Keep on rolling: functional evaluation of power-assisted wheelchair use

Prototype of newly developed power-assisted wheelchair wheels were evaluated to determine their potential alleviating value on shoulder load, daily activities and participation compared to hand-rim wheelchair propulsion. Five research questions were answered: 1. What is the current knowledge of power-assisted wheelchair propulsion? Power-assisted propulsion reduces the strain on the upper extremity and cardiovascular system compared to hand-rim propulsion. Precision tasks are easier to perform with hand-rim wheelchairs and tasks which require more torque are easier to perform with power-assisted wheelchairs. 2. Who might benefit from power-assist wheels? People having (temporally) difficulty propelling hand-rim wheelchairs because of pain, low cardiopulmonary reserves or insufficient arm strength, or in a challenging environment / on longer distances. 3. What are the wheelchair characteristics of the prototype and what are the differences with a hand-rim wheelchair, specifically rolling resistance, propulsion efficiency and energy expenditure? Significantly higher drag forces (due to mass), increased propulsion efficiency and decreased energy expenditure were found for the prototype power-assisted wheelchair (if well set) compared to the hand-rim wheelchair. 4. Is the assumption of the effectiveness of power-assisted propulsion in reducing potential risk factors for shoulder overuse injuries correct? With the prototype wheels partly. • minimize push frequency: Push frequency did not change significantly in healthy, while in hand-rim wheelchair users the push-frequency, even increased during propulsion. • minimize the force required: The peak resultant force at the rim reduced during propulsion as well as start-up. The changes in specified directions were ambiguous and varied between both populations (healthy vs. hand-rim wheelchair users) and movements (start-up vs. velocity propulsion). • minimizing extreme or potentially injurious positions at the shoulder. Internal rotation at the shoulder decreased during the peak force at the rim. At start-up the extension angle increased. 5. Are power-assist wheels beneficial in daily situations, and what is the user's opinion about the prototype power-assist wheels? Although increased ease of propulsion was reported, objective ratings showed no significant changes in wheelchair skills and self-efficacy during power-assisted hand-rim wheelchair propulsion. High work-capacity of the arm, use of a hand-bike and independent car transfers, seemed negative influencers for satisfaction with the power-assist-wheels.