WEEKLY RUNNING VOLUME AND RISK OF RUNNING. RELATED INJURIES AMONG MARATHON RUNNERS

Purpose/Background: The purpose of this study was to investigate if the risk of injury declines with increasing weekly running volume before a marathon race. Methods: The study was a retrospective cohort study on marathon finishers. Following a marathon, participants completed a web-based questionnaire. The outcome of interest was a self-reported running-related injury. The injury had to be severe enough to cause a reduction in distance, speed, duration or frequency of running for at least 14 days. Primary exposure was self-reported average weekly volume of running before the marathon categorized into below 30 km/week, 30 to 60 km/week, and above 60 km/week. Results: A total of 68 of the 662 respondents sustained an injury. When adjusting for previous injury and previous marathons, the relative risk (RR) of suffering an injury rose by 2.02 [95% CI: 1.26; 3.24], p < 0.01, among runners with an average weekly training volume below 30 km/week compared with runners with an average weekly training volume of 30-60 km/week. No significant differences were found between runners exceeding 60 km/week and runners running 30-60 km/week (RR=1.13 [0.5; 2.8], p=0.80). Conclusions: Runners may be advised to run a minimum of 30 km/week before a marathon to reduce their risk of running-related injury.