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

• Published in: Applied ergonomics Vol. 101; p. 103718
• Main Authors: Pinho, João Pedro, Forner-Cordero, Arturo
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.05.2022
• Subjects: Biomechanical Phenomena; Electromyography; Equipment design; Exoskeleton Device; Humans; Muscle, Skeletal - physiology; Musculoskeletal disorders; Range of Motion, Articular; Shoulder - physiology; Upper Extremity - physiology; Wearable assistive device; Musculoskeletal disorders; Equipment design; Wearable assistive device
• ISSN: 0003-6870; 1872-9126
• DOI: 10.1016/j.apergo.2022.103718

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≈0°, B ≈ 45°, C ≈ 90° and D ≈ 115° 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. [Display omitted] •ShoulderX reduces deltoid muscle activity up to 34%.•Deltoid muscle unloading with ShoulderX seems to increase with shoulder flexion.•ShoulderX increases the shoulder muscles co-contraction index.•ShoulderX increases the completion time of a task.