THE RELATIONSHIP BETWEEN ISOKINETIC STRENGTH IMBALANCES AND KICK SKILLS IN YOUNG ELITE CZECH SOCCER TEAM

Purpose: The aim of this study was to identify the relationship between isokinetic strength asymmetries and velocity and accuracy of the soccer kick. Methods: In the present study were monitored top-level young soccer players (n= 17, age = 17.33 +/- 0.61 years, body height = 180.12 +/- 9.87 cm, body mass = 75.15 +/- 8.75 kg). The role of the subject was to realize instep kick with maximal effort in the middle of the goal from distance 11 meters. We monitored the speed of the kick by Stalker ATS radar equipment and the kick accuracy was evaluated using 2D kinematic analysis. Strength performance was carried out by Humac Cybex Norm isokinetic dynamometer. Results: The speed of the ball by the kick by dominant limb was significantly correlated with muscle strength of flexors and extensor of knee at all angular velocities (r= 0,52 -0.73, p< 0.05). In the case of the non-dominant limb we found out significant relationship between velocity of the kick and muscle strength at low angular frequency (60 degrees/s) and in the case of the knee extensors at the rate of 180 degrees/s. The greater strength asymmetry between preferred and non-preferred legs in kicking, the greater inaccuracy was detected (knee extensors -r= 0.79, p< 0.05, knee flexors r= 0.89, p< 0.05) Conclusion: Strength imbalances may affect motor performance, the high strength asymmetry may negatively influence motor control and could be linked not only with kicking performance but also from a health prevention point of view.