Shoulder Pain Is Associated With Rate of Rise and Jerk of the Applied Forces During Wheelchair Propulsion in Individuals With Paraplegic Spinal Cord Injury

OBJECTIVE: To investigate the association between propulsion biomechanics, including variables that describe smoothness of the applied forces, and shoulder pain in persons with SCI. DESIGN: Cross-sectional, observational study. SETTING: Non-university research institution. PARTICIPANTS: 30 (age: 48.6±9.3 years, 83% males) community dwelling, wheelchair dependent participants with a chronic paraplegia between T2 and L1, with and without shoulder pain. INTERVENTIONS: Not applicable MAIN OUTCOME MEASURE: Rate of rise and jerk of applied forces during wheelchair propulsion. Participants were stratified in low, moderate and high pain groups based on their Wheelchair User Shoulder Pain Index (WUSPI) score at the day of measurement. RESULTS: A mixed-effect multilevel analysis showed that wheelchair users in the high pain group propelled with significantly greater rate of rise and jerk - measures that describe smoothness of the applied forces - as compared to persons with less or no pain, when controlling for all co-variables. CONCLUSIONS: Persons with severe shoulder pain propelled with less smooth strokes as compared to persons with less or no pain. This supports a possible association between shoulder pain and rate of rise and jerk of the applied forces during wheelchair propulsion