Ave. Watts or NP better to calcuate FTP?

Discussion in 'Power Training' started by tomUK, Jun 3, 2010.

  1. tomUK

    tomUK New Member

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    If I do a time-trial (all out) for an hour and my Average wattage is 260 but my NP is 280 then which is the better figure to use? From what i've read about NP it appears that this would be better. I guess the only thing i could assess from this difference is that i am somewhat eratic with putting power to the pedals - something which i assume you would expect and need to work on in order to pace oneself better.

    Anyhow, just wondering what is better for FTP figure.
    thanks.
     
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  2. Squint

    Squint New Member

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    Which one actually moves the bike forward?
     
  3. Alex Simmons

    Alex Simmons Member

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    If it was an all out TT effort, then FTP will be closer to NP than AP.
     
  4. dkrenik

    dkrenik Member

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    +1 to Alex's response.

    NP will (generally) overestimate FTP by a smaller amount than what AP (generally) underestimates FTP by. I'd pick 275 and call it a day.

    Dave
     
  5. jollyrogers

    jollyrogers New Member

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    Really? I thought that NP was closer to FTP than AP for a 1 hour event if and only if the effort was highly variable i.e. a criterium. Isn't the definition of FTP the average power during a ~1 hr ride?

    I guess a VI of 1.07ish is pretty variable though. At what VI would you consider NP a better predictor than AP?
     
  6. daveryanwyoming

    daveryanwyoming Well-Known Member

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    More like a ride of roughly an hour ( a sub hour 40K counts) ridden under ideal conditions. Those ideal conditions include motivation and good pacing and imply steady terrain for that good pacing. Ride a really hard hour in variable terrain perhaps including some steep or technical descents that bring down the AP and maybe some steeper sections that drive up the NP and AP can end up lowball.

    It's not really a matter of VI in and of itself. More like FTP is bounded both by best sustainable AP which assumes ideal conditions and NP which estimates the effective metabolic load. As VI approaches 1.0, NP approaches AP so that case is covered by both AP and NP. But in the same way that by definition you can't ride an hour with an AP above your FTP, you can't ride an hour with NP more than 5% above your FTP unless you've managed one of those rare NP busters which typically don't happen in time trials.

    In the case of a variable effort ride ridden near your limit whether it's a crit or a solo effort in variable terrain where AP and NP differ, NP is going to be a better estimate of FTP than AP at least according to the guy that coined the terms.

    -Dave
     
  7. Alex Simmons

    Alex Simmons Member

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    Yes but it's also meant to be a quasi-steady state effort without fatiguing (IOW AP=NP).

    From a hard one hour ride? At all VIs.
     
  8. acoggan

    acoggan Member

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    That's what the data show, anyway.
     
  9. jollyrogers

    jollyrogers New Member

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    So would it be appropriate to update the 7th sin to read NP vice AP?
     
  10. acoggan

    acoggan Member

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    "Better" does not mean "best".
     
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