title: Validity of 24-h physical activity recall: physical activity measurement survey.
abstract: OBJECTIVE
  The primary purpose of this study was to evaluate the validity of an interviewer-administered, 24-h physical activity recall (PAR) compared with that of the SenseWear Armband (SWA) for estimation of energy expenditure (EE) and moderate-to-vigorous physical activity (MVPA) in a representative sample of adults. A secondary goal was to compare measurement errors for various demographic subgroups (gender, age, and weight status).
  
  
  METHODS
  A sample of 1347 adults (20-71 yr, 786 females) wore an SWA for a single day and then completed a PAR, recalling the previous day's physical activity. The participants each performed two trials on two randomly selected days across a 2-yr time span. The EE and MVPA values for each participant were averaged across the 2 d. Group-level and individual-level agreement were evaluated using 95% equivalence testing and mean absolute percent error, respectively. Results were further examined for subgroups by gender, age, and body mass index.
  
  
  RESULTS
  The PAR yielded equivalent estimates of EE (compared with those in the SWA) for almost all demographic subgroups, but none of the comparisons for MVPA were equivalent. Smaller mean absolute percent error values were observed for EE (ranges from 10.3% to 15.0%) than those for MVPA (ranges from 68.6% to 269.5%) across all comparisons. The PAR yielded underestimates of MVPA for younger, less obese people but overestimates for older, more obese people.
  
  
  CONCLUSIONS
  For EE measurement, the PAR demonstrated good agreement relative to the SWA. However, the use of PAR may result in biased estimates of MVPA both at the group and individual level in adults.
authors.affiliation: 1Department of Kinesiology, Iowa State University, Ames, IA; and 2Department of Statistics, Iowa State University, Ames, IA.
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Welk
authors.forename: Youngwon
authors.initials: Y
authors.lastname: Kim
authors.forename: Bryan
authors.initials: B
authors.lastname: Stanfill
authors.forename: David A
authors.initials: DA
authors.lastname: Osthus
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Calabro
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Nusser
authors.forename: Alicia
authors.initials: A
authors.lastname: Carriquiry
mesh_terms: D056044:Actigraphy / Q000295:instrumentation; D000328:Adult; D000367:Age Factors; D000368:Aged; D015992:Body Mass Index; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D009043:Motor Activity; D057566:Self Report; D012737:Sex Factors; D055815:Young Adult