Shoulder muscle activity and perceived comfort of industry workers using a commercial upper limb exoskeleton for simulated tasks

We compared the effects of using a commercial exoskeleton on shoulder muscle activity, task completion time, perceived effort and comfort while performing four tasks in different shoulder positions. Fourteen automotive industry workers performed four simulated tasks with shoulder at A approximate to 0 degrees, B approximate to 45 degrees, C approximate to 90 degrees and D approximate to 115 degrees. flexion. The electromyographic activity of the Medial Deltoid (MD) and the Anterior Deltoid (AD) decreased when wearing the exoskeleton. The effect sizes (ES) were, for MD: ES = 0, ES = -0.2, ES = -0.6, ES = -0.3; and for AD: ES = 0.3, ES = -0.6, ES = -0.8, ES = -0.6; for tasks A, B, C and D, respectively. We also found increased Anterior Deltoid/Triceps Brachii co-contraction, a typical joint stabilization mechanism. Wearing the exoskeleton increased the completion time of task B and reduced the perceived effort of tasks A and C, improving overall comfort. These findings are useful to organize the logistics of the workstations that use upper limb exoskeletons to improve the effectiveness of this equipment.

Automated summary

Using a commercial exoskeleton for different shoulder positions can reduce electromyographic activity in the Medial Deltoid and Anterior Deltoid muscles, while increasing co-contraction in the Anterior Deltoid/Triceps Brachii. Wearing the exoskeleton can prolong task completion time for task B and reduce perceived effort for tasks A and C, improving overall comfort.