title: Influence of distance between the rotation axis of back support and the hip joint on shear force applied to buttocks in a reclining wheelchair's back support.
abstract: OBJECTIVE
  The purpose of this study was to investigate the influence of the distance between the position of the rotation axis of the back support and hip joint on the changes in the shear force applied to the buttocks.
  
  
  METHODS
  Repeated-measures design.
  
  
  METHODS
  The subjects were 11 healthy adult men without leg and/or trunk diseases. The shear force applied to the buttocks was measured using a force plate. This study had three experimental conditions: the position of hip joint was taken as the 3 cm, 6 cm, and 9 cm forward from the standard sitting position.
  
  
  RESULTS
  In returning to an upright position of back support, the shear force was 15.0 ± 2.9 %BW in the 3 cm forward condition, 16.7 ± 3.6 %BW in the 6 cm forward condition, and 19.5 ± 5.3 %BW in the 9 cm forward condition. Significant differences appeared between the 9 cm and the other conditions (p < 0.05).
  
  
  CONCLUSIONS
  The results of this study suggested that the shear force applied to the buttocks changed in reclining back support and an increase in the distance between the axis of rotation of the back support and hip joint led to an increase in the remaining shear force after reclining the back support.
authors: Kawasaki University of Medical Welfare, Kurashiki, Okayama, Japan.
authors: Kenichi
authors: K
authors: Kobara
authors: Daisuke
authors: D
authors: Fujita
authors: Hiroshi
authors: H
authors: Osaka
authors: Tomotaka
authors: T
authors: Ito
authors: Susumu
authors: S
authors: Watanabe
mesh_terms: D000328:Adult; D001415:Back / Q000502:physiology*; D001696:Biomechanical Phenomena / Q000502:physiology; D002081:Buttocks / Q000502:physiology*; D004867:Equipment Design; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D008297:Male; D011187:Posture / Q000502:physiology; D003668:Pressure Ulcer / Q000517:prevention & control; D012399:Rotation; D013314:Stress, Mechanical; D016474:Weight-Bearing / Q000502:physiology; D014910:Wheelchairs / Q000145:classification
keywords: Decubitus ulcer; shear force