Moderate‐to‐vigorous physical activity (
Over 12 months, both groups increased accelerometer‐measured MVPA (+22.5 min/week; 95% CI, 8.76–36.2 in intervention vs. +13.9 min/week, 95% CI, 2.97–24.9 in self‐help), with no between‐group difference (Changes in accelerometer‐measured and self‐reported moderate‐to‐vigorous physical activity by group over 12 months. Unadjusted means, with error bars showing 95% confidence intervals. The proportion of YACS meeting PA guidelines at 12 months based on accelerometer data was 8.5% in the intervention versus 5.0% in the self‐help group, with no differences in relative risk (1.76 [95% CI, 0.68–4.56]; 