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.

Whatever it does, it doesn’t give consistent results for me. The FTP range it estimates over different time periods is not at all realistic. Sometimes it is in the ballpark, but other times it can be way low or way high when I know my FTP hasn’t changed by more than around 10W between those periods.

I also use PILLAR which estimates FTP much more consistently using exactly the same input data.

It’s the FTP time frame that is a bit vague and varies among individuals in the same physiological state that FTP is supposed to represent. So one person might be able to hold their FTP for 40 mins, while another might manage 70 mins in the same physiological state.

So those two riders would have quite different 1 hour power, but the same FTP and any training power zones defined from it.

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.

makes sense - different factors or limits come into play over different time intervals. a few seconds is just a neuromuscular thing, at some point the heart and lungs come into play, at some point the ability to make glycogen available, at some point the body's tolerance for the cycling position.

since FTP is not a truly indefinite condition, i feel like it should be represented as "FTP60" or something, meaning the threshold of power beyond which the effort cannot be sustained for the time increment referenced. i think that's how most people are using it anyway, and the debate is about which numbers OTHER than an all out ideal circumstance 60 minute to collapse effort can estimate that value.

This guy claims he boosted his FTP from 340 to 379 after just 2-weeks of heat training ---- FWIW

I think it's probably mistaken to think of FTP as an indefinite condition. I think a better way to think about FTP is of a real threshold: that if you're 5 watts below FTP you can hold that for considerably longer than you can hold 5 watts above FTP. So FTP isn't really defined in terms of TTE (time to exhaustion), it sort of more like a point where the duration curve changes slope. (It doesn't help that almost all graphical representations of the MMP curve use a log transformed time axis).

I find this hard to rationalise too. But I think you have to think of FTP more in terms of power in a threshold physiological “state” or “balance” rather than power over a fixed time period. Your FTP60 is literally 60 min power, but that could be at or below an individual’s FTP depending on how long they are able to hold their FTP physiological “state”.

Whether or not you care much about that FTP “state” depends on what you are going to do with it. People typically use it to define training power zones and as a single point fitness tracker. Personally I prefer to look at my whole power curve and prefer the Wahoo 4 point power benchmark, which estimates FTP, but also 3 other points on the power curve.

I think it’s also iworth noting that people rarely go beyond measuring their max 20 min power as an estimate for FTP, which assumes everyone has the same extrapolation factor, often 0.95 x 20 min power. This is clearly not true so at best it is a rough estimate of power in a slightly vague threshold state!

this makes a lot more sense; the point on the curve of effort vs duration where the slope changes dramatically.

my interest has always been in the power zones - my heart rate changes relatively little compared to RPE, and when it does it could easily be time of day, caffeine, time since taking meds, a cold, that i had always hoped power based zones would be a consistent guide. but i think the whole concept is somewhat useless if you're not willing or able to do a "maximum effort" for at least 20 min.

Newbie question. What is “MMP”?

I think it stands for "mean max power" or "max mean power." It's a curve that show your maximal average power over different durations. mschwett posted a Strava chart of his MMP in the post below.

This was the original intention. Over the years, the concept got mixed up with *the way you might approximate it* so people think about it as "the power you can maintain for an hour" or "95% of the power you can maintain for 20 minutes." To go back to the original intent, it makes more conceptual sense to examine the derivative of the MMP curve and look for a change in slope, or do what I usually do and look at the integral of the MMP curve and look directly at its slope.

I think of power zones or heart rate zones as being simplified discrete versions of the MMP curve, sort of like what a histogram is to a continuous density distribution. Then you have an issue with how many bars in the histogram. Zones are a simple normalized way to communicate with a client or a coach or another rider what your effort was like -- but I don't do that much. I have the entire continuous curve in front of me so I don't usually use zones much.

I find power zones useful for both interval training and pacing on rides, but I’m not a fan of basing zones off a single FTP point. It makes the assumption that everyone with the same FTP has an identical power curve, which is at best a very crude approximation.

Wahoo addressed this issue with their 4DP test which provides power estimates at 4 points on your power curve, including FTP as the lowest point. It then uses those 4 points to set interval training power zones. I find this much better for setting AC and MAP interval power targets, which would be too low for me based on FTP alone. The 4DP test itself is absolutely brutal!

PILLAR uses a 5 point analysis of your power curve (from sprint to endurance) to set training interval targets and to track and report your progress. Like XERT, it doesn’t require a specific test, as long as your data includes some serious efforts across the power range.

It pegged the FTP at the inflection point after a relatively flat region on the PDC. It's an alternative to testing. Your PDC is incomplete, you didn't ride much, or rode very steady.

Apparently FTP has fallen out of favor of most professional cyclists. I haven't listened to the video yet, because I'm getting ready to head out on a ride, but hopefully will check it out later.

Have not watched the video yet. For me, FTP is a personal benchmark on fitness versus comparing mine to other people since we all have such different body types, experience, training habits etc.

For any kind of reasonably valid comparison the FTP #'s being compared would have to be calculated in exactly the same way for each individual, yes?

While I think FTP has value, making comparisons might lead one down a rabbit hole if not done with caution.

I watched the video. It's pretty amusing, if you find people suffering unnecessarily amusing. FTP isn't max 60 minute power, so the entire premise for that suffering was misplaced.

Yeah, I had to stop watching it after he continued to talk to the 2nd expert about the 1-hour ftp power.

As to the thread topic, I ride mtb with no power meter, but have a stationary bike (with a power meter) I do my zone 2 work, and occasional interval workouts, inside. Since I retired a little over 2 years ago (55 yo now), I've had time to pay some attention to ftp, and way more time to ride my bike, so my ftp is up from 235ish in Jan 2023 to somewhere between 300-325 now.

I was over 325 around Thanksgiving, but had a back/shoulder issue right after, so I backed off to zone 2 only and have been focusing on PT on the back/shoulder. Started riding outside and doing intensity a couple weeks ago, and am pleasantly surprised how quickly I'm getting back up to speed.

If you keep cranking those kind of numbers, we may have to kick you out of the 50+ club.

Nooooo, I just got here! (bikeforums, not 50+) Besides wanting to build a solid base of fitness to hopefully slow the inevitable downward trend, I really just wanted to keep up with my friends, and maybe overshoot a little so my perceived effort to keep up is comfortable. I overshot the overshoot, and may need new friends now .

I just don't see much value in FTP. I mean, what is the actionable result from knowing what it is? Setting your zones? I don't need an FTP to know where my zones are. Perceived effort is all I need.

Is FTP helpful to show you where your fitness sits? Not super helpful to me. I think the Best Efforts Power Curve is a lot better at that. Mine is telling me that my fitness is off from peak last year (but it's February, so). Or maybe I need to start pushing harder on rides.



Also...

All I have to say to you, MikeMunson , with those power numbers, I sure hope you weigh at least 200 lbs.

Note that the fact that while there are certainly alternate measures of performance, that's not the same thing as saying "fallen out of favor of most professional cyclists". FTP (albeit loosely defined) is still the standard unit of performance capacity. Maybe in a few years, one of the alternate measures will become the new standard, and there are certainly cyclists using alternate measures, but that's a far cry from saying "most professional cyclists".

Yeah, I'm just over 200#. I'm fat, though, and trying to lose 20-25#. I lost 15# while the power was increasing last year. It'll be interesting to see how much of that power I can retain while losing weight. Picking up a couple more mph would be (more) fun.

FTP (and w/kg) are certainly useful for setting zones, and as a measure of fitness. I've been using heart rate for almost 10 years, and have a pretty good handle on how my HR behaves and how different conditions affect it, and for zones. The HR zones haven't really changed in a long time, so without power, increased performance/fitness is measured with speed...lots of factors go into speed when on a mountain bike. So, watts are fun to watch increase and they're pretty clean as far as being a measure of fitness. I don't have a power meter on any of my mtbs, so HR is still tracked and I can combine that with calculators to estimate power for outdoor rides, but that power estimate is mostly just useful to cross-check the indoor power meter results.

I think the problem with doing a full hour at high (for me) level is to know what that high even feels like. I guess I’m not really motivated to know my FTP.