Originally Posted by
surak
Except the context is getting an accurate estimate of FTP, wherein it's already been noted that a 20-min block is difficult to pace properly in the best of conditions. Garmin's automagical calculation is anything but, and definitely not useful for getting a better estimate than what carbonfiberboy has done, for example. It basically "works" only if one just happens to ride their hardest for just the right length of time. Which for me hasn't happened in over a year, even as I've trained and improved my FTP significantly.
Correct, it doesn’t work for you. Think, however about somebody who does a weekly time trail series or does competitive hill climbs. A rider like that is regularly pushing up against the bumpers. Lots of the current software like TrainingPeaks will show you you best 20 in addition to other significant times.
Have you read this book yet?
https://wish4book.com/education/1141...d-edition.html The the use of best 20 minute power is a suggestion from this book.