Study protocol for the ACTIVE SCHOOL study investigating two different strategies of physical activity to improve academic performance in Schoolchildren.

"Declarations Ethics approval and consent to participateInformed consent was obtained from all parents/legal guardian(s) of participating children and participating teachers in a written form (see Supplementary Material 2). The study has been approved by the local Ethical Committee at University of Copenhagen (protocol: 504 − 0333/22-5000), and will be carried out in accordance with the Helsinki Declaration. The trial has been registered 25th of October 2022 in ClinicalTrials.gov, NCT05602948 and any important protocol modifications will be registered and verified here. Consent for publicationNot applicable. Competing interestsNone of the involved researchers have any financial or other competing interest in the trial. The academic test company Hogrefe has no commercial interest in the study. Competing interests None of the involved researchers have any financial or other competing interest in the trial. The academic test company Hogrefe has no commercial interest in the study."

"Funding Open access funding provided by Copenhagen University. The project is financially supported by the Independent Research Fund Denmark (0132-00160B). The funder has no influence on the study design; collection, management, analysis, and interpretation of data; writing of the report; or the decision to submit the report for publication. Open access funding provided by Copenhagen University"

"Trial registration The study was registered on the 25th of October 2022 in ClinicalTrials.gov, NCT05602948."