TEMPORAL-SPATIAL CHARACTERISTICS OF WHEELCHAIR PROPULSION: Effects of Level of Spinal Cord Injury, Terrain, and Propulsion Rate1

Abstract

The purpose of this investigation was to compare the temporal-spatial characteristics of wheelchair propulsion (velocity, cycle distance, and cadence) of customary wheelchair users in conditions designed to simulate community settings. Seventy adult males with spinal cord injuries (SCI) were grouped by their level of SCI: low paraplegia (n = 17); high paraplegia (n = 19); C-7 tetraplegia (n = 17); C-6 tetraplegia (n = 17). Testing was performed in a wheelchair that had the right pushrim instrumented with force transducers. Participants propelled the test wheelchair at a self-selected, free, and fast pace over tile and carpeted floors. A wheelchair ergometer was designed to simulate loads encountered during propulsion over graded surfaces. Participants propelled the test wheelchair during ergometer simulation of 4% and 8% grades. Mean velocity, cycle distance, and cadence were calculated for each group in all test conditions. A two-way repeated measures analysis of variance and simple main effects testing for comparison across conditions and between groups were performed. For all test conditions, participants with low paraplegia were the fastest and had the longest cycle distance. With successively higher levels of SCI, velocities were slower and cycle distances shorter. During free propulsion on tile, velocities ranged from 95 m/min in low paraplegics to 55 m/min in C-6 tetraplegics. Fast propulsion velocity increased to 141 and 55 m/min, respectively. There was a significant main effect of surface for velocity such that the carpet condition was slower than the tile for all groups. Differences in velocity were most often the result of changes in cycle distance. High and low paraplegic groups were statistically similar for all test conditions. Participants with C-6 tetraplegia were significantly slower than all other groups for most test conditions. Because their fast propulsion velocities were slower than typical community demands, their ability to function independently outside the hospital setting has been further questioned.