BikeParts Wiki

You should probably just read what Hunter Allen has to say but I'll include on this page odds and ends that may be of interest.

Determining your functional threshold power[]

Dr. Coggan calls this the Seven deadly, ways of determining your functional threshold power (roughly in order of increasing certainty):

  1. from inspection of a ride file.
  2. from power distribution profile from multiple rides.
  3. from blood lactate measurements (better or worse, depending on how it is done).
  4. based on normalized power from a hard ~1 h race.
  5. using critical power testing and analysis.
  6. from the power that you can routinely generate during long intervals done in training.
  7. 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...