title: The impact of office chair features on lumbar lordosis, intervertebral joint and sacral tilt angles: a radiographic assessment.
abstract: BACKGROUND
  The purpose of this study was to determine which office chair feature is better at improving spine posture in sitting.
  
  
  METHODS
  Participants (n = 28) were radiographed in standing, maximum flexion and seated in four chair conditions: control, lumbar support, seat pan tilt and backrest with scapular relief. Measures of lumbar lordosis, intervertebral joint angles and sacral tilt were compared between conditions and sex.
  
  
  RESULTS
  Sitting consisted of approximately 70% of maximum range of spine flexion. No differences in lumbar flexion were found between the chair features or control. Significantly more anterior pelvic rotation was found with the lumbar support (p = 0.0028) and seat pan tilt (p < 0.0001). Males had significantly more anterior pelvic rotation and extended intervertebral joint angles through L1-L3 in all conditions (p < 0.0001).
  
  
  CONCLUSIONS
  No one feature was statistically superior with respect to minimising spine flexion, however, seat pan tilt resulted in significantly improved pelvic posture. Practitioner Summary: Seat pan tilt, and to some extent lumbar supports, appear to improve seated postures. However, sitting, regardless of chair features used, still involves near end range flexion of the spine. This will increase stresses to the spine and could be a potential injury generator during prolonged seated exposures.
authors.affiliation: a Division of Epidemiology/Biomechanics, Discipline of Medicine, Faculty of Medicine , Memorial University of Newfoundland , St. John's , Canada.
authors.forename: Diana
authors.initials: D
authors.lastname: De Carvalho
authors.affiliation: b Graduate Education and Research Programs , Canadian Memorial Chiropractic College , Toronto , Canada.
authors.forename: Diane
authors.initials: D
authors.lastname: Grondin
authors.affiliation: c Faculty of Applied Health Science, Department of Kinesiology , University of Waterloo , Waterloo , Canada.
authors.forename: Jack
authors.identifier: http://orcid.org/0000-0002-8245-7084
authors.initials: J
authors.lastname: Callaghan
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007374:Interior Design and Furnishings / Q000295:instrumentation*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000502:physiology*; D008297:Male; D010388:Pelvis / Q000502:physiology*; D011187:Posture; D011859:Radiography; D012399:Rotation; D012447:Sacrum / Q000000981:diagnostic imaging / Q000502:physiology; D012737:Sex Factors; D055815:Young Adult; D021801:Zygapophyseal Joint / Q000000981:diagnostic imaging / Q000502:physiology
keywords: Office chair; design; low back pain; sitting; spine