Quantitative evaluation of the importance of coordination on jump achievements and kinematics in human vertical squat jump

Abstract

The effect of precise adjustment of muscle coordination on jump achievements and kinematics in human vertical squat jump (SQJ) was evaluated quantitatively using a musculoskeletal model and forward dynamics approach. In order to evaluate the effect of altered muscle coordination, an optimal solution muscle stimulation time was first found through an optimization method. The optimal stimulation time of muscles was systematically altered by the interval of 0.1 ms in the range±50 ms. It was found that jump performance critically depends on precise muscle control, especially in terms of inter-muscular coordination. The sensitivity of fine tuning the control of individual muscles was found to be correlated with maximum isometric muscle strength. The minimal time interval that significantly disrupted a SQJ performance amounted to less than 1 ms. It was found that intermuscular coordination is crucial in maximizing jump performance. Mutual coordination of mm. vasti and hamstrings ; m. gastrocnemius and m. rectus femoris ; m. adductor magnus and hamstrings ; m. gluteus maximus, m. adductor magnus and m. rectus femoris was found to be of great importance for jump achievement. The role of coordination of specific muscles in SQJ and possible implications of our findings to physical training have been discussed.