Originally Posted by mschwett

since all the experts are here … i have always been a little confused about what’s commonly referred to as FTP. i understood that physiologically it was a balanced state between aerobic and anaerobic activity where you’re not producing too much lactate (or whatever else it is) to sustain the effort. but the question is… for how long?

many definitions seem to be the maximum you can do for an hour, but if you crash hard after that hour it’s not really balanced and sustainable, is it?

my power curve is very flat, and the effort i could sustain for 45 minutes is not really much different than 3 hours. if i know without any doubt that i could regularly sustain an uninterrupted average power (not weighted or normalized) of say 200w for 3+ hours, and 225w for 1 hour without feeling too spent, is FTP even knowable from those data points or does it require an all out to the edge of failure effort to discover it?

the idea that FTP represents an unsustainable effort except for the length of time tested seems wrong to me.