The Effect of Passive Exoskeleton on Shoulder Muscles Activity during Different Static Tasks

In this study we used the bipolar surface electromyography to investigate whether a passive exoskeleton reduces the degree of activity of shoulder muscles. Twelve young healthy volunteers participated in the study. Subjects were asked to hold four different static postures: (P1) shoulder abducted at 90°, elbow flexed at 90°, elbow pronated at 90°; (P2) shoulder flexed at 90°, elbow flexed at 90°, elbow pronated at 90°; (P3) shoulder flexed at 90°, elbow pronated at 90°; (P4) shoulder abducted at 90°, elbow pronated at 90°. Subjects maintained each posture for 20 seconds five consecutive times, with a rest time in-between of 20 seconds. Surface EMG signals were collected from anterior, medial and posterior deltoids and upper trapezius muscles.