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Power Inside on Trainer vs. Outside, % Difference?

andidunlopandidunlop
in General Training Discussions

I'm new to power (~ 1 month using it).  I did my first FTP test outside.  Training indoors holding that FTP seemed a lot harder.  So I searched the forum and realized that it wasn't all in my head: it is harder!  If I had realized that I would have done the test indoors.   I'm still able to hold 95-100% on all my intervals, but I know that my FTP will likely go down on the next test, which will be indoors.  (I don't see getting that FTP including the 2 minute rest interval.)

So I'm curious in general what the power difference is from outside vs. indoors.  10%?  15%?  What's yours?  I figure if I can hold my next 42 minute FTP test within 90-95% of the first test I've probably improved?  Or it doesn't matter because it's comparing apples and oranges?  I hate feeling like I'm going "backwards". lol

I'm in week 6 of the advanced OS.  I use the cycleops fluid trainer.

Thanks,

Andi

Comments

  • [Deleted User][Deleted User]
    Indeed, you will see that your FTP is a tad lower indoors. I think the important thing to do is to find a test environment in which you can test consistently. If testing outdoors, find a course where it's easy to test (preferably with not too many winds). I think I recall Coach R saying he likes to test on long, steady climbs.
  • MattAaronsonMattAaronson
    There isn't a rule of thumb % because it seems to vary a lot with the individual. There was a good thread on this last year I recall. Personally I find the indoor FTP intervals to be muchmore brutal, but my FTP isn't actually all that different. It just goes to show the RPE difference...
  • Coach RichCoach Rich

    Whenever you test you want the test to reflect the venue you'll be using for interval training. So if that training will be indoors, you need to test indoors...but we want you to ride outside with power as long/frequently as you can because the numbers are always higher outside vs inside.

    April is about the opposite, as everyone who has been indoors with power starts to come outside and are, generally, confused by the numbers: friction from wrapping their head around outdoor vs inside numbers.

  • andidunlopandidunlop
    I think I'll just put that last test out of my mind after I test again. I'll certainly enjoy the spring/summer when I ride mostly outside and will see my "free gains" in power!
  • kurshingkurshing
    Andi: I live in the same region as you and am still doing the majority of my intervals outside. However, when I go inside I notice a difference as you have sited. I have only done a few workouts inside, but what I have done is to, during warmup, find a gear that I am going to agree to call z4/95-100 for purposes of that workout (in week 7 of OS and had done 3 trainer rides). For my test next week, I will go inside and then have a good metric for my 2.5/2.5 intervals for the trainer - those are tough to do outside in my opinion. Then I will probably stay mostly inside except for nicer weekend rides and I will use my power to my current outdoor power for those workouts and maybe add a few watts for 'assumed' improvement.

    It is kind of a trial and error thing if you and I, where we live, are going to be bouncing between indoor and outdoor. Come late Dec-Feb, staying on the trainer won't be as much of a problem since it will be cold enough to encourage that behavior.

  • andidunlopandidunlop
    Posted By Stephen Anderson on 15 Nov 2011 06:07 AM

    Andi: I live in the same region as you and am still doing the majority of my intervals outside. However, when I go inside I notice a difference as you have sited. I have only done a few workouts inside, but what I have done is to, during warmup, find a gear that I am going to agree to call z4/95-100 for purposes of that workout (in week 7 of OS and had done 3 trainer rides). For my test next week, I will go inside and then have a good metric for my 2.5/2.5 intervals for the trainer - those are tough to do outside in my opinion. Then I will probably stay mostly inside except for nicer weekend rides and I will use my power to my current outdoor power for those workouts and maybe add a few watts for 'assumed' improvement.  

      

    It is kind of a trial and error thing if you and I, where we live, are going to be bouncing between indoor and outdoor. Come late Dec-Feb, staying on the trainer won't be as much of a problem since it will be cold enough to encourage that behavior.



    This is so true.  I definitely ride outside on the weekend right now and anytime the weather will be nice out in the winter. That could be anytime around here - it's a crap shoot!  But I will definitely be doing the VO2Max workouts indoors.  I don't think it's safe for me to do these on the road. image
    I'll probably do my testing indoors going forward because I don't know what the weather will bring outdoors (wind/rain/cold).  It's more controllable.
    Andi





     

  • Shaughn SimmonsShaughn Simmons

    I see about a 6-7% difference when going outside.....................

  • DanielaDaniela
    What is the difference attributed to? Is it just mental, or are there other reasons? Curious as I don't think I much of a difference. Maybe 1-2%, if anything.
  • Shaughn SimmonsShaughn Simmons

    Daniela, read this link and think about inertia..............

    members.endurancenation.us/Training...aspx#50563

    SS

  • tuckermtuckerm
    @Andi, didn't see this asked or stated but do you have a fan blowing on you? Multiple fans? That will certainly help.
    Now most people seem to have indoor and outdoor FTPs, but NOT everyone. So I would not assume that you have a lower indoor FTP just yet. Also, you say you are able to complete the intervals in the 95-100% range. And please remember that you are in the 6th week of the Advanced OS. You have probably done a lot more work than you are used. (I'm making a generalization here, that may not be true.) So I would assume you have some good fatigue in the legs.
    So what I'm trying to say is that you just don't know yet. Keep crushing it and see what happens come week 8.
  • Matt SamojedenMatt Samojeden
    Posted By Daniela Williams on 15 Nov 2011 09:50 AM

    What is the difference attributed to? Is it just mental, or are there other reasons? Curious as I don't think I much of a difference. Maybe 1-2%, if anything.
    The biggest impact is cooling of the body.  As body temp rises power output drops.  Most cooling setups in the pain cave can't compare to the cooling in an outdoor  ride.





     

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