Role of moderate- to vigorous-intensity physical activity bouts in body fat and aerobic fitness in elementary school children

BACKGROUND: Improvements in obesity and aerobic fitness are important factors contributing to achievements of physical and mental health in children. Moderate-to vigorous-intensity physical activity (MVpA) can improve obesity and aerobic fitness. Although these beneficial effects of MVPA may vary with bout duration, the associations of moder- ate-to vigorous-intensity physical activity bouts (MVPA-bouts) with body fat and aerobic fitness have not been fully elucidated. The aim of this study was to examine the associations between accelerometer-derived MVPA-bouts, body composition, and aerobic fitness in elementary school children. METHODS: A total of 191 elementary school children (102 boys and 89 girls) were included in this study. MVPA-bout, percent body fat (PBF), and the 20m shuttle run were measured in all the children. MVPA-bout was defined by five thresholds of consecutive duration (over 16-sec, 32-sec, 1-min, 3-min, and 5-min) using a uniaxial accelerometer.RESULTS: There were significant correlations of 16-sec, 32-sec, and 1-min MVPA-bouts with PBF and 20m shuttle run, but not 3-min and 5-min MVPA-bouts, independent of grade and sex. Additionally, PBF was associated with the 20m shuttle run. Mediation analysis showed that PBF significantly mediated the relationship of 16-sec, 32-sec, and 1-min MVPA-bouts with the 20m shuttle run.CONCLUSIONS: A higher frequency of shorter MVPA-bouts is associated with higher aerobic fitness through lower body fat in elementary school children.(Cite this article as: Matsui M, Yokota Y, Togashi K. Role of moderate-to vigorous-intensity physical activity bouts in body fat and aerobic fitness in elementary school children. Gazz Med Ital -Arch Sci Med 2023;182:114-20. DOI: 10.23736/S0393-3660.22.04910-5)