Discrepancy between CP and 1 hour power

Discussion in 'Power Training' started by cheetahmk7, Dec 30, 2010.

  1. cheetahmk7

    cheetahmk7 Well-Known Member

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    I'm noticing a significant difference between my calculated CP and what I can actually achieve over an hour, hence I'm wondering which value I should use to calculate my traing zones?

    I have calculated my CP value of 281 Watts based on 5 minute interval of 372 Watts and 20 minute interval of 304 Watts. Both of these intervals were performed when I was well rested. They were maximum efforts performed on an indoor training using an SRM. These efforts were performed within two weeks of each other. A week prior to doing the 5 minute interval I hit current predicted MMP curve at the eight minute mark on a hillclimb - which helps verify its accuracy.

    What I have actually managed to achieve over an hour has been far less than the calculated CP or the predicted MMP at 60 minutes. The best I have managed over an hour is 266 watts whilst climbing Mt Buffalo and Falls Creek.

    So which value I should use to calculate my traing zones ? Can any other conclusion be made?

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  2. daveryanwyoming

    daveryanwyoming Well-Known Member

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    It's not unusual for folks to need several tries on different terrain (sustained climbs, long flats, etc.) before actually achieving their FTP for a full hour. Remember FTP represents your best possible power for a full hour under ideal conditions not your on demand hour power any day of the week, any issues with recovery, blocked up legs from too much rest, poor nutrition, hydration issues, poor pacing during the test or insufficient motivation to really give your all for a full hour can all contribute to falling short of your potential. It's one of the reasons so many folks use shorter tests including Monod testing to estimate their FTP, it's just really hard to nail your best possible power for a full hour out of competition and even during an actual 40K time trial it can be tough if everything doesn't click on race day.

    FWIW, I've never seen my best full hour on a long climb, first it's hard to find a full hour of climbing without flatter sections along the way but for whatever reasons I tend to do better for a full hour on the flats even though many of my best 5 to 20 minute efforts have been set on climbs. Everyone's different,but you might try some long efforts on different terrain to see what happens.

    You've also got the issue of Monod numbers set indoors on the trainer vs. outdoor riding. Many if not most folks can sustain different power indoors vs. outdoors though your recent 5 minute hillclimb MMP suggests that it might not be that different for you assuming that was a maximal 5 minute effort.

    I'd probably stick with your 280 estimate for FTP but it doesn't really matter that much. The key thing is to target appropriate durations for your intervals like 3 to 6 minute for VO2 Max work, 20 to 30 or up to 60 minutes for Threshold work and just ride them very hard but backed off enough to finish the efforts and finish the sessions. The appropriate levels will become really clear after a session or two and things will self correct very rapidly. If for instance you can't finish a 20 minute effort at 255 watts or more then your FTP is likely set too high, if you do a set of two or three and hold 280 or more for all of them without feeling you worked too hard then bump it up a notch next time. You'll know real soon what you can manage and hopefully those levels will change with additional training anyway.

    That's basically how I've approached things for several years now. I estimate my FTP based on what I can sustain for my regular repeatable long 20 to 30 minute intervals mostly to drive the Performance Manager in WKO+ and to keep tabs on how much weekly time I accumulate in training zones of interest. But out on rides I chose a duration for my intervals based on the systems I'm targeting and available training venues and then just ride. If I'm targeting L4 I'll try to make sure I hit at least 90% of my FTP for a 12 to 60 minute interval but I don't watch the numbers all that closely once I know I'm somewhere above 90% and if I feel great I don't hold back. Over time the numbers tend to float up and when I'm consistently holding higher numbers for those efforts I bump up my FTP estimate. I occasionally do a Monod test and do several full hour efforts and 40K time trials each year and the numbers agree nicely.

    Good luck,
    -Dave
     
  3. swampy1970

    swampy1970 Well-Known Member

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    Damn... be the bringer of seasons greating and holiday hope why don't ya :p

    Cheetah, you don't have to nail the numbers exactly, just be in the right ball park and you'll be able to tell from using the guestimated values for each zone in training whether you're pretty close. If you over estimated you'll know pretty quick. ;)
     
  4. daveryanwyoming

    daveryanwyoming Well-Known Member

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    Quote:
    ... be the bringer of seasons greating and holiday hope why don't ya :p...



    Bahhh Humbug...

    I guess I didn't word that very well as my intention was the opposite of the way you took it. I'm saying that his FTP is probably closer to the 280 value predicted by both the Monod and his 20 minute MMP rather than the 266 number he managed on his hour hill climb. IOW, I'm optimistic that his FTP is higher than what a full hour of climbing suggests.

    -Scrooge
     
  5. cheetahmk7

    cheetahmk7 Well-Known Member

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    I have achieved very similar results for my maximum one hour power on three occasions.

    I had a couple of good attempts at achieving my FTP up Mt Buffalo and the results were within a few watts of each other. I had a positive Chronic Stress both times, but my legs may have been a bit blocked up as I had waited three days for the rain to stop. It took me 62 minutes and I was trying hard to crack an hour.

    I defiantly had a pacing problem, as at the 10 minute mark I had averaged 281 Watts, but at 20 minutes it was 276 Watts, at half an hour it was 271 Watts and by the end of the hour it was down to 266 Watts.
    I have never had a crack at doing a 1 hour FTP test on the flat. The terrain around where I live is a bit on the rolling side, which is one of the reasons why I have done my power testing indoors or on long ascents.

    I was aware of this, but I have found pretty good correlation with my power numbers on the road, hills and the indoor trainer. I have however noticed an inability to reach my MMP curve in time trials, which may be part of the reason why I am so uncompetitive at them. For some reason, I can't time trial as well as people of similar weight who I can out climb.
    I have gone with the 280 estimate. After reading this, I did a 2 x 20 minutes session. The first was done at an average of 280 Watts and after 10 minutes rest I commence the second. I was feeling pretty comfortable at the half way mark, having averaged 280 Watts to this stage, so I upped the wattage until I felt uncomfortable and I ended up averaging 285 for the 20 minutes. If I was to have done three sets, 280 Watts would definitely have been achievable
     
  6. Nate Pearson

    Nate Pearson New Member

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    Definitely go with the higher FTP for training zones.

    Your results probably mean you have a higher than average anaerobic work capacity. For your shorter intervals (less than 30 min) you want to work that system still.

    If you were doing an ironman I would probably have you ride at a little lower percent of your FTP than the average person. But for day to day training, ride at that higher FTP.

    Worst case is you can't finish an interval at the prescribed power level. If that's the case then back it off next time or try again. It's better to do it that way then train too easy.

    -Nate
     
  7. jollyrogers

    jollyrogers New Member

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    What kind of numbers can you typically hit during your long intervals (i.e. 2 x 20) in training?

    NVM - read your later post. Seems like 280 is the right number for you.
     
  8. cheetahmk7

    cheetahmk7 Well-Known Member

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    I just hit 314 watts for a 1 x 20 min yesterday, so I'm now looking at a CP of 290. Perhaps I may be able to up my 60 minute power now.

    One thing I have just noticed is that I find it easier to sustain good power numbers at a cadence below 90 than above it and that I also produce far better power numbers riding with a tail wind than riding into a head wind. Riding with a tail wind feels similar to riding on my TACX flow, which I usually ride in the 53 x 12 to keep things nice and smooth. Does anybody else experience this kind of thing?
     
  9. daveryanwyoming

    daveryanwyoming Well-Known Member

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    Yes, I typically sustain my best power numbers on flat terrain with cadences closer to 75-80 than to 90-100 even though I tend to ride lighter gears and spin 90-110 rpm during crits and fast road races to better deal with attacks and pace changes. I also tend to sustain a bit more power when riding fast in a fairly large gear rather than plugging away into a headwind or on a steeper hill but manage to do all right on lower grade hills in the 1-4% range. Not sure of the exact reasons, but that's what I've seen over the years.

    Congrats on the progress,

    -Dave
     
  10. bubsy

    bubsy New Member

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    Yes, I typically sustain my best power numbers on flat terrain with cadences closer to 75-80 than to 90-100 even though I tend to ride lighter gears and spin 90-110 rpm during crits and fast road races to better deal with attacks and pace changes. I also tend to sustain a bit more power when riding fast in a fairly large gear rather than plugging away into a headwind or on a steeper hill but manage to do all right on lower grade hills in the 1-4% range. Not sure of the exact reasons, but that's what I've seen over the years.

    Congrats on the progress,

    -Dave



    Ditto,
    I seem to put out a higher avg power for longer durations when riding at much higher speeds in a fairly big gear at around 80 - 85rpm.
    On the the other hand for shorter efforts 30's out to about 8-10min I do much better on much steeper grades,
    going too hard on long steep climbs and l over heat and blow up; even though l am capable of the same power for longer durations on the flats at much high speeds.
     
  11. TShame

    TShame New Member

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    I think the discrepancy is indoor workouts compared to outdoor. Indoors is a very controlled environment (cooling fan, drinking more water, not having to concentrate on steering and tuck position. I would encourage you to try an hour tt on the trainer. Also, for outdoors try the 5 and 20 minute intervals and see how close you can come to your indoor trainer efforts. The good thing is if one can increase wattage on the trainer, it will carry over into the outdoor efforts.
     
  12. cheetahmk7

    cheetahmk7 Well-Known Member

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    I have yet to try doing 5 and 20 minute intervals outdoors, but I have had a crack at doing a 60 minute interval and a 30 minute interval indoors.

    My results for the 60 minute interval was an average of 272 Watts, which is 6 Watts better than I achieved climbing mountains in November and December. We must bear in mind that my 20 minute power improved by 18 Watts in the same period. I felt that I paced the effort pretty well, with a peak average wattage for 5 minutes of 275 Watts. I'm also confident that it was a maximal effort as I dry reached at the end of the hour, and that never happens to me.

    For my 30 minute effort I managed to average 292 Watts, which is pretty much what my calculated CP value is, but 18 Watts less than the Monod equation predicts I can do.
     
  13. TShame

    TShame New Member

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    Great. Your 30 minute improvement from 304 to 314 is a good indicator that your overall power went up.
    In other words, your five minute and 60 minute efforts are up, even without testing.
    I prefer flat time trial wattage rather than hills for it's accuracy. But, if you ride the same hills, that's fine too.
    (Average power is very tricky if one is doing a course of up and down hills. My wattage is horrible downhill.)
    I would try the five minute test again, aiming for a similar 3% improvement. (goal of 380)

    Eventually, you will get a grasp of how fast you can go outdoors based on your indoor results.
    It should result in better pacing for your efforts as well as more training time devoted to the right power level.

    Hope to hear some more results. Typically 1 or 2 % increase is sustainable.
     
  14. cheetahmk7

    cheetahmk7 Well-Known Member

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    That was actually 20 minutes for the 304 to 314 W improvement, not 30 minutes. I'm planning to do the 5 minute test again, but I find it easy to put off as I need to schedule it in for when I'm super fresh. Also (as you would be aware) it hurts so much and it is so easy to start out just a touch too hard and then be unable to complete the full 5 minutes.

    In regards to the 1 to 2% sustainable increase, over what period are you talking about? I have recorded a 1.7% monthly increase over the last 3 months for my hour power, and a 3.5% monthly increase over the same period for my 20 minute power. The gains for the four months preceding that were significantly larger.

    Is there any way to drag ones 60 minute power levels closer to ones 20 minute power levels?
     
  15. cheetahmk7

    cheetahmk7 Well-Known Member

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    5 minutes is now 376W = 5.53W/kg
     
  16. cheetahmk7

    cheetahmk7 Well-Known Member

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    A lot of water has passed under the bridge since my last post as shortly after I contracted what I believe to have been whooping cough despite having been immunised against it. This resulted in six weeks off the bike and a drop in power output of around 50 watts. Within 8 weeks of recommencing training I had recovered all but 10 of those watts and after another 8 weeks I managed to exceed my previous best 20 Min Peak Power by 3 watts.

    So now my CP is pretty much 300 watts, but from doing 2 x 20's and 1 x 60's I'm pretty confident that the best that I could do for an hour would be 280 or maybe 285 watts max. When doing a 1 x 60 it feels really obvious when I step over what I feel to be my FTP. As a result I'm using 280 as my FTP value in Golden Cheetah. I'm finding that this works pretty well for me as:
    a). I just can't sustain the same power numbers on the road as on the trainer (unless I'm climbing,) and hence riding SST on the road feels more like threshold does on the trainer.
    b). I find that I'm riding my 2 x 20's at an average of 280 watts when riding them hard

    A couple of other observations that I have made are that I'm just not putting out the same power on the open road (which where I live is typically on the rolly side) than I do on a hill or on my trainer. The other thing is that training with a Power Meter really seems to work as I'm doing far better in handicap races than I did last year. I figure that I have been moved back two bunches and I'm still more comfortable than last year. The funny thing is that I don't feel any stronger, it's just that everybody else in my bunch just seems weaker. I have even figured in the prize money a couple of times.
     
  17. daveryanwyoming

    daveryanwyoming Well-Known Member

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  18. An old Guy

    An old Guy Member

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    Part of training with power is determining what the various numbers numbers mean for you.

    What ever you are doing seems to be good.
     
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