Effects of wheel and hand-rim size on submaximal propulsion in wheelchair athletes.

PURPOSE

This study aimed to investigate the effects of fixed gear ratio wheel sizes on the physiological and biomechanical responses to submaximal wheelchair propulsion.

METHODS

Highly trained wheelchair basketball players (N = 13) propelled an adjustable sports wheelchair in three different wheel sizes (24, 25, and 26 inches) on a motor-driven treadmill. Each wheel was equipped with force-sensing hand-rims (SMARTWheel), which collected kinetic and temporal data. Oxygen uptake (V˙O2) and HR responses were measured with high-speed video footage collected to determine three-dimensional upper body joint kinematics.

RESULTS

Mean power output and work per cycle decreased progressively with increasing wheel size (P < 0.0005). Increasing wheel size also reduced the physiological demand with reductions in VO2 for 25-inch (0.90 ± 0.20 L · min(-1), P = 0.01) and 26-inch wheels (0.87 ± 0.16 L · min(-1), P = 0.001) compared with 24-inch wheels (0.98 ± 0.20 L · min(-1)). In addition, reductions in HR were observed for 26-inch wheels (99 ± 6 beats · min(-1)) compared with 25-inch (103 ± 8 beats · min(-1), P = 0.018) and 24-inch wheels (105 ± 9 beats · min(-1), P = 0.004). Mean resultant forces also decreased progressively with increasing wheel size (P < 0.0005). However, no changes in temporal or upper body joint kinematics existed between wheel sizes.

CONCLUSIONS

A greater power requirement owing to a greater rolling resistance in 24-inch wheels increased the physiological demand and magnitude of force application during submaximal wheelchair propulsion.