Changes in Sleep, Stress, and Fatigue Were Not Prospectively Associated With Running-Related Injuries Among High School Cross Country Runners

Background: Running-related injuries (RRI) are common among adolescent runners; however, our understanding of RRI risk factors in this population is limited. Sleep, stress, and fatigue are risk factors in other youth sports but have not been studied in high school runners. This study prospectively assessed the effect of changes in sleep duration and quality, stress, and fatigue on RRI among high school cross country runners.Hypothesis: Less and poorer quality sleep and greater stress and fatigue, compared with the previous week, would be associated with RRI.Study Design: Prospective, observational study.Level of Evidence: Level 2b.Methods: Runners completed a preseason demographics and injury history survey and daily surveys regarding sleep duration and quality, stress, fatigue, and current RRI. Values were summed within each week, and change scores were calculated relative to the previous week. Runners completing ≥75% of daily surveys were analyzed; sensitivity analyses for those completing ≥50% and ≥90% were also conducted. Generalized estimating equations assessed the association between change in each predictor, including its interaction with sex, and RRI, controlling for year in school, previous RRI, and repeated observations.Results: A total of 434 runners enrolled in the study; 161 (37%) completed ≥75% of daily surveys. No associations between change in sleep duration, sleep quality, or fatigue and RRI were observed (Pvalues ≥0.24). A significant change in stress × sex interaction with RRI was observed (P< 0.01). Associations among boys (P= 0.06) and girls (P= 0.07) were marginally significant. Sensitivity results were similar.Conclusion: Short-term changes in sleep duration, quality, and fatigue were not associated with RRI, but a significant interaction between change in stress and sex suggests that stress may influence RRI risk in high school cross country runners.Clinical Relevance: Large changes in stress levels should be monitored throughout the season, as these changes may precede RRI occurrence in this population.