Footnotes

• Correction notice This article has been corrected since it published Online First. The title has been corrected.

• Contributors The corresponding author has the right to grant on behalf of all authors and does grant on behalf of all authors, an exclusive license (or non-exclusive for government employees) on a worldwide basis to the BMJ Publishing Group Ltd and its licensees to permit this article (if accepted) to be published in Journal (British Journal of Sports Medicine) editions and any other BMJPGL products to exploit all subsidiary rights, as set out in our license.

• Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

• Competing interests None declared.

• Patient consent for publication Not required.

• Provenance and peer review Not commissioned; externally peer reviewed.