Endurance performance relies on the frequent execution of controlled-intensity training sessions, based on the precise measurement of blood lactate to remain in a 'golden zone' that optimizes physical condition without causing excessive fatigue.

noli's read

The Norwegian method emphasizes the aerobic-anaerobic threshold, a zone where the body learns to use energy efficiently without accumulating too much acidic fatigue. Scientific evidence, notably meta-analyses on polarized and threshold training (Seiler et al.), confirms that the majority of volume at low intensity, combined with targeted sessions below the threshold, is highly effective for improving endurance. The use of blood lactate as a marker is a validated practice in sports physiology (RCTs and observational studies), although its necessity for amateur athletes is sometimes debated in comparison to simpler measures like heart rate or perceived exertion (RPE). The idea of a 'double threshold' (two sessions in the same day) is an advanced strategy based on a logic of accumulated load while remaining in control, but it is primarily suited for high-level athletes capable of managing such density. The community is largely fascinated and convergent on the effectiveness of this structure, seeking primarily to understand how to adapt it to their schedule and individual physiology rather than questioning the principle.

the sources

1. 1Rosenblat MA, Perrotta AS, Vicenzino B 2019
2. 2Silva Oliveira P, Boppre G, Fonseca H 2024
3. 3Menshikova EV, Ritov VB, Ferrell RE, et al. 2007
4. 4r/AdvancedRunning