Asymmetry of conventional and functional strength ratios in youth male taekwondo players

Abstract

Muscular imbalance increases the risk of non-contact injuries among youth athletes. This study aimed to examine the isokinetic hamstring-to-quadriceps strength (H/Q) ratios between the dominant and non-dominant legs in youth taekwondo (TKD) players. Sixty-three youth TKD players voluntarily participated in this study. The isokinetic muscle strength test was performed at three different angular velocities (60°·s−1, 120°·s−1 and 240°·s−1) with concentric (Con) and eccentric (Ecc) contraction modes. The conventional (HCon/QCon) and functional (HEcc/QCon) H/Q strength ratios were determined. Hamstring muscle strength was significantly greater in the dominant leg than in the non-dominant leg at 60°·s−1 (Con contraction) and at 120°·s−1 and 240°·s−1 (Ecc contraction). Conventional and functional H/Q strength ratios were higher in the dominant leg than in the non-dominant leg at 240°·s−1, and the strength ratios increased with angular velocity. The asymmetry of conventional and functional H/Q strength ratios between the dominant and non-dominant legs may affect the risk of non-contact injuries among youth TKD players; thus, coaches should include specialized training programs to balance the H/Q strength ratios between legs. In particular, unilateral eccentric hamstring exercises for the nondominant leg are important for preventing noncontact injuries.

Keywords

• hamstring to quadriceps strength ratio
• hamstring strain injury
• non-contact injury
• young athletes