Isokinetic Strength Responses to Season-long Training and Competition in Turkish Elite Soccer Players

There are not enough studies that describe the isokinetic strength of professional soccer players at high angular velocities. The purpose of this study was to evaluate the seasonal changes in isokinetic strength of Turkish professional soccer players (n=14) over the course of a 24-week soccer season. The isokinetic strength of players who underwent usual soccer training and weekly competition throughout the soccer season was assessed by means of the Biodex System 3 dynamometer with the knee attachment. The peak torque of knee extensor and flexor muscles were measured at angular velocities of 60 degrees/s, 300 degrees/s and 500 degrees/s. Players were tested at the beginning and end of the competitive season. While the first- and second-test measurements did not show significant changes at 60 degrees/s and 300 degrees/s angular velocities, at the end of the training period, players' knee strength changed significantly at 500 degrees/s angular velocities. In addition, the H/Q ratio improved significantly for the dominant as well as non-dominant leg at 500 degrees/s. Significant bilateral strength improvements for knee flexors were also observed at 500 degrees/s. The findings of this study suggest that usual daily soccer training (technical, tactical, power, strength, endurance, flexibility, etc.) and weekly competition might produce changes in knee strength at high angular velocities.