Calibration of a new wheelchair ergometer: the wheelchair aerobic fitness trainer

A wheelchair ergometer called the wheelchair aerobic fitness trainer (WAFT) has been developed. Commercially available magnetic eddy current breaking devices (Minoura MAGTURBO) were incorporated into the wheelchair ergometer as a cost-effective and reliable method of creating variable power output for graded exercise testing and aerobic conditioning. The standard MAGTURBO was modified in order to simulate the physical stress normally experienced during daily wheelchair propulsion. The WAFT with modified MAGTURBO offers independent manipulation of speed and resistance for each wheel. The authors describe the WAFT and a series of calibration experiments designed to identify the operation characteristics of the device and to establish regression equations for calculating power output as a function of wheel speed and MAGTURBO resistance setting. Based on these power output relations, graded wheelchair exercise test protocols were defined for the WAFT. Results from tests performed by persons with a variety of lower limb disabilities and a wide range of cardiorespiratory fitness are reported