**5. Conclusions**

This study showed a positive association between BMCs, social integration, and HRQoL. In both preschool and primary school, children with better BMCs seemed to be better integrated socially in the class. Children with better BMCs showed better general HRQoL in primary school and better physical well-being in preschool. The improvement of BMCs and social integration in the class could contribute to higher HRQoL. Furthermore, additional opportunities for movement with an integrative character and opportunities for co-determination could be implemented both in PE and in extracurricular activities. Since both BMCs and social integration are linked to better HRQoL, we recommend creating inclusive situations in physical settings in which it is possible to improve both BMCs and social integration. Consequently, BMCs should be considered to improve both social integration and HRQoL.

**Author Contributions:** Conceptualization, C.H., K.B., I.F., R.K., J.K. and H.S.; methodology, C.H., K.B. and H.S.; validation, C.H. and H.S.; formal analysis, K.B.; investigation, S.S., I.F., J.K. and K.B.; data curation, K.B. and H.S.; writing—original draft preparation, K.B.; writing—review and editing, K.B., H.S., I.F., R.K., J.K, S.S. and C.H.; supervision, C.H.; project administration, C.H., S.S., J.K. and K.B..; funding acquisition, K.B., H.S., I.F., R.K., J.K., S.S. and C.H. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Health Promotion Switzerland (Gesundheitsförderung Schweiz, GFCH) and the Zurich University of Teacher Education (PHZH).

**Institutional Review Board Statement:** The study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committees of the University of Zurich (Nr. 21.2.5, 08.03.2021) and the Ticino canton (Nr. 2021-00252, Rif CE Ti 3819, 03.02.2021).

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study or their parents.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to the ethical guidelines of the Cantonal School Authorities.

**Acknowledgments:** The authors would like to thank all schools, teachers, pupils, and parents for participating in this study.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
