Physiological Factors of Female Runners With and Without Stress Fracture Histories: A Pilot Study

Abstract

Background: Female runners are at increased risk of stress fractures (SFs) compared with men. Literature is lacking with regard to best practice for preventing and treating SFs in women. The purpose of the study was to compare physiological measures and running-related factors between women of various ages and running abilities with and without a history of running-related SFs. Hypothesis: Women with and without SF histories will differ with regard to medical and menstrual history, bone health, body composition, nutrition, and running history. Study Design: Prospective cohort study. Level of Evidence: Level 2. Methods: A total of 20 female runners with SF histories were matched based on age and running distance with 20 women without SF histories. Data included medical, menstrual, running, injury, and nutritional histories; blood histology related to nutritional, hormonal, and bone-related risk factors; and bone density, fat, and lean tissue using dual energy x-ray absorptiometry. Paired t tests were used to examine differences between women with and without SF histories, and Spearmen correlations were conducted to examine relationships between physiological factors. Results: Women with SF histories had lower hip bone mineral density compared with women without SF histories ( P < 0.05). SF history was moderately correlated with menstrual changes during increased training times ( r = 0.580; P < 0.0001) but was not correlated with any other physiological factor. There was a moderate correlation within the SF group ( r = 0.65; P = 0.004) for bone markers for resorption and formation both increasing, indicating increased bone turnover. Conclusion: Female runners with low hip bone mineral density, menstrual changes during peak training, and elevated bone turnover markers may be at increased risk of SF. Clinical Relevance: Female runners need routine screening for risks associated with SF occurrence. As bone mineral density and bone turnover markers are not routinely assessed in this population, important risk factors may be missed.