Zone 2 training, often presented as essential for building an endurance base and stimulating mitochondria, is reportedly overrated or even ineffective compared to higher intensities for optimizing performance.

noli's read

The community is skeptical and largely defends Zone 2 as a tool for managing fatigue and preventing injury, rather than as a biological miracle solution. Scientifically, the idea that higher intensities stimulate greater mitochondrial biogenesis (the creation of cellular 'power plants') is documented in certain studies, as the cited journal notes (generally mechanical observations). However, reducing training to this single factor is a very narrow view: sports also rely on cardiovascular (blood volume, cardiac efficiency) and musculoskeletal adaptations that benefit greatly from the volume allowed by moderate intensity (meta-analyses on polarized training). The claim that Zone 2 is useless is therefore exaggerated, as it confuses 'pure biological efficiency' with the 'practical long-term viability of training.' The consensus on the forum is a marked resistance to this questioning, emphasizing that the ability to accumulate volume without injury remains the pillar of progress.

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/running