"the seven deadly sins.......er, ways of determining your functional threshold power (roughly in order of increasing certainty):
- from inspection of a ride file.
- from power distribution profile from multiple rides.
- from blood lactate measurements (better or worse, depending on how it is done).
- based on normalized power from a hard ~1 h race.
- using critical power testing and analysis.
- from the power that you can routinely generate during long intervals done in training.
- from the average power during a ~1 h TT (the best predictor of performance is performance itself).
Note the key words "hard ", "routinely", and "average" in methods 4, 6 and 7..."