Physiological response to the ambulatory performance of hand-rim and arm-crank propulsion systems

Two types of propulsion systems-the hand rim (HR) and the arm crank (AC)-are commonly used in wheelchair ambulation. The purpose of this study was to investigate the physiological response of the two propulsion systems under actual locomotive condition by the actual users. The energetics of locomotion manual wheelchair (HR propulsion) and arm-propelled three-wheeled chairs (AC-propelled) at their free chosen speed (FCS) were studied and compared. Thirty-four male subjects with dysfunctioning lower limbs; 17 manual wheelchair users and 17 arm-propelled three-wheeled chairs regular users volunteered to participate in the study. Speed (m.min-1), oxygen uptake (1 x min(-1)) and heart rate (b x min(-1)) were monitored during steady-state ambulation at FCS for 5 min. Oxygen consumption (VO2, ml x kg(-1) min(-1)), oxygen cost (VO2, ml x kg(-1) m(-1)), net locomotive energy cost (kcal kg(-1) km(-1)) and physiological cost index (b x m(-1)) were derived. The FCS of the AC propelled device is remarkably higher than the HR system, and the magnitude of the physiological variables of the AC propulsion system was significantly lower (p<0.001) in relation to the HR propulsion system, as revealed from the results of t test for two sample means at a significance level p=0.001. It can be inferred from the result that the AC propulsion system could be used for long distance rides with a higher speed required for outdoor ambulation and that the HR propulsion system is suitable only for indoor use, because of its excellent maneuverability where short-duration low-velocity ambulation is required.