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

Abstract

ObjectivesTo 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.DesignPooled 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.ParticipantsData for 6621 children and adolescents aged 4–18 years from 20 trials were included.Main outcome measuresPeak oxygen consumption (VO2Peak mL/kg/min) and minutes of moderate and vigorous physical activity.ResultsInterventions 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.ConclusionsFuture 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.

Scaling up Action Schools! BC: How Does Voltage Drop at Scale Affect Student Level Outcomes? A Cluster Randomized Controlled Trial

“…Despite greater PA delivery by teachers in year 1, students’ PA did not increase significantly. This is consistent with some [ 22 , 62 ], but not all [ 63 , 64 ], systematic reviews published in the last 10 years. Even when improvements in students’ PA were observed in other trials, the effect was modest.…”

“…While this was not statistically significant after controlling for the relatively small number of variably sized clusters, we recognize the limitations of relying solely on p values [ 54 ]. This between-group difference corresponds to approximately 30–60 s additional running or a difference in peak oxygen consumption of approximately 1.0 mL/kg/min for boys and 1.9 mL/kg/min for girls at the end of year one–two to four times greater than that observed in a recent pooled analysis of 20 controlled trials [ 63 ]. We consider the magnitude of change indicated by the meaningful effect sizes, particularly in girls, an important finding.…”

“…Even when improvements in students’ PA were observed in other trials, the effect was modest. For example, across 20 controlled trials students’ PA (moderate and vigorous) increased by approximately one min/day [ 63 ].…”

“…We consider the magnitude of change indicated by the meaningful effect sizes, particularly in girls, an important finding. On average, girls are less fit compared with boys—a difference which increases with age and maturation [ 65 ]—and, tend to benefit less from interventions than boys [ 63 ]. We also consider this result promising in light of the suggested secular decline in children’s fitness of 7.3% between 1981 and 2014 [ 7 ].…”

Socio-ecological correlates of physical activity in a nationally representative sample of adolescents across Ireland and Northern Ireland

“…For example, previous research found ‘no association’ between enjoyment and PA ( Sterdt et al, 2014 , Van Der Horst et al, 2007 ), our results suggest that this may be too simplistic an interpretation as we found that the PA enjoyment relationship differed in terms of its direction (positive or negative) and its strength depending on the individual’s activity status. As the effectiveness of PA interventions for adolescents is being questioned ( Hartwig et al, 2021 , Love et al, 2019 ), this more holistic approach to correlate investigation that accounts for individual activity status may highlight realistic and acceptable intervention strategies especially for the hard-to-reach groups.…”