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reverse engineering FTP

kjanracingkjanracing
in General Training Discussions

Hi all, I haven't yet done the power test for the bike yet to figure out my training numbers, but I do have an average power from my IMLOU.  Is there a way to have an idea what my FTP might be from that number?  Just wondering...  Also, I'm guessing that IM power/pace is a % of FTP.    What kind of numbers does a 5 hr or 6 hr/IM bike split  person have?

thanks! Kurt

Comments

  • dan_forbesdan_forbes

     Hi Kurt, as far as reverse engineering it, I'm not sure.  Usually you run 70-75% of your FTP for that kind of race, but if you didn't have an FTP prior, you don't know if your numbers are accurate.  If you have wko you can look up in the wiki alternate ways of determining your ftp from your athlete profile after many many rides.  Look at the link below:  http://endurancenation.us.dnnmax.co...mining+FTP

  • Matt SamojedenMatt Samojeden
    Kurt, we most often will race a IM bike segment in a range from .67 to .75 of your FTP level. Most people typicaly are in the .69 to .71 range. So if you rode at say 160 watts for IM lou using a .7 factor your FTP would roughly be 228W.
  • gilliattgilliatt
    Kurt, individual power is pretty hard to guess based one ride.....unless you are doing a test or a hard race. We assume a lot of people ride in the .7 to .75 range. Lou was pretty hot though so I rode easier. It also depends on the riders size, bike, his gear, and position.
    You can check the race report forums to see what kind of power guys were putting out at IMLOU and what it took. However, we had guys with similar power averages but different bike positions (Matt Samojeden and Michael Johnson come to mind). FWIW My norm power at IMLOU was 186 avg 175 and I think I rode a 5:47 in a moderately aero position.
    http://endurancenation.us.dnnmax.com/Resources/Wiki/tabid/108/Default.aspx?topic=Alternate+Means+of+Determining+FTP

    There is some alternative means too
  • gilliattgilliatt
    off the topic Kurt but you got 3 replies to a question on power in 10 minutes......do you think we like talking power here on EN? I couldn't even forumlate a response fast enough
  • NortonNorton

    Another part of the reverse engineering puzzle: after that bike, how well did you run?

  • Matt SamojedenMatt Samojeden

    Bill - right on about how did you run after - That is key!!



    Kurt as an alternative way to hack a FTP number go to the following site http://www.triathloncalculator.com/

    Put in your info ( assume an FTP level) and the proper bike course ascent for IMLOU (50) and let it calculate a bike split time. Keep changing your ftp level until your bike split time comes close to what your rode.



    Other factors: how smooth you rode the course , your VI will be a factor. How aero you are did you stay in the drops …



    Also eliminate any time for stops during the ride for this calculation. Now all these types of calculators are bult around averages and result is some level of approximation in the result, but it will give you an idea of relative FTP level.



     

  • manconamancona
    You have received some great responses, but why estimate your power if you can test and figure it out. I'm not trying to be a jerk, but there are sooo many variables that come into play.

    My advice is to suck it up and do a 2x20(2') and see what happens, at least you will get a good ~1 hour workout as opposed to spending time guessing what your power may be.

    Also, I would not recomend comparing your power to others as that is a very hard comparison to make. For example I have rode 5:07 at IMWI at under 190 watts (Normialized) and under 4:58 on a flat 112 training ride at under 197 watts (Normalized), but if you ask the guys over at slowtwitch you have to be able to hold 250+ watts to go under 5:00.

    Again, I'm not trying to be a jerk, but if you can test, I would ALWAYS test instead of estimate.

  • Shaughn SimmonsShaughn Simmons

    Kurt welcome to the team! 

    Seriously consider the feedback and advice from the veterans.  There is a really good reason why these guys are at the top of their game.

    SS

  • ht001ht001
    I agree with Mancona about testing.(also not trying to be a jerk) It is really the only way to get your true baseline on which to build and from which to determine your (just YOUR) optimal racing watts. Otherwise it seems to me that you are introducing even more variables into the mix on one of the few things that can be objective and foundation.

    The only other thing I would mention is to be cautious that by reverse engineering you're not trying to force fit an FTP that you WANT but have yet to fully achieve. it would stink to over or under train/race because you were basing everything off of hypothetical numbers.
  • kjanracingkjanracing
    Thanks for all the answers. I fully intend to do the test. I was just wondering what I might be looking at. I am really looking forward to training more scientifically.
    Looks like I need to get WKO! Tomorrow I'm doing the 5K run test.
  • Chris GChris G

    Unless you are looking for a WAG it is not a very usefull exercise.  Got any data from a sprint or olympic?  While still not a very good way to estimate FTP it would get you much closer.  Go out and test, it will be fun...well not really fun but likely educational.  A 2x20 (2) is the best way to dig into EN.  Might as well go for it.

    FWIW - Matt and Kitima are super jerky

  • Eric RueppelEric Rueppel
    The 2x20(2) is tough but seeing the results climb after completing it can be awesome!
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