Wheelchair coasting downhill is a reliable work task

Objective: To measure test-retest reliability of physiological responses during submaximal wheelchair downhill and horizontal treadmill ergometry. Design: A test-retest design was used on a convenience sample. Four male and three female non-wheelchair users, (22-43 years of age) propelled or coasted in a wheelchair under steady-state conditions. Four minute work bouts were performed at 1, 2, 3, and 4 km/hr. (0.62, 1.24, 1.86 and 2.5 mph, respectively) at 0°, -2°, and -4°. Subjects were studied twice under each of the 12 conditions. Six tests were performed daily, with testing occurring over four days. Dependent variables included oxygen consumption, minute ventilation and heart. Intraclass correlation coefficients were determined for each set of paired tests. Results: Intraclass correlation coefficients were high for absolute VO₂ (R = 0.84 - 0.99), V(E) (R = 0.86 - 0.98) and HR (R = 0.95 - 1.0) over the range of 4 speeds and 3 inclinations studied. On average, % differences from test 1 to test 2 were less than 3%. Conclusion: At the treadmill speeds and inclinations (positive and negative) studied in this investigation, untrained wheelchair users responded in a physiologically reliable manner.