1238 - Exploratory Examination of Patterns of Wheelchair Propulsion Biomechanical Adaptations to Increasing Rolling Resistance Workloads among Non-Disabled Adults

Objectives: To characterize patterns in wheelchair propulsion biomechanics adaptations to increases in rolling resistance workload.

Design: Participants included 11 non-disabled adults. (Male=7, Female=4; mean (SD)); age 24 years (2.3), BMI 23.8 kg/m2(4.3)). N=16 1-minute manual wheelchair propulsion trials at a self-selected speed on a wheelchair ergometer were conducted. Each trial was a unique rolling resistance (RR) workload between 25% and 100% of estimated maximum RR workload. All 5% increments in RR workload between 25% and 100% were completed once.

Results: Speed uniformly decreased as RR increased (one cluster, BIC=70, intercept =0.88 m/s). Average force increased as RR increased (three clusters, BIC=-591). The clusters had different intercepts (10-20 N) and rates of increase. Push frequency was stable as RR increased, with three clusters identified (BIC=-511), differing only in intercept (40-59 pushes/min). Push length response varied (BIC=-578, three clusters). Cluster 1 (N=5) was stable as RR increased (intercept=58 degrees), with cluster 2 (intercept=62 degrees) and 3 (intercept=71 degrees) demonstrating increased push length as RR increased.

Conclusions: Multiple response patterns to increasing RR were identified for most variables. There is potential that such patterns could help identify individuals at elevated risk for developing upper extremity pain and injury. Future studies using manual wheelchair users are necessary to further explore this phenomenon and to evaluate for associations between particular patterns and the development of upper extremity pain and pathology.