Towards an introduction of a lumbar-assist exoskeleton in the agriculture industry: A pilot test

Abstract

Lumbar-assist exoskeleton is gaining attention as an ergonomic intervention to reduce low back stress. Previous studies have shown the effectiveness of lumbar-assist exoskeletons in various industries, but their impact on the agriculture industry remains unclear. Our laboratory has demonstrated that exoskeleton use can reduce low back muscle fatigue during a 3-minute bush-crop harvesting task, but there is no published data on the effectiveness of exoskeleton under uneven ground surfaces (often seen in the agriculture industry). The focus of this pilot test was to explore the effect of a passive lumbar-assist exoskeleton on low back biomechanical responses under different harvesting trunk postures and sloped ground surfaces. Noting the active and passive tissue contributions to trunk extensor moments vary with the combination of those two variables, it was necessary to investigate the effectiveness of the exoskeleton on both active and passive tissue loads. Six human subjects were asked to maintain simulated static harvesting trunk postures (stooping, squatting, kneeling) on sloped ground surfaces (20° incline, -20° decline, 0° flat), with and without exoskeleton. Lumbar muscle activity and passive extensor moment were employed as dependent variables. Results showed the exoskeleton was effective in reducing the passive extensor moment—the magnitude of reduction increased in the order of kneeling, squatting, and stooping—and in reducing the lumbar muscle activity in kneeling and squatting. The exoskeleton consistently reduced the passive extensor moment regardless of the sloped ground surfaces but further studies are needed for the lumbar muscle activity due to inter-subject variability.