The aim of this study is to identify the relationship between isokinetic knee extension, flexion strength parameters with soccer kick ball speed during six different kicking techniques in amateur and professional soccer players. 10 (age: 23.10±2.64) professionals and 17 (age:23.38±2.96) amateurs, volunteered to participate the current study. Professionals produced a significantly higher (p<0.05) ball speed than amateurs in 5 kicks types (inside, lofted, instep, outside, outside curve). As a consequence the flexor/extensor (H/Q) ratio was significantly higher in professionals than amateurs. However, there were no significant differences between professionals and amateurs although amateurs tended to have a lower knee flexion peak torque over all speeds. For the professionals, none of the muscle torque data correlated significantly with ball speeds while significant correlations were found between different isokinetic angular velocities with different ball speeds in amateurs. In conclusion, ball velocites differ according to kick types and the resultant ball velocities occurs regarding knee extensor and especially flexor strength in amateurs; however; the developed muscular coordination is more important determinant factor for professionals. Therefore, additional strength training is recommended against a resistance while the ankle, knee and hip movement represent the kicking techniques in order to train spesific kicking motion strength generation.
soccer, isokinetic strength, ball velocity