title: Evaluation of active video games intensity: comparison between accelerometer-based predictions and indirect calorimetric measurements.
abstract: BACKGROUND
  Several active video game (AVG) intervention studies failed in showing an increase in physical activity by using accelerometry measurements.
  
  
  OBJECTIVE
  To test the validity of accelerometry for monitoring AVG playing intensity.
  
  
  METHODS
  Twenty-two adults performed 80 activities included in the Wii Sports and Wii Fit Plus series. The energy expenditure (EE) and subsequent MET values were measured by indirect calorimetry using metabolic chambers. Subjects wore an accelerometer-based monitor displaying MET values. For each activity, METs values obtained from indirect calorimetry and accelerometry were compared. Each activity was classified as light or moderate to vigorous physical activity (LPA: < 3METs or MVPA: ⩾ 3METs) for the two methods.
  
  
  RESULTS
  AVG intensities have been slightly but significantly underestimated by the acceleromater-based monitor compared to the indirect calorimetry (2.5 ± 1.0 instead of 2.7 ± 0.9 METs). Fourty percent of activities have been significantly misestimated, and 20% have been misclassified.
  
  
  CONCLUSIONS
  Those results point out the potential bias of accelerometry measurements for evaluating AVG intensities. Because average AVG intensity lays at the boundary between LPA and MVPA classes, misclassifications can frequently occur. Accelerometry data should be interpreted with caution in intervention studies using AVG.
authors.affiliation: Department of Health Promotion and Exercise, National Institute of Health and Nutrition, Tokyo, Japan.
authors.forename: Julien
authors.initials: J
authors.lastname: Tripette
authors.affiliation: Department of Nutritional Sciences, National Institute of Health and Nutrition, Tokyo, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ando
authors.affiliation: Department of Health Promotion and Exercise, National Institute of Health and Nutrition, Tokyo, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Murakami
authors.affiliation: Department of Integrative Physiology, University of North Texas Health Science Centre, TX, USA.
authors.forename: Kenta
authors.initials: K
authors.lastname: Yamamoto
authors.affiliation: Faculty of Informatics and Engineering, University of Electro-Communications, Tokyo, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Ohkawara
authors.affiliation: Department of Nutritional Sciences, National Institute of Health and Nutrition, Tokyo, Japan.
authors.forename: Shigeho
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Health Promotion and Exercise, National Institute of Health and Nutrition, Tokyo, Japan.
authors.forename: Motohiko
authors.initials: M
authors.lastname: Miyachi
mesh_terms: D061725:Accelerometry / Q000379:methods*; D000328:Adult; D000465:Algorithms; D000886:Anthropometry; D015992:Body Mass Index; D002151:Calorimetry / Q000379:methods*; D015331:Cohort Studies; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D018910:Video Games
keywords: Exergame; accelerometry; energy expenditure; metabolic chamber; metabolic equivalent