Purpose To describe physical activity (PA) intensity across a school day and assess the percentage of girls and boys achieving recommended guidelines.

Methods The authors measured PA via accelerometry in 380 children (8–11 years) and examined data representing (1) the whole school day, (2) regular class time, (3) recess, (4) lunch and (5) scheduled physical education (PE). Activity was categorised as sedentary (SED), light physical activity (LPA) or moderate to vigorous physical activity (MVPA) using age-specific thresholds. They examined sex differences across PA intensities during each time period and compliance with recommended guidelines.

Results Girls accumulated less MVPA and more SED than boys throughout the school day (MVPA −10.6 min; SED +13.9 min) recess (MVPA −1.6 min; SED +1.7 min) and lunch (MVPA −3.1 min; SED +2.9 min). Girls accumulated less MVPA (−6.2 min), less LPA (−2.5 min) and more SED (+9.4 min) than boys during regular class time. Fewer girls than boys achieved PA guidelines during school (90.9% vs 96.2%), recess (15.7% vs 34.1%) and lunch (16.7% vs 37.4%). During PE, only 1.8% of girls and 2.9% of boys achieved the PA guidelines. Girls and boys accumulated similar amounts of MVPA, LPA and SED.

Conclusion The MVPA deficit in girls was due to their sedentary behaviour as opposed to LPA. Physical activity strategies that target girls are essential to overcome this deficit. Only a very small percentage of children met physical activity guidelines during PE. There is a great need for additional training and emphasis on PA during PE. In addition schools should complement PE with PA models that increase PA opportunities across the school day.