Originally Posted by
rubiksoval
Thirdly, 8 minutes and 20 minute tests are NOT FTP tests. Your FTP is NOT the power you can put out for 8 minutes or 20 minutes, and any number extrapolated from that is a pure guess that may or may not be remotely accurate.
Andy Coggan considered critical power testing (one kind of short effort, one kind of long) to be reliable enough that he included it in his list of seven deadly sins for determining FTP.
https://wattmatters.blog/home/2008/0...adly-sins.html