The concept of "muscle synergies" has been proposed as a working hypothesis to explain how the central nervous system coordinates the numerous degrees of freedom of the musculoskeletal system. In this study, to examine this hypothesis, we extracted muscle synergies from human electromyography (EMG) patterns during grasping movements. The EMG patterns observed in movements to achieve different goal postures and execution times were represented by combinations of the same set of synergies. © 2006.