“Don’t worry”: Similar to ordinary PE in separate classes but students have the opportunity to choose their activity. “Be happy”: students pursue activities of their choice, in groups across homeroom classes, that they formed themselves

Students choose activity based on interest, not based on who they can be together within the group. Groups should stay together. Maximum eight students per group

Sufficient information must be given to the students. Students must use the activity contract to conduct long-term planning. All groups must have a leadership structure, group goals and plan for conflict resolution

5% of time from other subjects should be taken to make room for one lesson. The second comes in addition to the ordinary schedule

Sufficient facilities and equipment

Sufficient teacher-to-student ratio

Teachers should be available and able to help when necessary. They should interfere when necessary by recognizing the need for flexibility, evaluation, group alterations and conflict resolution

Positive response toward DWBH, and regarding the intervention as relevant, useful, advantageous in any way

Responsiveness also applies to how the teachers respond to the intervention

Two lessons per week during the 29-week intervention period

No predetermined adaptations have been defined. Small adaptations can be made if necessary and/or if they benefit overall implementation