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.
I try not to be an expert in FTP but when Andy first presented the idea in the Wattage group 22 years ago we sort of hashed out some of the biggest issues. Andy imagined a functional test that would approximate maximum lactate steady state (MLSS) but MLSS is itself sort of open to interpretation, and more interestingly for your question, even steady state lactate will eventually cause fatigue. That means that even if your aerobic system can hold lactate steady, lactate level isn't the sole determinant of how long you can continue working at that level. The lactate is steady but you can't exercise indefinitely even with steady lactate. A similar observation applies to CP (critical power): there does appear to be a physiological plateau but it's not an unlimited plateau. So although lactate (and thus FTP) can't tell you the whole story, it can tell you some (a reasonable amount?) of the story. How much of the whole story it tells varies by individual.
[Edited to add] So I don't pay *a lot* of attention to FTP: I pay *some* attention to it, but only loosely. I pay more attention to what my entire MMP curve looks like, and where it looks unusually low (and increasingly rarely over the years, where it looks unusually high). I think the entirety of the MMP curve tells me more than a single number like FTP. Actually, although I look at the MMP, I don't do much analytically with it: I usually switch into Joules view (from watts view) and do analysis on that.