Biomechanical validation of upper extremity exercise in wheelchair users: design considerations and improvements in a prototype device

Purpose: To develop guidelines for proper exercise execution on a novel device and to recommend design changes to the device based on biomechanical data and user feedback. Method: Seven manual wheelchair users were instructed on proper exercise technique with a novel device, which allows a person to complete a seated row. Kinematics and kinetics of the dominant upper limb and trunk were measured with motion capture and electromyography data were collected on select muscles. Results: All subjects were able to exercise on the device with a mean power of 21.3 W (SD 7.1 W). Subjects did not keep the elbows close to the trunk during the drive phase of the row; rather, they moved from mean 75° (SD 12°) shoulder flexion to mean 62° (SD 11°) shoulder abduction. Identified problems included difficulty gripping the hand grips and user stability within the wheelchair. Conclusions: The accessory unit should be adjustable to accommodate a wide range of user sizes and abilities. Proper exercise execution is important to maximize the potential benefit and minimize risk of injury. When executed properly, this exercise may benefit wheelchair users by improving cardiovascular fitness and strengthening muscle groups linked to the reduction of shoulder pain.