Funding for this research was provided by:
Centrum for Idrottsforskning (P2018-0167)
Text and Data Mining valid from 2019-04-13
Received: 12 September 2018
Accepted: 1 April 2019
First Online: 13 April 2019
Compliance with ethical standards
: All authors declare no conflict of interest.
: This study was approved by the Regional Ethical Review Board in Linköping (Project number Dnr 2017/294-31).