Funding for this research was provided by:
Marga und Walter Boll-Stiftung (220-09-14, 220-03-16)
Received: 7 August 2020
Accepted: 19 August 2020
First Online: 10 September 2020
Ethics approval and consent to participate
: The Ethics Committee of the German Sport University Cologne (No 108/2014), the Ethics Committee of the University Bonn Medical School (No. 087/15) and the Ethics Committee of the University of Düsseldorf (No 2017034172) have approved all protocols. Protocol modifications need to be reported to the Ethics Committees. The study will be conducted in accordance with the declaration of Helsinki and was registered under registration trial number DRKS00007702 on DRKS. Informed written consent will be obtained from each participant (mother and father) prior to enrolment. The informed consent remains at the study center at the German Sport University Cologne.
: Not applicable.
: The authors declare that they have no competing interest.