Sample
Of Norwegian public schools that met the inclusion criteria, we randomly invited schools to participate in ScIM. If a school declined the invitation, another school in the respective region was randomly selected and invited, until the target of 30 schools was included. Thereafter, 20 schools were randomly allocated to the intervention group and 10 to the control group. One control school withdrew from the study after randomization, and one intervention school withdrew after 12 weeks of performing the intervention, resulting in 28 schools in the final sample. We invited 2733 pupils whereas 2084 agreed to participate in the data collection (response rate 76%), and 1370 had valid pre-post data on travel habits in all four outcomes. Exclusion criteria for participation were that the schools had (1) less than 25 pupils in 9th grade, (2) any initiatives to increase mandatory physical activity during school hours, (3) participation in another comprehensive research project, and (4) private schools or (5) schools exclusively for pupils with special needs.