The Effect of Mobile Wearable Waist Assist Robot on Lower Back Pain during Lifting and Handling Tasks

The rapid growth in nursing demand in P.R.China and the slow increase in the number of qualified nurses has led to a serious increased in workload of existing nurses. Most of their works include heavyweight handling which causes low back pains. Thus a mobile, flexible, comfortable and wearable waist assist device, the Mobile Wearable Waist Assist Robot using pneumatic artificial muscles as power actuators has been developed. The wearer wears the device like a backpack, which can provide wearer the necessary assistance when he lifts loads or performs a static maintenance work, which will reduce the risk of lower back pain. The device is evaluated through an experiment which include three tests - heavy load handling, maximum weight lifting test, and Center of gravity (CoG) trajectory test during static weight lifting. Surface electromyography of erector spinae was recorded during the first test. The iEMG is significantly reduced by about 39% and 27%, respectively (p < 0.05). The angular velocity significantly decreases until the load reaches 35 kg (p < 0.05). When the device is in use, the CoG moving distance is significantly lower than not in use (p < 0.05). These three tests well verified the effectiveness of the Mobile Wearable Waist Assist Robot, which provides waist assists and reduces the risk of lower back pain.