Optimal seat and footrest positions of manual standing wheelchair

A standing wheelchair is highly recommended to an individual suffering from secondary complications due to long-term sitting in a standard wheelchair. However, the newly-designed standing wheelchair has hand rims separate from the wheels, likely affecting the biomechanical characteristics and the efficiency of propulsion. The objectives of this dissertation were aimed to propose a method to determine the optimal riding position by evaluating energy expenditure during manual standing wheelchair propulsion. Ten elderly male subjects were asked to propel the hand rims with nine different seat (while sitting) and footrest (while standing) positions. During the experiments, kinematic and kinetic data were simultaneously obtained using a 3D motion capture system and a brake-type wheelchair dynamometer, respectively. Upper-limb joint torques and total propulsion energy were determined using a planar link-segment model with the optimization technique based on minimal joint torque criteria. Shorter subjects had the lowest total propulsion energy expenditure in the downward-forward and middle-forward positions, while closest to the hand rims. However, taller subjects had the lowest total propulsion energy expenditure in the downward-center and middle-center positions, while a little further from the hand rims. We believe that these methods and results will be helpful in assessing the adequacy of the riding position of various types of wheelchair.