Evaluation of a prototype geared pushrim design : comparison with standard manual pushrim and analysis of wheelchair users' physiological data

Abstract EN

Five spinal cord injured (level C4 - T6) male subjects with mean age (28 ± 8 6 yr.), height (175.8 ± 7.0 cm.), and weight (71.5 ± 14.6 kg.) volunteered for this study.

Oxygen consumption per body weight and ventilation were collected during three trial conditions: 1) uphill simulation at .89 m/s (2 mph), 2) flat surface at .89 m/s, and 3) flat surface at 1.79 m/s (4 mph).

The physiological data were collected at twenty-second intervals with a metabolic cart.

The last two minutes of each trial were used for data analysis.

There was a significant difference for the ventilation (VE) (p = .

0001) and oxygen consumption (V02) (p = .08) for the flat surface simulation 1.79 m/s trial between the geared and standard pushrims.

Power was calculated with torque sensors attached to the motor/roller system and the power was found significantly different for the flat surface simulation trial at 1.79 m/s (p = .07).

This study indicates that a geared pushrim can make it easier for someone to propel over a flat surface at 1.79 m/s (4 mph).

The results show that the geared pushrim can help an individual work at a lower physiological work level but produce a similar output power using a higher gear and lower propelling frequency.