Stroke pattern refers to the trajectory of the hand during propulsion. During the propulsive phase, the hand follows the path of the handrim. However, during the recovery phase the user can choose any trajectory to prepare for the next push. Four stroke patterns have been identified for users of manual wheelchairs (Shimada et al. 1998; Boninger et al. 2002):
- Semicircular (SC): the hands fall below the hand rim during recovery phase.
- Single looping over propulsion (SLOP): the hands rise above the hand rim during recovery phase.
- Double looping over propulsion (DLOP): the hands rise above the hand rim, then cross over and drop below the hand rim during the recovery phase.
- Arcing (ARC): The third metacarpophalangeal (MP) follows an arc along the path of the hand rim during the recovery phase.
There are two studies that have investigated the effect of stroke pattern on wheelchair propulsion in the spinal cord injured population.
Boninger et al. (2002) studied the stroke patterns of 38 individuals with paraplegia while propelling their own wheelchair on a dynamometer at two different steady state speeds. The SC and DLOP patterns were found to have significantly lower cadence and least time spent in each phase of propulsion. The SC and ARC patterns had the greatest amount of time spent in propulsion relative to the recovery phase. A correlation has been found between cadence and the risk of median nerve injury (Boninger et al. 1999). The authors concluded a stroke pattern that minimized cadence may reduce the risk of median nerve injury.
Richter et al. (2007a) studied the stroke patterns of 25 individuals with paraplegia propelling their own wheelchairs at self-selected speeds on a treadmill set to level and at 3 and 6 degree grades. In this study, the SC pattern was not used by any of the subjects. For level propulsion, the number of subjects using the remaining 3 patterns was fairly even. However, once the subjects started going uphill 73% were using the ARC pattern. No significant difference was found in the handrim biomechanics between the different stroke patterns. The authors caution against training wheelchair users to adopt a certain pattern until more is known about the consequences.
There is level 4 (from one case series study; Boninger et al. 2002) evidence that the “semicircular” and “arcing” wheelchair propelling patterns reduce cadence and time spent in each phase of propulsion. Thus using these patterns may reduce the risk of median nerve injury.
There is level 4 evidence (from one case series study; Ritcher et al. 2007) that there is no difference in propulsion biomechanics between the different stroke patterns. Thus there may be no advantage to using one pattern over another.
- The evidence appears to be inconclusive as to whether there is an advantage to one stroke pattern over another.