Should I use Normalized Power or Average Power for determining FTP?

Discussion in 'Power Training' started by HillyGoat, Jun 26, 2012.

  1. HillyGoat

    HillyGoat New Member

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    I have had a PM and WKO+ software for three months now and with testing I estimated my FTP to be 250W. After riding today in the hills with some strong climbers I saw that my peak 20 minute Normalized Power was 296W but average power only 229W. What is more relevant, NP or average? If NP is more accurate in determining FTP then my true FTP would be 296 x .95 = 285?
     
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  2. RServranckx

    RServranckx New Member

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    For your FTP estimation using 20min, you should use your average power - 5%. If you see your NP consistently higher than your FTP during 60 min intervals, then it's time to reevaluate your FTP. Rob
     
  3. HillyGoat

    HillyGoat New Member

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    Are you saying 60 min NP approximates FTP reasonably accurately?
     
  4. RServranckx

    RServranckx New Member

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    Only if the VI is relatively close 1.0.... :) If you're doing "intervals" over 1 hour (hills, burst of effort, etc), such that the VI is significantly higher than 1.0 (say above 1.15 maybe?), you're no longer working your FTP, so you cannot use that to correlate the NP to your FTP. However, if on your rides your NP is frequently over your FTP over 1 hour, and assuming you're trying to keep a reasonably steady effort, then this is an indicator that your FTP is under-estimated. Rob
     
  5. acoggan

    acoggan Member

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    It does.
     
  6. ric_stern/RST

    ric_stern/RST New Member

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    Your "true" FTP is not worked out by multiplying anything by 0.95. Your true FTP is ascertained by finding out what you can do 'all-out' for ~1hr on a regular basis.

    If you want to estimate your FTP, then there are far better ways than the multiplying by 0.95. Alex's deadly sins is a good read http://alex-cycle.blogspot.co.uk/2008/05/seven-deadly-sins.html
     
  7. acoggan

    acoggan Member

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    :)
     
  8. HillyGoat

    HillyGoat New Member

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    Thanks for your insight guys. I found three 60 min sessions with Normalized Power at 255W which is pretty close to my estimated FTP.
     
  9. acoggan

    acoggan Member

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    Not true.
     
  10. HillyGoat

    HillyGoat New Member

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    What is V1? Also what is Pw:HR and Pa:HR?

    Thanks.....
     
  11. RServranckx

    RServranckx New Member

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    I'm actually surprised to read this.... I figured, for example, that if a person does high intensity interval repeats for one hour (say 2 mins on, 2 mins off), NP would not necessarily be a good indicator of FTP (I thought I'd read that somewhere). I don't question you at all (have and love your book) - but I'm really surprised. :) As its difficult for me to do true 60min TT-type rides ar more or less even intensity to determine my FTP, knowing that I can use NP on irregular terrain is actually good news! :D Do you have any online articles I can read about this? Thanks! Rob
     
  12. Alex Simmons

    Alex Simmons Member

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    I missed that one. Far be it from me to claim another's sins.
     
  13. Alex Simmons

    Alex Simmons Member

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    Indeed the higher the (ugh) VI is, the more likely NP (from a hard hour) is a better indicator of FTP than AP.

    It is anyway, but it becomes more apparent the bigger the difference is between AP & NP.
     
  14. Alex Simmons

    Alex Simmons Member

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    VI is an acronym for Variability Index, a term coined to represent the ratio of Normalised Power to Average Power.

    e.g. if you have a ride with an NP of 250W and an average of 200W, then the VI is 250/200 = 1.25

    It loosely indicates how "variable" the power output was for a ride, although that's not strictly true.

    As for the other two, well you can look them up on training peaks website. Whether or not they have any practical application is another matter.
     
  15. RapDaddyo

    RapDaddyo Active Member

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    Actually, it is even predictable. Let's say that your FTP is 250W and you do interval sets as you describe (2mins on + 2mins off) for an hour. If you do the "on" segments at, say, 275W, you should be able to do your "off" segments at 213W. You can always back into this calculation by using the NP formula in which you compute the weighted average of watts to the fourth (exponential) power. I sometimes do an FTP ride exactly like this on my trainer to break up the monotony of constant power rides.
     
  16. acoggan

    acoggan Member

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    No worries (to/for Rick, either), I just figured that if I didn't say anything, people would be even more likely to think we are one-and-the-same person. (Not that that would happen in real life, since I'm much better looking. /img/vbsmilies/smilies/ROTF.gif)
     
  17. Alex Simmons

    Alex Simmons Member

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    The worst part about you being right (again) is we have photographic evidence of the fact!
     
  18. ric_stern/RST

    ric_stern/RST New Member

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    opps sorry guys.

    :)
     
  19. yeaux

    yeaux New Member

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    I started a new thread similar to this (more specific to myself), but I guess it is in moderation to be approved.

    Eitherway, I was wondering a couple things based on this thread and another regarding NP:
    1. Say a higher-than-FTP 60 minute NP ride comes from repeats of 30 second sprints with resting time or a hard group ride, is this method still valid for increasing FTP?
    2. Wouldn't the reliance on NMP and AWC in forming the higher 60 min NP overstate the other training levels? For instance, If one produces a 290+ watt 60 min NP for the above workouts, but the best 20 minute effort one has put out to date is approx. 275 watts, wouldn't setting an FTP level of 290 watts overstate the other "endurance" levels (L2, L3, L4, etc.)?

    Thanks for any thoughts or comments - I'm trying to wrap my head around this concept some more and want to make sure TSS isn't overstated too greatly.
     
  20. bgoetz

    bgoetz Member

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    I would say that if you are seeing an NP of 290 watts if you were to do 20 minutes at threshold your AP will be higher than 290 for that effort. If you have not done 20 minutes at threshold and are just basing your peak 20 min from race/hard training rides, then in those situations it can be difficult to get a true 20min max due to the extremly variable nature. The highest 20 min I have recorded from race data is 10 watts under my FTP, while I have done 20 min TTs that figured to be 15 watts over my FTP.
     
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