Efficiency and perceived exertion of novel wheelchair wheels: A comparative study.

New geared wheelchair wheels have been developed allowing the user to pull backwards on the rims to move forward. Theoretically, this utilizes larger muscle groups compared to conventional propulsion preventing repetitive stress injuries. This study compared the gross mechanical efficiency (GME), perceived effort and energy expenditure of propelling the wheelchair using two types of these geared wheels and standard forward propulsion wheels. A within participants repeated measures design was used. Participants' energy expenditure and perceived exertion were measured. GME was calculated based on power output and energy expenditure values. Ten able-bodied participants were enrolled in the study. Standard wheels required the least energy expenditure and were perceived as the lightest to propel for nine of the participants; while the low-geared wheels were perceived as the hardest to propel. Results favored the standard wheels under these conditions. Research is needed to explore the effect of training and different slope angles.