While some of it could be attributed to the differences in the design of the subjects' wheelchairs, it is postulated that factors influencing propulsion technique, such as stroke rate and stroke intensity, as well as upper-body involvement and body posture during wheeling also contributed to this variation. It is recommended that studies be undertaken to examine the effects of these variables on the wheeling economy of subejects wit? SCI, so that factors which optimIze racmg performance can be established for this population.