Received: 19 August 2020
Accepted: 9 November 2020
First Online: 24 November 2020
Ethics approval and consent to participate
: The study design was reviewed and approved by the Ethics Committee of the Faculty of Medicine, University of Miyazaki (approval number 0-0759). The procedures were in accordance with the ethical standards of the responsible committees on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2013. Information regarding the conduct of this study was disclosed at both HP of Japan Rugby Football Union and the Faculty of Medicine, University of Miyazaki, and research participants were provided an opportunity to refuse inclusion in this study. The participants who did not want to take part were not enrolled in this study. No participants refused inclusion in the study.
: Not applicable
: The authors declare that they have no competing interest.