The goal of this study was to identify and compare body composition (BC) variables in elite female athletes (age ± years): volleyball (27.4 ± 4.1), softball (23.6 ± 4.9), basketball (25.9 ± 4.2), soccer (23.2 ± 4.2) and handball (24.0 ± 3.5) players. Fat-free mass (FFM), fat mass, percentage of fat mass (FMP), body cell mass (BCM), extracellular mass (ECM), their ratio, the percentage of BCM in FFM, the phase angle (α), and total body water, with a distinction between extracellular (ECW) and intracellular water, were measured using bioimpedance analysis. MANOVA showed significant differences in BC variables for athletes in different sports (F60.256 = 2.93, p < 0.01, η2 = 0.407). The results did not indicate any significant differences in FMP or α among the tested groups (p > 0.05). Significant changes in other BC variables were found in analyses when sport was used as an independent variable. Soccer players exhibited the most distinct BC, differing from players of other sports in 8 out of 10 variables. In contrast, the athletes with the most similar BC were volleyball and basketball players, who did not differ in any of the compared variables. Discriminant analysis revealed two significant functions (p < 0.01). The first discriminant function primarily represented differences based on the FFM proportion (volleyball, basketball vs. softball, soccer). The second discriminant function represented differences based on the ECW proportion (softball vs. soccer). Although all of the members of the studied groups competed at elite professional levels, significant differences in the selected BC variables were found. The results of the present study may serve as normative values for comparison or target values for training purposes.

The aim of this study was to investigate whether climbing in children leads to the development of upper limb strength and endurance, and changes in body composition. Fifty young climbers aged 10-17 participated in an 8 week climbing program. Metres climbed were used as a factor to assess the effect of climbing. Two groups were ex post formed with a limit of 320 metres climbed. Boys and girls from the group that climbed more metres significantly increased their performance in bent-arm hang time (boys from 35.1 ± 3.9 s to 48.4 ± 4.4 s; girls from 18.9 ± 3.9 s to 24.4 ± 4.9 s) and grip strength related to body mass (boys from 0.65 ± 0.03 to 0.71 ± 0.03; girls from 0.52 ± 0.03 to 0.57 ± 0.03). Significant changes in the ECM/BCM ratio (extra cellular/body cellular mass) were found in the group that climbed more metres (boys from 0.88 ± 0.10 to 0.85 ± 0.09; girls from 1.00 ± 0.09 to 0.94 ± 0.09). There were no changes found in body fat in either group. The findings suggest that a climbing program with higher volume of metres climbed can influence grip strength, upper body muscular endurance and the amount of relative body cellular mass.

Background Monitoring of physical fitness characteristics in very young players could be helpful for the selection of talented youth or identification of the strengths and weaknesses in motor predispositions for physical performance. Muscular strength tested on an isokinetic dynamometer belongs to the most widely used methods of the identification of knee extensors (KE) and flexors (KF) strength in adult soccer players It appears that there is the lack of information concerning monitoring of isokinetic strength of lower limbs and its parameters in very young soccer players. The purpose of the study was to find out the level of isokinetic strength (IS) of KE and KF and to compare the selected characteristics of IS related to the movement velocity and limb dominancy in very young players. Methods Young players (n=16, age 8.8±0.4 years, body height=137.5±6.2 cm, body weight=30.7±4.1 kg) were tested on an isokinetic dynamometer Cybex Humac Norm. Maximum peak muscle torque (PT) of KE and KF, their mutual ratio (H:Q) and bilateral ratio between Q:Q or H:H were assessed during concentric contraction at different velocities (60,180,300°.s-1) in the dominant leg (DL) and nondominant leg (NL). Mixed-design ANOVA was used for evaluation of PT differences between the factors (angular velocity, limb dominancy, muscle groups-KE, KF). For multiple comparisons we used Bonferonni's post-hoc test. Statistical significance was set at p≤0.05. Effect size was assessed using the ηp2 coefficient. ResultsThe results of PT during 60,180 and 300°.s-1 were (KE [DL]: 60.9±11.6, 39.2±7.3, 30.9±5.4 N•m, [NL]: 60.8 ±12.2, 41.1±7.8, 33.6±6.3 N•m and for KF [DL]: 34.5 ±6.2, 24.5±4.1, 19.7±4.3 N•m, [NL]: 33.2±5.7, 24.6±5.8, 20.0±4.8 N•m). Movement velocity had a significant effect on the level of PT ( peak torque) in the players F(1.3, 77.9) =414.9, p<0.01, ηp2=0.874 and HQ ratio (F(1.7, 49.8) =7.6, p<0.01, ηp2=0.202. With increasing velocity, significant differences were revealed in PT (L vs M, L vs H, M vs. H p<0.01) and HQ ratio (L vs M, L vs H p <0.05).

The aim of this study was to determine the effect of muscular strength, strength asymmetries, and fatigue on the speed and accuracy of an instep kick in soccer players. We measured ball velocity (BV) and kicking accuracy (KA) in the preferred (PL) and non-preferred leg (NPL) before (PRE) and after (POST) physical load in the PL. Maximum peak muscle torque of the knee extensors and flexors in the PL and NPL as well as ipsilateral knee flexors and knee extensors ratio (H:Q ratio) for both legs were assessed. BV was significantly decreased in POST physical load (5.82%, BV=30.79±1.70 m·s, BV=29.00±1.70 m·s, t=3.67, p=0.00, d=1.05). Instep kick accuracy after the physical load worsened by an average of 10% in the most accurate trials. Results revealed a significant decrease in instep kick accuracy after physical loading (KA=2.74±0.70 m, KA=3.85±1.24 m, t=-3.31, p=0.00, d=1.10). We found an insignificant correlation between H:Q ratio and KA in PRE test value, whereas a lower ipsilateral ratio (higher degree of strength asymmetry) in the POST physical load significantly correlated with KA in all angular velocities (r=-0.63 up to -0.67, p=0.00).

The aim of the study was to identify the level of isokinetic strength and power of lower limbs in 13-year-old untrained boys (n=22, height: 158.5±8.0 cm, mass: 49.1±12.6 kg), to determine bilateral deficit between the limbs in the tests and examine their mutual relationship. Maximum peak muscle torque of knee extensors (PTQ) and flexors (PTH) on dominant (DL) and non-dominant leg (NL) were measured by isokinetic dynamometer. Three types of a vertical jump: countermovement jump with (CMJFA) and without arms (CMJ) and squat jump (SJ) were performed on two force platforms.We found the significant effect (p<.01) of independent variables (knee extensors, flexors, AV) and their interaction on PT. AV did not indicate any significant effect on bilateral ratio of knee extensors (F4,84=.74, p>.05, ηp2=0.03), however a significant effect of AV was found in knee flexors (F4,84=2.70, p<.05, ηp2=.114). The type of jump had no effect on the difference between force exerted by DL and NL (F1,21=.102, p>.05, ηp2=.01). Bilateral deficit (Q:Q, H:H) did not significantly correlate with bilateral deficit in jumps (p>.05).Despite the possibility of identifying muscle asymmetries in the sense of strength imbalances, their mutual relationship with results in isokinetic dynamometry and power jump tests is still unclear.