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

Summary: 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. MV_KE, MV_KF, MV_PF and MV_DF) 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. MV_KE/MV_KF and MV_PF/MV_DF for soccer players were not significantly different from those for non-soccer players. Additionally, there were no significant correlations between MV_KE/MV_KF and TQ_KE/TQ_KF and between MV_PF/MV_DF 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.