We have designed, constructed and tested a restraining apparatus to permit safe uninhibited hand propulsion of a wheelchair on a motor driven treadmill. The special design features of the tracking assembly minimize any potential hazard or apprehension associated with possible lateral or rearward displacement of a chair from the belt surface. Special linear bearings minimize any increase in rolling resistance (less than 1.23 X 10(-3) N force displacement) at speeds ranging from 4 to 282 m. min.-1. The supporting frame is adjustable for variations in treadmill belt widths and different model wheelchairs. Easy removal of the chair enables convenient conversion of the treadmill for walking/running activity.