What is the source of the criteria of having AeT within 10% of AT, and when might it break down? To me, 10% seems low. I’ve been tested (VO2 respiration/metabolic test, not blood test) a few years ago at 170/130 (which jives with years of using a HR monitor and observing my condition), which is 30%, and I’ve been deliberately training Z1/Z2 for years with almost no increase in AeT. As a coach, at what point would you abandon that 10% target, and how would you adjust training targets accordingly?