Impact of a high body mass index on lower extremity injury in marathon/half-marathon participants

Background: To evaluate whether a high body mass index (BMI) predisposes marathon/half-marathon participants to lower extremity injuries. Methods: Consenting adult participants at the 2008 National Marathon to Fight Breast Cancer were enrolled in this observational study. The primary outcome measure was prevalence of self-reported lower extremity injury, during both training and race participation, with respect to BMI. Results: There were 194 subjects with complete data: 139 females (72%) and 55 males. Forty-six percent of females and 51% of males ran the full marathon (P = .63). Median BMI was 23.7 kg/m ² for females and 26.2 kg/m² for males (P = .001). Eleven (24%) females in BMI tertile 1 (T1) suffered a training injury, while 9 (18%) from T2 and 4 (9%) from T3 suffered injuries (P = .072; OR 0.89; 95% CI 0.78 to 1.01). Twenty-six (19%) females suffered an injury during the race. Females in T1 were more likely to suffer a race-related injury (P = .038; OR 0.87; 95% CI 0.77 to 0.99). Females were 13% less likely to suffer a race-related injury with each 1-unit increase in BMI. Rates of injury did not differ by BMI tertile in males. Conclusions: A high BMI did not impart an increased risk of lower extremity injury during training or race participation.