Sensitivity analysis, school c7 excluded.

PA in the intervention (n = 376) and control (n = 344) group at baseline and follow-up.
aEffect analyses adjusted for baseline PA, sex, age, weekend/weekdays. School, class and student were included as random effects to account for clustering. bEffect analyses adjusted for baseline PA, sex, age. School and class included as random effects to account for clustering.*Back-transformed estimate based on analysis of log-transformed outcome. Due to log-transformation, no confidence interval is calculated. PA: physical activity, MVPA: moderate and vigorous physical activity. Cpm: counts per minute, ICC: Intraclass correlation.