Using shorter durations (e.g., 8 or 10-minute power) to estimate functional threshold power is metabolically dangerous and less accurate than using 60-minute power.

“the problem very often is that people use much shorter dur durations they use 8 Minute power 10 minute power and it's very different Y and then and then and then the problem if you now extrapolate that and you still call that functional tral power for example and you divide it by your weight what you don't know when you're looking at it this way is how much does how much of energy comes from oxidative phosphorization and how much come from the glycolysis for example and the shorter the duration is and you're extrapolating that up to a larger value the more dangerous it is metabolically”