Generalizability of muscle synergies in isometric force generation versus point-to-point reaching in the human upper extremity workspace

Isometric force generation and kinematic reaching in the upper extremity has been found to be represented by a limited number of muscle synergies, even across task-specific variations. However, extent generalizability synergies between these two motor tasks within arm workspace remains unknown. In this study, we recorded electromyographic (EMG) signals from 13 different arm, shoulder, back muscles ten healthy individuals while they performed isometric center-out target matches one 12 equidistant directional targets horizontal plane at each four starting positions. Non-negative matrix factorization was applied EMG data identify synergies. Five six were represent point-to-point reaches. We also that composition conserved per task. Similar tuning directions synergy activation profiles observed locations. Between tasks, out five common The greater involved achieving match task compared may explain complexity neuromotor control movements. Overall, our results provide further insight into compartmentalization shared can utilized assess disabilities with limb impairments.