title: Garment fit and protection from sustained +Gz acceleration with 'full-coverage' anti-G trousers.
abstract: BACKGROUND
  Garment fit may influence the effectiveness with which Full-Coverage Anti-G Trousers (FCAGT) transmit pressure to the skin surface, and hence provide protection from sustained +Gz acceleration. A search of the available literature, however, did not reveal any prior work quantifying this effect.
  
  
  METHODS
  Three related studies were performed. In Study I, using a mannequin, garment-to-surface pressure transmission ratios were measured at various locations under normally fitted (NF) and loosely fitted (LF) FCAGT. In Study II, garment pressure-volume ratios and lung volumes were measured at +1 Gz in six men wearing FCAGT in three conditions: NF, LF, or NF with inflatable socks at 13 kPa differential pressure (NF+SOCKS). In Study III, relaxed +Gz tolerance (RGT) and ratings of perceived exertion (RPE) at +7, +8, and +9 Gz were measured in eight men wearing FCAGT in four experimental conditions: NF; LF; abdomen LF, legs NF; or abdomen NF, legs LF.
  
  
  RESULTS
  LF did not affect pressure transmission over the lower limbs or lower abdomen, but transmission over the upper abdomen was significantly compromised. Lung volumes were reduced with FCAGT inflation, but LF was associated with greater expiratory reserve volumes and increased FCAGT volume. Under +Gz acceleration, LF over the abdomen (with or without lower limb LF) decreased RGT and increased RPE, but not with lower limb LF when abdominal fit was normal.
  
  
  CONCLUSIONS
  Care should be taken to achieve and maintain a snug FCAGT fit, especially of the abdominal portion of the FCAGT, to ensure optimal anti-G protection during sustained acceleration.
authors.affiliation: Aircrew Systems Group, Human Sciences, Air Division, QinetiQ, Farnborough, Hampshire, UK. atstevenson@qinetiq.com
authors.forename: Alec T
authors.initials: AT
authors.lastname: Stevenson
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Lythgoe
authors.forename: Catherine L J
authors.initials: CL
authors.lastname: Darby
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Devlin
authors.forename: Desmond M
authors.initials: DM
authors.lastname: Connolly
authors.forename: Jonathan P R
authors.initials: JP
authors.lastname: Scott
mesh_terms: D000005:Abdomen / Q000502:physiology; D000054:Acceleration; D000328:Adult; D000337:Aerospace Medicine; D000704:Analysis of Variance; D005105:Expiratory Reserve Volume; D005676:Gravity Suits; D006339:Heart Rate; D006801:Humans; D018471:Hypergravity; D035002:Lower Extremity / Q000502:physiology; D008297:Male; D008348:Manikins; D008889:Military Personnel; D005082:Physical Exertion; D011312:Pressure; D011481:Protective Clothing; D014797:Vital Capacity