title: Relationship between shoulder pain and kinetic and temporal-spatial variability in wheelchair users.
abstract: OBJECTIVE
  To examine intra-individual variability of kinetic and temporal-spatial parameters of wheelchair propulsion as a function of shoulder pain in manual wheelchair users (MWUs).
  
  
  METHODS
  Cohort.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  Adults with physical disabilities (N=26) who use a manual wheelchair for mobility full time (>80% ambulation).
  
  
  METHODS
  Participants propelled their own wheelchairs with force-sensing wheels at a steady-state pace on a dynamometer at 3 speeds (self-selected, 0.7m/s, 1.1m/s) for 3 minutes. Temporal-spatial and kinetic data were recorded unilaterally at the hand rim.
  
  
  METHODS
  Shoulder pain was quantified with the Wheelchair Users Shoulder Pain Index. Intra-individual mean, SD, and coefficient of variation (CV=mean/SD) with kinetic and temporal-spatial metrics were determined at the handrim.
  
  
  RESULTS
  There were no differences in mean kinetic and temporal-spatial metrics as a function of pain group (P values >.016). However, individuals with pain displayed less relative variability (CV) in peak resultant force and push time than pain-free individuals (P<.016).
  
  
  CONCLUSIONS
  Shoulder pain had no influence on mean kinetic and temporal-spatial propulsion variables at the handrim; however, group differences were found in relative variability. These results suggest that intra-individual variability analysis is sensitive to pain. We propose that variability analysis may offer an approach for earlier identification of MWUs at risk for developing shoulder pain.
authors.affiliation: Departments of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL.
authors.forename: Ian M
authors.initials: IM
authors.lastname: Rice
authors.affiliation: Industrial Enterprise Systems Engineering, University of Illinois at Urbana-Champaign, Urbana, IL.
authors.forename: Chandrasekaran
authors.initials: C
authors.lastname: Jayaraman
authors.affiliation: Mechanical Sciences and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL.
authors.forename: Elizabeth T
authors.initials: ET
authors.lastname: Hsiao-Wecksler
authors.affiliation: Departments of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL. Electronic address: jsosnoff@illinois.edu.
authors.forename: Jacob J
authors.initials: JJ
authors.lastname: Sosnoff
mesh_terms: D000054:Acceleration; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D015331:Cohort Studies; D006233:Persons with Disabilities; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion / Q000502:physiology; D020069:Shoulder Pain / Q000503:physiopathology*; D064232:Visual Analog Scale; D014910:Wheelchairs; D055815:Young Adult
keywords: Rehabilitation; Shoulder; Wheelchairs