title: Objective Versus Self-Reported Physical Activity in Overweight and Obese Young Adults.
abstract: BACKGROUND
  To compare moderate-to-vigorous intensity physical activity (MVPA) assessed via questionnaires to an objective measure of MVPA in overweight or obese young adults.
  
  
  METHODS
  MVPA was assessed in 448 [median BMI = 31.2 (Interquartile Range: 28.5-34.3) kg/m2] young adults [median age: 30.9 (Interquartile Range: 27.8-33.7) years]. Measures included the SenseWear Armband (MVPAOBJ), the Paffenbarger Questionnaire (MVPAPAFF), and the Global Physical Activity Questionnaire (GPAQ). The GPAQ was used to compute total MVPA (MVPAGPAQ-TOTAL) and MVPA from transportation and recreation (MVPAGPAQ-REC).
  
  
  RESULTS
  The association between MVPAOBJ and MVPAPAFF was rs = 0.40 (P < .0001). Associations between MVPAOBJ and MVPAGPAQ-TOTAL and MVPAGPAQ-REC were rs = 0.19 and rs = 0.32, respectively (P < .0001). MVPAGPAQ-TOTAL was significantly greater than MVPAOBJ (P < .0001). Median differences in MET-min/week between MVPAOBJ and MVPAPAFF or MVPAGPAQ-REC were not significantly different from zero. There was proportional bias between each self-reported measure of MVPA and MVPAOBJ. There were significant associations between all measures of MVPA and fitness. MVPAOBJ was significantly associated with BMI and percent body fat.
  
  
  CONCLUSIONS
  Objective and self-reported measures of MVPA are weakly to moderately correlated, with substantial differences between measures. MVPAOBJ provided predictive validity with fitness, BMI, and percent body fat. Thus, an objective measure of MVPA may be preferred to self-report in young adults.
authors.affiliation: Dept of Health and Physical Activity, Physical Activity and Weight Management Research Center, University of Pittsburgh, PA.
authors.forename: John M
authors.initials: JM
authors.lastname: Jakicic
authors.forename: Wendy C
authors.initials: WC
authors.lastname: King
authors.forename: Bethany Barone
authors.initials: BB
authors.lastname: Gibbs
authors.forename: Renee J
authors.initials: RJ
authors.lastname: Rogers
authors.forename: Amy D
authors.initials: AD
authors.lastname: Rickman
authors.forename: Kelliann K
authors.initials: KK
authors.lastname: Davis
authors.forename: Abdus
authors.initials: A
authors.lastname: Wahed
authors.forename: Steven H
authors.initials: SH
authors.lastname: Belle
mesh_terms: D000273:Adipose Tissue; D000328:Adult; D015992:Body Mass Index; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009765:Obesity / Q000503:physiopathology*; D050177:Overweight / Q000503:physiopathology*; D010809:Physical Fitness / Q000502:physiology*; D011998:Recreation / Q000502:physiology*; D057566:Self Report; D013334:Students; D011795:Surveys and Questionnaires; D055815:Young Adult