Relationships between single-leg jumping ability and isotonic strength of the trunk and lower limb

Abstract

This study investigated the characteristics of the single-leg countermovement jump (SCMJ) and single-leg rebound jump (SRJ), and examined their relationships with isotonic strength parameters of the trunk and lower limbs in healthy young adults. Eleven female university students, all with similar levels of physical activity, voluntarily participated in the study. Participants performed a series of SCMJ and SRJ trials, during which contact time and jump height were carefully recorded using high-precision measurement devices. Isotonic strength was assessed using a dynamometer to measure the peak concentric torque of the trunk extensors, hip extensors, hip abductors, knee extensors, and ankle plantar flexors. Correlations between the jump performance indices and the isotonic strength parameters were analyzed to identify key muscular contributors to single-leg jump performance. Analysis of peak concentric torque values revealed that hip abduction torque was lower than hip extension and knee extension torque but higher than ankle plantar flexion torque. The SCMJ jump height exhibited moderate to strong positive correlations with trunk extension torque, hip abduction torque, hip extension torque, ankle plantar flexion torque, and the total lower limb extension torque. In contrast, no significant correlations were found between SRJ jump height and the absolute peak torque values of any individual muscle group. However, a moderate positive correlation was observed between SRJ jump height and the proportion of hip extension torque relative to the total lower limb extension torque. These findings suggest that trunk and hip extensor strength play crucial roles in enhancing single-leg jumping performance, particularly in the SCMJ and SRJ.