Background Many studies attempt to identify the risk factors for running-related injuries (RRI), but these are not yet well established.

Objectives To investigate the risk factors of RRI.

Design Retrospective online survey-based study among population of runners injured and non-injured.

Setting Leisure road and trail runners

Patients Participants have to be at least 18 years old and have to practice running at least for 12 months. 3669 runners reported information which were included for statistical analysis.

Assessment of Risk Factors The online survey included 41 questions with five main categories: personal characteristics - daily lifestyle– training and running characteristics - practice of others sports activities and prevention habits.

Main Outcome Measurements Occurrence of running-related injury over the last 12 months.

Results Amongst the 3669 runners, 1852 (50.5%) reported at least one injury over the last 12 months. Overuse injury were largely represented (60.6%). The variables associated with RRI which remained significant in the fully-adjusted model were: previous injury (OR=1.63, IC 95% = 1.42–1.47), competition running (OR = 1.62, IC 95% = 1.26–2.09), more than 2 hours running per week (OR = 1.30, IC 95%= 1.03–1.65), mileage (>20km/week) (OR = 1.25, IC 95%= 1.01–1.55) and speed training (OR = 1.23, IC 95%= 1.06–1.48). Univariate analysis revealed other variables associated with more RRI: Trail runners (versus road runners, p<0.001), men (versus women, p<0.001), higher age (p<0.001), >2 running session/week (p<0.001).

Conclusions Previous injury remains the most relevant RRI risk factor according to the current study and previous data. Many training characteristics seem to be involved but still have to be confirmed in view of conflicting data in literature. Trail runners are more at risk of RRI. Further research would help to understand better RRI and to prevent them.