Lower extremity preference and knee extensor torques in intercollegiate soccer players.

The purpose of this study was to determine whether lower extremity preference influenced the relationship between the dominant and nondominant knee extensors of intercollegiate soccer players. Twelve recreational athletes and 12 soccer players completed isometric contractions at 60 degrees flexion, and concentric-eccentric contraction cycles at angular velocities of 60 degrees and 180 degrees/s through a range of motion from 90 degrees to 10 degrees knee flexion. Although the soccer players demonstrated greater peak and average torques, and greater differences between their dominant and nondominant legs, they responded similarly to recreational athletes during isometric, concentric and eccentric contractions and produced similar torque-velocity patterns. The concentric/eccentric ratios were similar for both legs and both groups, and decreased as angular velocity increased. The nondominant/dominant ratios of the soccer players, however, were significantly lower than those of the recreational athletes when calculated using peak torque (p less than .02) and nearly so when calculated using average torque (p less than .08). Nondominant/dominant ratios were not affected by the type of contraction or by the angular velocity. Further study is required to determine whether the small asymmetry (about 7%) in knee extensor strength of the soccer players is significant with respect to performance or injury rates, or may be inconsequential.