The aim of the thesis was to discover which factors effect speed and accuracy of a ball flight in a soccer kick with front inside part of the foot. The research group included 16 soccer players. Our testing battery included anthropometric measurements (length of leg, femur and tibia), measurements of body composition (percentage of fat mass and muscle mass), knee extensors and knee flexors isokinetic strength measurements (maximal isokinetic torque and the size of growth of isokinetic torque), a single leg balance test, measurements of speed and accuracy of the ball flight and description of technical performance during soccer kicks. We wanted to discover the connection between investigated variables and speed and accuracy of the ball flight and after that find out what percentage of ball speed and accuracy can be explained with these variables.
With the use of Pearson's correlation coefficient we found middle connections between dependent variable speed of the ball flight in soccer kick with an aim of reaching the highest speed of ball flight and body mass ((r = 0,677), size of growth of isokinetic torque for knee extensors of kicking leg at the speed of extension 60 °/s (r = 0,630), size of growth of isokinetic torque for knee flexors of kicking leg at the speed of flexion 60°/s (r = 0,639) and size of growth of isokinetic torque for knee flexors of kicking leg at the speed of flexion 180 °/s (r = 0,693) (all at p < 0,001). We also found the middle connection between dependent variable highest speed of ball flight in soccer kick with aim of reaching maximal accuracy of ball fligth and size of growth of isokinetic torque for knee extensors of kicking leg at the speed of extension 60 °/s (r = 0,629) (p < 0,001).
Multiple regression analysis of dependent variable speed of ball flight in the soccer kick with the aim of reaching maximal speed of ball flight showed that the best predictor of ball flight speed is size of growth of isokinetic torque for knee flexors of kicking leg at the speed of flexion 180 °/s, which explains 48 % of variance. Results of maximal isokinetic torque of knee flexors at the speed of flexion 180 °/s additionally explains 18,3 % of variance. We also made multiple regression analysis of dependent variable speed of ball flight in the soccer kick with the aim of reaching maximal accuracy of ball flight and found out that the best predictor is size of growth of isokinetic torque for knee extensors of kicking leg at the speed of extension 60 °/s, which explains 39,6% of variance.
To improve the speed of the ball after soccer kick with front inside part of the foot it is necessary to incorporate the maximal and explosive strength training of knee flexors into our training programme.
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