Florida-based designer and engineer Salim Nasser knows how difficult wheelchair ergonomics are. How? "Personal experience, since I am in a wheelchair myself," he writes in his project brief for this year's Create the Future design competition. His entry, which won Grand Prize, was to "make manual wheelchair propulsion more efficient while reducing stresses to shoulder and arm muscles."
Nasser's experience and research indicated that traditional wheelchair locomotion, in which the user pushes on wheels connected to the main wheels, is biomechanically inefficient, uses the weaker muscles groups in the arm, and causes a high percentage of tendonitis and carpal tunnel syndrome among the wheelchair-using populace.
His solution is the Rowheel, special wheels that convert a rowing motion into forward energy for the main wheels; this forward energy takes advantage of the arms' naturally stronger muscles, which Nasser further amplifies by using gear ratios to provide mechanical advantage. And most importantly, Rowheels were designed to be retrofitted to existing wheelchairs. Check out the details here.