title: Daily walking in older adults: day-to-day variability and criterion-referenced validity of total daily step counts.
abstract: OBJECTIVE
  To determine the day-to-day variability of older adults' physical activity, and to evaluate the accuracy of the 10,000-step goal for classifying whether older adults obtain 30 minutes of MVPA.
  
  
  METHODS
  Ninety-one adults of age over 60 years of age wore a Yamax pedometer and Actigraph accelerometer for 7 days. Interday reliability was estimated via two-way ANOVA ICCs, and classification accuracy was evaluated via sensitivity, specificity, and ROC curve analysis.
  
  
  RESULTS
  Interday reliability was high; 4 of 5 outcome measures had a reliability of > or = .80 with only 2 days of data. The 10,000-step cut point had high accuracy for identifying days with less than 30 minutes of MVPA, but poor accuracy for identifying days with more than 30 minutes of MVPA.
  
  
  CONCLUSIONS
  Day-to-day variability in physical activity is lower in older adults than other age groups. The 10,000-step goal is inadequate for determining whether daily physical activity includes 30 minutes of MVPA in this population.
authors.affiliation: Department of Sport, Culture and the Arts, University of Strathclyde Jordanhill Campus, 76 Southbrae Drive, Glasgow, UK.
authors.forename: David A
authors.initials: DA
authors.lastname: Rowe
authors.forename: Charles D
authors.initials: CD
authors.lastname: Kemble
authors.forename: Terrance S
authors.initials: TS
authors.lastname: Robinson
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Mahar
mesh_terms: D000367:Age Factors; D000368:Aged; D003625:Data Collection; D016552:Ergometry; D005080:Exercise Test; D005260:Female; D015438:Health Behavior; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D010809:Physical Fitness; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D013997:Time Factors; D016138:Walking / Q000502:physiology*