The aims of the study were to investigate the differences in kinematics and kinetics between the dominant and nondominant leg during single-leg jumps without arm swing, and to determine the relationship between bilateral asymmetry in isokinetic knee strength and the single-leg jump. Isokinetic knee strength and single-leg jump kinematics and kinetics were measured in 11 male participants. The bilateral asymmetry index was calculated for each parameter. For isokinetic knee strength, there were no significant differences between the dominant and nondominant legs. Significant correlations were observed for the bilateral asymmetry index for isokinetic knee strength at 180 degrees per second and the bilateral asymmetry indexes for maximum flexion angle and the mean knee joint torque during the single-leg jumps. In conclusion, the findings of the current study suggest an association between knee strength imbalances and the joint angle, as well as the torque produced in single-leg jumps, although no relationship between knee strength and jump height was observed.
Yuji Kobayashi (Corresponding Author), Takeo Matsubayashi, and Akifumi Matsuo are with the Japan Institute of Sports Sciences, Kita-ku, Tokyo, Japan. Junjiro Kubo is with Heisei International University, Kazo, Saitama, Japan. Kando Kobayashi is with the Research Center for Total Life Health and Sport Sciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, Japan. Naokata Ishii is with the Department of Human and Engineered Environmental Studies, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa, Chiba, and with the Department of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Tokyo, Japan.