Internal Training Load Measures During a Competitive Season in Collegiate Women Lacrosse Athletes

Monitoring internal load provides useful and non-invasive markers of training stress and adaptation. However, the relationship between internal load measures across a competitive window remains inconclusive and limited. The purpose of this study was to report various internal load measures, as well as their relationship, across a season in Division I women lacrosse athletes (n = 20). Ultra-short natural logarithm of the root mean square of successive differences (lnRMSSD), salivary testosterone, cortisol, the testosterone:cortisol ratio, and self-reported measures of fatigue and recovery were collected weekly for 13 weeks. Means ± SD were calculated to provide descriptive values and a repeated measure analysis of variance (ANOVA) was used to analyze changes in testosterone, cortisol, testosterone:cortisol ratio (n = 8), and lnRMSSD (n = 8) over the course of the season. Pearson correlations assessed relationships between all internal load measures. No significant time effect was observed in testosterone (p = 0.059), cortisol (p = 0.544), testosterone:cortisol ratio (p = 0.120), or lnRMSSD (p = 0.062). lnRMSSD was correlated with testosterone (r = 0.265), cortisol (r = -0.232), testosterone:cortisol ratio (r = 0.345), and fatigue (r = -0.256) (p < 0.05). More research is needed to examine relationships among markers of internal stress across all phases of the training cycle. Routine monitoring may help practitioners optimize training programming to reduce injury, illness, and overtraining.