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Open access

Stewart G. Trost, Christopher C. Drovandi, and Karin Pfeiffer

Background:

Published energy cost data for children and adolescents are lacking. The purpose of this study was to measure and describe developmental trends in the energy cost of 12 physical activities commonly performed by youth.

Methods:

A mixed age cohort of 209 participants completed 12 standardized activity trials on 4 occasions over a 3-year period (baseline, 12-months, 24-months, and 36-months) while wearing a portable indirect calorimeter. Bayesian hierarchical regression was used to link growth curves from each age cohort into a single curve describing developmental trends in energy cost from age 6 to 18 years.

Results:

For sedentary and light-intensity household chores, YOUTH METs (METy) remained stable or declined with age. In contrast, METy values associated with brisk walking, running, basketball, and dance increased with age.

Conclusions:

The reported energy costs for specific activities will contribute to efforts to update and expand the youth compendium.

Open access

Kimberly A. Clevenger, Aubrey J. Aubrey, Rebecca W. Moore, Karissa L. Peyer, Darijan Suton, Stewart G. Trost, and Karin A. Pfeiffer

Background:

Limited data are available on energy cost of common children’s games using measured oxygen consumption.

Methods:

Children (10.6 ± 2.9 years; N = 37; 26 male, 9 female) performed a selection of structured (bowling, juggling, obstacle course, relays, active kickball) and unstructured (basketball, catch, tennis, clothespin tag, soccer) activities for 5 to 30 minutes. Resting metabolic rate (RMR) was calculated using Schofield’s age- and sex-specific equation. Children wore a portable metabolic unit, which measured expired gases to obtain oxygen consumption (VO2), youth METs (relative VO2/child’s calculated RMR), and activity energy expenditure (kcal/kg/min). Descriptive statistics were used to summarize data.

Results:

Relative VO2 ranged from 16.8 ± 4.6 ml/kg/min (bowling) to 32.2 ± 6.8 ml/kg/min (obstacle course). Obstacle course, relays, active kickball, soccer, and clothespin tag elicited vigorous intensity (>6 METs), the remainder elicited moderate intensity (3–6 METs).

Conclusions:

This article contributes energy expenditure data for the update and expansion of the youth compendium.

Open access

Nicole K. Nathan, Rachel L. Sutherland, Kirsty Hope, Nicole J. McCarthy, Matthew Pettett, Ben Elton, Rebecca Jackson, Stewart G. Trost, Christophe Lecathelinais, Kathryn Reilly, John H. Wiggers, Alix Hall, Karen Gillham, Vanessa Herrmann, and Luke Wolfenden

Aim: To assess the impact of a multistrategy intervention designed to improve teachers’ implementation of a school physical activity (PA) policy on student PA levels. Methods: A cluster-randomized controlled trial was conducted in 12 elementary schools. Policy implementation required schools to deliver 150 minutes of organized PA for students each week via physical education, sport, or class-based activities such as energizers. Schools received implementation support designed using the theoretical domains framework to help them implement the current policy. Results: A total of 1,502 children in kindergarten to grade 6 participated. At follow-up compared with control, students attending intervention schools had, measured via accelerometer, significantly greater increases in school day counts per minute (97.5; 95% confidence interval [CI], 64.5 to 130.4; P < .001) and moderate to vigorous physical activity (MVPA) (3.0; 95% CI, 2.2–3.8, P < .001) and a greater decrease in sedentary time (−2.1; 95% CI, −3.9 to −0.4, P = .02) per school day. Teachers in intervention schools delivered significantly more minutes (36.6 min) of PA to their students at follow-up (95% CI, 2.7–70.5, P = .04). Conclusions: Supporting teachers to implement a PA policy improves student PA. Additional strategies may be needed to support teachers to implement activities that result in larger gains in student MVPA.