title: Manual wheelchair propulsion patterns on natural surfaces during start-up propulsion.
abstract: OBJECTIVE
  To classify propulsion patterns over surfaces encountered in the natural environment during start-up and compare selected biomechanical variables between pattern types.
  
  
  METHODS
  Case series.
  
  
  METHODS
  National Veterans Wheelchair Games, Minneapolis, MN, 2005.
  
  
  METHODS
  Manual wheelchair users (N=29).
  
  
  METHODS
  Subjects pushed their wheelchairs from a resting position over high-pile carpet, over linoleum, and up a ramp with a 5 degrees incline while propulsion kinematics and kinetics were recorded with a motion capture system and an instrumented wheel.
  
  
  METHODS
  Three 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.
  
  
  RESULTS
  SL 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< or =P< or =.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).
  
  
  CONCLUSIONS
  Classifying 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.
authors.affiliation: Human Engineering Research Laboratories (151R1-H), VA Pittsburgh Health Care System, 7180 Highland Dr., 151R1-H, Pittsburgh, PA 15206, USA. akoontz@pitt.edu
authors.forename: Alicia M
authors.initials: AM
authors.lastname: Koontz
authors.forename: Bailey M
authors.initials: BM
authors.lastname: Roche
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Collinger
authors.forename: Rory A
authors.initials: RA
authors.lastname: Cooper
authors.forename: Michael L
authors.initials: ML
authors.lastname: Boninger
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001132:Arm / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D004867:Equipment Design; D005260:Female; D005430:Floors and Floorcoverings; D006801:Humans; D007700:Kinetics; D008124:Locomotion / Q000502:physiology*; D008297:Male; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D013499:Surface Properties; D013647:Task Performance and Analysis; D014728:Veterans; D014910:Wheelchairs