Week-to-week changes in training were not prospectively associated with injuries among Wisconsin high school cross-country runners.

Background: Training characteristics, such as volume and duration, have been studied in relation to running-related injury (RRI) risk, with mixed findings in adult runners. There is a lack of research assessing how training characteristics relate to RRI in youth runners, despite the high RRI rates observed in this population.

Purpose: To prospectively determine associations between (1) total weekly running volume and duration and (2) week-to-week changes in running volume, duration, intensity and training stress with in-season RRI among high school cross-country runners.

Methods: Runners completed a preseason demographics and injury history survey and daily surveys regarding training distance, duration, intensity and current RRI. Values were summed weekly and change scores were calculated relative to the prior week. Runners completing ≥75% of daily surveys were analysed; sensitivity analyses for those completing ≥50% and ≥90% were conducted. Generalised estimating equations assessed associations between change in each predictor, including interactions with sex and RRI within the subsequent week, controlling for year in school, prior RRI and repeated observations.

Results: 434 runners enrolled in the study; 161 (37%) completed ≥75% of daily surveys. No associations between total volume, total duration or week-to-week change in training characteristics and in-season RRI were observed (p≥0.54). Sensitivity analyses did not detect any significant associations.

Conclusion: Total weekly running volume and duration and weekly changes in training were not associated with RRI. RRI are multifactorial and assessing the interaction between training characteristics and other lifestyle factors is likely necessary for determining RRI risk in youth runners.