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Introduction: Manual material handling remains prevalent across industries and is linked to high rates of musculoskeletal disorders. Passive exoskeletons have emerged as ergonomic interventions to reduce physical strain during carrying tasks. However, evidence of their effectiveness in realistic, dynamic conditions such as walking remains limited. This project evaluated the biomechanical and physiological effects of a passive upper-body exoskeleton (CarrySuit^®) across four load-carrying scenarios: flat surface walking, inclined treadmill walking, and stair ascent and descent, considering sex-specific responses. It examined muscle activity, joint kinematics, discomfort, and heart rate during these tasks.

Methods: Across four studies, sixty healthy participants (30 males, 30 females) performed carrying tasks under two conditions: with and without the CarrySuit. The tasks included walking on a flat route, walking on a 12° inclined treadmill, and navigating stairs while carrying a 12–15 kg box. EMG data were collected from the erector spinae, biceps brachii, gastrocnemius, and vastus lateralis, along with heart rate and motion capture-based kinematic analyses. Discomfort ratings were gathered pre- and post-task.

Results: The exoskeleton consistently reduced upper limb muscle activity, and heart rate across all conditions. Leg muscle activity remained constant during flat surface walking and stair descent, while upper leg activity increased during inclined walking and stair ascent for both males and females. Sex-specific effects were observed in the lower back and lower leg. Peak erector spinae activity was reduced on the flat surface and incline for both sexes, but during stair navigation, this reduction was significant only in males. Gastrocnemius activity remained constant on flat surfaces and during stair descent, decreased during inclined walking for both sexes, and was reduced during stair descent only in males. Kinematic adaptations included increased knee flexion on flat surfaces and inclines for males, and during stair navigation for both sexes. Thorax tilt increased on flat surfaces and inclines for females, and during stair navigation for both sexes. A more neutral neck posture was observed in all participants across all conditions. Discomfort ratings for the arms, back and legs were consistently lower when using the exoskeleton.

Discussion: The passive upper-body exoskeleton demonstrated beneficial effects across diverse carrying tasks, notably reducing muscular load in the arms and back, as well as cardiovascular effort and perceived discomfort. Moreover, the exoskeleton appeared to alter posture, although its impact on whole-body biomechanics and the presence of sex-specific responses warrant further investigation.

Conclusion: These findings highlight the exoskeleton’s potential to mitigate physical strain and reduce injury risk in occupations involving repetitive load carrying. However, task- and sex-specific biomechanical responses emphasize the need for tailored implementation strategies and further research into its long-term usability and effectiveness.