Abstract
We developed a gas-spring-powered device for assisting activities of sit-to-stand and stand-to-sit for the elderly andpersons with disability. The assistive device is fitted to both normal chair and wheelchairs, and is comprised of three mainparts; a seat, two support frames and two gas-springs. The assistive device was evaluated in comparison experimentswith or without this assistive device and commercially available assistive chair. Ten young healthy subjects aged from 21 to 24 yr-old had measurements of joint torque of knee and elbow using a force plate, load-cell attached on an armrest andposition of joint marker in video. In addition electromyography of upper arm and thigh were also measured. From theresults, maximum values of joint torque decreased by 29%-78%in both activities of sit-to-stand and stand-to-sit by usingthe assistive device. In addition, maximum and integrated values of electromyography output of upper arm and thighdecreased by50%-74%in both activities of sit-to-stand and stand-to-sit. In contrast, percentage decrease of commerciallyavailable device(joint torque: -7%-40%, EMG: -24-43%)was lower than the present device. We suggest that thenewly developed device could be a useful means for assisting sit-to-stand and stand-to-sit activities.
