Abstract
[Purpose] The aim of this study was to investigate the effect differences in left and right lower limb function had on ground reaction force in heavy load lifting from the half knee squat position. [Subjects] The subjects were 30 students, mean age 20.5 ± 3.6 years. [Method] We defined the dominant leg as the leg used to kick a ball. We measured the isometric knee extensor strength of both the dominant and non-dominant sides, and the ground reaction force in lifting a heavy load from the floor from a half knee squat position with both the dominant and non-dominant side knee forward at the start position. [Results] We found no significant difference between knee extensor strength of the dominant and non-dominant sides. Likewise, between the two leading knee positions, there were no significant differences between the ground reaction force components (Fx, Fy, Fz) in the heavy lifting task. No significant correlation was found between left and right muscle strength and Fx or Fy. A significant correlation was found between Fz and extensor strength, and the correlation was stronger when the dominant knee was forward. [Conclusion] From the results, when the dominant leg performs an action, we infer that it possibly reflects the true muscle strength; in a sense it's an adept leg. In contrast, the non-dominant leg in action cannot reflect only the true muscle strength, as other factors such as intricacy and cooperation are needed in order to arrive at the movement, and it can be considered a less adept leg.
