Dynamics analysis of upper-extremity motions of stroke survivors during reaching tasks at different levels

Reaching is one of crucial tasks in order to assist activities of daily living and to support therapeutic rehabilitation. We investigated the dynamics of upper-extremity motions for the reaching tasks at different levels by stroke and able-bodied participants. The two different levels were at the head and chest. The results indicated that the joint moments with respect to levels differed slightly for the stroke and able-bodied participants. The stroke participants showed an increase in the shoulder flexion-extension moment compared to the able-bodied participants for reaching tasks at the upper level. Stroke participants showed an increase in the elbow flexion-extension moment compared to able-bodied participants for reaching tasks at the lower level. The dynamics results of the motions at different levels may provide a fundamental understanding of the design for assistive robots to help stroke survivors with activities of daily living tasks including vertical motions. To be able to support stroke participants by using assistive robots for ADL tasks, the shoulder flexion-extension motion should be strongly supported for vertical movements of an upper extremity. For therapeutic application, the abnormally large joint moments of stroke participants can be restricted.