Effect of a Passive Shoulder Support Exoskeleton on Fatigue During Working with Arms over Shoulder Level

Work-related musculoskeletal disorders have a high prevalence across industries and are a leading cause for days away from work. Exoskeletons can assist their users during physically demanding tasks to reduce the workload and the prevalence of work-related musculoskeletal disorders. This paper explores the physiological effect of a novel passive shoulder exoskeleton on the development of fatigue during overhead work. A sample of 32 healthy participants performed a two-minute isometric task simulating tool handling above shoulder level with and without the exoskeleton. Muscular activation and fatigue in the arm, shoulder, neck and back muscles were recorded using surface electromyography. Cardiac cost was measured using optical heart rate tracking at the wrist. The exoskeleton significantly reduced muscle activity in shoulder, neck and back muscles up to 32% (p<0.01) and reduced the rate of fatiguing up to 45% (p<0.01) in the Deltoidanterior. The cardiac cost while performing the task with the exoskeleton was 16% (p<0.05) less than without the exoskeleton. Using the proposed passive shoulder support exoskeleton substantially reduced the muscular load and perceived effort as well as the cardiovascular load. This suggests users can perform overhead tool-handling tasks for longer periods of time while feeling less tired. It also might positively influence the development of injuries.