Traditionally, handrims on lightweight and ultralight weight wheelchairs consist of a metal hoop rigidly mounted to the wheel. During propulsion, this hand rim is contacted with each push stroke. Research suggests that the use of rigid hand rims may be a contributing factor to developing repetitive strain injuries of the hand, elbow and shoulder. The three studies included in this subsection examined the use of flexible hand rims.
Richter et al. (2006) investigated finger and wrist flexor activity when using a flexible handrim as compared to a standard handrim. A flexible hand rim consisting of high friction urethane spanning between a standard tubular handrim and the wheel has been developed. The urethane takes the shape of the hand when gripping. 24 subjects pushed their own wheelchairs on a level surface and at three and six degree grades using both types of handrims. Use of the flexible handrim significantly reduced wrist and finger flexor activity when averaged across all grade conditions. This suggests that over a period of years flexible handrims may be a factor in preserving upper extremity health.
Richter et al. (2005) explored the balance between compliance hand rims and the acceptability of this type of rim to 17 participants who propel manual wheelchairs. They note previous research indicating that compliant rims reduce the impact loading during the push phase but are found to be an unfavourable option by people who propel manual wheelchairs. This study found that participants were accepting of a moderately compliant hand rim. It also found that compliant hand rims did not differ greatly from rigid hand rims in relation to push frequency, push angle, push timing, and peak forces. Where differences were noted was in the forces that contribute to impact loading, and subsequently increase the risk of repetitive strain injuries. Impact forces, with an equal or decreased peak rate of rise at impact loading of hand on the rim and a decrease in the average rate of rise of the contact force. The authors suggest that moderately complaint rims are acceptable to most people who propel manual wheelchairs, and have been shown to reduce the impact forces associated with propulsion in comparison to standard rigid hand rims.
Dieruf et al. (2008) surveyed 87 people who purchased a specific ergonomic contoured hand rim to gain their perspective on the impact the hand rims had on propulsion. Participants reported improved comfort in propulsion, reduced upper extremity symptoms and for people over the age of 50, improved ability to maintain functional abilities for those experiencing wrist or hand pain. The survey results indicated that there was greater satisfaction with the contoured hand rims the longer they were used; only nine participants reported negative changes following use of the contoured hand rims, and only seven participants had stopped using the rims.
There is level 4 evidence (from one pre-post study; Richter et al. 2005 and one case series study; Richter et al. 2006) that a flexible or compliant hand rim can reduce impact forces and reduce wrist and finger flexor activity during wheelchair propulsion.
There is level 4 evidence (from one pre-post study; Richter et al. 2005; and one observational study; Dieruf et al. 2008) that contoured or flexible hand rims are found to be acceptable to people who propel manual wheelchairs, with perceived benefits of comfort, reduced upper extremity pain and improved propulsion.
- Use of flexible or contoured handrims may reduce upper extremity strain thereby reducing discomfort and pain symptoms during wheelchair propulsion.