School-based interventions modestly increase physical activity and cardiorespiratory fitness but are least effective for youth who need them most: an individual participant pooled analysis of 20 controlled trials.

OBJECTIVES: To determine if subpopulations of students benefit equally from school-based physical activity interventions in terms of cardiorespiratory fitness and physical activity. To examine if physical activity intensity mediates improvements in cardiorespiratory fitness. DESIGN: Pooled analysis of individual participant data from controlled trials that assessed the impact of school-based physical activity interventions on cardiorespiratory fitness and device-measured physical activity. PARTICIPANTS: Data for 6621 children and adolescents aged 4-18 years from 20 trials were included. MAIN OUTCOME MEASURES: Peak oxygen consumption (VO2Peak mL/kg/min) and minutes of moderate and vigorous physical activity. RESULTS: Interventions modestly improved students' cardiorespiratory fitness by 0.47 mL/kg/min (95% CI 0.33 to 0.61), but the effects were not distributed equally across subpopulations. Girls and older students benefited less than boys and younger students, respectively. Students with lower levels of initial fitness, and those with higher levels of baseline physical activity benefitted more than those who were initially fitter and less active, respectively. Interventions had a modest positive effect on physical activity with approximately one additional minute per day of both moderate and vigorous physical activity. Changes in vigorous, but not moderate intensity, physical activity explained a small amount (~5%) of the intervention effect on cardiorespiratory fitness. CONCLUSIONS: Future interventions should include targeted strategies to address the needs of girls and older students. Interventions may also be improved by promoting more vigorous intensity physical activity. Interventions could mitigate declining youth cardiorespiratory fitness, increase physical activity and promote cardiovascular health if they can be delivered equitably and their effects sustained at the population level.

The effect of physical-activity intervention on children's health-related quality of life.

Aims: We investigated the effect of a school-based physical-activity intervention on children's health-related quality of life (HRQoL) and the potential influence of moderate to vigorous physical activity (MVPA). Methods: A randomised, controlled trial (Active School) involving fifth-grade children was conducted during the 2014/15 school year. The sample included 435 children (10-11 years old) at five intervention schools and four control schools. The weekly interventions concerned two 45 min of physically active lessons, five 10 min of physically active breaks and five 10 min of physically active homework. The children's HRQoL was measured using KIDSCREEN-27 and a self-report questionnaire, while physical activity was measured using accelerometers. Results: The results of multilevel analysis showed a significant effect on psychological wellbeing (p = 0.005), social support and peers (p = 0.005) and school environment (p = 0.013). No gender differences were observed. Children's MVPA did not influence their KIDSCREEN-27 score. Conclusions: The school-based physical-activity intervention (Active School) shows positive effects on children's self-reported psychological wellbeing, social support and peers, and school environment.

Physically active academic lessons and effect on physical activity and aerobic fitness. The Active School study: A cluster randomized controlled trial.

The Active School program was designed to positively impact health and academic-related outcomes in school. The core intervention component was physically active academic lessons, a teaching activity that combines physical activity and educational content. The purpose of this study was to investigate the effect of a 10-month, cluster-randomized controlled trial on physical activity level and aerobic fitness conducted in the city of Stavanger, Norway, in 2014-15. The physical activity level during physically active academic lessons was also studied. A total of 447 children (9-10 years) participated. The weekly intervention consisted of physically active academic lessons, physically active homework and physically active recess. Physical activity level and aerobic fitness were measured objectively by accelerometry and a 10-minute interval running test. Intervention effects were found for time in moderate to vigorous physical activity (MVPA) (adjusted mean difference of 8 min/day, 95% CI: 3.4-13, p < 0.001) and total physical activity (60 counts/min, 95% CI: 15-105, p = 0.009). Children with low aerobic fitness increased their running distance compared to controls (d = 0.46; p = 0.001). During physically active academic lessons children spent 26% of the time in MVPA, which was comparable to physical education lessons. The Active School program successfully increased physical activity for the intervention group and aerobic fitness for the least fit children. The activity level during physically active academic lessons was as high as in physical education lessons. Clinicaltrail.gov ID identifier: NCT03436355.