Biomechanics of upper extremities during manual wheelchair maneuvers

Abstract

High prevalence of joint pains have been associated with the wheelchair users in their upper extremities. Over the past several decades, studies have been done to investigate the biomehchanics of wheelchair propulsion and its relationship with pain at the joints and other secondary injuries. In most of the earlier studies, experiments were conducted on wheelchair ergometers or treadmills to simulate the wheelchair propulsion along level or inclined straight-road. However, to the author's knowledge, no study has been done to investigate the joint kinetics and kinematics during the initiation of wheelchair movement and wheelchair turning. In this study, joint kinetics and kinematics, timing parameters, wheelchair speeds and the movement trajectory of the upper extremities on the rims during straight-line propulsion, initiation of wheelchair movement and ninety degrees turning were systematically documented and analyzed. Differences and similarities among different wheelchair maneuvers and among subject groups were studied. Six normal and six spinal cord injured (SCI) subjects attended the study. Results indicated that the arm dominance could significantly affect the joint loading during wheelchair maneuver. Joint loadings were highest during turning when compared with straight-line propulsion while the joint loadings during the initiation of wheelchair movement was lower than those associated with straight-line propulsion. Differences were found between SCI and unimpaired subjects. The joint loadings in unimpaired subjects were higher than those of SCI subjects. Higher joint loadings were not related to larger joint movements during maneuvers as the joint movements were actually smaller during turning among unimpaired subjects.