title: Challenging gait conditions predict 1-year decline in gait speed in older adults with apparently normal gait.
abstract: BACKGROUND
  Mobility often is tested under a low challenge condition (ie, over a straight, uncluttered path), which often fails to identify early mobility difficulty. Tests of walking during challenging conditions may uncover mobility difficulty that is not identified with usual gait testing.
  
  
  OBJECTIVE
  The purpose of this study was to determine whether gait during challenging conditions predicts decline in gait speed over 1 year in older people with apparently normal gait (ie, gait speed of ≥1.0 m/s).
  
  
  METHODS
  This was a prospective cohort study.
  
  
  METHODS
  /b> Seventy-one older adults (mean age=75.9 years) with a usual gait speed of ≥1.0 m/s participated. Gait was tested at baseline under 4 challenging conditions: (1) narrow walk (15 cm wide), (2) stepping over obstacles (15.24 cm [6 in] and 30.48 cm [12 in]), (3) simple walking while talking (WWT), and (4) complex WWT. Usual gait speed was recorded over a 4-m course at baseline and 1 year later. A 1-year change in gait speed was calculated, and participants were classified as declined (decreased ≥0.10 m/s, n=18), stable (changed <0.10 m/s, n=43), or improved (increased ≥0.10 m/s, n=10). Analysis of variance was used to compare challenging condition cost (usual--challenging condition gait speed difference) among the 3 groups.
  
  
  RESULTS
  Participants who declined in the ensuing year had a greater narrow walk and obstacle walk cost than those who were stable or who improved in gait speed (narrow walk cost=0.43 versus 0.33 versus 0.22 m/s and obstacle walk cost=0.35 versus 0.26 versus 0.13 m/s). Simple and complex WWT cost did not differ among the groups.
  
  
  CONCLUSIONS
  The participants who declined in gait speed over time walked the fastest, and those who improved walked the slowest at baseline; thus, the potential contribution of regression to the mean to the findings should not be overlooked.
  
  
  CONCLUSIONS
  In older adults with apparently normal gait, the assessment of gait during challenging conditions appears to uncover mobility difficulty that is not identified by usual gait testing.
authors: Department of Physical Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA. jbrach@pitt.edu
authors: Jennifer S
authors: JS
authors: Brach
authors: Subashan
authors: S
authors: Perera
authors: Jessie M
authors: JM
authors: VanSwearingen
authors: Elizabeth S
authors: ES
authors: Hile
authors: David M
authors: DM
authors: Wert
authors: Stephanie A
authors: SA
authors: Studenski
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005080:Exercise Test / Q000379:methods*; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D051346:Mobility Limitation; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013647:Task Performance and Analysis; D016138:Walking / Q000502:physiology*