Statistical analyses
Sample size calculations are based on the assessment of the neuropsychological outcome measures using “G-Power 3.1.” Based on an expected effect size of The effect of the intervention relative to the control condition was analyzed using linear mixed-effects models. Compound outcome measures were standardized over time. Group (intervention versus control) was included as a factor. A random intercept was included in all models. Percentage of missingness of all outcome variables varied between 0.37 and 2.21%. The linear mixed model analyses were repeated using the increase in physical activity between T0 and T2 as grouping variable, i.e., ≥ 35%, increase in average number of steps per day versus no increase, or < 35% in average number of steps per day at T2, 9 months after the start of the intervention. All analyses were adjusted for baseline performance, age, and sex (model A) and additionally for education level and 