This study was designed to model the relationship between an ActiGraph-based “in-school” physical activity (PA) and the daily one among children and to quantify how school can contribute to the daily PA recommendations.
Fifty boys and 43 girls (aged 8 to 11 years) wore ActiGraph for 2 schooldays of no structured PA. The daily moderate-to-vigorous PA (MVPAd) was regressed on the school time MVPA (MVPAs). Then, a ROC analysis was computed to define the required MVPAs.
Children spent 57% of their awaking time at school. School time PA opportunities (ie, recesses: ~18% of a child’s awaking time) accounted for >70% of the MVPAd among children. Then, MVPAd (Y) could be predicted from MVPAs (X) using the equation: Y = 2.06 X 0.88; R 2 = .889, P < .0001. Although, this model was sex-specifically determined, cross-validations showed valid estimates of MVPAd. Finally, with a sensitivity of 100% and a specificity of 90%, MVPAs, a 34 min.d−1 was required to prompt the daily recommendation.
The current study shows the contribution of MVPA at school to recommended activity levels and suggests the value of activity performed during recesses. It also calls for encouraging both home- and community-based interventions, predominantly directed toward girls.