Background: To examine the relationships among school day sedentary times (SED), light physical activity (LPA), and moderate to vigorous physical activity (MVPA) with gross motor skills in children using Compositional Data Analysis. Methods: Participants were 409 children (mean age = 8.4 [1.8] y) recruited across 5 low-income schools. Gross motor skills were assessed using the test for gross motor development—third edition (TGMD-3), and physical activity was assessed using accelerometers. Isometric log-ratio coordinates were calculated by quantifying the relative proportion of percentage of the school day spent in SED, LPA, and MVPA. The associations of the isometric log-ratio coordinates with the TGMD-3 scores were estimated using general linear mixed-effects models adjusted for age, body mass index, estimated aerobic capacity, and school affiliation. Results: A higher proportion of the school day spent in %MVPA relative to %SED and %LPA was significantly associated with higher TGMD-3 total scores (γ MVPA = 14.44, P = .01). This relationship was also observed for the ball skills subtest scores (γ MVPA = 16.12, P = .003). Conclusions: Replacing %SED and %LPA with %MVPA during school hours may be an effective strategy for improving gross motor skills, specifically ball skills, in low-income elementary school-aged children.
Ryan D. Burns, Youngwon Kim, Wonwoo Byun, and Timothy A. Brusseau
Greg Welk, Youngwon Kim, Robin P. Shook, Laura Ellingson, and Roberto L. Lobelo
The study evaluated the concurrent and criterion validity of a new, disposable activity monitor designed to provide objective data on physical activity and energy expenditure in clinical populations.
A sample of healthy adults (n = 52) wore the disposable Metria IH1 along with the established Sensewear armband (SWA) monitor for a 1-week period. Concurrent validity was examined by evaluating the statistical equivalence of estimates from the Metria and the SWA. Criterion validity was examined by comparing the relative accuracy of the Metria IH1 and the SWA for assessing walking/running. The absolute validity of the 2 monitors was compared by computing correlations and mean absolute percent error (MAPE) relative to criterion data from a portable metabolic analyzer.
The output from 2 monitors was highly correlated (correlations > 0.90) and the summary measures yielded nearly identical allocations of time spent in physical activity and energy expenditure. The monitors yielded statistically equivalent estimates and had similar absolute validity relative to the criterion measure (12% to 15% error).
The disposable nature of the adhesive Metria IH1 monitor offers promise for clinical evaluation of physical activity behavior in patients. Additional research is needed to test utility for counseling and behavior applications.
Jung-Min Lee, Pedro F. Saint-Maurice, Youngwon Kim, Glenn A. Gaesser, and Gregory Welk
The assessment of physical activity (PA) and energy expenditure (EE) in youth is complicated by inherent variability in growth and maturation during childhood and adolescence. This study provides descriptive summaries of the EE of a diverse range of activities in children ages 7 to 13.
A sample of 105 7- to 13-year-old children (boys: 57%, girls: 43%, and Age: 9.9 ± 1.9) performed a series of 12 activities from a pool of 24 activities while being monitored with an indirect calorimetry system.
Across physical activities, averages of VO2 ml·kg·min-1, VO2 L·min-1, EE, and METs ranged from 3.3 to 53.7 ml·kg·min-1, from 0.15 to 3.2 L·min-1, from 0.7 to 15.9 kcal·min-1, 1.5 MET to 7.8 MET, respectively.
The energy costs of the activities varied by age, sex, and BMI status reinforcing the need to consider adjustments when examining the relative intensity of PA in youth.