title: Acute effects of walking at moderate normobaric hypoxia on gait and balance performance in healthy community-dwelling seniors: A randomized controlled crossover study.
abstract: Hiking at moderate altitude is a popular outdoor activity in seniors. Acute exercise or altitude can diminish balance performance. Thus, the present study examined the combined effects of altitude and walking on static and dynamic balance.
  
  
  
  Thirty-six healthy seniors (age: 62 (SD: 4) y; BMI: 25 (5) kg/m(2)) were examined on three days. Firstly, walking velocity was determined at 85% of the first ventilatory threshold (VT1). Therefore, a ramp walking test on a treadmill was completed. On day two or three, a 40-minute treadmill walk under sea level or normobaric hypoxia (2600m) was performed using a random, double-blind study design. Balance performance was assessed on a force-plate during single leg stance with eyes open (SLEO, 10s on a force-plate) immediately before and after walking. Spatio-temporal gait characteristics were collected during walking at 5 and 35min.
  
  
  
  Condition×time interaction effects were not found for either parameter (0.13<p<0.60; 0.007<ηp(2)<0.07). Only time effects were observed for cadence (-1.5%, p<0.001, ηp(2)=0.29), stride time (+2.3%, p=0.007, ηp(2)=0.28), and temporal gait variability (+22.6%, p=0.01, ηp(2)=0.16). A moderate time×condition effect was observed for postural sway during SLEO (p=0.04, ηp(2)=0.11). Subseqent post hoc testing revealed difference between hypoxia and normoxia at 35min (p=0.01) and between 5 and 35min testing during hypoxia and normoxia (both p<0.001).
  
  
  
  Alterations of cadence, stride time, and temporal gait variability might be attributed to fatigue-induced changes of temporal gait adjustments. Normobaric hypoxia did not acutely impair gait patterns. We assume that demanding postural standing tasks that require more central control may be affected to a greater extent by altitude exposure.
authors.affiliation: Northern Michigan University, School of Health and Human Performance, 1401 Presque Isle Ave., Marquette, MI 49855, United States.
authors.forename: Scott N
authors.initials: SN
authors.lastname: Drum
authors.affiliation: Department of Sport, Exercise and Health, University of Basel, Switzerland.
authors.forename: Oliver
authors.initials: O
authors.lastname: Faude
authors.affiliation: Northern Michigan University, School of Health and Human Performance, 1401 Presque Isle Ave., Marquette, MI 49855, United States.
authors.forename: Emilie
authors.initials: E
authors.lastname: de Fay du Lavallaz
authors.affiliation: Northern Michigan University, School of Health and Human Performance, 1401 Presque Isle Ave., Marquette, MI 49855, United States.
authors.forename: Remo
authors.initials: R
authors.lastname: Allemann
authors.affiliation: Northern Michigan University, School of Health and Human Performance, 1401 Presque Isle Ave., Marquette, MI 49855, United States.
authors.forename: Gilles
authors.initials: G
authors.lastname: Nève
authors.affiliation: Northern Michigan University, School of Health and Human Performance, 1401 Presque Isle Ave., Marquette, MI 49855, United States; Department of Sport, Exercise and Health, University of Basel, Switzerland. Electronic address: lars.donath@unibas.ch.
authors.forename: Lars
authors.initials: L
authors.lastname: Donath
mesh_terms: D018592:Cross-Over Studies; D004311:Double-Blind Method; D005080:Exercise Test; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D012307:Risk Factors; D016138:Walking / Q000502:physiology*
keywords: Elderly; Gait variability; Hypoxia; Older; Upright stance; Walking