Multivariate physical activity signatures of physical well-being in children: a cross-sectional study

Background: Physical activity is advocated to promote well-being among children. However, our understanding of the association between the full spectrum of physical activity intensity and physical well-being is limited. Methods A cross-sectional study design was applied to explore the associations between physical well-being and physical activity signatures in 10-year-olds. We also conducted stratified analyses for girls and boys without and with overweight/obesity. Kidscreen-27 was used to assess physical well-being, and accelerometers (ActiGraph GT3X+) were used to measure physical activity by deriving 23 intensity levels ranging from 0–99 to ≥ 10,000 counts per minute (cpm). Associations between physical well-being and physical activity were examined using partial least square regression analysis, adjusted for covariates. Results We included 722 fifth graders (10.2 ± 0.3 years, waist circumference 61.8 ± 7.4 cm, 51% boys). In the total sample, the physical activity signature explained 5.23% of the variance in physical well-being, 2.03% for girls and 9.06% for boys. The explained variance for boys without overweight/obesity was 8.63%, compared to 20.03% for those with overweight/obesity. There was no association for girls without overweight/obesity compared to an explained variance of 8.93% in those with overweight/obesity. The strongest associations were found for high-intensity physical activity (6000–7000 cpm). Conclusion Signatures displaying high-intensity physical activity were associated with better physical well-being in children, particularly in those with overweight/obesity. Trial registration: This study presents a cross-sectional secondary analysis of a cluster-randomised controlled trial: The Active Smarter Kids (ASK) study (Clinicaltrials.gov ID number, NCT02132494).