The Effect of Handrim Position on Torque Development for Wheelchair Propulsion

It was thought that the position of the handrim on a standard wheelchair may not always provide the optimal work efficiency for an individual. The purpose of this study was to examine the optimal handrim position on torque development at the start period of static wheelchair propulsion. Fifteen healthy volunteers performed wheelchair propulsion at nine different handrim positions, which were determined by sets of joint angles of the shoulder and elbow. The peak and average torque measured during static wheelchair propulsion were compared among the various handrim positions. The torque development was dependent on the forward-backward shift of the handrim position but not the change in height. The maximum torque was produced in the front and low handrim position. As a mechanism responsible for the results, the force vector applied to a handrim can be worked more efficiently as torque at the front handrim position by changing the direction of the force vector rather than its amplitude. Thus, the handrim position, which influences torque development for wheelchair propulsion at the start period, should be taken into account in the design of the wheelchair.