Exploring the biomechanical link between wheelchair propulsion, shoulder injury and shoulder pain: A scoping review

A high prevalence of shoulder pain and injuries exists in manual wheelchair users (MWUs). Wheelchair propulsion is believed to be related to shoulder pain and injuries, but the exact cause-effect relation remains unclear. The research questions of this narrative review were: 1) What are the differences in propulsion biomechanics for MWUs with different levels of shoulder pain and injuries? 2) How much proof is there for a cause-effect relationship between wheelchair propulsion and the development of shoulder pain and injuries in MWUs? A systematic literature search identified 18 articles matching the selection criteria. MWUs with shoulder pain or injury exhibited different propulsion patterns than those without. A long push angle, low stroke frequency, low peak forces and sufficient variability possibly relate to lower levels of shoulder pain and injuries. However, it is not yet clear whether this propulsion technique decreases the risk of developing shoulder pain and injuries, or if it serves as a protective mechanism of MWUs who have already developed pain and injuries. More longitudinal studies, including real-life biomechanical measurements, with a focus on within-subject changes are needed to better understand the bidirectional and time-varying biomechanical relationship between shoulder pain and injuries and wheelchair propulsion.