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20min Average Increase not during test

Hurricane151Hurricane151 Posts: 632
edited February 2013 in Training, fitness and health
I have been testing my 20min Ave power and calculating my FTP from this on the turbo using the testing protocol from "training and racing with power" and to date i have done two tests.

Tonight however i went out on the club chain gang and when i have downloaded the data the max average power is up by about 20watts from the turbo test.

Simple question, do i now revise my FTP as power is power no matter where it is one but as i am not comparing apples with apples as they say should I stick with tested numbers.

The average on the turbo was a nice steady maintained power over the 20mins whereas tonights was much more "peaky" with harder efforts and obvious periods of sitting in, but i guess that's why you take an average.

So, increase FTP or not?

Posts

  • mattshropsmattshrops Posts: 1,134
    My initial thought would be yes, you produced x power for y minutes therefore yes.
    BUT if you're sitting in for long periods and then smashing it well above ftp then i'm not so sure.
    Expert rquired please.
    Death or Glory- Just another Story
  • kamil1891kamil1891 Posts: 658
    I think you should use the best ave power for 20min. Doesn't really matter whether you sprint for 1m and then you rest for 2 or you do 20m steady, best average is best average. When you come to a race it's not going to be steady effort.
    That's what I think :)
  • HerbsmanHerbsman Posts: 2,029
    Both will give you poor results I think.

    You may not produce as much power on the turbo as outdoors.
    95% of 20 min steady effort will not give a very accurate estimate of FTP and may actually be totally wrong. My 1hr best is actually 98% of my 20min best... If I'd estimated my FTP based on it, I would have underestimated my FTP by 10 watts.

    95% of chaingang definitely won't be accurate IMO, as FTP is supposed to be estimated from a steady effort rather than one with a mix of hard and easy efforts. I think it's likely that average power from a 20min chaingang would result in an overestimate, but it depends how often hard efforts were made and how hard they were...

    I suggest doing a better quality test as in an hour outdoors if you can find a long enough road. I have an 8 mile stretch with roundabouts each end (and a couple in the middle) so only have to ease off the pedals for a couple of seconds about 10 times for the hour. Alternatively enter a 20 mile time trial on a flat course. If that's not possible, an hour on the turbo isn't as bad as some people suggest and I reckon it will give you a better estimate than a 20min test. With regards to mental stress, IMO it's no worse than 2x20 or 3x20 especially if you have a cold room with good ventilation and good fan to keep you cool, a video of a race to distract you, some appropriate music to motivate you. You just need to psych yourself up for it and for extra motivation it helps if you have something nice waiting for you for when you're finished.
    CAPTAIN BUCKFAST'S CYCLING TIPS - GUARANTEED TO WORK! 1 OUT OF 10 RACING CYCLISTS AGREE!
  • amaferangaamaferanga Posts: 6,789
    What was the NP / VI for the 20min?
    More problems but still living....
  • Tom ButcherTom Butcher Posts: 3,830
    Why would a 20 minute chaingang be an over estimate (couple of posts up) - surely an up and down effort would if anything be an inefficient way to ride resulting in a lower average than you were capable of ?

    I think what this points to is that for a lot of people the motivation of having people around you means you can push yourself harder - it can feel like you are giving it everything sat in your garage - but you find that bit more on a chaingang or better still with a number on your back.

    it's a hard life if you don't weaken.
  • amaferanga wrote:
    What was the NP / VI for the 20min?

    Not sure as it wasn't a specific lap on garmin so I don't think it tells you, just the ride overall.

    Not sure if you can get this from GC. what would this tell me?
  • amaferanga wrote:
    What was the NP / VI for the 20min?

    Not sure as it wasn't a specific lap on garmin so I don't think it tells you, just the ride overall.

    Not sure if you can get this from GC. what would this tell me?

    In general, if VI is high NP tends to overestimate.
  • amaferangaamaferanga Posts: 6,789
    amaferanga wrote:
    What was the NP / VI for the 20min?

    Not sure as it wasn't a specific lap on garmin so I don't think it tells you, just the ride overall.

    Not sure if you can get this from GC. what would this tell me?

    If by GC you mean Golden Cheetah then you can create intervals by clicking on the ride plot.
    More problems but still living....
  • amaferanga wrote:
    What was the NP / VI for the 20min?

    Not sure as it wasn't a specific lap on garmin so I don't think it tells you, just the ride overall.

    Not sure if you can get this from GC. what would this tell me?

    In general, if VI is high NP tends to overestimate.
    Overestimate what?
  • amaferanga wrote:
    What was the NP / VI for the 20min?

    Not sure as it wasn't a specific lap on garmin so I don't think it tells you, just the ride overall.

    Not sure if you can get this from GC. what would this tell me?

    In general, if VI is high NP tends to overestimate.
    Overestimate what?

    Poor choice of words. With a low VI, NP during a big effort over a given period can often be used as an estimate for what one might be able to hold sustainably for that period. For a high VI, it can't. I've had sessions where my NP for an hour has been almost 400w, and I assure you I couldn't hold that for more than 5 or 6 minutes if you put a gun to my head.
  • amaferanga wrote:
    What was the NP / VI for the 20min?

    Not sure as it wasn't a specific lap on garmin so I don't think it tells you, just the ride overall.

    Not sure if you can get this from GC. what would this tell me?

    In general, if VI is high NP tends to overestimate.
    Overestimate what?

    Poor choice of words. With a low VI, NP during a big effort over a given period can often be used as an estimate for what one might be able to hold sustainably for that period. For a high VI, it can't. I've had sessions where my NP for an hour has been almost 400w, and I assure you I couldn't hold that for more than 5 or 6 minutes if you put a gun to my head.
    OK, yes, in terms of estimating what one is capable of sustaining for that period.

    However I will say that (provided it is correctly calculated), NP from a hard hour long effort (irrespective of ratio of NP to AP), will be closer to FTP than AP.
  • Wrath RobWrath Rob Posts: 2,918
    Back to the OP's question. If you think your power has moved substantially, and 20w is a substantial FTP increase, then either your original test was inaccurate giving too low a ready; or like many people you produce a lower power on the turbo compared to out in the field and you're just seeing a result of this; or you've had a great training block and need to re-test yourself.
    FCN3: Titanium Qoroz.
  • I think you should ask why you are estimating ftp.

    If you want to know your ftp in order to determine how hard to ride on the trainer,
    then estimate your ftp based on your power output on the trainer.

    If you want ftp to decide how hard to ride outside, use the outside based estimate.

    ftp and power levels are just tools.
  • Tom ButcherTom Butcher Posts: 3,830
    Yes but surely the idea of training at a % of ftp is that it offers certain physiological adaptations. It doesn't seem likely that training at say 80% of a figure indoors will give the same adaptations as training at 80% of a higher figure outdoors.

    I don't structure my training around power as I only have power measurement on the turbo not outdoors but if it were me I'd take the higher outdoor figure as an indicator that perhaps I should be working harder on the turbo.

    it's a hard life if you don't weaken.
  • Wrath RobWrath Rob Posts: 2,918
    Look at Alex's Blog for more help.
    FCN3: Titanium Qoroz.
  • Yes but surely the idea of training at a % of ftp is that it offers certain physiological adaptations. It doesn't seem likely that training at say 80% of a figure indoors will give the same adaptations as training at 80% of a higher figure outdoors.

    True, but the other half of training is fatigue.
    If 90% of your outdoor figure is ~100% of your indoor figure (perhaps you overheat indoors?)
    then you could exhaust and then demotivate yourself by going too hard indoors.

    Its a common theme in the forum that being specific gives you better results.
    Doesn't this apply in this case too?

    And extending the idea, if you mainly do 20 min intervals, do a 20 min ftp test;
    but if you mainly do 4-12min intervals, wouldn't a 8 min test be more relevant?
  • Tom ButcherTom Butcher Posts: 3,830
    Well if it's overheating that's an identifiable issue that can be sorted with a massive fan aimed at your face. I'm assuming here the issue is simply that it is psychologically easier to produce power when the motivation is higher.

    You shouldn't become more fatigued (talking about post session) if the only relevant difference between two sessions is because one felt harder because it was on the turbo.

    it's a hard life if you don't weaken.
  • Well if it's overheating that's an identifiable issue that can be sorted with a massive fan aimed at your face. I'm assuming here the issue is simply that it is psychologically easier to produce power when the motivation is higher.

    i think so...
    You shouldn't become more fatigued (talking about post session) if the only relevant difference between two sessions is because one felt harder because it was on the turbo.

    ...and a i think you are probably right physiologically, but i still have some doubts that pushing yourself
    so hard is psychologically sustainable (although it sounds like it is for you).
  • sorry to keep flogging this, but suppose my ftp_indoor is 240W (mmp20_indoor=252w)
    and my ftp_outdoor is 260W (mmp20_outdoor=273W).

    My training plan includes [email protected] indoors.
    If i attempt this using the ftp_outdoors, i'll be attempting 260w which is higher than my mmp20_indoors.
    So i will expect to fail.
    If i use my ftp_indoor, i should complete the interval, but it won't do what i hoped for pysiologically.

    So is it better to complete a lower intensity interval, or fail (manfully) at the higher intensity?
  • Complete the lower intensity. 40 minutes at 92% ftp_outdoor is a reasonable session - 12 minutes at 100% (followed by tears) is not.

    Or just change your plan and do it outside. I too hate hard intervals on the turbo so I contrive to do them outdoors e.g. taking a 2.5 hour lunch.
  • So I did revise my ftp in line with the outdoor session and this morning did a 2 x 20 session at 100% ftp on the rollers.

    Both intervals were tough and I have to say I don't think I could got close to 60 mins at that level which suggests that it is over estimating my ftp.

    It was still a good session but I think ill be reducing my ftp numbers for turbo / roller sessions.
  • leflef Posts: 728
    Taking an average from a 'peaky' ride is unlikely to be a good representation of ftp. I would disregard the group ride results. For example I could do a 1hr ride, I could sprint for 15 seconds then drop back down to a bit below FTP then after a little recovery repeat and then repeat throughout the ride. It is quite possible I would end up with an average power or NP that is higher than my actual FTP.

    NP should be used with caution and certainly not for shorter rides. If you can't ride at that power (or at least near to it) for an hour it's not your FTP. I'm quite light and had a NP on one ride ages ago thats was 322w. As above it was from an interval type ride with recovery at quite high intensity. I stupidly set all my zones to it and by the end of the year I was zonked.
  • ChrisSAChrisSA Posts: 455
    I was musing something similar today.
    Trainerroad FTP was 220W, with my PowerCal showing FTP of 235W for the same test. A poorly paced test recently showed an FTP of 223W on TR, but no improvement on the PowerCal.

    Cut to yesterday's duathlon - 20km so a tad over 33 minutes. AP and NP both 252 W, so a VI of 1.00 :)
    What does this suggest for my 'Outdoor FTP'?
    TrainingPeaks data
  • Tom ButcherTom Butcher Posts: 3,830
    Isn't having an indoor and an outdoor ftp - unless there is some relevant difference such as cooling or perhaps flywheel effect - training to perceived exertion. It "feels" harder on the turbo so you knock the watts back.

    it's a hard life if you don't weaken.
  • Isn't having an indoor and an outdoor ftp - unless there is some relevant difference such as cooling or perhaps flywheel effect - training to perceived exertion. It "feels" harder on the turbo so you knock the watts back.

    Pretty much
  • ChrisSAChrisSA Posts: 455
    It's a cooling thing for me.
    I use TrainerRoad so I wouldn't agree it is perceived exertion, rather prescribed exertion. Up until now I hadn't known there was such a gap. I agree it makes more sense, once I have the FTP value, to use that for everything.
  • Tom ButcherTom Butcher Posts: 3,830
    Isn't having an indoor and an outdoor ftp - unless there is some relevant difference such as cooling or perhaps flywheel effect - training to perceived exertion. It "feels" harder on the turbo so you knock the watts back.

    Pretty much

    Well that saves all this twatting about with ftp then - just ride hard for 20 minutes - I knew you were old school.

    it's a hard life if you don't weaken.
  • Isn't having an indoor and an outdoor ftp - unless there is some relevant difference such as cooling or perhaps flywheel effect - training to perceived exertion. It "feels" harder on the turbo so you knock the watts back.

    Pretty much

    Well that saves all this twatting about with ftp then - just ride hard for 20 minutes - I knew you were old school.

    Nah, if you can't do it on the turbo then get on the road, innit?
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