1 Department of Anaesthesiology, The University of Auckland, Private Bag 92019, Victoria Street West, Auckland, 1142, New Zealand. jweb018@aucklanduni.ac.nz.
2 Surf Life Saving New Zealand, PO Box 39129, Lower Hutt 5045, Wellington, New Zealand. jweb018@aucklanduni.ac.nz.
3 Department of Emergency Medicine, University of Florida College of Medicine-Jacksonville, 655 W 8th St, Jacksonville, FL, 32209, USA.
4 Lifeguards Without Borders, 1311A Canal Dr, Carolina Beach, NC, 28428, USA.
5 Lifeguards Without Borders, PO Box 737, Kuna, ID, 83634, USA.
6 Sociedade Brasileira de Salvamento Aquático, Av das Américas 3555, Bloco 2, Sala 302, Barra da Tijuca, Rio de Janeiro, RJ, 22631-004, Brazil.
7 EPI-Unit, Institute of Public Health, University of Porto, Rua das Taipas, 135, 4050-600, Porto, Portugal.
8 School of Kinesiology and Health Science, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada.
9 Surf Life Saving Australia, Locked Bag 1010, Rosebery, NSW, 2018, Australia.