Funding for this research was provided by:
Marga und Walter Boll-Stiftung (Grant number: 210-06.01-19)
Text and Data Mining valid from 2019-12-01
Received: 30 October 2019
Accepted: 26 November 2019
First Online: 6 December 2019
Ethics approval and consent to participate
: This study was approved by the regional ethics committee of the German Sports University Cologne. Prior to study participation, a written consent form will be signed by each participant.
: Not applicable.
: The authors declare that they have no competing interests.