Effects of Daily Physical Activity Level on Manual Wheelchair Propulsion Technique in Full-Time Manual Wheelchair Users During Steady-State Treadmill Propulsion

Abstract Objective To examine whether differences in propulsion technique as a function of intraindividual variability occur as a result of shoulder pain and physical activity (PA) level in full-time manual wheelchair users (MWUs). Design Observational study. Setting Research laboratory. Participants Adults (N=14) with spinal cord injury (mean age: 30.64±11.08) who used a wheelchair for >80% of daily ambulation and were free of any condition that could be worsened by PA. Interventions Not applicable. Main Outcome Measures PA level was measured using the Physical Activity Scale for Individuals with Physical Disabilities (PASIPD), and shoulder pain was measured using the Wheelchair User's Shoulder Pain Index (WUSPI) survey. Mean and intraindividual variability propulsion metrics were measured for propulsion analysis. Results WUSPI scores indicated participants experienced low levels of shoulder pain. The results of the Spearman rank-order correlation revealed that PASIPD scores were significantly related to mean contact angle ( r s =−.57) and stroke frequency ( r s =.60) as well as to coefficient of variation of peak force ( r s =.63), peak torque ( r s =.59), contact angle ( r s =.73), and stroke frequency ( r s =.60). WUSPI scores were significantly correlated with only mean peak force ( P =.02). No significant correlations were observed between PASIPD, WUSPI, and body mass index scores. Conclusions Differences in propulsion technique were observed on the basis of PA levels. Participants with higher PASIPD scores used a more injurious stroke technique when propelling at higher speeds. This may indicate that active individuals who use injurious stroke mechanics may be at higher risk of injury. A strong relation was found between peak propulsion forces and shoulder pain. Rehabilitation professionals should emphasize the use of a protective stroke technique in both inactive and active MWUs during exercise and faster propulsion.