Manual Wheelchair Propulsion Patterns on Natural Surfaces During Start-Up Propulsion

Koontz AM, Roche BM, Collinger JL, Cooper RA, Boninger ML. Manual wheelchair propulsion patterns on natural surfaces during start-up propulsion.ObjectivesTo classify propulsion patterns over surfaces encountered in the natural environment during start-up and compare selected biomechanical variables between pattern types.DesignCase series.SettingNational Veterans Wheelchair Games, Minneapolis, MN, 2005.ParticipantsManual wheelchair users (N=29).InterventionSubjects pushed their wheelchairs from a resting position over high-pile carpet, over linoleum, and up a ramp with a 5° incline while propulsion kinematics and kinetics were recorded with a motion capture system and an instrumented wheel.Main Outcome MeasuresThree raters classified the first 3 strokes as 1 of 4 types on each surface: arc, semicircular (SC), single looping over propulsion (SL), and double looping over propulsion (DL). The Fisher exact test was used to assess pattern changes between strokes and surface type. A multiple analysis of variance test was used to compare peak and average resultant force and moment about the hub, average wheel velocity, stroke frequency, contact angle, and distance traveled between stroke patterns.ResultsSL was the most common pattern used during start-up propulsion (44.9%), followed by arc (35.9%), DL (14.1%), and SC (5.1%). Subjects who dropped their hands below the rim during recovery achieved faster velocities and covered greater distances (.016≤P≤.075) during start-up on linoleum and carpet and applied more force during start-up on the ramp compared with those who used an arc pattern (P=.066).ConclusionsClassifying propulsion patterns is a difficult task that should use multiple raters. In addition, propulsion patterns change during start-up, with an arc pattern most prevalent initially. The biomechanical findings in this study agree with current clinical guidelines that recommend training users to drop the hand below the pushrim during recovery.