Brad reads about polarised training after the cardio embarrassment in Vol. 18. He decides he's going to "do endurance properly." He reads the 80/20. He misreads it. He runs 80% of his weekly mileage at threshold or above, 20% easy. Five weeks in: shin splints, resting heart rate climbing, sleep degraded. He concludes endurance isn't for him.
The framework didn't fail him. He inverted it.
Inside this one
- Not medical advice.
- Personas in the volume are composite illustrations, not specific individuals.
- For pregnancy, chronic conditions, or clinical questions, see a qualified clinician.
The standard it is held to
Every factual claim in this volume names its source, and every claim carries a confidence grade — settled, strong, emerging or contested. Where the evidence is thin, the text says so. How it’s made, in full → · What we’ve got wrong →