Emanuelsen, E., Sandbakk, O., Welde, B., & Mork, P. J. (2009). Autonomic recovery during high training loads in female world-class biathlon athletes. A paper presented at the 14th Annual Congress of the European College of Sport Science, Oslo, Norway, June 24-27.

This study investigated the relationships between heart rate variability, training load, and self-reported form and fatigue during three weeks of competitive training in world-class female Norwegian biathlon skiers (N = 7). Heart rate variability, training load, and self-reported form and fatigue were recorded on a daily basis during a 3-week competitive training period. Heart rate variability was recorded each morning for five minutes in the supine position. Low intensity, moderate intensity, and high intensity endurance training were quantified by heart rate recordings during each training session. Overall training load (TRIMP) was calculated by multiplying the accumulated duration spent in each intensity zone by 1, 2, and 3 for the low, moderate, and high intensities, respectively. Self-reported fatigue was scored on a 1 to 6 point scale (1 = no fatigue; 6 = maximal fatigue), and self-reported form on a +4 to -4 point scale (+4 = extremely good form/light feeling; -4 = extremely bad form/heavy feeling) after every training session.

There were no significant relationships between heart rate variability, overall training load, and self-reported fatigue and form. Inter-individual variation was substantial. For some athletes, self reports of fatigue and form showed a time lag (1-4 days) after indices of autonomic recovery (e.g., indices of improved or reduced form were preceded by reduced or increased heart rate variability. Variation in form and fatigue was small giving the overall impression that most athletes quickly obtained autonomic recovery even after two days of competition.

Implication. In general, world-class female biathlon athletes’ show fast autonomic recovery during a hard training and competition period, despite extremely high training loads. An overnight rest seems to be sufficient to recover from two training sessions and 2-4 hours daily training. However, the inter-individual variation is substantial and recordings of heart rate variability may be a useful tool, but only for some athletes, to monitor autonomic recovery during periods with high training loads.

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