Strength and size ratios between reciprocal muscle groups in the thigh and lower leg of male collegiate soccer players

This study investigated the strength and size ratios between reciprocal muscle groups in the thigh and lower leg of soccer players. In 11 male collegiate soccer players and 21 male non-soccer players, the joint torques developed during isometric maximal voluntary contractions of the knee extensors (TQ(KE)) and flexors (TQ(KF)), plantar flexors (TQ(PF)) and dorsiflexors (TQ(DF)) were determined using a dynamometer. The muscle volumes of the same muscles (i.e. MVKE, MVKF, MVPF and MVDF) were determined by magnetic resonance imaging. There were no significant differences in any of the joint torques or muscle volumes between soccer and non-soccer players. TQ(KE)/TQ(KF) was significantly lower for soccer players than for non-soccer players. On the other hand, no significant difference in TQ(PF)/TQ(DF) was found between soccer and non-soccer players. MVKE/MVKF and MVPF/MVDF for soccer players were not significantly different from those for non-soccer players. Additionally, there were no significant correlations between MVKE/MVKF and TQ(KE)/TQ(KF) and between MVPF/MVDF and TQ(PF)/TQ(DF) of soccer players. Thus, the strength ratios appear not to be affected by the size ratios between the knee extensors and flexors and between the plantar flexors and dorsiflexors in soccer players.