Abstract
Kicking speed in soccer has increased in recent times, the evidence of which is a development tendency of the ball's speed in penalty kicks. Kicking speed and accuracy of both legs are determinants of its success in modern soccer. With increasing distance of the shooting point from the goal, demands on its speed increase as well.
PURPOSE: The purpose of the study was to find out the speed of the ball after instep kicking and differences in terms of age and limb dominance.
METHODS: Elite players of 4 age categories (U16=19, U17=18, U18=17 and U19=17) participated in a test of maximal shooting speed in instep kicking on natural grass. The ball's velocity was recorded using a STALKER ATS radar gun. The players conducted 3 trials with maximum effort with the dominant leg (DL) and 3 trials with the non-dominant leg (NL) at a distance of 11 m from the measuring device. ANOVA with two independent variables (age (A), laterality (L)) was used for investigating the effect on shooting speed (SS).
Bonferonni's post hoc tests were used for multiple comparisons of group means. Eta square (η2) coefficient was used for evaluation of effect size.
RESULTS: Analysis of variance of the dependent variable (SS) showed a significant effect of age F3,142 = 16.42; p<.01, η2=.27. The factor of limb dominance also had a significant effect on kicking speed F1,142 = 178.81; p0.05; η2= .01). Difference of means of kicking speed between the dominant and non-dominant leg revealed a significant difference in all age categories (p<.01). The percentage difference between DL vs. NL was as follows: U16=12.2+-6.5%, U17=12.9+-4.9%, U18=13.4+-4.6 % and U19=11.6+-5.7%. Post-hoc tests showed the following differences in shooting speed in the tested age categories: U16<U17, U18, U19; U17=U18, U17<U19, U18=U19.
CONCLUSIONS: Age and limb dominance have a significant effect on kicking speed in elite young players. The factor of limb dominance explained the variance of the dependent variable for more than 50%. Despite increasing shooting speed from the perspective of age categories, percentage differences between the limbs are similar.
Supported by MSM0021620864, PRVOUK P38, GACR P407/11/P784