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How Smooth is Smooth?

On TrainerRoad, we are given a level of accuracy after each set based on how i maintain my power during that set.  I wanted to know: how smooth is smooth? Or consistent is consistent?  is +90% smooth/consistent enough?  Or is 95%?  99%?  where should i be?

Any advice would be appreciated.

Comments

  • This metric is usually called "Variability Index" -> shortname = VI
    You will hear people talking a lot of that metric when it comes to race execution where you should be able to "virtually flatten" the course by achieving a VI below 1.03

    Basically a VI of 1.0 means your power output was totally consistent meaning for example 220W ALL THE TIME ... no matter which hill comes along.

    I believe in our trainings workouts we should aim for a VI of 1.0 FOR EACH SEGMENT.
    Of course this doesn't mean you will have a VI of 1.0 for the entire workout but it will help you to develop the ability to reach a VI of 1.0 (which is not that easy)!
  • Great question - I also ride TR all the time and have wondered this - I think what is being measured is the amount of time the white dot is touching the "Goal" watts line for that set - the TR guys are awesome and very responsive to questions - I am going to post your question to them now - we can likely both find the answer on their forum - I I get something back I'll post it here.

     

    -edward

  • You should not concern yourself with VI (or the TR Precison metric) on a trainer...

    There is not terrain change, hills, up and down, road texture, wind, or coasting etc inside on the trainer....so  in theory a ride on the trainer always has a VI of 1.0 (NOTE: because VI is Pnorm/Pavg...but because you have a "flat road" (the trainer)...Pnorm = Pavg always...thus VI = 1 always ..but I think TrainerRoad may be measuring something else...which is not imporant to us...see Wiki link below)

    The VI we are interested in is outdoors and in learning steady smooth power for race execution....the key to successful race exectuion is disciplined dispense of power over the course of the ride...no spikes...up or down.....and this is challenging on roads which have changes in  elevation, terrain, exposure to wind etc....

    The key is to learn smooth pedaling that delivers power to the pedals within a narrow range of power targets no matter the conditions or changing terrain....on the flat your PM is at target power +/- 5....going up hill...your gearing and cadence allow you to maintain your PM at target power + 15-20watts (no spikes)....going downhill....your pedaling and maintaining Target Watts -15-20 (no let off until your going 30mph...then get aero and soft pedal)....into the wind...your at target watts....the Net-Net is you are targeting to dispense work at target watts evenly over the course...and a VI of 1.05 or better....

    So...don't worry about Variablity measures on the Trainer....but worry about them alot outside especailly in Race Prep....(High VI is okay when you out mashing around in an ABP ride...but not when your are practicing race prep/execution)

    http://members.endurancenation.us/Resources/Wiki/tabid/91/Default.aspx?topic=Riding+Steady:+Training+vs+Racing

  • Information related to the TR rides is below - these guys are very responsive...

     

    Rob Bradford (Trainer Road)

    Feb 27 10:56

    Hey Edward,

    Here is an article that should explain what is being displayed: http://support.trainerroad.com/entr...-explained

    Have a good one!

    Rob Bradford

    Customer Support

    rob@trainerroad.com

     

  • How/if to ride Steady, and what Steady means, will be a more common topic in the next couple months as the trainer-bound start riding outside. 

    Please read this wiki article: Riding Steady: Training vs Racing

  • Posted By Joseph Lombardi on 27 Feb 2014 12:45 PM

    You should not concern yourself with VI (or the TR Precison metric) on a trainer...

    There is not terrain change, hills, up and down, road texture, wind, or coasting etc inside on the trainer....so  in theory a ride on the trainer always has a VI of 1.0 (NOTE: because VI is Pnorm/Pavg...but because you have a "flat road" (the trainer)...Pnorm = Pavg always...thus VI = 1 always ..but I think TrainerRoad may be measuring something else...which is not imporant to us...see Wiki link below)

    http://members.endurancenation.us/Resources/Wiki/tabid/91/Default.aspx?topic=Riding+Steady:+Training+vs+Racing

    This isn't true.  VI is not necessarily 1 on the trainer, even "in theory" and it has nothing to do with lack of hills or other terrain. You can have a VI = 1 outside just the same as inside if your Pnorm = Pavg.  Obviously on the trainer you don't have all those other external factors to contend with so it's easier to ride steady power. 

    Pnorm is a form of weighted averaging. The steadier you ride the closer Pnorm is to Pavg and the closer VI is to 1. Spikes, dips, surges or simply variability of power output causes Pnorm to differ from Pavg - doesn't matter if you are riding outside or on the trainer - the metric calculation is the same.  The precision value on TR isn't the same as VI.  TR Precision is defined as the percent of time that power was +/- 10 watts from the target. So if you were supposed to be riding a 200W steady interval and kept it between 190-210 the entire time your precision would be 100% but your VI could still be above 1 if you bounced around in that range significantly.

    The real question though is does it matter.  For training it's more important as a tool to learn to ride steady and get an objective score of how well you did.  90% means you were only outside of the 20w target range 10% of the time and that may only be by 1W.  For racing VI is important because it can identify rides where you spiked power significantly, which is generally bad for pacing and subsequently running well off the bike.

  • Joel and JCL are both right, in that Joel is technically right and JCL is right from an execution standpoint -- since nothing stands between you and the stated goal of 250 Watts for a 20' interval, you should be PDC (pretty damn close) to a VI of 1. Whereas outside there's wind/terrain/traffic that all conspire to interrupt that amazing smooth ride you have.

    In the context of the OP, the metric to me is just a means of how well I rode the segment as listed. The more tired I am, the worse I do!!! image
  • OK, so i think i get it. But i am not 100% i get it.

    During my training rides, on the trainer, my goal is to hit close to 100% as possible but to kill the workout. ? But outside is to try and stay at 100% or VI of 1 as much as possible. Is this correct?

    What if i am hitting close to 94% on the trainer? Is that acceptable? Or do i have more work to do?

  • Posted By Jonathan Brown on 04 Mar 2014 08:29 AM


    OK, so i think i get it. But i am not 100% i get it.



    During my training rides, on the trainer, my goal is to hit close to 100% as possible but to kill the workout. ? But outside is to try and stay at 100% or VI of 1 as much as possible. Is this correct?



    What if i am hitting close to 94% on the trainer? Is that acceptable? Or do i have more work to do?

    JB, did you read the wiki link above re Steady in training vs racing? Short answer:

    • Riding Steady (low VI) is a style of riding.
    • For training, don't worry about it too much, other than to practice it so you can do it well in racing.
    • In racing it is VERY valuable. 
    • As for training on a trainer, your VI is going to be low because that's the nature of riding on a trainer vs outside. 

    But a low VI shouldn't be a goal of training, watts are the goal. Unless you are closer to your race and are using rides as an opportunity to learn and practice this Steady riding style. IE, you're riding with the purpose of achieving a low VI so you can ride with a low VI on race day. 

  • When looking back at my numbers last year, watts where all over the place during my training and during my racing. So keeping steady during any ride was a train wreck. My biggest issues is that one moment i was at 300 watts and the next i was at 50. keeping that steady cadence and steady power was very hard for me. (Please keep in mind i only got a power meter last May and really only started riding 2.5 years ago)

    Since i was unable to keep steady, one would think working on that steady riding would help me significantly during my training. Also it will help when i get out onto the road. Is that incorrect?

    I have read the link above a few times. It makes sense but if i cannot ride stead because of in-experience riding steady, am I not at a disadvantage?
  • Sure, sounds like you could use more opportunity to consciously ride steady and develop that school. But focus on doing that when you're outside vs inside on a trainer. The trainer is a much more artificial venue. 

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