9.92 18.24 6.83 ± 1.00 4.15 9.50 6.64 ± 1.24 4.25 9.02 6.47 ± 1.57 4.32 8.63 5.93 ± 0.86 3.60 8.26 122.47 ± 4.39 112.87 132.07 121.78 ± 6.15 109.04 134.52 116.46 ± 7.12 103.71 129.21 115.42 ± 8.21 102.98 127.85 Table 7a. Forwards effects size across Quarter Forwards Zone 1 0 -.16m/s Zone 2 .17 - 1.68 m/s Zone 3 1.69 - 3.07 m/s Zone 4 3.08 - 4.18 m/s Zone 5 4.19 -5.27 m/s Zone 6 > 5.27 m/s m/min Lower Q3 95% CI 1st vs. 2nd ES -0.66 -0.48 0.22 0.81 0.31 -0.01 1.12 Qual Moderate Small Small Moderate Small Trivial Large 1st vs. 3rd ES -0.77 -0.73 -0.01 0.61 0.63 0.47 1.66 Qual Moderate Moderate Trivial Small Moderate Small Large 1st vs. 4th ES -0.80 -0.73 0.22 0.69 0.27 0.37 1.36 Qual Moderate Moderate Small Moderate Small Small Large 93 2nd vs. 3rd ES -0.24 -0.17 -0.20 -0.08 0.27 0.50 0.65 Qual Small Trivial Trivial Trivial Small Small Moderate 2nd vs. 4th ES -0.34 -0.23 0.00 0.10 0.03 0.39 0.44 Qual Small Small Trivial Trivial Trivial Small Small 3rd vs. 4th ES -0.13 -0.08 0.20 0.15 -0.17 -0.15 -0.17 Qual Trivial Trivial Trivial Trivial Trivial Trivial Trivial Table 7b. Midfields effects effect size across Quarters Midfielders ES Qual 1st vs. 3rd ES Qual 1st vs. 4th ES Qual 2nd vs. 3rd ES Qual 2nd vs. 4th ES Qual 3rd vs. 4th ES Qual Zone 1 0 -.16m/s -0.07 Trivial -0.47 Small -0.83 Moderate -0.48 Small -0.86 Moderate -0.42 Small Zone 2 .17 - 1.68 m/s -0.33 Small -0.58 Small -0.64 Moderate -0.16 Trivial -0.27 Small -0.15 Trivial Zone 3 1.69 - 3.07 m/s -0.25 Small -0.68 Moderate -0.29 Small -0.45 Small -0.10 Trivial 0.27 Small Zone 4 3.08 - 4.18 m/s 0.58 Moderate 1.13 Large 1.05 Moderate 0.47 Small 0.46 Small 0.05 Trivial Zone 5 4.19 -5.27 m/s 0.51 Moderate 0.94 Moderate 0.90 Moderate 0.32 Small 0.33 Small 0.03 Trivial Zone 6 > 5.27 m/s 0.46 Small 0.29 Small 0.25 Small -0.15 Trivial -0.25 Small -0.06 Trivial m/min 0.66 Moderate 1.12 Large 1.34 Large 0.34 Small 0.53 Small 0.20 Small Table 7c. Screens effect size across Quarters Screens Zone 1 0 -.16m/s 1st vs. 2nd ES Qual 1st vs. 3rd ES Qual 1st vs. 4th ES Qual 2nd vs. 3rd ES Qual 2nd vs. 4th ES Qual -0.17 Trivial -0.48 Small -0.75 Moderate -0.43 Small -0.84 Moderate Zone 2 .17 - 1.68 m/s -0.21 Small -0.43 Small -0.35 Small -0.17 Trivial -0.10 Zone 3 1.69 - 3.07 m/s 0.02 Trivial 0.30 Small 0.12 Trivial 0.28 Small Zone 4 3.08 - 4.18 m/s 1.26 Large 1.29 Large 1.98 Large 0.18 Zone 5 4.19 -5.27 m/s 0.40 Small 0.25 Small 0.47 Small 0.29 Small 0.27 Small 0.06 1.02 Moderate 1.50 Large 1.80 Zone 6 > 5.27 m/s m/min 1st vs. 2nd 3rd vs. 4th ES Qual -0.22 Small Trivial 0.07 Trivial 0.10 Trivial -0.18 Trivial Trivial 0.34 Small 0.07 Trivial -0.18 Trivial 0.06 Trivial 0.24 Small Trivial -0.07 Trivial -0.19 Trivial -0.16 Trivial Large 0.45 Small 0.47 Small -0.09 Trivial 94 Table 7d. Defenders effect size across Quarters Defenders ES Zone 1 0 -.16m/s 0.27 Small -0.33 Small -0.42 Small -0.09 -0.15 Trivial Trivial -0.46 -0.54 Small Small -0.54 -0.58 0.10 0.31 Trivial Small 0.95 1.16 Moderate Moderate 0.16 1.47 Zone 6 > 5.27 m/s 0.17 Trivial 0.27 Small m/min 0.13 Trivial 1.02 Moderate Zone 2 .17 - 1.68 m/s Zone 3 1.69 - 3.07 m/s Zone 4 3.08 - 4.18 m/s Zone 5 4.19 -5.27 m/s 1st vs. 2nd Qual 1st vs. 3rd ES Qual 1st vs. 4th ES 0.97 1.07 Qual 2nd vs. 3rd ES 2nd vs. 4th 3rd vs. 4th Qual ES Qual ES Qual -4.58 Very Large -4.53 Very Large -0.10 Trivial Small Small -0.32 -0.28 Small Small -0.38 -0.34 Small Small -0.02 -0.10 Trivial Trivial Trivial Large 0.58 0.72 Small Moderate 0.04 1.08 Trivial Moderate -0.57 0.62 Small Moderate Moderate 0.12 Trivial 0.67 Moderate 0.43 Small Moderate 0.80 Moderate 0.88 Moderate 0.14 Trivial Graph 3a. PercentofTotalDistance FowardsRelativePercentDistancebyQuarter 50.00 45.00 40.00 35.00 30.00 25.00 20.00 15.00 10.00 5.00 0.00 Quarter1 Quarter2 Quarter3 Quarter4 Zone10-.16m/s Zone2.17- 1.68 Zone31.69- 3.07 Zone43.08- 4.18 Zone54.19-5.27 Zone6>5.27m/s m/s m/s m/s m/s Note: n=5 95 Graph 3b. PercentofTotalDistance MidfieldersRelativePercentDistancebyQuarter 50.00 45.00 40.00 35.00 30.00 25.00 20.00 15.00 10.00 5.00 0.00 Quarter1 Quarter2 Quarter3 Quarter4 Zone10-.16m/s Zone2.17- 1.68 Zone31.69- 3.07 Zone43.08- 4.18 Zone54.19-5.27 Zone6>5.27m/s m/s m/s m/s m/s Note: n=4 96 PercentofTotalDistance Graph 3c. ScreensRelativePercentDistancebyQuarter 50.00 45.00 40.00 35.00 30.00 25.00 20.00 15.00 10.00 5.00 0.00 Quarter1 Quarter2 Quarter3 Quarter4 Zone10-.16m/s Zone2.17- 1.68 Zone31.69- 3.07 Zone43.08- 4.18 Zone54.19-5.27 Zone6>5.27m/s m/s m/s m/s m/s Note: n=3 97 PercentofTotalDistance Graph 3d. 50.00 45.00 40.00 35.00 30.00 25.00 20.00 15.00 10.00 5.00 0.00 DefendersRelativePercentDistancebyQuarter Quarter1 Quarter2 Quarter3 Quarter4 Zone10-.16m/sZone2.17- 1.68m/s Zone31.69- 3.07m/s Zone43.08- 4.18m/s Zone54.19-5.27m/sZone6>5.27m/s Note: n=4 98 Discussion This study was an investigation of the action profiles of US Women’s National Team during the 2015 World League 3 Semi-Finals, and the 2015 Pan American games (Table 1). These tournaments represent games played with the 2015 FIH game time formatting change. It should be noted that disparities exist between the rankings of competition during the two tournaments. It has also been reported that more high intensity running is performed when teams play against better opposition (Rampinini, Coutts, Castagna, Sassi, & Impellizzeri, 2007). Due to the team’s success at the Pan American Games, the US national team may not have had to perform as much intensity running as the opposing team. However the opposition during the World League 3 Semi-Finals was considered to be a high caliber, possibility resulting in more high intensity running. It is important to note that the official time of a game has changed from 70 minute to 60 minute. However, the newly implemented clock stoppage for corners, and goals can drastically affect the game length. The new match formatting rules stop the clock for corners and goals. The official game clock is stopped on a corner, or after a goal, and an independent running clock of forty seconds begins. Once the forty seconds ends, the official game clock resumes. The quarter lengths ranged from 15 minutes to 24 minutes. The actual game time will depend on the number of corners and goals awarded during the game. For this reason, caution must be used when examining m/min as an indicator of fatigue, because changes in m/min may be due to the varying durations in quarter length. The seeming increases in low intensity actions during the clock stoppage could also decrease the reported m/min. To retain ecological validity corner and goal clock 99 stoppages were not removed when calculating time on pitch. Future research should examine the effect of removing the additional time from corners and goals on action profiles. Previous research has suggested that a large sample size is needed to provide true average action profiles for elite level athletes (Carling, 2013; Cummins, Orr, O'Connor, & West, 2013). Due to the small sample size p-values were not determined for the positional data across quarters. While this was a specific limitation, it should be noted that this study is one of only a few on elite level field hockey players. Thus, this study is a first step in characterizing the US women’s elite level of play, and allowing for comparisons with other countries elite athletes. The data reported in this paper is specific to the 2015 US Women’s National Team during both the World League 3 Semi-Finals, and the Pan American Games. Using high-level athletes allows for a unique opportunity to examine elite performance. Although it adds uncontrollable variability due to competitors, team tactics, injuries, and other environmental factors, ecologically valid measurements are of value to the sport science research. Conclusion To the author’s knowledge, this is the first study to examine the action profiles of international field hockey player’s during games played under the newly implemented match duration and clock stoppage rules. The findings demonstrated that the teams low intensity actions in zone 2 gradually increased, while the percent distance covered in zones 4 and 5 decreased when comparing 1st vs. 2nd, 1st vs. 3rd and 1st vs. 4th quarters. 100 However, no statistical significance occurred when comparing zone 6 across the game. The US women’s national team increased the percent distance covered walking and decreased the distance running and fast running to possibility maintain the percent distance covered sprinting across a game. References Bangsbo, J., & Lindquist, F. (1992). Comparison of various exercise tests with endurance performance during soccer in professional players. Int J Sports Med, 13(2), 125132. Carling, C. (2013). Interpreting physical performance in professional soccer match-play: should we be more pragmatic in our approach? Sports Med, 43(8), 655-663. Cummins, C., Orr, R., O'Connor, H., & West, C. (2013). Global Positioning Systems (GPS) and Microtechnology Sensors in Team Sports: A Systematic Review. Sports Medicine, 43(10), 1025-1042. FIH. (2012). Rules of Hockey Including Explanations Lausanne, Switzerland FIH. (2014). Rules of Hockey Including Explanations Lausanne, Switzerland Gabbett, T. J. (2010). GPS analysis of elite women's field hockey training and competition. J Strength Cond Res, 24(5), 1321-1324. Hopkins, W. G., Marshall, S. W., Batterham, A. M., & Hanin, J. (2009). Progressive statistics for studies in sports medicine and exercise science. Med Sci Sports Exerc, 41(1), 3-13. 101 Jennings, D., Cormack, S. J., Coutts, A. J., & Aughey, R. J. (2012). GPS analysis of an international field hockey tournament. Int J Sports Physiol Perform, 7(3), 224231.. Johnston, R. J., Watsford, M. L., Kelly, S. J., Pine, M. J., & Spurrs, R. W. (2014). Validity and interunit reliability of 10 Hz and 15 Hz GPS units for assessing athlete movement demands. J Strength Cond Res, 28(6), 1649-1655. Lothian, F., & Farrally, M. (1992). Estimating the energy cost of womens hockey using heart rate and video analysis. . Journal of Human Movement Studies, 23, 215-231. MacLeod, H., Bussell, C., & Sunderland, C. (2007). Time-motion analysis of elite women's field hockey, with particular reference to maximum intensity movement patterns. International Journal of Performance Analysis in Sport, 7(2). Macutkiewicz, D., & Sunderland, C. (2011). The use of GPS to evaluate activity profiles of elite women hockey players during match-play. Journal of Sports Sciences, 29(9), 967-973. Rampinini, E., Alberti, G., Fiorenza, M., Riggio, M., Sassi, R., Borges, T. O., et al. (2015). Accuracy of GPS devices for measuring high-intensity running in fieldbased team sports. Int J Sports Med, 36(1), 49-53. Rampinini, E., Coutts, A. J., Castagna, C., Sassi, R., & Impellizzeri, F. M. (2007). Variation in top level soccer match performance. Int J Sports Med, 28(12), 10181024. Varley, M. C., Fairweather, I. H., & Aughey, R. J. (2012). Validity and reliability of GPS for measuring instantaneous velocity during acceleration, deceleration, and constant motion. J Sports Sci, 30(2), 121-127. 102 Vescovi, J. D., & Frayne, D. H. (2015). Motion characteristics of division I college field hockey: Female Athletes in Motion (FAiM) study. Int J Sports Physiol Perform, 10(4) 103 CHAPTER 5 CHANGES IN ELITE FIELD HOCKEY PLAYER ACTION PROFLIES DUE TO THE 2015 RULE CHANGE Authors: Heather A Abbott1, Kimitake Sato1, Satoshi Mizuguchi1, Dave Hamilton2, Michael H. Stone1 Affiliations: Center of Excellence for Sport Science and Coach Education Department of Exercise and Sport Sciences, East Tennessee State University, Johnson City, TN, USA1 USA Field Hockey, Manheim, PA2 Prepared for Submission International journal of sport Science and Coaching 104 Abstract The objective of this study was to analyze the effects of the 2015 International Hockey Federation (FIH) rule changes on the United State Women’s National Field Hockey Team’s game action profiles. The purpose was to determine the magnitude of effect of the rule change on game action profiles. Comparisons were made between two international tournaments before and two international tournaments after the match formatting rule change, resulting in three hundred and forty-three files. Relative actions profiles consisted of meters per minute (m/min), and the percent of the total distance covered in zone 1 standing (0-.16 m/s), zone 2 walking (.19-1.6 m/s), zone 3 jogging (1.69-3.05 m/s), zone 4 running (3.08-4.16 m/s), zone 5 fast running (4.19-5.27 m/s), and zone 6 sprinting (>5.27 m/s). The results indicated that team’s relative action profiles (n=16) across a game were only statistically significant in zone 1 (p=0.0000005) pre to post rule change. After the rule change, the team’s percent of the total distance in the 1st half was statically lower in zones 1 (p= 0.0000002), and greater in 5 (p= 0.02) and 6 (p= 0.02), and, in the 2nd half, lower in zone 1 (p= 0.000009). Meters per minute were also statistically lower in the 2nd half (p= 0.003). Wilcoxon signed ranks tests revealed statistical significance changes for midfielders in both halves after the rule change (1st half: decrease in zone 1 (p= 0.04), increase in zone 5 (p= 0.04) and 6 (p= 0.04) and 2nd half: decrease in zone 1 (p= 0.04) and m/min (p= 0.04)).It may not be possible for this elite team to experience increases in game action profiles However, the tactical position of midfielders, with the opportunity to play offensively and defensive, may benefits from the additional 2 minute rest in between quarters under the new rules. Key Words: Global Positioning System, Team Sports, Substitutions, Game Formatting 105 Introduction Global Positioning System (GPS) has have provided coaches, trainers and sports scientist with an understanding of the action profiles of athletes during field hockey games and training (Dwyer & Gabbett, 2012; Gabbett, 2010; Jennings, Cormack, Coutts, & Aughey, 2012a, 2012b; Lythe & Kilding, 2011; Macutkiewicz & Sunderland, 2011; Polglaze, Dawson, Hiscock, & Peeling, 2014; Vescovi & Frayne, 2015; White & MacFarlane, 2014; Wyldea, Yonga, Azizb, Mukherjeec, & Chiac, 2014). However, the rules of sport are always evolving. Every two years rule changes are implemented by field hockey governing body, the FIH. With the new match duration and clock stoppage during corners and after goals, implemented by the FIH in January 2015, it is important to determine if elite athlete action profiles have changed. Comparisons need to be made in order to assess the need for altered high performance training. Comparing the action profiles pre and post the rule change will allow for the further development of training recommendations when athletes are transitioning from college (two 35 minute halves) to international play (four 15 minute quarters). It has been speculated that the rule change provides teams with the ability to maintain and produce more high intensity actions. However, this potential alteration in play has not been documented. The examination of the evolution of the players’ action profiles in response to changes in the game time constraints due to the 2015 FIH rule changes is novel. The availability of activity profile changes for women’s field hockey in relationship to rule changes are scarce. For example only one study exists examining the effect of the 2009, free-hit rule on the game (Tromp & Holmes, 2011). Performance analysis pre and post rule change 106 can be used to determine the effect of the change on varying aspects of the game and examine the evolution of the players in response to the change. The information divulged from this study will allow for the continued development of attributes specific to the new style of match formatting. Knowledge of the ongoing action profile transitions taking place will be beneficial for strength and conditioning practitioners when designing training programs for the development of athletes, specifically those transitioning from college to the national team. Therefore the purpose of this study was to determine the effect of the FIH game formatting rule change on the team and positional action profiles produced by the US women’s national team during international tournaments before and after the game formatting rule change. Methods Athletes Twenty players form the US Women’s’ National Field Hockey team (pre rule age 24.8 ± 2.4 years, post rule age 25.5 ± 2.1 years, pre rule body weight 61.1 ± 4.6 kg, post rule body weight 60.6 +/-5.1 kg) participated in this study. The East Tennessee State University Institutional Review Board approved this study. Data Collection Wearable GPS technology allowed for the measurement of relative variables (m/min, and percent of the total distance covered in zones 1, 2, 3, 4, 5, and 6) from the US Women’s 107 National Field Hockey Team. The GPS devices used during pre-collection were the Catapult MinimaxX (Catapult Innovations, Melbourne, Australia), which sample at 10 Hz. The post rule activity profile data were collected using Optimye S5GPS units (Catapult Innovations, Team S4, Melbourne, Australia), also sampling at 10 Hz. Both GPS units are valid for measuring distance and velocity during liner and sport specific movements (Johnston, Watsford, Kelly, Pine, & Spurrs, 2014; Rampinini et al., 2015; Varley, Fairweather, & Aughey, 2012). Pre GPS data were collected during the 2014 Champions Challenge in Glasgow, Scotland and the 2014 Rabobank Hockey World Cup in The Hague, Netherlands (Table 1). Post GPS data were collected during the 2015 World League 3 Semi Finals in Valencia, Spain and the 2015 Pan American Games in Toronto, Canada (Table 1). All matches were played on a water based, synthetic turf, which were in compliance with FIH field of play rules (FIH, 2014). GPS units were positioned between the scapulae in a custom built harness worn in compliance with previous research recommendations (Barrett, Midgley, & Lovell, 2014). Players wore the same MinimaxX units during pre-collection, and the same Optimye S5 units during post collection. All players were acclimated to wearing the GPS units as a result of previous practice, and game monitoring. 108 Table 1. Tournament Schedule Tournament Finish Location Champions 1st Glasgow, ChallengeI Scotland 2014 Rabobank 4th Hockey TheHague, WorldCup Netherlands 2014 World League3 SemiFinals 5th Pan American Games 1st Valencia, Spain Toronto, Canada 4/27/2014 ESP 3to1(14) 6/1/2014 ENG Date/Opponent/Score/WorldRanking 4/28/2014 4/30/201 5/1/2014 5/3/2014 RSA 4IRL INDIA ESP 1to2(11) 3to0(15) 1to0(13) 3to1(14) 6/3/2014 6/6/2014 6/8/2014 6/10/2014 ARG CHN GER RSA 2to1(6) 2to2(2) 5to0(5) 4to1(8) 4to2(11) 6/11/2015 URU 6/13/2015 RSA 6/14/201 5GER 6/16/201 5IRL 6/18/2015 ARG 5/4/2015 IRL 3to1(15) 6/12/2014 AUS 2to2(1to 3)(3) 6/20/2015 IRL 2to0(25) 4to1(11) 2to2(8) 0to2(15) 0to3(2) 6to1(15) 7/13/2015 URU 7/15/2015 CHIL 7/17/201 5CUBA 7/22/2015 CAN 7/24/2015 ARG 5to0(25) 2to0(21) 12to0 (NA) 3to0(19) 2to1(2) 109 7/20/201 5DOM REP 15to0 (37) 6/14/20 14ARG 1to2(2) 6/21/20 16ESP 3to 1(14) Data Analysis Data analyzed included three hundred forty-three samples, collected over four tournaments matches, which included twenty-six games. GPS data were downloaded using the manufacturer-supplied software (Logan Plus, version 5.1.7). The GPS data were edited to only include time spent on the field of play, during the regulation game time. The time on the substitution bench, and the time during the 2 minute and 10 minute rest periods were not included in any calculations. This is in accordance with recommendations from White and MacFarlane (2013). The velocity zones used to determine the relative percent distance covered were chosen from previously published international field hockey research (stand 0-.16 m/s, walk .19-1.6 m/s, jog 1.69-3.05 m/s, run 3.08-4.16 m/s, fast run 4.19-5.27 m/s, and sprint>5.27 m/s) (Lythe & Kilding, 2011; Macutkiewicz & Sunderland, 2011). GPS Data were then exported to Microsoft Excel for further analysis Each individual athlete’s data files were averaged across games to obtain the relative measures. This data processing was chosen to account for several missing files due to a few corrupted data files. Players were divided into four positional groups: forwards, midfielder, screens, and defenders. In order to provide an estimate of a player’s action profile playing a certain position, data obtained from all players of a particular position were averaged across those players (e.g. forward player). Players were substituted into the same positions; therefore each player only contributes to one positional group. It is important to note that for these analyses, not all players played an equal number of minutes, and the new match formatting caused variation between quarter lengths. . Total 110 distance covered was considered relative to the total number of minutes played for each athlete (m/min), and total distance covered in each velocity zone (1-6) was considered relative to the total distance covered in percentage to account for the difference in time on pitch. Analysis of the relative variables allows for comparisons for the teams pre to post rule change. Team relative action profiles across the 1st and 2nd half and positional relative action profiles were then determined for 1st and 2nd half. The ten minute half time, that takes place in both the pre and post-game formatting, was chosen to divide the of game into 1st and 2nd halves Statistical Analysis All statistical procedures were performed with SPSS (IBM, New York, NY). Paired sample t tests were used to compare team full game data pre rule change to the corresponding team full game data post rule change at the team level. Paired sample t tests were also used to compare each half of the pre rule change to the corresponding half of the post rule change at the team level. Differences within a position between the pre and post rule change were examined for each of the halves using a Wilcoxon signed ranktest due to limited sample sizes. Statistical significance was set at p ≤0.05, and all data were reported as mean ± SD and 95% confidence interval. Cohen’s d effect sizes (d) were determined as trivial <0. 2, small 0.2-0.6, moderate 0.61-1.20, large 1.21-2.00 and very large 2.01-4.0 (Hopkins, Marshall, Batterham, & Hanin, 2009). 111 Results Team Full Game Pre vs. Post Rule Change The paired samples t-test used to evaluate the relative actions profiles from pre to post rule change, indicated no statistical difference in zones 2, 3, 4, 5, 6 and m/min. However, statistical significance was produced for zone 1 with a very large effect size (d = 2.55) for the decrease in percent distance covered pre to post rule change in zone 1 (Table 2). Team pre 1st vs. post 1st and pre 2nd vs. post 2nd The paired sample t-test indicated statistical significance in zones 1, 5 and 6 during the 1st half of the game. Statistical differences in zone 1 represented a decrease in the percent total distance covered from pre to post rule change. Statistical differences in zones 5 and 6 represented an increase in the total percent of distance-covered pre to post rule change, with small effects sizes (Table 3a). During the 2nd half of the game statistically significant decreases occurred in zone 1 and m/min (Table 3b). Position pre 1st vs. post 1st and pre 2nd vs. post 2nd Mean differences in relative variables during a positional breakdown for per 1st to post 1st and pre 2nd to post 2nd were assessed with a Wilcoxon Signed Rank Test. No statistical significance was found for all relative variables for forwards, screens and defenders (Table 4a, 4c, 4d). Midfielders were found to have statistical changes in both halves of the game pre to post. They had a statistical decrease in zone 1, and a statistical increase in zones 5 and 6 pre to post during the 1st half of the game. During the 2nd half of the game, zones 1 and 3 and m/min had statistical decreases (Table 4b). The Wilcoxon Signed Rank 112 Test showed that all 5 players in the midfielders positional group were involved in the significant changes during the 1st and 2nd half of the game. 113 Table 2. Paired t-test for Team Full Game Action Profiles Pre vs. Post Pre Full Game Mean ± SD Zone 1 0 1.06 ± 0.32 .16m/s Zone 2 .17 24.12 ± 4.83 1.68 m/s Zone 3 1.69 33.11 ± 3.62 3.07 m/s Zone 4 3.08 24.89 ± 3.23 4.18 m/s Zone 5 4.19 12.04 ± 3.04 5.27 m/s Zone 6 > 5.27 4.75 ± 2.04 m/s m/min 120.58 ± 10.25 Note: ES is effect size, p – value ≤0.05 Post Full Game Mean ± SD 95% Confidence Interval of the Difference Mean Difference Lower Upper t df pvalue ES Qualitative Descriptor 0.42 ± 0.16 0.65 0.48 0.81 8.35 15 0.00 2.55 Very Large 23.87 ± 5.19 0.25 -1.51 2.01 0.30 15 0.76 0.05 Trivial 32.07 ± 4.41 1.04 -0.31 2.39 1.64 15 0.12 0.26 Small 24.46 ± 2.84 0.43 -0.23 1.09 1.39 15 0.19 0.14 Trivial 13.19 ± 3.66 -1.15 -2.51 0.21 -1.81 15 0.09 -0.34 Small 5.52 ± 2.35 -0.77 -1.58 0.05 -2.01 15 0.06 -0.35 Small 118.16 ± 9.38 2.42 -1.75 6.58 1.23 15 0.24 0.25 Small 114 Table 3a. Paired t-test for Team Full Game Action Profiles pre 1st vs. post 1st 95% Confidence Interval of the Mean Difference st st Pre 1 Mean SD Post 1 Mean SD Difference Lower Upper p-value Zone 1 0 0.97 ± 0.25 0.36 ± 0.12 0.61 0.49 0.73 0.00 .16m/s Zone 2 .17 23.50 ± 4.72 22.85 ± 5.14 0.65 -0.59 1.88 0.28 1.68 m/s Zone 3 1.69 33.37 ± 3.59 32.24 ± 4.47 1.12 -0.42 2.66 0.14 - 3.07 m/s Zone 4 3.08 25.30 ± 3.15 25.03 ± 2.85 0.27 -0.33 0.87 0.35 - 4.18 m/s Zone 5 4.19 12.19 ± 3.13 13.83 ± 4.08 -1.64 -2.98 -0.30 0.02 -5.27 m/s Zone 6 > 4.67 ± 2.17 5.70 ± 2.54 -1.03 -1.90 -0.16 0.02 5.27 m/s m/min 122.24 ± 10.12 124.21 ± 11.02 -1.98 -5.96 2.00 0.31 Note: ES is effect size, p – value ≤0.05 115 t df ES Qualitative Descriptor 10.63 15 3.11 Very Large 1.12 15 0.13 Trivial 1.56 15 0.28 Small 0.96 15 0.09 Trivial -2.61 15 -0.45 Small -2.52 15 -0.44 Small -1.06 15 -0.19 Trivial Table 3b. Paired t-test for Team Full Game Action Profiles pre 2nd vs. post 2nd 95% Confidence Interval of the Mean Difference nd nd Pre 2 Mean SD Post 2 Mean SD Difference Lower Upper p-value Zone 1 0 1.14 0.39 0.49 0.22 0.65 0.44 0.86 0.00 .16m/s ± ± Zone 2 .17 24.79 4.94 25.06 5.02 -0.27 -1.75 1.20 0.70 1.68 m/s ± ± Zone 3 1.69 32.91 3.71 32.39 4.02 0.53 -0.93 1.98 0.45 3.07 m/s ± ± Zone 4 3.08 24.43 3.38 24.04 3.09 0.39 -0.67 1.45 0.45 4.18 m/s ± ± Zone 5 4.19 11.88 2.96 12.75 3.58 -0.88 -2.12 0.37 0.15 5.27 m/s ± ± Zone 6 > 5.27 4.80 1.97 5.27 2.16 -0.47 -1.19 0.25 0.18 m/s ± ± m/min 120.34 ± 10.49 115.45 ± 10.39 4.89 1.90 7.89 0.00 Note: ES is effect size, p – value ≤0.05 116 t df 6.53 15 -0.40 15 0.77 15 0.78 15 -1.50 15 -1.39 15 3.48 15 ES Qualitative Descriptor 2.05 Very Large -0.06 Trivial 0.14 Trivial 0.12 Trivial -0.27 Small -0.23 0.47 Small Small Table 4a. Forwards Pre 1st vs. Post 1st & 2 Pre 2nd vs. Post 2nd Wilcoxon Signed Rank Tests Pre Post Quarter 1 Zone 1 0 -.16m/s Zone 2 .17 - 1.68 m/s Zone 3 1.69 - 3.07 m/s Zone 4 3.08 - 4.18 m/s Zone 5 4.19 -5.27 m/s Zone 6 > 5.27 m/s m/min Quarter 2 Zone 1 0 -.16m/s Zone 2 .17 - 1.68 m/s Zone 3 1.69 - 3.07 m/s Zone 4 3.08 - 4.18 m/s Zone 5 4.19 -5.27 m/s Zone 6 > 5.27 m/s m/min Note: ES is effect size, p – value ≤0.05 Mean SD 0.90 ± 0.09 21.95 ± 2.09 30.14 ± 1.54 25.89 ± 1.78 14.21 ± 0.57 6.91 ± 1.24 126.83 ± 3.45 0.93 ± 0.17 23.49 ± 1.80 29.84 ± 1.88 25.13 ± 2.24 13.70 ± 0.25 6.91 ± 0.31 126.00 ± 4.34 Mean SD 0.34 ± 0.05 20.83 ± 1.92 29.20 ± 2.35 25.19 ± 2.27 16.20 ± 1.08 8.25 ± 1.20 128.90 ± 7.48 0.34 ± 0.09 23.01 ± 1.46 29.34 ± 1.61 24.56 ± 0.89 15.30 ± 1.23 7.47 ± 1.30 120.67 ± 7.20 117 Z -1.83 -1.46 -1.10 -1.46 -1.46 -1.46 -0.73 -1.83 -0.73 -1.46 -0.73 -1.46 -1.10 -1.46 pvalue 0.07 0.14 0.27 0.14 0.14 0.14 0.47 0.07 0.47 0.14 0.47 0.14 0.27 0.14 ES 7.26 0.56 0.48 0.34 -2.30 -1.09 -0.36 4.33 0.29 0.28 0.33 -1.80 -0.59 0.90 Qualitative Descriptor Very Large Small Small Small Very Large Moderate Small Very Large Small Small Small Large Small Moderate Table 4b. Midfielders Pre 1st vs. Post 1st & 2 Pre 2nd vs. Post 2nd Wilcoxon Signed Rank Tests Pre Post Zone 1 0 -.16m/s Zone 2 .17 - 1.68 m/s Zone 3 1.69 - 3.07 m/s Zone 4 3.08 - 4.18 m/s Zone 5 4.19 -5.27 m/s Zone 6 > 5.27 m/s m/min Quarter 2 Zone 1 0 -.16m/s Zone 2 .17 - 1.68 m/s Zone 3 1.69 - 3.07 m/s Zone 4 3.08 - 4.18 m/s Zone 5 4.19 -5.27 m/s Zone 6 > 5.27 m/s m/min Note: ES is effect size, p – value ≤0.05 Quarter 1 Mean SD Mean SD 0.84 ± 0.19 0.36 ± 0.18 20.94 ± 3.96 20.47 ± 5.41 32.75 ± 1.64 29.94 ± 2.44 26.59 ± 2.48 26.56 ± 2.24 13.70 ± 1.61 16.14 ± 3.16 5.18 ± 1.71 6.53 ± 1.27 124.88 ± 11.90 129.82 ± 11.52 1.08 ± 0.39 0.46 ± 0.22 21.81 ± 4.40 22.62 ± 5.58 32.10 ± 2.06 30.41 ± 1.98 25.59 ± 2.63 25.49 ± 3.01 13.63 ± 1.11 14.93 ± 1.94 5.77 ± 0.63 6.10 ± 0.64 126.79 ± 9.89 119.46 ± 13.18 118 Z -2.03 -0.14 -2.02 -0.41 -2.02 -2.02 -0.67 -2.02 -0.41 -2.02 -0.14 -1.48 -0.94 -2.02 pvalue 0.04 0.89 0.04 0.69 0.04 0.04 0.50 0.04 0.69 0.04 0.89 0.14 0.35 0.04 ES 2.59 0.10 2.44 0.01 -0.97 -0.90 -0.42 1.96 -0.16 0.84 0.03 -0.82 -0.52 0.60 Qualitative Descriptor Very Large Trivial Very Large Trivial Moderate Moderate Small Very Large Trivial Moderate Trivial Moderate Small Small Table 4c. Screens Pre 1st vs. Post 1st & 2 Pre 2nd vs. Post 2nd Wilcoxon Signed Rank Tests Pre Post Zone 1 0 -.16m/s Zone 2 .17 - 1.68 m/s Zone 3 1.69 - 3.07 m/s Zone 4 3.08 - 4.18 m/s Zone 5 4.19 -5.27 m/s Zone 6 > 5.27 m/s m/min Quarter 2 Zone 1 0 -.16m/s Zone 2 .17 - 1.68 m/s Zone 3 1.69 - 3.07 m/s Zone 4 3.08 - 4.18 m/s Zone 5 4.19 -5.27 m/s Zone 6 > 5.27 m/s m/min Note: ES is effect size, p – value ≤0.05 Quarter 1 Mean SD 0.94 ± 0.13 21.79 ± 0.88 32.61 ± 4.58 27.35 ± 1.82 13.11 ± 2.41 4.21 ± 1.68 127.96 ± 2.83 1.14 ± 0.17 23.74 ± 2.04 32.84 ± 5.45 26.21 ± 3.13 12.25 ± 2.29 3.74 ± 1.27 119.53 ± 1.07 Mean SD 0.44 ± 0.13 21.95 ± 4.15 31.26 ± 2.00 26.87 ± 0.63 14.18 ± 3.14 5.31 ± 2.19 124.55 ± 9.78 0.80 ± 0.26 24.71 ± 4.14 31.62 ± 1.41 26.41 ± 0.82 11.97 ± 2.82 4.50 ± 1.91 114.79 ± 7.75 119 Z -1.60 0.00 0.00 -0.54 0.00 -0.54 -0.54 -1.60 0.00 0.00 0.00 0.00 0.00 -0.54 pvalue 0.11 1.00 1.00 0.59 1.00 0.59 0.59 0.11 1.00 1.00 1.00 1.00 1.00 0.59 ES 3.76 -0.05 0.38 0.35 -0.38 -0.56 0.47 1.58 -0.30 0.31 -0.09 0.11 -0.47 0.86 Qualitative Descriptor Very Large Trivial Small Small Small Small Small Large Small Small Trivial Trivial Small Moderate Table 4d. Defenders Pre 1st vs. Post 1st & 2 Pre 2nd vs. Post 2nd Wilcoxon Signed Rank Tests Pre Post pMean SD Mean SD Z value 1.24 ± 0.33 0.33 ± 0.08 -1.84 0.07 Quarter 1 Zone 1 0 -.16m/s Zone 2 .17 - 1.68 m/s 29.52 ± 4.47 28.52 ± 4.41 -1.83 0.07 Zone 3 1.69 - 3.07 m/s 37.92 ± 1.38 38.90 ± 1.61 -0.73 0.47 Zone 4 3.08 - 4.18 m/s 21.58 ± 3.22 21.58 ± 2.34 0.00 1.00 Zone 5 4.19 -5.27 m/s 7.57 ± 1.70 8.29 ± 2.18 -1.10 0.27 Zone 6 > 5.27 m/s 2.14 ± 0.62 2.40 ± 0.94 -0.37 0.72 m/min 110.04 ± 5.90 112.27 ± 6.25 -1.83 0.07 1.44 ± 0.57 0.46 ± 0.02 -1.83 0.07 Quarter 2 Zone 1 0 -.16m/s Zone 2 .17 - 1.68 m/s 30.60 ± 5.23 30.44 ± 4.09 -0.37 0.72 Zone 3 1.69 - 3.07 m/s 37.05 ± 1.79 38.47 ± 1.66 -0.37 0.72 Zone 4 3.08 - 4.18 m/s 20.95 ± 3.75 19.93 ± 1.53 -0.73 0.47 Zone 5 4.19 -5.27 m/s 7.58 ± 2.07 8.08 ± 2.45 -0.73 0.47 Zone 6 > 5.27 m/s 2.29 ± 0.84 2.63 ± 1.11 -0.73 0.47 m/min 107.23 ± 7.63 105.70 ± 5.12 -1.10 0.27 Note: ES is effect size, p – value ≤0.05 120 ES 3.76 0.23 -0.65 0.00 -0.37 -0.32 -0.37 2.42 0.03 -0.82 0.35 -0.22 -0.34 0.24 Qualitative Descriptor Very Large Small Moderate Trivial Small Small Small Very Large Trivial Moderate Small Small Small Small Discussion The official game time has changed from 70 minute to 60 minute. However, under the newly implemented clock stoppage for corners, and goals, the actual game time will depend on the number of corners, and goals awarded during the game. Results indicate that this elite team did not show statistical changes in m/min and percent distance covered in zones 2 – 6. The percent of distance covered in zone 1 (standing) had a statistically significant increase. This is possibly due to the refined accuracy of the Optimye S5 units used during post collection. The team experience decreases across the 1st and 2nd half of the game in zone 1. During positional examination midfielders showed statically significance differences in the 1st and 2nd half of the game pre to post. It is possible that the 2 minute rest provided players with the ability to passively recover from the repeated sprints associated with field hockey. This would be particularly important for midfielders, whose tactical demands result in the playing both offense and defense. Their greater involvement gives players less recovery time on pitch, compared to forwards and defender. The high intensity intermittent activities of field hockey occur above most players’ critical speed (Spencer, Bishop, Dawson, & Goodman, 2005; Spencer et al., 2004), resulting in the need to return below critical speed to recover. The recovery time from the 2 minute rest periods in between quarter might allow the athlete to subsequently work above critical speed again. 121 Recovery is dictated by a multitude of factors. The more anaerobic mechanisms used during an action the more likely it takes a longer time to recover below critical speed. The farther below critical speed an athlete is allowed to rest, the more likely they will recover faster. Passive recovery may facilitate quicker recovery than active recovery (Buchheit et al., 2009). Upon numerical observation of the relative percent of total distance covered by position, midfielders cover the least percent distance in zones 1, 2, and 3 compared to screens and defenders. All three zones are indicative of active recovery on pitch. Previous research has noted that forwards are substituted more often than midfields (MacLeod, Bussell, & Sunderland, 2007; Polglaze et al., 2014) allowing for passive recovery off the pitch. Strategic techniques likely allow the US Women’s National Team to produce high m/min compared other field hockey team, and other sports. The team produced 120.58 ± 10.25 m/min before the rule change and 118.16 ± 9.38 m/min after the rule change. Lythe and Kilding (2011) reported an average of 116.6 m/min during men’s field hockey. This is less than the average m/min produced by the Women’s National Team (Pre 1 - 124.88 ±11.90 Post 1- 129.82 ±11.52 and Post 1 126.79 ± 9.89 to Post 2 119.46 ± 13.18). However it is important to note that m/min are affect by the number of substitutions and analysis methods used (Varley, Gabbett, & Aughey, 2014). Conclusion A major focus of the US Women’s National Team was to develop the athletes’ physical capacity to maintain and repeat high intensity actions. The combination of physical 122 preparation and tactical strategies, such as player substitutions, allow the team to express high m/min and high intensity actions throughout a match. Due to these previously used substitutions techniques, and the high level of play examined in this study, the addition of 2 minute rest periods allowed the team to produce statistically significant high relative action profiles during the entire game. However midfielders experienced changes during the new rule system, possibly due to the tactical requirements of the position. They had a decrease in zone 1, and an increase in zones 5 and 6 pre to post during the 1st half of the game, and a decrease in zones 1 and 3 and m/min during the 2nd half of the game. References Barrett, S., Midgley, A., & Lovell, R. (2014). PlayerLoad: reliability, convergent validity, and influence of unit position during treadmill running. Int J Sports Physiol Perform, 9(6), 945-952. Buchheit, M., Cormie, P., Abbiss, C. R., Ahmaidi, S., Nosaka, K. K., & Laursen, P. B. (2009). Muscle deoxygenation during repeated sprint running: Effect of active vs. passive recovery. Int J Sports Med, 30(6), 418-425. Dwyer, D. B., & Gabbett, T. J. (2012). Global positioning system data analysis: velocity ranges and a new definition of sprinting for field sport athletes. J Strength Cond Res, 26(3), 818-824. Eaves, S. J., Lamb, K. L., & Hughes, M. D. (2008). The impact of rule and playing season changes on time variables in professional in rugby league in the United Kingdom. International Journal of Performance Analysis in Sport, 8(2), 44-54. FIH. (2014). Rules of Hockey Including Explanations Lausanne, Switzerland 123 Gabbett, T. J. (2010). GPS analysis of elite women's field hockey training and competition. J Strength Cond Res, 24(5), 1321-1324. Hopkins, W. G., Marshall, S. W., Batterham, A. M., & Hanin, J. (2009). Progressive statistics for studies in sports medicine and exercise science. Med Sci Sports Exerc, 41(1), 3-13. Jennings, D., Cormack, S. J., Coutts, A. J., & Aughey, R. J. (2012a). GPS analysis of an international field hockey tournament. Int J Sports Physiol Perform, 7(3), 224231. Jennings, D., Cormack, S. J., Coutts, A. J., & Aughey, R. J. (2012b). International Field Hockey Players Perform More High-Speed Running Than National-Level Counterparts. Journal of Strength and Conditioning Research, 26(4), 947-952. Johnston, R. J., Watsford, M. L., Kelly, S. J., Pine, M. J., & Spurrs, R. W. (2014). 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Varley, M. C., Fairweather, I. H., & Aughey, R. J. (2012). Validity and reliability of GPS for measuring instantaneous velocity during acceleration, deceleration, and constant motion. J Sports Sci, 30(2), 121-127. 125 Varley, M. C., Gabbett, T., & Aughey, R. J. (2014). Activity profiles of professional soccer, rugby league and Australian football match play. J Sports Sci, 32(20), 1858-1866. Vescovi, J. D., & Frayne, D. H. (2015). Motion characteristics of division I college field hockey: Female Athletes in Motion (FAiM) study. Int J Sports Physiol Perform, 10(4), 476-481. White, A. D., & MacFarlane, N. (2013). Time-on-pitch or full-game GPS analysis procedures for elite field hockey? Int J Sports Physiol Perform, 8(5), 549-555. White, A. D., & MacFarlane, N. G. (2014). Analysis of International Competition and Training in Men's Field Hockey by Global Positioning System and Inertial Sensor Technology. J Strength Cond Res. Williams, J., Hughes, M., & O'Donoghue, P. (2005). The effect of rule changes on match and ball in play time in rugby union. International Journal of Performance Analysis in Sport, 5(3), 1-11. Wyldea, M., Yonga, L. C., Azizb, A. R., Mukherjeec, S., & Chiac, M. (2014). Application of GPS technology to create activity profiles of youth international field hockey players in competitive match-play. International Journal of Physical Education, Fitness and Sports, 3(2), 75-78. 126 CHAPTER 6 SUMMARY AND FUTURE INVESTIGATIONS The following conclusions are draw from the presented literature review, and the findings from the studies in this dissertation. The relative action profiles before the rule change revealed that defenders work at a lower meter per minute (m/min) when compared with all other positions, and that forwards, midfielders, and screens perform similar m/min during a game, and percent of total distance covered in zone 1 through 6. This data supports the need for position specific conditioning with defenders. Examination of pre rule change difference from the 1st to the 2nd half play showed that elite level field hockey players are able maintain high-intensity actions in zone 6 throughout the game by increasing actions in zones 1 and 2, and decreasing actions in zones 4 and 5. The relative action profiles after the rule changed revealed the team was unable to match the percent of distance covered in zones 4 and 5 during the 1st quarter all in subsequent quarters. The low intensity actions in zone 1 and 2 gradually increased, while m/min gradually declined. When positional differences were examined forwards covered the greatest percent of distance in zones 5 and 6, followed by midfielders, screens, and defenders. This pattern varies for zone 4, within which the midfielders possesses the greatest percent distance covered. The comparison of relative action profile comparisons for the team, pre to post rule change did not indicate a significant change in zones 2, 3, 4, 5, and 6. However zone 1 experience a statistically significant decrease. Positional analysis of relative action profiles pre to post rule change showed statistically significant changes for midfielders 127 only. The changes were a decrease in zone 1, and increase in zone 5 and 6 during the first half of the game, and decrease in zone 1 and m/min during the second half of the game. The combination of physical preparation, tactical strategies, and elite level of the athlete’s profiles resulted in high intensity actions throughout a match. Further research, specific to the US Women’s national field hockey team is needed in the utilization of recovery strategies during 2 minute rest periods and 10 minute half time. This could allow the team to reduce the increases in in zones 1 and 2, and dampen the reduction in m/min and percent distance covered in zones 4 and 5. Further research done on the new FIH game formatting should consider removing the 40 second running clock during corners, and goals to allow for a better understand of the quarter system. Standardizing the time in each quarter would allow for the examination of m/min in relation to fatigue. In addition to examining the current definition of velocity bands used in the literature. Understanding the requirements of field hockey is important for developing effective training programs. The action profiles of elite level athlete’s provide coaches with the ability to assess athlete’s current level of fitness in relationship to those produced at the elite level. The more accurately the published action profiles represent the actual action produced in a game the more useful the profiles are for coaches. Previous research using 1 and 5 Hz GPS units may have underestimated the actions performed by athletes. 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Retrieved from <Go to ISI>://WOS:000299857600024 146 APPENDIX ETSU Institutional Review Board Approval Form Office for the Protection of Human Research Subjects Box 70565 Johnson City, Tennessee 37614-1707 Phone: (423) 439-6053 Fax: (423) 439-6060 IRB APPROVAL – Initial Expedited Review April 11, 2016 Heather Abbott Re: Analysis of the US Women’s National Field Hockey team in relationship to 2015 FIH rule change IRB#:c0316.9sw ORSPA #: The following items were reviewed and approved by an expedited process: New protocol submission xForm, references, PI CV, variables list On March 31, 2016, a final approval was granted for a period not to exceed 12 months and will expire on March 30, 2017. The expedited approval of the study will be reported to the convened board on the next agenda. A waiver or alteration of informed consent has been granted under category 45 CFR 46.116(d). The research involves no more than minimal risk because it involves a retrospective analysis of data only. The waiver or alteration will not adversely affect the rights and welfare of the subjects as the athletes whose data is involved have already given consent to have their data added to the research repository whereby data may be drawn for research purposes. The research could not practicably be carried out without the waiver or alteration as many of the athletes in the study population are no longer available to consent. Providing participants additional pertinent information after participation is NOT appropriate. The following enclosed stamped, approved Informed Consent Documents have been stamped with the approval and expiration date and these documents must be copied and provided to each participant prior to participant enrollment: n/a retrospective Federal regulations require that the original copy of the participant’s consent be maintained in the principal investigator’s files and that a copy is given to the subject at the time of consent. 147 Accredited Since December 2005 Projects involving Mountain States Health Alliance must also be approved by MSHA following IRB approval prior to initiating the study. Unanticipated Problems Involving Risks to Subjects or Others must be reported to the IRB (and VA R&D if applicable) within 10 working days. Proposed changes in approved research cannot be initiated without IRB review and approval. The only exception to this rule is that a change can be made prior to IRB approval when necessary to eliminate apparent immediate hazards to the research subjects [21 CFR 56.108 (a)(4)]. In such a case, the IRB must be promptly informed of the change following its implementation (within 10 working days) on Form 109 (www.etsu.edu/irb). The IRB will review the change to determine that it is consistent with ensuring the subject’s continued welfare. Sincerely, Stacey Williams, Chair ETSU Campus IRB cc: Kimitake Sato 148 VITA HEATHER ABBOTT Education: Doctor of Philosophy in Sports Physiology East Tennessee State University (ETSU), TN Graduation: August 2016 Master of Education Frostburg State University (FSU), MD Graduation: May 2013 Bachelor of Health Science Drexel University (DU), PA Graduation: June 2011 Experience: Olympic Training Site at East Tennessee State University Head Sport Scientist Ph.D., Weightlifting 8/2013 to Current USA Field Hockey Assistant Sport Scientist Ph.D., 12/2013 to Current East Tennessee State University Teaching Associate (Teacher of Record), 8/2013 to Current Head Coach and Strength & Conditioning Coach for the ETSU Men's Rugby Club, 4/2014 to Current Women’s Golf Strength and Condition Coach, 8/2013 to 4/2014 Frostburg State University Graduate Assistant Coach Field Hockey DIII, 8/2011 to 5/2013 Publications: Refereed Publications Bazyler, C. D., Abbott, H. A,Bellon, C. R., Taber, C. B., & Stone, M. H. (2015). Strength Training for Endurance Athletes: Theory to Practice. Strength & Conditioning Journal, 37(2), 1-12. Taber, C. B., Bellon, C. R., Abbott, H.A., Bingham, G. (2016). The Roles of Maximal Strength and Rate of Force Development in Maximizing Muscular Power. Strength &Conditioning Journal 38(1), 71-78. 149 Refereed Proceedings Abbott, H.A., Taber, C.B., Griggs, C., Rhudy, J., Keck, S. Power Output at Varying Loads during Squat Jumps. East Tennessee State University 10th Annual Coaches and Sports Science College, December 2015. Abbott, H.A., Taber, C.B., Ricker. D., Weiss M. Monitoring the Effects of Volume Load on Static Jump Height in Weightlifters. East Tennessee State University 10th Annual Coaches and Sports Science College, December 2015. Swisher, A.M., Abbott, H.A. A Call to Reform Coach Education in the United States. East Tennessee State University 9th Annual Coaches and Sports Science College, December 2014. Swisher, A.M., Dotterweich, A.R., Clendenin, S., Palmero, M., Greene, A.E, Walker, J.T., Abbott, H. Using Benefits-Based Models To Manage Sport Performance Enhancement Groups. East Tennessee State University’s 8th Annual Coaches and Sports Science College, December 2013. Smith, S.A., Berry, H., Lenzi, R., Abbott, H. Effect of Altering Stride Frequency on Constant Speed Running Economy and Perceived Exertion. 34th Annual Meeting, Mid-Atlantic Regional Chapter of the American College of Sports Medicine, November 2011. 150
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