title: Validity of the ActivPAL™ and the ActiGraph monitors in preschoolers.
abstract: OBJECTIVE
  This study aimed to compare three objective measures (GT1M ActiGraph, ActivPAL™, and direct observation) of sedentary behavior in preschoolers.
  
  
  METHODS
  Fifty-two 4- to 6-yr-old preschoolers wore an ActivPAL™ and a GT1M ActiGraph for five consecutive days and were videotaped for 1 h during classroom activities at preschool. The area under the receiver operating characteristic curve was calculated to assess the criterion validity of the ActivPAL™ (sitting/lying, with and without standing still) and the GT1M ActiGraph (<100 counts per minute) to estimate sedentary behavior (directly observed sitting behaviors). A two-way repeated-measures ANOVA was used to define the convergent validity of the ActivPAL™ and the GT1M ActiGraph sedentary behavior estimates across the measurement days. The practical utility of the ActivPAL™ was tested in the same sample by asking the parents how their child perceived wearing the ActivPAL™.
  
  
  RESULTS
  Results indicated a poor classification accuracy for both devices (area under the receiver operating characteristic curve, 0.6) to measure sedentary behavior based on the direct observation, with and without the inclusion of standing. Time defined as sedentary behavior (sitting/lying) was lower for the ActivPAL™ compared with the GT1M ActiGraph (mean bias, 7.7%; limits of agreement, -29.01% to 13.6%). According to the parental reports, 38% of the preschoolers had skin irritation due to wearing the ActivPAL™ for consecutive days.
  
  
  CONCLUSIONS
  Low classification accuracy was found for the ActivPAL™ and the GT1M ActiGraph to measure sedentary behavior in preschoolers. No correction factor can be suggested to make the sedentary estimates of the GT1M ActiGraph and the ActivPAL™ convergent as no systematic bias and wide limits of agreement were found. Furthermore, the practical utility of the ActivPAL™ was perceived to be lower compared with the ActiGraph accelerometer in preschoolers.
authors.affiliation: 1Department of Movement and Sport Sciences, Ghent University, BELGIUM; and 2Faculty of Health Science, University of León, Ponferrada, SPAIN.
authors.forename: Ellen
authors.initials: E
authors.lastname: De Decker
authors.forename: Marieke
authors.initials: M
authors.lastname: De Craemer
authors.forename: Alejandro
authors.initials: A
authors.lastname: Santos-Lozano
authors.forename: Eveline
authors.initials: E
authors.lastname: Van Cauwenberghe
authors.forename: Ilse
authors.initials: I
authors.lastname: De Bourdeaudhuij
authors.forename: Greet
authors.initials: G
authors.lastname: Cardon
mesh_terms: D061725:Accelerometry / Q000009:adverse effects / Q000295:instrumentation*; D019540:Area Under Curve; D002648:Child; D002675:Child, Preschool; D003877:Dermatitis, Contact / Q000209:etiology; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D019370:Observation; D012372:ROC Curve; D057185:Sedentary Behavior; D014743:Videotape Recording