Estimated FTP From Workout Duration

Discussion in 'Power Training' started by wiredued, Apr 14, 2007.

1. wiredued New Member

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Looking for some peer reveiw on this method. A month ago my 1 hour TT was 250 watts so I have been doing 91% of that at 227.5 watts for 60 minutes as my workout. I can now comfortably do 70 minutes non stop at this intensity. If I raise the intensity to 232.5 watts and fade shortly after 60 minutes isn't it safe to say my FTP is 232.5 x 1.099 = 255.5 watts?

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2. rmur17 New Member

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you're joking, correct?

3. daveryanwyoming Well-Known Member

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If you fade after an hour while riding at a steady 91% of your FTP your fade is most likely mental or related to fueling and not physiological. By definition you should be able to last for a lot more than an hour at 91% of your FTP, even if you're not fully rested. That makes it difficult to try to apply linear conversion factors (to three decimal places for gods sake) to figure out what your FTP would be.

I suppose it's fair to say that if your FTP was tested to 250 fairly recently and you had tuned into the RPE associated with an hour at 91% of that validated FTP, and now the RPE for those efforts is less then your FTP has probably gone up.

I suppose you've seen these from Andy's "7 Deadly Sins" piece as guidelines for the best ways to estimate FTP in ascending order of accuracy
Take a look at number 6. The second best method of determing FTP according to Andy is to observe the power you can routinely do for long intervals performed in training. Maybe you should try some harder intervals a bit shorter than your current hour long variety( 20 to 30 minutes comes to mind) and see what kind of numbers those give you.

But I sure wouldn't use your 1/(91%) approach and expect any sort of accuracy. For training purposes it really doesn't matter. Do your long intervals as hard as you can while still being able to complete them. You can gauge your progress on those power numbers alone. If you want to know your FTP to hypothetically compare to other racers then do a real test like a two or three point Monod or better yet, just enter a race and you'll see where you stand.

Good luck,
-Dave

4. wiredued New Member

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Nope... I just aimed to high on my last time trial again (264w only did 35 minutes) and was sitting there next to my KKR thinking there must be an easier way without screwing up a 60 minute workout. Dave just gave me an idea though maybe I'll just go up 1 watt per 60 minute ride and if I can't do 60 back off for a few weeks.

5. daveryanwyoming Well-Known Member

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If you really blew up, as in you managed the 264 watts for 35 minutes but just couldn't hold it any longer then you're half way to a two point Monod test. Just do one more max effort in the 3 to 5 minute range or try for 275 to 280 watts and see how long you can hold it. Ideally Monod test points are in the 3 to 30 minute range but I expect you'll get a good CP estimate from your existing 35 minute test and one more data point. This doesn't have to sacrifice a pefectly good workout. Do the first test and call it L5 work and then rest a bit before continuing with some longer SST/L4 intervals.

6. tomdavis80 New Member

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No way, you can't really say that because if you can sustain 235 watts for 60 minutes and then fade, then that's your FTP. I'm under the impression that the longer the effort, the slower the maximum power your body's capable of putting out drops. For instance, if you can give out 250 watts for your maximum over 60 minutes, then your maximum over 70 minutes would be somewhere around 245 and so forth. And since you can do 227.5 watts at 70 minutes "comfortably", I'm assuming you could sustain this for another half hour or something rather than completely cracking after 70 minutes at 232 watts. There is also the chance that you may be closer to 85% of your FTP at 227-235 watts now because you don't have any bonafide testing to back up your new FTP.

Thomas Davis

7. frenchyge New Member

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How about starting at a 250w pace, then at 30 minutes pick it up to 255-260w, and then at 50 minutes hold whatever you can to the end? At 60 minutes, if you're still going strong then keep riding as long as you can keep it over 250w, since those extra minutes will replace one's at the beginning of the ride when you figure your highest 60min AP.

Even if you can't get over 250w for your 60min AP, at least you've had a good workout.

8. wiredued New Member

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Maybe Fade was the wrong word and you are right it starts to turn into perceived exertion not real numbers. I think to avoid overshooting again but find my FTP in as few workouts as possible I might just try to do my next one starting at 255 for 70 minutes and if I get through 65 minutes go up by 2 watts on the following workout aiming for 60 minutes.

9. wiredued New Member

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Your right I do a variation of that now ie if my target is 255 I will do five minutes at about 245 then five min at 255 then 5min at 265 then repeat three more times for an hour it seems to fight fatigue.

10. wiredued New Member

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L4 indoors is cool L5 indoors gets me kinda sick and indoors is where I can measure power.