Passive Exoskeletons Reduce Low-Back Passive Tissue Creep

Area of Science:

• Biomechanics
• Ergonomics
• Musculoskeletal research

Background:

• Prolonged stooping causes stress-relaxation deformation (creep) in low-back passive tissues.
• Previous research focused on active tissues, neglecting passive tissue responses.
• Exoskeletons offer a potential strategy to mitigate stoop-induced tissue creep.

Purpose of the Study:

• To investigate the effect of passive exoskeletons on low-back passive tissue creep.
• To analyze changes in active and passive tissue mechanics during prolonged stooping with and without exoskeleton use.

Main Methods:

• Twelve healthy males performed 12-minute stooping trials, with and without a passive exoskeleton.
• Body kinematics and lumbar muscle activity were measured before and after stooping.
• Analysis focused on stress-relaxation deformation and load transfer mechanisms.

Main Results:

• Passive exoskeleton use prevented changes in low-back active and passive tissues.
• Without the exoskeleton, significant stress-relaxation deformation was observed.
• Delayed flexion-relaxation angle, increased lumbar muscle activity, and greater lumbar flexion occurred without the exoskeleton.

Conclusions:

• Passive exoskeletons effectively limit stress-relaxation deformation in low-back passive tissues.
• By preventing excessive elongation, exoskeletons reduce the risk of spinal instability and low back pain.
• Findings support the use of passive exoskeletons as assistive devices for occupational safety.