One in Five Trail Running Race Entrants Sustained an Injury in the 12 Months Training Period before the 2021 Mac Mac Ultra Race

Background: Trail running is characterised by large elevation gains/losses and varying uneven running surfaces. Limited literature is available to help guide injury prevention strategies among trail runners. The purpose of this study was to determine the epidemiology, clinical characteristics, and related risk factors for running-related injuries (RRIs) amid trail runners who entered the 2021 Mac Mac Ultra races. Methods: Design: Descriptive cross-sectional study. Setting: 2021 Mac Mac Ultra Race. Participants: Consent for data analysis was given by 251 of 330 (76%) race entrants. Main outcome measures: Point prevalence (%), frequency (n, %), retrospective annual incidence (RRIs/100 athlete-years), characteristics (pathology type, tissue type, body area, anatomical region), and associated injury risk factors (training and demographic variables) of RRIs. Results: In the sample, the retrospective annual incidence was 19.92/100 athlete-years. The point prevalence was 4%. Injuries mostly appeared in the lower limb (95%), with the lower leg (26%), thigh (22%), ankle and foot (13%) described as the highest injured body areas. Of tissue type injuries, muscle/tendon comprised 60%. Muscle injury (36%), tendinopathy (24%), and joint sprain (9%) were the most reported pathology types. No related injury risk factors were discovered in this study. Conclusions: One in five trail runners reported one or more RRI during the 12 months before a competitive event. RRIs commonly involved the lower limb, especially the lower leg, thigh, foot, and ankle. More studies are needed to establish injury risk factors.