title: Influence of rotational axis height of back support on horizontal force applied to buttocks in a reclining wheelchair.
abstract: BACKGROUND
  Studies have not been conducted to investigate the influence of the height of the rotational axis of a wheelchair's back support on the shear force applied to the buttocks during the reclining motion.
  
  
  OBJECTIVE
  The purpose of this study was to investigate the influence of the difference in the rotational axis position of back support in the vertical direction on the horizontal force applied to buttocks for preventing decubitus ulcers.
  
  
  METHODS
  Repeated measures design.
  
  
  METHODS
  The subjects were 13 healthy adult men without leg and/or trunk diseases. The shear force was measured using a force plate. A comfortable sitting posture in the experimental chair was selected for measurement. The rotational axis was positioned 13 cm forward on the horizontal plane from the intersection between the seat and the back support. The axis positions on the vertical plane as two experimental conditions were the seat height and the 7.5-cm upward from the seat height which was nearer to the hip joint.
  
  
  RESULTS
  In returning the back support to an upright position, the horizontal force was 12.4 ± 1.6 (percent body weight) under the seat height-axis condition and 10.1 ± 1.8 (percent body weight) under the upward-axis condition (p < 0.01).
  
  
  CONCLUSIONS
  This result suggested that the wheelchair might have to be capable of adjusting the height of the rotational axis of the back support to reduce the horizontal force applied to buttocks.
  
  
  CONCLUSIONS
  This study shows one of the suggestions regarding seating approach for the prevention of decubitus ulcers. There is a possibility of reducing horizontal force applied to buttocks after reclined back support, by adjusting the height of the rotational axis position of wheelchair back support.
authors.affiliation: Department of Rehabilitation, Kawasaki University of Medical Welfare, Kurashiki, Japan rptkob@mw.kawasaki-m.ac.jp.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kobara
authors.affiliation: Department of Rehabilitation, Kawasaki University of Medical Welfare, Kurashiki, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Osaka
authors.affiliation: Department of Rehabilitation, Kawasaki University of Medical Welfare, Kurashiki, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Rehabilitation, Kawasaki University of Medical Welfare, Kurashiki, Japan.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Ito
authors.affiliation: Department of Rehabilitation, Kawasaki University of Medical Welfare, Kurashiki, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Fujita
authors.affiliation: Department of Rehabilitation, Kawasaki University of Medical Welfare, Kurashiki, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Watanabe
mesh_terms: D000293:Adolescent; D000328:Adult; D001415:Back; D002081:Buttocks; D004867:Equipment Design; D006621:Hip Joint / Q000502:physiology; D006801:Humans; D008297:Male; D011187:Posture / Q000502:physiology*; D003668:Pressure Ulcer / Q000517:prevention & control*; D016474:Weight-Bearing / Q000502:physiology*; D014910:Wheelchairs; D055815:Young Adult
keywords: Horizontal force; back support; reclining wheelchair; rotational axis