RT Journal Article SR Electronic T1 Medical encounters, cardiac arrests and deaths during a 109 km community-based mass-participation cycling event: a 3-year study in 102 251 race starters—SAFER IX JF British Journal of Sports Medicine JO Br J Sports Med FD BMJ Publishing Group Ltd and British Association of Sport and Exercise Medicine SP 605 OP 611 DO 10.1136/bjsports-2018-100417 VO 54 IS 10 A1 Jannelene Killops A1 Martin Schwellnus A1 Dina Christina Janse van Rensburg A1 Sonja Swanevelder A1 Esme Jordaan YR 2020 UL http://bjsm.bmj.com/content/54/10/605.abstract AB Background There are few data on medical encounters, including deaths during mass-participation cycling events.Objective To determine the incidence and nature of medical encounters during a community-based mass-participation cycling event.Design Cross-sectional study across three annual events.Setting 2012–2014 Cape Town Cycle Tour (109 km), South Africa.Participants 102 251 race starters (male=80 354, female=21 897).Methods Medical encounters (moderate, serious life-threatening, sudden cardiac arrest/death), using the 2019 international consensus definitions, were recorded on race day for 3 years as incidence rates (IR per 1000 starters; 95% CI). Overall illness-related (by organ system) or injury-related (by anatomical region) encounters, and severity were recorded.Results We recorded 539 medical encounters (IR 5.3; 4.8 to 5.7). The IR was 3.2 for injuries (2.9 to 3.6), 2.1 for illnesses (1.0 to 2.4) and 0.5 for serious life-threatening medical encounters (0.4 to 0.7). In the 3-year study, we encountered three cardiac arrests and one death (2.9 and 1.0 per 100 000 starters, respectively). Injury IRs included upper limb (1.9; 1.6 to 2.1), lower limb (1.0; 0.8 to 1.0) and head/neck (0.8; 0.6 to 1.0). Illness IRs included fluid/electrolyte abnormalities (0.6; 0.5 to 0.8) and the cardiovascular system (0.5; 0.4 to 0.6).Conclusion In a 109 km community-based mass-participation cycling event, medical encounters (moderate to severe) occurred in about 1 in 200 cyclists. Injury-related (1/300 cyclists) encounters were higher than illness-related medical encounters (1 in about 500). Serious life-threatening medical encounters occurred in 1/2000 cyclists. These data allow race organisers to anticipate the medical services required and the approximate extent of demand.