Kinematic characterization of wheelchair propulsion.

Rehabilitation scientists and biomedical engineers have been investigating wheelchair propulsion biomechanics in order to prevent musculoskeletal injuries. Several studies have investigated wheelchair propulsion biomechanics; however, few have examined wheelchair propulsion stroke patterns. The purpose of this study was to characterize wheelchair propulsion stroke patterns by investigating joint accelerations, joint range of motions, wheelchair propulsion phases, and stroke efficiency. Seven experienced wheelchair users (5 males, 2 females) were filmed using a three-camera motion analysis system. Each subject pushed a standard wheelchair fitted with a force-sensing pushrim (SMARTWheel) at two speeds (1.3 and 2.2 m/s). The elbow angle was analyzed in the sagittal plane, while the shoulder joint was analyzed in the sagittal and frontal planes. Three distinctly different stroke patterns: semi-circular (SC), single looping-over-propulsion (SLOP), and double looping-over-propulsion (DLOP), were identified from the kinematic analysis. Through our analysis of these patterns, we hypothesized that SC was more biomechanically efficient than the other stroke patterns. Future studies using a larger number of subjects and strokes may reveal more significant distinctions in efficiency measures between stroke patterns.