Abstract

Background

Wheelchair propulsion strategies vary widely among individuals with complete spinal cord injury (SCI), yet research typically focuses on differences between injury levels rather than variability within the same level. This study investigated how physical activity (PA) level and time since injury affect wheelchair propulsion biomechanics in individuals with identical T12/L1 SCI classification.

Methods

Eleven participants with complete T12/L1 SCI performed wheelchair propulsion at maximum and self-selected speeds. Joint kinematics and electromyography data were collected from six upper body muscles. Participants were categorized by time since injury (Short: < 10 years, Medium: 10–25 years, Long: ≥ 25 years) and physical activity level (Low, Moderate, High). Group differences were analyzed using one-way ANOVA with Tukey post-hoc tests.

Results

Significant differences in propulsion biomechanics were observed despite identical injury levels. Time since injury significantly affected elbow kinematics (p = 0.009) and biceps activity (p = 0.009), with the Long-time group showing increased elbow range of motion during maximum effort compared to the Medium-time group. PA level influenced trunk flexion (p = 0.036) and upper trapezius activity (p = 0.012), with the High-PA group demonstrating greater trunk flexion during maximum effort compared to the Low-PA group. Notably, propulsion velocity showed no significant differences between groups.

Conclusions

Wheelchair propulsion strategies vary significantly among individuals with identical SCI level, demonstrating that neurological classification alone does not determine movement patterns. The adaptive strategies observed in experienced and physically active wheelchair users suggest rehabilitation approaches should consider these factors beyond injury classification. These findings highlight the importance of promoting long-term PA participation and ongoing biomechanical adaptation throughout the lifespan of individuals with SCI.