Adjusting Wheelchair Set-Up to Minimize Shoulder Joint Forces During Propulsion

Individuals who use a manual wheelchair depend upon their upper limbs to provide a means of locomotion during completion of their activities of daily living. As a result of greater than normal usage of the upper limbs, shoulder pain and pathology is common among manual wheelchair users. Accordingly, proper wheelchair set-up may be paramount to preventing injuries and maintaining comfort during locomotion. The purpose of this research study is to create a subject-specific computer model of wheelchair propulsion to provide information on wheelchair set-up (in particular, axle placement). The primary objective of this study is to investigate the effect of wheelchair set-up on shoulder joint forces during wheelchair propulsion; the secondary objective is to develop a predictive model to identify differences in shoulder joint forces that result from altering the axle position and seating set-up in user's wheelchairs. The hypothesis of the study is that outputs from a patient-specific model will reveal that the current axle position for each subject results in peak shoulder joint forces that are greater than those predicted from an altered axle position (determined by the model). The overall goal is to then adjust each manual wheelchair user's axle placement to one that minimizes the magnitude of shoulder joint forces throughout propulsion. It is intended that in doing so, the repetitive strain injuries associated with manual wheelchair propulsion may be reduced, prolonging a pain-free way of life for this population.