title: The reliability and validity of measures of gait variability in community-dwelling older adults.
abstract: OBJECTIVE
  To examine the test-retest reliability and concurrent validity of variability of gait characteristics.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Research laboratory.
  
  
  METHODS
  Older adults (N=558) from the Cardiovascular Health Study.
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Gait characteristics were measured using a 4-m computerized walkway. SD determined from the steps recorded were used as the measures of variability. Intraclass correlation coefficients (ICC) were calculated to examine test-retest reliability of a 4-m walk and two 4-m walks. To establish concurrent validity, the measures of gait variability were compared across levels of health, functional status, and physical activity using independent t tests and analysis of variances.
  
  
  RESULTS
  Gait variability measures from the two 4-m walks demonstrated greater test-retest reliability than those from the single 4-m walk (ICC=.22-.48 and ICC=.40-.63, respectively). Greater step length and stance time variability were associated with poorer health, functional status and physical activity (P<.05).
  
  
  CONCLUSIONS
  Gait variability calculated from a limited number of steps has fair to good test-retest reliability and concurrent validity. Reliability of gait variability calculated from a greater number of steps should be assessed to determine if the consistency can be improved.
authors.affiliation: Department of Physical Therapy, University of Pittsburgh, Pittsburgh, PA 15260, USA. jbrach@pitt.edu
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Brach
authors.forename: Subashan
authors.initials: S
authors.lastname: Perera
authors.forename: Stephanie
authors.initials: S
authors.lastname: Studenski
authors.forename: Anne B
authors.initials: AB
authors.lastname: Newman
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D015444:Exercise; D005260:Female; D005684:Gait; D006304:Health Status; D006801:Humans; D008297:Male; D010414:Pennsylvania; D012046:Rehabilitation; D015203:Reproducibility of Results