Stability analysis of muscle synergies in wrist movements

Hand function has a great influence on our daily life. It is common sense that hand rehabilitation training is of vital significance to improve the living standard of patients with neural trauma. Muscle synergy, an important research method of biomechanics, can be viewed as a useful tool to reveal the control mechanism of the central nervous system over limbs. Despite many advances in the research on muscle coordination of human hand movements, it is necessary to conduct more detailed research on different joint movements because of the characteristics of hands with multiple joints and multiple degrees of freedom. A muscle synergies analysis was made herein to study three degrees of freedom and six hand movements of the wrist for muscle coordination analysis with the results indicating that the six hand movements have the same amount of muscle synergies. In terms of synergy stability, the results showed poor consistency in the muscle synergies of external rotation and radial deviation of wrist in contrast to great consistency in the extension and ulnar deviation. This study is of great significance to the motor function rehabilitation of different degree of freedoms (DoFs) of wrist for stroke survivors.