ABSTRACT
PURPOSE: To test the hypothesis that movement of the head and trunk increases as a consequence of speed during manual wheelchair propulsion over the ground in individuals with tetraplegia. METHODS: Seven adult participants with tetraplegia who used manual wheelchairs (5 men and 2 women, aged 33.0 ± 10.2) were selected for the study. Participants propelled over the ground at three different speeds while video motion capture methods collected kinematic data. Variables investigated were forward flexion, lateral flexion and axial rotation for both the head and trunk. Repeated measures ANOVA were used to determine effects of speed on head and trunk movements. RESULTS: Both neck and trunk forward flexion significantly increased as a result of speed (p = 0.034, p = 0.031), with a large effect size (r = 0.6, r = 0.6) between slow and fast speeds. Lateral flexion and axial rotation were minimal for the neck and trunk and did not significantly increase with speed. CONCLUSIONS: Results suggest that manual wheelchair users with tetraplegia compensate for trunk muscle weakness by flexing the upper trunk and neck forward during manual wheelchair propulsion and that these movements increase with speed. Further studies should examine if these movements relate to overuse injuries and interventions that focus on improving manual wheelchair biomechanics of individuals with tetraplegia. IMPLICATIONS FOR REHABILITATION: Individuals who use manual wheelchairs utilize their upper extremities almost exclusively for both everyday mobility and participation in daily life activities which can often lead to overuse injuries and pain. Despite having a lack of trunk muscle innervation, manual wheelchair users with tetraplegia are able to compensate for this weakness by using the upper trunk and neck. The way in which force is translated from the trunk through the upper extremities to the pushrim may impact propulsion biomechanics, and ultimately the extent in which upper extremity pain and injury develops. A better understanding of how individuals with trunk impairments propel a manual wheelchair will help clinicians determine optimal wheelchair positioning and training during rehabilitation for individuals with tetraplegia. Clinicians can determine ways in which they can support manual wheelchair users to allow for most efficient biomechanics.
