Bone stress injuries in elite runners: intrinsic and extrinsic risk factors in Italian track and field athletes

Bone stress injuries (BSIs) are overuse injuries that occur when a normal bone is no longer able to withstand repetitive mechanical loading. Given the high occurrence of BSIs in track and field athletes, this study aimed to evaluate risk factors associated with BSI development in elite athletes competing in different track events. In this retrospective observational study, 172 Italian elite track and field athletes (mean age 23.7 ± 3.5) were interviewed using a closed-ended questionnaire that encompassed participant characteristics, history of BSI, and potential contributing factors. Female participants were also asked to answer the Low Energy Availability in Female Questionnaire (LEAF-Q). In the total cohort, no sex differences were found in the presence or lifetime number of BSIs. Injured athletes had a different site distribution according to their event specialization, with endurance athletes experiencing more forefoot and more leg BSIs compared to sprinters. Among female athletes, those with menstrual irregularities reported a higher lifetime number of BSIs compared to those without irregularities, and athletes with higher LEAF-Q score had a higher number of BSIs. In regression analysis, age at menarche emerged as the only significant predictor, with each unit increase associated with a 20.1% increased risk of a higher number of BSIs. This study highlights the absence of sex differences in the presence and number of BSIs but reveals event-specific differences in BSIs distribution in specific anatomical sites in elite Italian runners. Among female athletes age at menarche appears to be a key factor associated with BSI burden, supporting its relevance as a marker to consider in the assessment of BSI risk.