Footnotes

• Twitter @MartensGege, @c_pgr

• Contributors GM and RSe drafted the manuscript outline. GM, RSe, CP and RSi wrote the manuscript. CP, RSe, MO, JMF, PD, JNA and PT critically reviewed the manuscript for intellectual content. All authors approved the final version of the manuscript.

• Funding Part of this work was supported by the International Olympic Committee Medical and Scientific Commission through the IOC Research Centres Network.

• Competing interests None declared.

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