Effects of passive exoskeleton on trunk and gluteal muscle activity, spinal and hip kinematics and perceived exertion for physiotherapists in a simulated chair transfer task: a feasibility study  

Despite being a topic of increasing concern, work-related musculoskeletal disorders (WMSDs) among physiotherapists, have not been comprehensively explored. This study evaluated the effects of using a passive exoskeleton on biomechanics (i.e. muscle activity of back and hip extensors) and kinematics (trunk and hip flexion angles) during a simulated chair transfer task. A simulated patient was used for the chair transfer task. Twenty working physiotherapists performed the chair transfer task with or without using a passive exoskeleton. The biomechanics and kinematics during the tasks were measured using surface electromyography (sEMG) and motion sensors, respectively. Change in exertion level was examined using the Borg CR-10 scale, and an acceptance questionnaire was adopted from previous studies and used in investigating user acceptance of the exoskeleton. Results revealed that (1) using a passive exoskeleton in performing transfer tasks significantly decreased the sEMG activities of thoracic erector spinae, lumbar erector spinae and gluteal muscles, decreasing the maximum voluntary isometric contraction by 7.78%–10.95%; (2) no significant differences in the maximal flexion angles of thoracic and lumbar spines and trunk between performing the task with and without the exoskeleton; (3) a nonsignificant decrease in exertion level when performing the transfer task with the exoskeleton; and (4) no significant between-group differences in the score of acceptance questionnaire. These findings suggested that using the exoskeleton may help alleviate loading on the back by decreasing back extensor and hip extensor muscle activities while not considerably changing sagittal plane kinematics at the trunk and hip.