Physical work capacity after 7 wk of wheelchair training: effect of intensity in able-bodied subjects.

Abstract

The purpose of this study was to study the effects of a 7-wk wheelchair training program on physical work capacity in able-bodied subjects. Effects of training intensities of 50 and 70% heart rate (HR) reserve (HRR) were studied for different subject groups. Twenty-seven able-bodied male subjects participated in this study. They were randomly divided into a control group (N = 8), a 50%-intensity group (N = 9), and a 70%-intensity group (N = 10). The 50%- and the 70%-intensity groups received a 7-wk wheelchair training program: three times a week, one-half hour wheelchair exercise on a motor driven treadmill at an average intensity of 50 and 70% of the HRR, respectively. Before and after the training period, parameters for physical work capacity (maximal isometric strength (Fiso), sprint power (P30), maximal power output (POmax) and peak oxygen uptake (VO2peak)), and submaximal performance (mechanical efficiency, HR) at 20 and 40% of the estimated POmax (ME20, ME40; HR20, HR40) were obtained during tests on a stationary wheelchair ergometer. A two-factor ANOVA for repeated measures on the within-subjects factor "pre-post tests," the between-subject factor training (50% and 70% training vs control) and the interaction term showed that the 50%-intensity group significantly increased on P30 and POmax compared with the control group. The 70% intensity group significantly increased on P30, POmax and VO2peak compared with the control group (P < 0.05). The 70% group did not show significantly higher increases in P30 and POmax over training than the 50% intensity. No significant effects were found for the Fiso and the parameters at submaximal PO. The wheelchair training at both intensities can have favorable effects on maximal physical work capacity in able-bodied subjects, and possibly also on mechanical efficiency at submaximal power output. Effects are seen in parameters for both aerobic and anaerobic work capacities. Although training at 70% intensity was more effective than the 50% intensity, training at 50% HRR may initially be more appropriate in untrained individuals, such as novice wheelchair users at the start of their rehabilitation, to prevent fatigue and enhance motivation.