Strength training effects on physical conditioning and instep kick kinematics in young amateur soccer players during preseason.

The purpose of this study was to examine effects of lower limb strength training on physical conditioning and kinematic characteristics of instep kicking in 16 young amateur soccer players who participated in initial and final laboratory tests. In addition to their standard preseason soccer program, 8 players comprised the experimental group, who performed an 8-wk. strength-training program. Maximal and relative isometric force of the lower limbs were significantly improved. Moreover, toe and ankle linear velocity during ball contact, ball velocity, as well as ankle, knee and hip angular velocities of the kicking leg were significantly increased. It is concluded that conditioning and kinematic indices of the kicking performance could be improved after strength training of the lower limbs.