Work

Illness is common in trail runners during training: a prospective cohort study

Year: 2025

Type: article

Abstract: Objectives Trail runners often experience illness during event preparation. We aimed to prospectively determine prevalence, incidence, clinical characteristics, severity (time-loss, burden) and associated illness risk factors among South African male and female recreational trail runners of different ages over a 30-week training period. Design Prospective cohort. Method Illness and training data from 152 trail runners (120 males, 32 females) were collected every 14 days over 30 weeks using the updated OSTRC-H questionnaire. Illness prevalence (%), incidence ( I : per 1000 trail running exposure-days), incidence ratio (IR), severity [% time-loss; illness burden (IB: days lost/1000 trail running exposure-days)], and associated risk factors are reported. Results Over 30 weeks, 52 % of runners reported illness, with a mean two-weekly all-illness prevalence of 10.1 %. The overall illness incidence was 7.2 (95%CI: 5.7–9.2). The winter-to-summer IR was 1.6 (p = 0.022). Illness incidence in females ( I = 9.7) was higher than in males ( I = 6.6), with a female:male IR of 1.5 (p < 0.05). Most illnesses affected the respiratory (64.3 %), digestive (15.9 %) and musculoskeletal (5.7 %) systems. Moderate illness severity (8–28 days time-loss) occurred in 29.3 % of runners. The overall IB was 43.2 days lost. BMI ≥25 kg/m 2 was associated with illness, but no significant illness risk factors were identified via Poisson regression. Conclusion During a 30-week training period, 52 % of runners reported illness, with a higher incidence in females. The respiratory tract accounted for >60 % of illnesses. One in three trail runners experienced >one week time-loss. A higher BMI >25 kg/m 2 was associated with illness. Further research is needed to identify risk factors and develop prevention strategies.

Source: Journal of science and medicine in sport

DOI: 10.1016/j.jsams.2025.12.008