title: The effects of backward adjustable thoracic support in wheelchair on spinal curvature and back muscle activation for elderly people.
abstract: OBJECTIVE
  To investigate the effects of backward adjustable thoracic support on spinal curvature and back muscle activation during wheelchair sitting.
  
  
  METHODS
  Twenty elderly people were recruited for this study. The backward adjustable thoracic support sitting posture was compared with the slumped, normal, and lumbar support sitting postures. Spinal curvatures (pelvic, lumbar, and thoracic angles) and muscle activations of 4 back muscles on both sides (maximal voluntary isometric contraction of the lumbar multifidus, lumbar erector spinae, iliocostalis lumborum pars thoracis, and thoracic erector spinae at T9) were measured and compared between the different sitting postures using one-way analysis of variance with repeated measures.
  
  
  RESULTS
  The backward adjustable thoracic support sitting posture showed a relatively neutral pelvic tilt (-0.32±4.80°) when compared with the slumped (22.84±5.27°) and lumbar support (-8.97±3.31°) sitting postures (P<0.001), and showed relatively higher lumbar lordosis (-23.38±6.50°) when compared with the slumped (14.77±7.83°), normal (0.44±7.47°), and lumbar support (-16.76±4.77°) sitting postures (P<0.05). It also showed relatively lower back muscle activity when compared with the normal and lumbar support sitting postures (P<0.05).
  
  
  CONCLUSIONS
  The backward adjustable thoracic support sitting concept was suggested because it maintains a more neutral pelvic tilt, higher lumbar lordosis, and lower back muscle activation, which may help maintain a better sitting posture and reduce the risk of back pain.
authors.affiliation: Institute of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chun-Ting
authors.initials: CT
authors.lastname: Li
authors.affiliation: Institute of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan; Metal Industries Research & Development Centre, Kaohsiung, Taiwan.
authors.forename: Yen-Nien
authors.initials: YN
authors.lastname: Chen
authors.affiliation: Institute of Biomedical Engineering, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chih-Han
authors.initials: CH
authors.lastname: Chang
authors.affiliation: Graduate Institute of Mechatronic System Engineering, National University of Tainan, Tainan, Taiwan.
authors.forename: Kuen-Horng
authors.initials: KH
authors.lastname: Tsai
mesh_terms: D000368:Aged; D064131:Back Muscles / Q000502:physiology*; D001416:Back Pain / Q000503:physiopathology / Q000517:prevention & control; D001696:Biomechanical Phenomena; D005853:Geriatrics / Q000379:methods; D006801:Humans; D008159:Lumbar Vertebrae / Q000502:physiology; D008161:Lumbosacral Region; D009989:Orthotic Devices; D010388:Pelvis; D011187:Posture / Q000502:physiology; D015203:Reproducibility of Results; D013121:Spinal Curvatures / Q000503:physiopathology* / Q000517:prevention & control; D013904:Thoracic Vertebrae / Q000502:physiology*; D014910:Wheelchairs