Poor Sleep Quality Is Associated With an Increased Risk of Running-Related Injuries: A Prospective Study of 339 Runners Over Six Months.

Association between sleep and running-related injuries (RRI) risk remains still unclear. This prospective cohort study investigated whether sleep quality and quantity, along with training load and complementary recovery factors, were associated with the risk of RRI. Over a 26 week period, adult runners, with at least 1 year of running experience, weekly reported their RRI and completed the Hooperm questionnaire assessing sleep (quality, quantity, latency), fatigue, muscle soreness, perceived stress, through a smartphone application. We also measured training load through participants' personal watches. We analyzed the association between RRI, Hooperm variables, and training load using time-to-event models. We compared Hooperm and training load through the 2 weeks preceding an RRI (RRI-1, RRI-2) and injury-free weeks using linear mixed models. A total of 339 runners (16.2% females, age: 43.4 ± 10.2, 92.9% competing regularly) from 24 countries were included. Lower sleep quality was significantly associated with an increased risk of RRI (HRR 1.36, 95% 1.04 to 1.78; p = 0.02). Compared to no-RRI weeks, muscle soreness was higher during RRI-2 (p = 0.02) and RRI-1 (p < 0.001), whereas fatigue was elevated during RRI-1 (p = 0.04). No further significant results were observed among the other factors. Poor sleep quality was associated with an increased risk of RRI and may represent an early warning sign. Elevated fatigue and muscle soreness may signal a heightened risk of injury in the weeks following this onset. While interpreted with caution, these findings highlight the importance for runners to improve sleep quality and regularly monitor recovery, to proactively reduce the likelihood of RRI.