Multi-speed Ergonomic Wheelchair

Over one million Americans rely on their upper extremities for manual wheelchair propulsion. Shoulder overuse injuries are prevalent among manual wheelchair users and these injuries often result in shoulder pain. Severe shoulder pain can lead some wheelchair users to transition from manual to powered mobility, complicating transportation, and reducing independence in activities of daily living. This project will expand the understanding of a new wheelchair design that allows better positioning of the hand rims and allows for different gearing. The investigators will study steady-state propulsion efficiency with different gear ratios and develop a new system with multiple gear ratios. The advanced gearing will allow for a low gear when initiating movement, going uphill, or when moving over carpet, and then a higher gear option for movements on hard flat level terrain. This system has the potential to dramatically improve shoulder ergonomics and reduce pain in many future manual wheelchair users.