Alex Hutchinson PhD explains why elite endurance performance can't be predicted by VO2 max and other physiological metrics alone. Mental state matters enormously: the right headspace lets athletes exceed their theoretical ceiling, while an off-day causes them to fall short without any physical cause.
Chapters
If you could understand all the parts of the machine, the VO2 max, the muscles, the running economy, all these different aspects, and, you know, the fueling, what sorts of fuel the muscles run on, you could understand what are the limits. And so I could go and run a race and say, my body is capable of X today and let's see how close I can get to X. But the truth is, you know, anyone who spends a reasonable amount of time pushing their own limits and racing realizes that it's not so mathematical and that some days you're able to achieve far more than you ever thought you'd be capable of. Other days it just doesn't click. And it's not necessarily because you have the flu or something. It may be just because you're not able to get into the right headspace. And so there is that other element of trying to understand what's happening there. Why is it that some people can push much closer to their limits, or that some days I can push much closer to my limits than others?