Universidade de São Paulo
Biblioteca Digital da Produção Intelectual - BDPI
Departamento Esporte - EEFE/EFE
Artigos e Materiais de Revistas Científicas - EEFE/EFE
2010
Performance of young male swimmers in the
100-meters front crawl
PEDIATRIC EXERCISE SCIENCE, v.22, n.2, p.278-287, 2010
http://producao.usp.br/handle/BDPI/14608
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Pediatric Exercise Science, 2010, 22, 278-287
© 2010 Human Kinetics, Inc.
Performance of Young Male Swimmers
in the 100-Meters Front Crawl
Fabrício de Mello Vitor and Maria Tereza Silveira Böhme
University of São Paulo
Youth swimming performance may be influenced by anthropometric, physiology
and technical factors. The present paper examined the role of these factors in
performance of 100m freestyle in swimmers 12–14 years of age (n = 24). Multiple regression analysis (forward method) was used to examine the variance of
the 100 meters front crawl. Anaerobic power, swimming index and critical speed
explained 88% (p < .05) of the variance in the average speed of 100 meters front
crawl among young male pubertal swimmers. To conclude, performance of young
swimmers in the 100 meters front crawl is determined predominantly by physiological factors and swimming technique.
Performance in high level swimming has been depended by components like
technique (stroke technique, coordination, starts and turns), physical conditioning
(aerobic conditioning, anaerobic conditioning, flexibility and strength) and psychological conditioning (stress control, motivation) (19).
Some studies in sports science literature have used different methodologies
to investigate performance in young swimmers. Klika and Thorland (13) sought
to discriminate faster and slower swimmers, while other researchers examined
a combination of variables that best explained performance of young swimmers
in short distance (1,9,11,23) and medium distance (12) events. In some studies,
biological age was assessed by level of sexual maturation (12,23) and the skeletal
age (9), while others were not taken into account gender (11) or competitive levels
(11,23). Furthermore, researchers have based on different methodologies to measure aerobic and anaerobic conditioning, anthropometric components, swimming
techniques and body composition. Although internal validity of the measures has
been selected by some studies, they have not taken into consideration real situations
like competitions or training (ecological validity).
Based on the findings of previous studies (1,4,5,9,11–13,23,26), anthropometric measures, general and specific physical conditioning, swimming technique,
competitive level and maturational aspects should be analyzed in young swimmers
performance. In comparison with high-level swimming, young swimmers studies
have not showed any relevance in regarding to psychological aspects of performance.
Vitor and Böhme are with Physical Education and Sports School—Research Group of Youth Sports
and Training, University of São Paulo, Brazil.
278
Performance of Young Male Swimmers 279
Therefore, the main hypothesis of the current study was that 100m front crawl
in young male swimmers should be dependent on anthropometric, physical conditioning and swimming technique factors.
Several determinants of young swimming performance may be associated with
outcomes and processes of growth and maturation. Moreover, there are not studies
investigating the performance of young Brazilian swimmers.
Specifically, the aims of the current study were:
1.To assess the relationship among anthropometric variables, specific physical
conditioning, swimming techniques and performance of young swimmers in
the 100 m distance front crawl swimming;
2.To determine a combination among anthropometric variables, specific physical
conditioning and swimming techniques that improves prediction of 100 m
distance front crawl swimming.
Materials and Methods
Subjects
Twenty-four male swimmers participated in this investigation after giving
informed consent in accordance with the guidelines outlined by Ethics Committee
of Physical Education and Sport School at São Paulo University (Protocol No.
2008/09). Swimmers competed at the state (São Paulo, SP) and national levels
(Brazil) in 2007. All swimmers were classified as pubescent in agreement with
Tanner stages (27). Subjects had trained for 3 to 4 years and 15 hr per week for
at least the last two years. During the testing period (i.e., April), the weekly training volume was around twenty kilometers and training was performed mainly at
aerobic pace and technique drills. The swimmers were in a ninth week of base
period of training.
Study Design
The measurements were undertaken over 2 days: on Day 1, anthropometric measures, self-assessment of sexual maturation, anaerobic power test, performance in
100 m front crawl swimming, swimming technique, and chronological age while
the critical speed test (CS) was taken on Day 2.
Anthropometric Measures, Sexual Maturation
and Chronological Age
Anthropometric measurements were taken before beginning of training and are
described as follow: height, was measured by Kawe tape measure to the nearest
0.1 cm fixed to the smooth wall and an object to identify the scope of the maximum size (e.g., ruler or clipboard); body mass, was measured by a digital scale to
the nearest 0.10 kg (Techline, Model BAL-180,BR); arm span, was measured by
a Eccofer tape measure with 3 m in length to the nearest 0.1 cm fixed at smooth
surface and an object to identify the scope of the maximum distance between
dactylion points (e.g., ruler or clipboard); hand length (was taken by the distance
280 Vitor and Böhme
from styloid process of radius (located at the wrist) and dactiloid process (tip of
middle finger), biacromial breadth (was taken by the distance from lateral edge of
acromion process), biiliac breadth (was taken by the distance from lateral edge of
iliac crest) were measured by a sliding caliper to the nearest 0.1cm (Sanny, American
Medical from Brazil, BR); skinfolds (triceps and subscapular), were measured by a
skinfold caliper to the nearest 0.1 mm (Sanny, American Medical from Brazil, BR)
(14); hand width (was taken by the distance from first and fifth metacarpal of the
hand) and foot width (was taken by the distance from first and fifth metatarsus of
the foot) were measured by a sliding caliper to the nearest 0.1cm (Sanny, American
Medical from Brazil, BR) (18), and finally, foot length (was taken by the distance
from most posterior point of the heel to the tip of the most anterior projecting toe)
was measured by a sliding caliper to the nearest 0.1cm (Sanny, American Medical
from Brazil, BR) (4,18). Body fat measurement was according to the methods of
Slaughter et al. (24). From the arm span and height measures, was calculated the
Arm Span/Height Index, and from the biacromial and biiliac breadth measures,
was calculated the Biacromial/Biiliac Index (18).
The self-assessment of sexual maturation was analyzed by drawings of representative stages for sexual pilosity from one to five (stage 1 means biological
immaturity while stage 5 means biological maturity) according Tanner stages (27).
Chronological age was obtained by birth date.
Swimming Performance
All tests were performed in a 50 m pool (long course). Water temperature was kept
between 25 and 28 degrees, as determined by FINA (Fédération Internationale de
Natation). A stopwatch (Technos, YP2151/8P, BR) with precision of one hundredth
of a second was used. The front crawl swimming was performed according to the
regulations of FINA.
Anaerobic Power Test (15)
Anaerobic power test was performed by eight front crawl repetitions in a maximum
effort, over a 25 m distance (8 × 25m front crawl), with three minutes of passive
rest among repetitions. Subjects began the swim in the water and researchers started
the timing manually when swimmers feet left the wall of the pool and times were
finished when any hand was achieving the distance of 25 m. After eight repetitions, the average time was calculated and converted into average speed (m/sec)
representative of each subject’s performance. Athletes were not wearing bathing
costumes that could offer potential hydrodynamic advantages. The warm-up session in the pool lasted around twenty minutes and was composed of technical and
low intensity aerobic exercises
Performance in the 100 Meter Front-Crawl
Performance in the 100 m front crawl was measured in a maximum effort and
start was given when the swimmers were in the water. This performance occurred
after forty minutes of active recovery after the anaerobic power test with purpose
of regenerate metabolic system. According to literature (16), after forty minutes
Performance of Young Male Swimmers 281
of moderate continuous exercise, high lactate concentration obtained after a high
intensity effort decrease at rest levels. During the forty minutes, swimmers performed technical exercises as well as moderate intensity aerobic exercises to allow
recovery from their mental and physical tiredness.
Times were recorded in seconds, afterward, average speeds were calculated.
This performance measure was the same one (100 m front crawl) used to
measure the swimming techniques as follow:
Stroke Rate, Distance Per Stroke, Swimming Index (25)
The stroke rate was determined from the elapsed time for three arm cycles between
15m and 45meters of the 100 m sprint swim. That distance considered to eliminate
the effects of starting from the wall and of turning. The timing was started when
the right hand of the swimmer was entered the water and was stopped when the
right hand of the swimmer was entered the water for the fourth time, completing
three arm cycles.
The values for distance per stroke and stroke index were extracted from the
measure of stroke rate, where:
(a) Distance per stroke (m/cycle) = 100m swimming speed (m/s) divided by
stroke rate (cycles/s).
Although this method overestimates distance per stroke by 4-5% due to the push
off from the side of the pool (25) because these results did not taken into account
the dive start or any variation in mid-pool swimming speed and turning times, this
is a systematic error which does not significantly influence subsequent comparisons
between swimmers (7).
(b) Swimming Index was calculated by multiplying the swimming speed
(m/s) by distance per stroke (m/cycle). This index assumes that, at a given
speed, the swimmer who moves the greatest distance per stroke has the
most efficient swimming technique (25).
Critical Speed Test (CS) (8). A greater velocity that can be maintained continually
without fatigue defines Critical Velocity (17). The amount of work performed at the
expense of the complete utilization of anaerobic stores and the mechanical power
sustainable at the expense of the maximal O2 consumption of the muscle group in
question underlying the critical power definition (17). Based on them, di Prampero
(22) states that critical velocity must be calculated with exhaustive times that are
situated between two and twenty minutes. Others studies have supported the critical
speed evaluation method by two distances in swimming (23)
The test was performed by one repetition of 200 m front crawl and one repetition of 800 m front crawl at maximum speed intensity with interval of forty minutes
between repetitions with purpose of regenerate metabolic system (16). The times
were recorded in seconds and after that, were converted in speed (m/sec). The
warm-up session in the pool lasted approximately twenty minutes supervised by
their coach and was composed of technical and moderate intensity aerobic exercises. Forty minutes of active rest between 200m and 800m was done with aerobic
exercises of low intensity. The critical speed was obtained through a regression
slope between the distance and the time.
282 Vitor and Böhme
Statistical Analysis
The average speed during the 100 m front crawl swim was considered as dependent
variable and all other variables were considered independent variables. Pearson’s
correlation coefficients were used to evaluate relationships between the variables.
Multiple regression analysis (forward method) was used to verify the combination of significant independent variables that could predict the dependent variable
(the average speed of the 100 m front crawl). A p-value of 0.01 was used to select
variables to be included in the multiple regression models, and a p-value of 0.05
was used to evaluate the fit of multiple regression models. Statistical analyses were
conducted using SPSS 13.0 (Chicago, IL).
Results
With regard to sexual maturation, among all twenty-four subjects, seven subjects
were classified as stage three of pilosity while seventeen subjects were classified as
stage four of pilosity, by then, all subjects engaged on pubescent stage as purposed
by Tanner (1962). The chronological age was 13.0 ± 0.7 years.
The descriptive values of the subjects are displayed in Table 1.
Anaerobic power (r2 = .67), swimming index (r2 = .62), body mass (r2 = .35),
critical speed (r2 = .34), biacromial breadth (r2 = .32), chronological age (r2 = .28)
and height (r2 = .28) were significantly correlated positively with the average speed
of 100 m front crawl (p < .01; Table 2). Moreover, distance per stroke (r2 = .28)
was associated too with 100m front crawl at p < .05 (Table 2).
To explore a model that gives the best prediction of performance, all the
assumptions were tested (10) and the prediction model obtained is presented in Table
3. This procedure was only followed where an adequate number of observations
existed. The normal distribution of residuals was checked and the model obtained
was statistically significant (p < .05).
Results indicated that prediction model explained 88% of variability of timing
in 100 m front crawl performance in agreement with adjusted coefficient (Table
3). Anaerobic power had greater influence in observed model as showed by beta
standard coefficient (0.49).
Discussion
Present data showed a significant relationship between 100m front crawl in eight
(anaerobic power, swimming index, body mass, critical speed, biacromial breadth,
chronological age and height) of twenty variables measured (Table 1). Furthermore,
correlations showed that two variables were associated with physical conditioning (anaerobic power, critical speed), one variable was associated with swimming
technique (swimming index), three variables were associated with anthropometry
(body mass, biacromial breadth, height). These results are in agreement with the
literature (9,11,12,23).
The main finding of this study was that anaerobic power, swimming index,
critical speed are the only variables that best explained (88%) 100 m front crawl
performance in young swimmers with 13.0 ± 0.7 years. In other words, physical
conditioning and technique seems like be more determinant than anthropometric
283
Variables
Chronological Age (years)
Anthropometry
Body mass (kg)
Height (cm)
Arm Span (cm)
Hand length (cm)
Hand width (cm)
Foot length (cm)
Foot width (cm)
Biacromial breadth (cm)
Biiliac breadth(cm)
Calculated Index
Arm span/height index
Biacromial/Biiliac index
Body composition
Triciptal skinfold(mm)
Subescapular skinfold (mm)
Body fat (%)
Specific Physical Conditioning
Anaerobic Power (m / s)
Critical Speed (m / s)
Stroke Parameters
Stroke rate (cycles/s)
Distance per stroke (m/cycle)
Swimming Index (m2/cycle/s)
Dependent Variable
100 meters front-crawl average speed (m/s)
Standard Deviation
0.7
8.4
6.3
8.4
0.9
0.7
1.2
0.5
1.9
1.4
0.0
0.1
2.4
2.9
4.8
0.08
0.07
0.06
0.17
0.34
0.07
Mean
13.0
52.3
163.5
169.0
18.1
10.1
25.3
9.7
37.2
25.9
1.0
1.4
8.4
8.4
20.4
1.65
1.15
0.79
1.85
2.71
1.46
1.31
0.68
1.56
2.09
1.52
1.02
5.3
4.9
13.4
1.0
1.3
39.1
152.0
156.0
16.7
9.1
23.2
8.7
34.2
23.3
Minimum
12.0
1.58
0.92
2.08
3.24
1.83
1.30
13.8
16.0
31.8
1.1
1.5
68.2
175.0
184.0
19.9
12.0
27.7
10.9
40.5
28.0
Maximum
14.0
Table 1 Mean ± SD, Minimum and Maximum Values of Anthropometric Variables, Physical Conditioning
and Stroke Parameters of Young Male Swimmers
284 Vitor and Böhme
Table 2 Correlation Coefficients (r) and r2 Values of Variables
Associated with the 100-Meters
Variables
R
r2
Anaerobic power
0.82**
0.67
Swimming index
0.79**
0.62
Body mass
0.59**
0.35
Critical speed
0.58**
0.34
Biacromial breadth
0.57**
0.32
Chronological age
0.53**
0.28
Height
0.53**
0.28
Distance per stroke
0.53*
0.28
Biiliac breadth
0.50
0.25
Hand width
0.33
0.11
Arm span
0.32
0.10
Arm span/height index
–0.24
0.06
Subscapular median
0.23
0.05
Foot length
0.21
0.04
Foot width
0.21
0.04
Hand length
0.18
0.03
Body fat
0.13
0.02
Triceps median
–0.05
0.00
Biacromial/Biiliac index
Stroke rate
0.03
0.03
0.00
0.00
* p < .05; ** p < .01
Table 3 Multiple Linear Regression Model for Performance in the
100-Meters Front Crawl Race Among Young Male Swimmers
Beta
Linear
Colinearity
Standard
B Model Significance
Coefficient Coefficient
Level
Tolerance VIF
N = 24
R = .95
Intercept
R = .90
Anaerobic Power
average speed
R2aj.=0.88 Swimming Index
S.E= 0.03 Critical speed
2
*p < .05
0.11
0.41
0.49
0.45
0.00*
0.62
1.59
0.39
0.31
0.08
0.31
0.00*
0.00*
0.61
0.88
1.61
1.12
Performance of Young Male Swimmers 285
measures in this specific case. On the other side, anthropometry did not have any
variable that could explain 100m front crawl performance in prediction model.
The finding of a greater significant contribution of anaerobic power in 100 m
swimming performance in the current study may be explained by energy expenditure
along the race. Taking into account that subjects in the current study had an average
time of 68.5 s (Table 1) in 100m front crawl, the metabolic point-of-view suggests
that efforts rounded by 60 s has 70% of anaerobic contribution in performance (16).
Moreover, Capelli, Pendergast and Termin (2) analyzed the metabolic contribution in 100 yards (91.4 m) with male swimmers (18.9 ± 0.9 years) and found that
anaerobic contribution response for 66.8% of performance. This results showed
that swimming performance of 100m distance is depended more of anaerobic
metabolism than aerobic metabolism. Some studies have investigated anaerobic
performance in young swimmers (9,11,23), but all of them was done with tests in
land, however, other studies have analyzed anaerobic performance in a pool (13),
but none of them measured anaerobic performance exactly like in current study.
Nonetheless, no matter how was measured, anaerobic performance have showed be
relevant to performance in short races (50 and 100 m) for young swimmers (9,11).
Furthermore, anaerobic power in current study was strongly correlated with body
mass (r = .62, p < .01), height (r = .55, p < .01), hand width (r = .57, p < .01) and
biacromial breadth (r = .67, p < .01). Despite the fact anthropometric measures
not entered in prediction model, they are fundamental to understand anaerobic
performance. Except body mass, all other measures are determinate genetically
(18) in agreement with literature, which states that genetics contribute around 50%
of variance in short-term anaerobic performance (28).
Swimming index was also significant to predicted model in present study
corroborating with others studies in literature (11, 12, 13, 23; Table 3). Strazla,
Tyka and Krezalek (26) found a medium value of 3.09 m2/cycle/s in young swimmers (14.7 ± 0.5 years) when performed 100 front crawl compared with a 2.71
m2/cycle/s of current subjects (13.0 ± 0.7 years). A short explanation to this fact
may be due to difference in chronological age. Pelayo et al. (20) analyzed scholar
swimmers between eleven to seventeen years-old and found that chronological age
was together with arm span, the only swimming index predictors of best results
when compared younger with older swimmers. Besides that, chronological age
was statistically significant with 100 front crawl in current study (r = .53 p < .01)
corroborating with Pelayo et al. (20). Based on literature (3), these results suggests
that during learning, improvement is achieved mainly by attaining longer strokes
as result of better orientation of motor surfaces (the surfaces of swimmer´s arms
and legs that generate a propulsive force) and increase in the span of the motor
paths (distance covered by motor surfaces). Moreover, faster swimmers have better
swimming index and consequently better technique in agreement with former and
recent studies (6,25).
Critical speed analyzed in present study was the third best variable that
explained significantly the variance in 100 front crawl (Table 3). Other studies
have showed aerobic performance as predictor of results for young swimmers
(12). According Platonov (21), the 100 m front crawl race can be considered in
terms of energy efficiency, with 55% contribution from anaerobic metabolism
286 Vitor and Böhme
and 45% from aerobic metabolism, and it can be classified as a mixed race,
because the aerobic energy source is also important to ensure endurance during
the swim. This is consistent with the study by Capelli, Pendergast and Termin
(2). These data confirm the significance of both anaerobic power and critical
speed (an indicator of aerobic capacity) for predicting performance in the 100
m front crawl.
According with studies that sought examine the combination of variables to
explain 100m front crawl performance in young male swimmers, Geladas, Nassis
and Pavlicevic (9) found 59% of the variance in the performance explained by the
combination of the total upper extremity length, horizontal jump and grip strength
in athletes between 12–14 years-old. Klika and Thorland (13) observed that both
distance per stroke and muscularity index (lean body mass/stature2) had significant
influence (p < .05) on the performance of faster swimmers between 9–12 years-old.
Based on these results, it became difficult has an idea about what is right because
methodologies used by researchers are very different. In spite of this fact, almost
all studies discussed at current study included variables related with anaerobic performance, swimming technique and aerobic performance as significant to explain
100m swim performance in young swimmers.
Limitations of Study
In the current work was not included any psychological indicators that might have
influence in the environment of training.
In addition, technical swimming parameters were not evaluated by a video
camera.
Conclusion
In summary, anaerobic power test, swimming index and critical speed test explained
88% of the variability of the average speed for the 100 m front crawl swim. The
absence of anthropometric variables in the regression model suggests that the performance of young swimmers in the 100 m front crawl is determined predominantly
by physiological factors and swimming technique.
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