Muscle Synergy Analysis on Upper Limb Movements of Human Arms

Upper limb movements of human arms are natural behaviors which require both the spatial and temporal coordination of multiple muscles. We now investigate how the neural strategy control upper limb movements in the human movement control. These upper limb movements include abduction, adduction, shoulder flexion and shoulder extension. According to our research, we make a hypothesis that a few muscle synergies across different subjects may have similar properties. To validate this hypothesis, we collected and analyzed EMG data in six healthy subjects. Nine muscles were required to reproduce the movement of each subjects. We used a nonnegative factorization approaches to identify muscle synergies during the tasks and to examine the functional significance of such synergies for natural behaviors. Through this finding, the neuromuscular control strategies of upper limb in these movements could be explained clearly, which may also provide significant evidence to support the hypothesis of muscle synergies and a basis for rehabilitation.