Effects of Varying Training Load on Heart Rate Variability and Running Performance Among an Olympic Rugby Sevens Team

Flatt, A. A.; Howells, D.

The objective of this retrospective study was to evaluate the weekly heart rate variability (HRV) responses to varying training loads among an Olympic rugby sevens team and to assess whether these HRV responses provided insight into training adaptation. The study analyzed the natural logarithm of the root mean square of successive differences (LnRMSSD), psychometrics, and training load data from a rugby sevens team consisting of 12 male athletes over a 3-week period. Week 1 served as a baseline, while weeks 2 and 3 involved peak training loads from the 2016 Olympic preparatory period. Maximum aerobic speed (MAS) was evaluated at the beginning of weeks 1 and 3.

The results indicated that LnRMSSD, its coefficient of variation (LnRMSSDcv), and psychometrics did not significantly change across time (p > 0.05). Effect sizes (ES) showed a small increase in LnRMSSDcv after the first week of intensified training (ES = 0.38), followed by a moderate reduction in week 3 (ES = -0.91). Individuals with a smaller LnRMSSDcv during the first week of intensified training exhibited more favorable changes in MAS (r = -0.74, p = 0.01), although individual changes ranged from -1.5 to 2.9%.

In week 3, players managed greater external training loads with minimal impact on internal load, while wellness was preserved. Concurrently, players demonstrated fewer fluctuations in LnRMSSD, suggesting an improved ability to maintain cardiac-autonomic homeostasis despite increases in training load. The study suggests that monitoring the magnitude of daily fluctuations in LnRMSSD in response to varying training loads may be useful in evaluating training adaptations among elite rugby players.

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