Randomization
The Movementss study is a two-arm randomized controlled trial; patients fulfilling eligibility criteria and willing to participate will be randomized after baseline assessment (1:1 allocation ratio) in either the lifestyle intervention or CAU group using block randomization, with varying random block sizes of 2, 4 or 6. A priori, an independent statistician will prepare a computer-generated randomization schedule stratified for weight (underweight, normal, overweight), sex (male, female), and age (6–8 years, 9–12 years) to ensure that the number of participants in both treatment arms is closely balanced within each stratum. Castor EDC will be used for the actual randomization process. After obtaining informed consent and baseline measurements, the study coordinator will provide the randomization code. Participants, researchers, and practitioners are aware of treatment allocations.