title: Effects of five days of bed rest with and without exercise countermeasure on postural stability and gait.
abstract: OBJECTIVE
  We tested whether intermittent standing or a combination of heel raising, squatting and hopping exercises was sufficient to prevent alteration in balance and gait following a 5-day bed rest.
  
  
  METHODS
  This cross-over design study was performed with 10 male subjects during 6° head down tilt: (a) with no countermeasure; (b) while standing 25 min per day; (c) during locomotion-like activities 25 min per day. Gait was evaluated by grading subjects' performance during various locomotion tasks. Equilibrium scores were derived from peak-to-peak anterior-posterior sway while standing on a foam pad with the eyes open or closed or while making pitch head movements.
  
  
  RESULTS
  When no countermeasure was used, head movements led to decreased postural stability and increased incidence of falls immediately after bed rest compared to before. When upright standing or locomotion-like exercises were used, postural stability and the incidence of falls were not significantly different after the bed rest from the baseline.
  
  
  CONCLUSIONS
  These results indicate that daily 25-min of standing or locomotion-like exercise proves useful against postural instability following a 5-day bed rest. The efficacy of these countermeasures on locomotion could not be evaluated, however, because gait was not found to be altered after a 5-day bed rest.
authors.affiliation: Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Mulder
authors.forename: D
authors.initials: D
authors.lastname: Linnarsson
authors.forename: W H
authors.initials: WH
authors.lastname: Paloski
authors.forename: J
authors.initials: J
authors.lastname: Rittweger
authors.forename: F L
authors.initials: FL
authors.lastname: Wuyts
authors.forename: J
authors.initials: J
authors.lastname: Zange
authors.forename: G
authors.initials: G
authors.lastname: Clément
mesh_terms: D000328:Adult; D001510:Bed Rest / Q000009:adverse effects*; D004244:Dizziness / Q000503:physiopathology; D015444:Exercise / Q000502:physiology; D005684:Gait / Q000502:physiology*; D006801:Humans; D008124:Locomotion / Q000502:physiology; D008297:Male; D004856:Postural Balance / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D011434:Proprioception / Q000502:physiology; D018544:Weightlessness Countermeasures; D018474:Weightlessness Simulation