Received: 4 August 2020
Accepted: 21 December 2020
First Online: 7 January 2021
Ethics approval and consent to participate
: The Ethics Committee of the German Sport University Cologne (reference: 127/2019) approved the study. Informed consent was given (via check box) prior to the beginning of the online survey.
: Not applicable.
: The authors declare that they have no competing interests.