FIT FIRST FOR ALL - The Dose-Response Study

In the present study, FIT FIRST 10 will run over 20 weeks, with cardiometabolic fitness as the primary outcome and project acceptability as the co-primary outcome. In this study the investigators will be testing the dose-response of the FIT FIRST concept by having two experimental groups. This will be a cluster RCT with a 1:1:1 recruitment of control schools, intervention schools with 3 weekly 40-min FIT FIRST 10 lessons, and intervention schools with 1.5 weekly 40-min session. There will be recruited a total of 1000 children, with 500 8-9-year-olds from 2nd and 3rd grade in each group from a minimum of 40 classes from 16 schools. There will be subgroup analyses of children with low socioeconomic status and ethnic minority background. Intervention effects will be tested as on health profile, cardiometabolic and musculoskeletal fitness, motivation for physical activity, acceptability of the programme for stakeholders as well as the implementation potential. The study will be running in Q1 and Q2 in 2023. It is hypothesized that the FIT FIRST 10 concept will improve the well-being, increase sports club participation as well as increase fitness and health levels among 8-9-year-old children with low fitness, low socioeconomic and/or ethnic minority background. However, it is also hypothesized that the effects on well-being and fitness levels caused by the intervention may be most significant among ethnic minority children not enrolled in sports clubs.