Effect of Wheelchair Stroke Pattern on Upper Extremity Muscle Fatigue

Shoulder dysfunction is common in persons with spinal cord injury (SCI) with an incidence of up to 63%. Dysfunction is a result of muscle imbalances, specifically denervated rotator cuff muscles that are repetitively used during manual wheelchair propulsion.

To determine which arm stroke technique, pump (P) or semicircular (SC), is most energy efficient for long periods of propulsion.

A randomized study with repeated measures observations.

The study was performed at an institutional gait analysis laboratory.

18 able-bodied (AB) male participants were studied and randomized into one of 2 conditions, SC or P.

Shoulder muscle fatigue was measured by changes in Borg CR10 Rate of Perceived Exertion (Borg RPE) and upper extremity strength via a handheld dynamometer. Participants were studied and assigned into one of 2 conditions of wheelchair arm propulsion patterns, SC or P group, and propelled on a wheelchair treadmill for 10 minutes.

The primary outcomes included recordings of Borg RPE scale during continuous wheelchair propulsion and pre- and post-test dynamometer testing means for bilateral elbow and shoulder extension. Analysis of covariance, t-tests, and Kruskal-Wallis tests were used in analyzing data.

Although not significant (P = .23), the Borg RPE scores for the SC condition were consistently higher than the scores for the P condition. In addition, the dynamometer pre- and post-test readings demonstrated a larger decrease for the SC condition participants than for the P condition participants, but were not statistically significant.

These data demonstrate that the SC wheelchair propulsion pattern appears to be more fatiguing to shoulder muscles than the P propulsion pattern. However, more data would need to be collected to find a significant difference.

II.