RT Journal Article SR Electronic T1 262 Stress fractures during top-level international athletics championships 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 A102 OP A102 DO 10.1136/bjsports-2021-IOC.241 VO 55 IS Suppl 1 A1 Edouard, Pascal A1 Vinther, Anders YR 2021 UL http://bjsm.bmj.com/content/55/Suppl_1/A102.1.abstract AB Background Stress fracture is a frequent injury among athletics athletes. During international Athletics championships, although stress fractures represented a small percentage of all injuries (2.9% of all injuries and 4.9% of in-competition time-loss injuries for female athletes), it exists and should not be neglected, because it could be one symptom of Relative Energy Deficiency in Sport.Objective To specifically analyse stress fractures during top-level international Athletics championships from 2007 to 2019.Design Prospective study.Setting 21 international championships from 2007 to 2019.Participants 26281 (14130 male and 12151 female) international-level registered athletes.Main Outcome Measurements The national medical team and the local organizing committee physicians reported all injuries daily on a standardised injury report form during 21 international championships. Only stress fractures were included in the descriptive analysis.Results During the 21 international athletics championships, a total of 36 stress fractures were reported, representing 1.6% of all reported injuries. 14 were in male and 22 in female athletes, and 54% in endurance and 46% in explosive disciplines. The overall stress fracture incidence was 1.4 per 1000 registered athletes (95%CI=1.0–1.8). The relative risk was almost doubled in female compared to male athletes although this was not statistically significant (relative risk (RR)=1.83, 95%CI=0.94–3.57). Most of stress fractures involved the lower extremity (92%). In female athletes, 46% were located at the lower leg and 41% at the foot, compared to 14% and 64%, respectively for male athletes. More than half of the stress fractures were classified as severe injuries (i.e. estimated number of days of absence >28 days).Conclusions Stress fractures also occurred during major international athletics championships, representing a severe injury, with sex differences in location and most likely also in overall risk.