The interactive relationship of dietary choline and betaine with physical activity on circulating creatine kinase (CK), metabolic and glycemic markers, and anthropometric characteristics in physically active young individuals.

"Declarations Ethics approval and consent to participateThis study protocol was approved by the ethics committee of the Tabriz University of Medical Sciences (Code: IR.TBZMED.REC.1401.033). Written informed consent was obtained from all of the participants before participation in the study. All methods in the current research were performed according to the Declaration of Helsinki's guidelines and regulations. Consent for publicationNot applicable. Competing interestsThe authors declare no competing interests. Competing interests The authors declare no competing interests."

"Funding The present study was financially supported by a grant from Tabriz University of Medical Sciences. (Code: IR.TBZMED.REC.1401.033). The funders had no role in hypothesis generation, recruiting, and designing the study. Their role was only financial support."