Effects of wheelchair design on metabolic and heart rate responses during propulsion by persons with paraplegia.

The purpose of this study was to investigate the metabolic and heart rate (HR) responses of individuals with paraplegia to propulsion in wheelchairs of different design. Eight male and one female wheelchair-bound adults with paraplegia were studied. Each subject propelled a conventional wheelchair and a sports wheelchair on a level wooden surface at four velocities ranging from 1 to 3 m/sec. Steady-rate oxygen consumption (VO2) and immediate postexercise HR measurements were obtained. A linear regression analysis of VO2 (L/min) as a function of velocity (m/sec) revealed a slope and correlation coefficient of 0.614 and .93, respectively, for the conventional chair, and 0.510 and .96, respectively, for the sports chair. The intercepts of these relationships did not differ between wheelchair designs. The data analysis revealed no difference between chair designs in the relationship between velocity and work rate. Thus, the energy cost of propelling the sports chair at a specific velocity was 17% less than that of the conventional chair. The greater efficiency of the sports chair is attributed to differences in wheelchair design, rather than to the total mass of the device.