Pre-existing injuries and illnesses in trail running: sex-based epidemiological findings from a 2022 forest marathon

Trail running is a growing sport with increased injury and illness risk. We investigate the epidemiology of running-related injuries (RRI) and illnesses in male and female trail runners in the lead-up to the 2022 Magoebaskloof Forest Marathon, South Africa.

A descriptive cross-sectional study across 10 km, 20 km, 30 km, and 50 km distances using pre-race medical screening data completed 2 weeks before the event. We report frequency (n, %), prevalence ratio (PR, %), incidence (per 1000 trail running-hours), severity [% time-loss; Burden (days lost/1000 running-hours)], and associated risk factors (odds ratio, OR) of chronic and acute injuries and illness.

The annual injury incidence was 2.79/1000 trail running-hours, with most injuries affecting the lower limb in both males (47.15%) and females (45.53%; PR = 0.99). Muscle/tendon injuries (49.59%) and muscle strains (21.95%) were most common, with no statistical significant difference between sexes. The overall injury burden was 32.7 days lost/1000 running-hours. Chronic conditions were reported by 14.22% of runners, while only seven reported acute illnesses. Although 46.62% of runners had > 5 years total overall running experience, only 22.14% had equivalent years of trail running experience. Injury risk increased with longer race distances entered and >3 weekly training sessions.

One in four trail runners reported a RRI within the 6 months prior to the event, mainly affecting the lower limb. Chronic conditions were present in 14% of trail runners. While this study offers key insights into trail running injury and illness, further research on risk factors is needed.