title: Evaluation of Actical equations and thresholds to predict physical activity intensity in young children.
abstract: Abstract This study examined the validity of current Actical activity energy expenditure (AEE) equations and intensity cut-points in preschoolers using AEE and direct observation as criterion measures. Forty 4-6-year-olds (5.3 ± 1.0 years) completed a ~150-min room calorimeter protocol involving age-appropriate sedentary behaviours (SBs), light intensity physical activities (LPAs) and moderate-to-vigorous intensity physical activities (MVPAs). AEE and/or physical activity intensity were calculated using Actical equations and cut-points by Adolph, Evenson, Pfeiffer and Puyau. Predictive validity was examined using paired sample t-tests. Classification accuracy was evaluated using weighted kappas, sensitivity, specificity and area under the receiver operating characteristic curve. The Pfeiffer equation significantly overestimated AEE during SB and underestimated AEE during LPA (P < 0.0125 for both). There was no significant difference between measured and predicted AEEs during MVPA. The Adolph cut-point showed significantly higher accuracy for classifying SB, LPA and MVPA than all others. The available Actical equation does not provide accurate estimates of AEE across all intensities in preschoolers. However, the Pfeiffer equation performed reasonably well for MVPA. Using cut-points of ≤6 counts · 15 s(-1), 7-286 counts · 15 s(-1) and ≥ 287 counts · 15 s(-1) when classifying SB, LPA and MVPA, respectively, is recommended.
authors.affiliation: a Interdisciplinary Educational Research Institute , University of Wollongong , Wollongong , Australia.
authors.forename: Xanne
authors.initials: X
authors.lastname: Janssen
authors.forename: Dylan
authors.initials: D
authors.lastname: Cliff
authors.forename: John
authors.initials: J
authors.lastname: Reilly
authors.forename: Trina
authors.initials: T
authors.lastname: Hinkley
authors.forename: Rachel
authors.initials: R
authors.lastname: Jones
authors.forename: Marijka
authors.initials: M
authors.lastname: Batterham
authors.forename: Ulf
authors.initials: U
authors.lastname: Ekelund
authors.forename: Søren
authors.initials: S
authors.lastname: Brage
authors.forename: Tony
authors.initials: T
authors.lastname: Okely
mesh_terms: D056044:Actigraphy / Q000706:statistics & numerical data*; D002151:Calorimetry; D002648:Child; D002675:Child, Preschool; D003627:Data Interpretation, Statistical; D004734:Energy Metabolism; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity / Q000502:physiology*; D012680:Sensitivity and Specificity
keywords: accelerometry; preschoolers; room calorimeter