Effect of chronic use of different propulsion systems in wheelchair design on the aerobic capacity of Indian users.

BACKGROUND & OBJECTIVE The use of wheelchairs (WC) of ergonomically different propulsion mechanisms may influence the cardiorespiratory capacity of the WC user. The purpose of the present investigation was to observe the impact of chronic use of four ergonomically different propulsion systems and age of the WC users on their aerobic capacity. METHODS The male subjects (n=77), exclusively using hand rim (n=20), arm crank using both arms (n=22), arm crank using one arm (n=17), and arm lever using one arm (n=18) propelled WCs and 20 able-bodied (AB) subjects as the control group participated They performed maximal exercise test in continuous, step-wise incremental workload at a crank rate of 50 rpm on an arm-crank ergometer. The VO(2) and heart rate obtained during 2.45 to 3 min of each test exercise, and VO(2max) and HR(max) were derived respectively. Two-way ANOVA and multiple comparison tests were performed to compare the groups with respect to VO(2max) and HR(max). Age was used as a classificatory variable. RESULTS The maximal physiological response of the AB subjects was superior to the WC users but the WC user groups did not show any significant differences amongst them. The aerobic capacity decreased with advancement of age and for WC users this is more pronounced. Equations for age predicted VO(2max) and HR(max) were also derived. INTERPRETATION & CONCLUSION As the WC users used the four distinct propulsion systems, it was anticipated that it would induce variation in the physiological variables of the users. But the results of the study revealed that there was no significant difference. Suggesting that the WC users might have developed certain self-regulatory mechanisms in order to overcome the variation induced by the different propulsion systems.