Strength distribution in adolescent sportsmen practicing various sports

Strength distribution in adolescent sportsmen practicing various sports
J. Mazur1, J. Gajewski1,3, K. Buśko2,3
1
Dept. of Statistics and Information Technology, Józef Piłsudski University of Physical Education, Warsaw
Dept. of Anthropology, Józef Piłsudski University of Physical Education, Warsaw
3
Dept. of Biomechanics, Institute of Sport in Warsaw
2
1. Introduction
Measurements of the maximal muscle torques of the main muscle groups under static conditions are commonly
used to estimate muscle strength in laboratory tests [3]. It has been shown that strength distribution among muscle
groups (strength profile) is related to the sport technique utilized by athletes [4]. Strength profile can be also
affected by training [1] [6]. Usually, strength analysis concerns right (or dominant) extremities and trunk of
sportsman [2]. However, there are studies analyzing strength of both upper [5] and lower extremities [8]. More
complex approach was presented by Trzaskoma and Trzaskoma [7], who presented the strength profiles including
both body sides and lower as well upper extremities and trunk. Most of the above mentioned works concern the
strength comparison between male and female practicing the same sports [7]. Not many studies deal with profiles
of the athletes muscle strength taking into consideration gender and the sport practiced.
The aim of the study was to indicate regularities of the strength distribution in adolescent athletes taking into
consideration gender and the sport discipline practiced.
2. Material and methods
Young athletes (85 males and 59 females) practicing taekwondo, judo, weight lifting, kayaking and speed skating
took part in the study. The age, body weight and body height in males were 17.1±1.1 years, 77.2±7.6 kg and
178.9±2.8 cm, respectively. The same in females were 16.7±1.2 years, 60.4±4.8 kg, and 165.0±2.9 cm,
respectively. Anthropological characteristics of all groups are presented in Table 1.
Table 1 Anthropological characteristics (mean±SD) of the all groups tested
Males
Females
N
Age
[years]
Body mass
[kg]
Body
height [cm]
N
Age
[years]
Body mass
[kg]
Body
height [cm]
Taekwondo
8
15.8±0.9
62.6±13,1
178.4±9.7
10
15.7±1.0
53.3±8.3
164.5±6.4
Judo
20
17.5±1.5
81.5±20.2
177.2±7.7
17
18.2±1.9
57.9±7.5
163.1±5.5
Weight lifting
10
16,2±1,2
81,9 ±17,9
176,1±4,6
10
15.4±1.2
63.5±17.9
162 ±10.4
Kayaking
35
17.8±0.9
82.1±6.2
183.5±6.1
14
16.7±1.2
64.9±6.6
169.4±5.5
Speed skating
12
18.3±0.7
76.1±6.9
179.2±3.7
8
17.6±1.6
62.5±3.3
166.0±2.2
All measurements were conducted after the subject has been familiarized with the equipment and assay protocol
and after a standard warm-up consisting of exercises engaging the studied muscle groups. The subject was to
attain maximal torque within 3 s, first for flexion, then for extension, for the right and left hand and leg separately
and for trunk. Averages of results for left and right extremities were used for further analysis. Logarithm transform
was applied to the muscle torques values. The two-way MANCOVA procedure was applied to reveal significant
differences of means. The SPORT and GENDER factors were taken into consideration. A logarithm of the body
mass was used as a covariate. Significance level was set at 0.05.
3. Results
The linear regression procedure was utilized separately for boys and girls to estimate dependencies of log-torques
vs. log-body mass for each muscle group. Strength profiles, represented by the averaged normalized log-torque
residuals, are shown in Fig. 1.
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Fig. 1 Normalized strength profiles of the tested groups of boys and girls practicing various sports;
muscle groups description: first character E, A, K, H and T – elbow, arm, knee, hip and trunk,
respectively; second character E and F – extension and flexion, respectively
The MANCOVA procedure (log-body mass as covariate) revealed significant impact of SPORT (F10,30=9.83,
p<0.001) as well as GENDER factor (F10,30=19.73, p<0.001) on mean log-torques values. Significant interaction
SPORT x GENDER (F10,30=2.19, p<0.05) indicated differences in sports being dependent on gender. As shown
in Fig. 1, women judokas occurred relatively stronger from other female athletes than males practicing judo from
other male athletes.
4. Discussion
As it was shown by Trzaskoma and Trzaskoma [7] judokas exhibit relatively high level of muscle torques
comparing to athletes from other sports. This statement especially concerns female athletes. As it was expected,
both males and females practicing speed skating and taekwondo show relatively high strength of lower extremities
and trunk, what can be explained by specificity of these sports. Kayakers achieved high results for elbow flexion
and arm extension. This may be also attributed to specificity of their sport. Surprisingly, weight lifters occurred
relatively weak.
Acknowledgments The study was supported by grant DS-140
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