The use of the intensity gradient and average acceleration metrics to explore associations with BMI z-score in children

Duncan S. Buchan, Gillian McLellan, Samantha Donnelly, Rosie Arthur

Research output: Contribution to journalArticle

Abstract

This study used the intensity gradient (IG) and average acceleration metrics to describe children’s activity profiles and explore associations with body mass index (BMI) z-score. Two hundred and forty-six children (n = 138 girls) aged 9.6 ± 1.4 years wore a wrist-mounted ActiGraph wGT3X-BT accelerometer for 7 days on their non-dominant wrist. Physical activity (PA) metrics captured included: the IG which describes the intensity distribution of accelerations across the 24 h monitoring period; average acceleration which provides a measure of the volume of activity; total moderate-to-vigorous PA (MVPA) and inactive time. Acceleration was averaged over 5s epochs. Finally, BMI z-score was calculated for each participant. Average acceleration was negatively associated with BMI z-score (p<0.05) independent of age and gender but not IG. The IG was negatively associated with BMI z-score independent of potential correlates and average acceleration. Total MVPA was not associated with BMI-z score. The IG and average acceleration metrics may be used to explore the independent or cumulative effects of the volume and intensity distribution of activity upon measures of health and well-being in children to inform specific activity recommendations.
Original languageEnglish
Pages (from-to)2751-2758
Number of pages8
JournalJournal of Sports Sciences
Volume37
Issue number23
Early online date10 Sep 2019
DOIs
Publication statusPublished - 2 Dec 2019

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Keywords

  • ActiGraph
  • Accelerometer
  • Activity metrics
  • Wrist-worn
  • Raw acceleration

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