1 Division of Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
2 Department of Public and Occupational Health and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands.
3 South African Rugby Union, Cape Town, South Africa.
4 Chris Burger Petro Jackson Players' Fund, Sports Science Institute of South Africa, Cape Town, South Africa.
5 Australian Collaboration for Research into Injury in Sport and its Prevention (ACRISP), Federation University Australia, Ballarat, Australia.