title: Time requirement for young and elderly women to move into a position for breaking a fall with outstretched hands.
abstract: BACKGROUND
  Risk for hip fracture during a fall is reduced by contacting the ground first with the outstretched hands. However, it is unclear whether the time required for young and elderly individuals to move the hands into a protective position exceeds that available during a typical fall.
  
  
  METHODS
  We tested whether young (n = 30; aged 18-35 years) and elderly women (n = 30; aged 70-88 years) differed in the time required to move their hands into a protective position for breaking a fall. Participants stood either facing or sideways to shoulder-height targets (simulating forward and sideways falls, respectively), which they were instructed to contact as quickly as possible after hearing an aural go cue. Total contact time was partitioned into reaction time and movement time.
  
  
  RESULTS
  Young women contacted the targets faster than elderly women in both forward (530 +/- 60 vs 615 +/- 88 ms; p <.001) and sideways trials (658 +/- 80 vs 799 +/- 145 ms; p <.001). This difference was due to faster movement times for young participants. There was no difference between groups in reaction time.
  
  
  CONCLUSIONS
  Previous studies have shown that during actual falls from standing, wrist and pelvis contact occur at 680 +/- 116 and 715 +/- 160 ms, respectively. Comparing these values to our results suggests that the typical elderly woman should be able to move her hands quickly enough to break a forward fall, but not a sideways fall.
authors.affiliation: School of Kinesiology, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada. stever@sfu.ca
authors.forename: Stephen N
authors.initials: SN
authors.lastname: Robinovitch
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Normandin
authors.forename: Paula
authors.initials: P
authors.lastname: Stotz
authors.forename: Jessica D
authors.initials: JD
authors.lastname: Maurer
mesh_terms: D000058:Accidental Falls; D000328:Adult; D000367:Age Factors; D000368:Aged; D005260:Female; D006225:Hand / Q000502:physiology*; D006801:Humans; D012018:Reflex / Q000502:physiology*; D013997:Time Factors