Training Q: CP vs FTP
#1
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Training Q: CP vs FTP
Google and search function exhausted. Perhaps I'm not using the right terms.
I was looking for something that shows critical power to FTP equivalency. There is a lot out there that mentions CP60 is FTP. However, I was interested in other CP points. For example, CP30 is clearly not 200% of FTP (more like 105%?). How about CP1, CP5 or CP180? Is there a formula that one could apply?
Thanks!
Mr. Burns
I was looking for something that shows critical power to FTP equivalency. There is a lot out there that mentions CP60 is FTP. However, I was interested in other CP points. For example, CP30 is clearly not 200% of FTP (more like 105%?). How about CP1, CP5 or CP180? Is there a formula that one could apply?
Thanks!
Mr. Burns
Last edited by burnsce; 11-12-10 at 09:11 AM.
#2
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It's going to be different for everyone depending on several factors. That is why you can test at several durations and the various power profile such as sprinter, pursuit, and time trial. Also note that CP for shorter durations is going to be higher than longer durations. One "standard" is that FTP (60) is roughly 95% of 20 minutes, BUT someone with a higher anaerobic capacity will be able to produce more power over 20 minutes for the same FTP, and therefore FTP would be a lower percentage.
#3
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From: Albuquerque, NM
I was looking for something that shows critical power to FTP equivalency. There is a lot out there that mentions CP60 is FTP. However, I was interested in other CP points. For example, CP30 is clearly not 200% of FTP (more like 105%?). How about CP1, CP5 or CP180? Is there a formula that one could apply?
https://alex-cycle.blogspot.com/2008/...adly-sins.html
#4
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There is definitely a formula. Usually it is obtained by a test at 2-3 minutes and another test at 15-20 minutes. A curve is fit though those two points which can tell you an estimate for critical power at other time intervals. Unfortunately, I can't tell you the equation off the top of my head, but it should be in any number of training books. I believe it is listed in Friel's book, though I am not sure.
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"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
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"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
#6
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From: The Mean Streets of Bethesda, MD
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click on the link on this page for velofit's Monod spreadsheet (which you can download) - basically slope of work vs time is "long term" CP, and then you can back out CPs for specific time points. You'll need a powermeter or very good estimate of power for any given interval. As much as I like my KK Road Machine trainer, it turns out the published power curve is not that accurate when I benchmark against my PT.
https://velo-fit.com/new/tools.php
I think Golden Cheetah uses the same calculator.
https://velo-fit.com/new/tools.php
I think Golden Cheetah uses the same calculator.
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#8
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From: Albuquerque, NM
#9
There is definitely a formula. Usually it is obtained by a test at 2-3 minutes and another test at 15-20 minutes. A curve is fit though those two points which can tell you an estimate for critical power at other time intervals. Unfortunately, I can't tell you the equation off the top of my head, but it should be in any number of training books. I believe it is listed in Friel's book, though I am not sure.
Two data points to do a CP curve is pretty light if you're looking for real accuracy. Best measure of various CP's is obtained by shoving all your data files into a custom WKO periodic and setting the dates you want to get data from. Even that presumes you have hit max at the different CP numbers. If you've got a lot of race/TT/test data you can usually get a pretty good handle on this.
#10
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Wow, great question, I had never really considered that until you asked. I think the value of trying to do something like this is for setting up training zones and developing pacing strategies. Even taking an MMP curve is really just a best guess as I am certain I have never gone all out for 90 minutes. So under the context of this being a guide, I find that it tracks to a point. After 3 years of using this, I have learned that when I reach about 95% of my peak fitness for the season, I struggle to hit the CP12 and CP6 numbers (I have no idea why, but I can still hit CP1). Prior to that cross-over point the numbers are achievable (I do a 3 X 5's @ CP6 during the season which is my reference). That being said, over the last 3 years as my ftp has increased, there has been a close tracking of the 30,12, and 6 numbers. I am primarily a TT racer so that should give you an idea of where most of my time is spent. I should also add that as I move from late base to build, the lower CP#'s are more challenging, but after a couple of weeks they get easier so it certainly does take some work. So short answer, some natural tracking, but some work is required as well. I am certain it would not work the other way for me.
#11
If you're a 'rounder who does TT's MMP will give you good numbers out to 60, beyond that, see above. And I say this as a guy who's spent more than 2 hours OTF by hisself.
#13
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From: The Mean Streets of Bethesda, MD
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Here's another cautionary bit re relying on calculated projections -
Yesterday I did my hardest/best 5 min interval in terms of watt output. When that number get's crunched into a calculation using my older outputs for longer intervals, the net result is that the calculated FTP goes down - you might think of it as more work in the longer interval is attributed to my increased anaerobic output.
Did my FTP really decrease over the last month? Maybe, but I don't think so. More likely, I've gained across the board and this is an artifact of not having done a long interval that shows this. (My weekend cross races are not done with a powermeter, so I'm not getting data from these 40-45 minute efforts.)
Yesterday I did my hardest/best 5 min interval in terms of watt output. When that number get's crunched into a calculation using my older outputs for longer intervals, the net result is that the calculated FTP goes down - you might think of it as more work in the longer interval is attributed to my increased anaerobic output.
Did my FTP really decrease over the last month? Maybe, but I don't think so. More likely, I've gained across the board and this is an artifact of not having done a long interval that shows this. (My weekend cross races are not done with a powermeter, so I'm not getting data from these 40-45 minute efforts.)
__________________
“Courage is going from failure to failure without losing enthusiasm." (Churchill)
"I am a courageous cyclist." (SpongeDad)
“Courage is going from failure to failure without losing enthusiasm." (Churchill)
"I am a courageous cyclist." (SpongeDad)
#14
fuggitivo solitario

Joined: Jun 2009
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What warmups do you guys use for CP12 and CP6 testing? Also, how do you guys suggest go about doing them? I know for CP1, you sprint hard for 15-20seconds and try to maintain as much power as possible for the remainder of the test. What about CP6 & 12? Do you try to keep it above a certain estimated average power?
Thanks in advance
Thanks in advance
#16
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Here's another cautionary bit re relying on calculated projections -
Yesterday I did my hardest/best 5 min interval in terms of watt output. When that number get's crunched into a calculation using my older outputs for longer intervals, the net result is that the calculated FTP goes down - you might think of it as more work in the longer interval is attributed to my increased anaerobic output.
Did my FTP really decrease over the last month? Maybe, but I don't think so. More likely, I've gained across the board and this is an artifact of not having done a long interval that shows this. (My weekend cross races are not done with a powermeter, so I'm not getting data from these 40-45 minute efforts.)
Yesterday I did my hardest/best 5 min interval in terms of watt output. When that number get's crunched into a calculation using my older outputs for longer intervals, the net result is that the calculated FTP goes down - you might think of it as more work in the longer interval is attributed to my increased anaerobic output.
Did my FTP really decrease over the last month? Maybe, but I don't think so. More likely, I've gained across the board and this is an artifact of not having done a long interval that shows this. (My weekend cross races are not done with a powermeter, so I'm not getting data from these 40-45 minute efforts.)
#18
From my own testing:
CP20: 105%
CP60: 100%
CP90: 94%
CP120: 91%
CP180: 86%
I'd say Ex and I have similar tactics. Grind people down then attack when everyone is dead. The longer the breakaway the better. Oh yea, I hate crits.
CP20: 105%
CP60: 100%
CP90: 94%
CP120: 91%
CP180: 86%
I'd say Ex and I have similar tactics. Grind people down then attack when everyone is dead. The longer the breakaway the better. Oh yea, I hate crits.
#19
#20
I bet your 90 and 120 are closer to your 60 than most.
#23
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See SpongeDad.
Two data points to do a CP curve is pretty light if you're looking for real accuracy. Best measure of various CP's is obtained by shoving all your data files into a custom WKO periodic and setting the dates you want to get data from. Even that presumes you have hit max at the different CP numbers. If you've got a lot of race/TT/test data you can usually get a pretty good handle on this.
Two data points to do a CP curve is pretty light if you're looking for real accuracy. Best measure of various CP's is obtained by shoving all your data files into a custom WKO periodic and setting the dates you want to get data from. Even that presumes you have hit max at the different CP numbers. If you've got a lot of race/TT/test data you can usually get a pretty good handle on this.
FWIW, I use golden cheetah, which calculates a CP based on historical data, but I don't use that number. I have a pretty good feel for what I can do for an hour and that is probably more accurate than some blind, 2-point correlation model.
__________________
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --the tiniest sprinter
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