The hybrid assisted limb (HAL) for Care Support, a motion assisting robot providing exoskeletal lumbar support, can potentially reduce lumbar load in repetitive snow-shoveling movements.

An excessive lumbar load with snow-shoveling is a serious problem in snowfall areas. Various exoskeletal robots have been developed to reduce lumbar load in lifting work. However, few studies have reported the attempt of snow-shoveling work using exoskeletal robots. The purpose of the present study was to test the hypothesis that the HAL for Care Support robot would reduce lumbar load in repetitive snow-shoveling movements. Nine healthy male volunteers performed repetitive snow-shoveling movements outdoors in a snowfall area for as long as possible until they were fatigued. The snow-shoveling trial was performed under two conditions: with and without HAL for Care Support. Outcome measures were defined as the lumbar load assessed by the VAS of lumbar fatigue after the snow-shoveling trial and the snow-shoveling performance, including the number of scoops, and snow shoveling time and distance. The mean of VAS of lumbar fatigue, the number of scoops, and snow-shoveling time and distance without HAL for Care Support were 75.4 mm, 50.3, 145 s, and 9.6 m, while with HAL for Care Support were 39.8 mm, 144, 366 s, and 35.4 m. The reduction of lumbar fatigue and improvement of snow-shoveling performance using HAL for Care Support were statistically significant. There was no adverse event during snow-shoveling with HAL for Care Support. In conclusion, the HAL for Care Support can reduce lumbar load in repetitive snow-shoveling movements.