Strength and Flexibility Self-Assessment and Subsequent Training Injuries Among Runners of the New York City Marathon.

Objective: To identify strength and flexibility measures that are associated with the risk of running-related overuse injuries.

Design: Prospective observational study.

Setting: Secondary analysis of a previously reported cohort of runners.

Participants: Runners registered for the 2019 New York City Marathon.

Independent Variables: Participants were asked to complete a baseline strength and flexibility self-assessment 16 weeks before the marathon date.

Main Outcome Measure: Participants were asked to respond to surveys on running-related injuries occurring within 4-week "training quarters" at 16, 8, 4, and 1 week(s) before the marathon date.

Results: Of the n = 867 runners included in our final analytic sample, 36.1% sustained a running-related overuse injury while preparing for the marathon. The only significant difference in odds and/or hazard of injury was found in the single-leg glute bridge test. Participants who reported that they could hold a single-leg glute bridge on their weaker side for 20 to 29 seconds had 64% lower risk of running-related overuse injury (aHR: 0.36; 95% CI, 0.18-0.72; P = 0.0036) than those who could only hold for 0 to 9 seconds on their weaker side. In addition, participants who reported that they could hold a single-leg glute bridge on their weaker side for 30 seconds or more had 49% lower risk of running-related overuse injury (aHR: 0.51; 95% CI, 0.29-0.92; P = 0.0245).

Conclusions: Strength training programs, particularly targeting hip abductors and related muscle groups, may provide benefits for distance runners, though more rigorous research is needed.