Passive shoulder exoskeleton support partially mitigates fatigue-induced effects in overhead work

Area of Science:

• Ergonomics and Human Factors
• Occupational Health
• Biomechanics

Background:

• Occupational passive shoulder exoskeletons (PSEs) show promise for reducing strain during overhead work.
• Limited understanding of PSEs' effect on precision performance under fatigue hinders industrial adoption.

Purpose of the Study:

• To evaluate how PSE support influences task performance degradation due to physical fatigue.
• To assess the impact of PSEs on precision during physically demanding overhead tasks.

Main Methods:

• A randomized, counterbalanced cross-over design compared PSE support versus no support in fatigued and control conditions.
• Precision performance was measured by execution speed and drilling errors.
• Muscle activity and shoulder kinematics were monitored.

Main Results:

• Physical fatigue negatively impacted task performance, shoulder kinematics, muscle activity, and subjective experience.
• PSE support partially mitigated fatigue-induced changes in shoulder kinematics and muscle co-activation.
• Reduced activity in the anterior and medial deltoid muscles was observed with PSE use.

Conclusions:

• Fatigue leads to compensatory movements and increased muscle co-contraction, potentially increasing musculoskeletal load.
• PSEs reduced specific muscle activity but had limited direct impact on overall precision performance.
• Wearing PSEs while fatigued may offer additional benefits beyond standard overhead work support.