title: Seat-interface pressure: a pilot study of the relationship to gender, body mass index, and seating position.
abstract: OBJECTIVE
  To investigate the relationship between interface pressure and gender, body mass index (BMI), and seating positions, and to evaluate the implications for clinical practice.
  
  
  METHODS
  Group design.
  
  
  METHODS
  Pressure mapping laboratory.
  
  
  METHODS
  Sixty-three student volunteers (44 women, 19 men; mean age, 22.2+/-5.1y).
  
  
  METHODS
  Seated-interface pressure was measured using the Force Sensing Array pressure mapping system. Seating positions used included recline (10 degrees, 20 degrees, 30 degrees ), foot support, and foot elevation.
  
  
  METHODS
  Interface pressure in the form of both average pressure (mean of the pressure sensor values) and maximum pressure (highest individual sensor value).
  
  
  RESULTS
  Both average and maximum pressures were independent of gender, while average pressure had a significant positive correlation with BMI (r=.381, alpha=.01 level). Recline of the chair by 30 degrees significantly reduced average pressure (P<.001), whereas recline by 10 degrees or 20 degrees had no significant effect. Recline by 10 degrees, 20 degrees, and 30 degrees did not significantly alter maximum pressure. Elevation of the feet on a footstool reduced average pressure to a level approaching statistical significance, while supporting participants' feet versus leaving them unsupported significantly increased average pressure at a 0 degrees, 10 degrees, 20 degrees, and 30 degrees recline (P<.01) and maximum pressure at 0 degrees, 10 degrees (P<.01), and 30 degrees (P<.05).
  
  
  CONCLUSIONS
  Elevating clients' feet and reclining their chair by 30 degrees reduced interface pressure and the associated risk of pressure ulcer development. Additional research is required, however, to replicate this study with participants at increased risk of pressure ulcer development.
authors.affiliation: Rehabilitation Sciences Research Group, University of Ulster, Northern Ireland. maystinson@hotmail.com
authors.forename: May D
authors.initials: MD
authors.lastname: Stinson
authors.forename: Alison
authors.initials: A
authors.lastname: Porter-Armstrong
authors.forename: Pamela
authors.initials: P
authors.lastname: Eakin
mesh_terms: D000328:Adult; D015992:Body Mass Index; D006804:Ergonomics / Q000706:statistics & numerical data; D005260:Female; D005528:Foot / Q000502:physiology; D006801:Humans; D008297:Male; D010865:Pilot Projects; D011187:Posture / Q000502:physiology*; D011312:Pressure / Q000009:adverse effects; D003668:Pressure Ulcer / Q000209:etiology / Q000517:prevention & control*; D012016:Reference Values; D012737:Sex Factors; D014160:Transducers, Pressure / Q000706:statistics & numerical data