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.