Trainer optimization for vo2 max workouts

Just picked up a kickr v5 having been using a schwinn ic4 spin bike the last 18 months. Just did my first workout on it. A vo2 max 30x30. One thing i noticed was the time it took for the power to settle down as each 30sec segment began. It resulted in my avg power for each segment being 10 to 20w lower than the prescribed power. Is there a setting i can change to change this in any way? Will that lower avg affect my workout adaptations? I did have TR also synced to my garmin power pedals so maybe that had something to do with the high power fluctuations prior to them settling. I tried to keep my cadence as smooth as i could. Thank you

I heard that some trainers adjust faster when you settle the cadence first, so that the trainer adjusts the resistance in one go. (I hope you understand what I mean.)

  • No, unless you are REALLY having an excessive lag between the targets and/or missing overall. The system is not looking at that granular of a level in terms of Pass/Fail for intervals or workouts.
  • No. The best you can do is control the primary input which is your cadence.

  • There is a trick I use for intervals overall, that helps minimize the lag at the start. If my aim is to hit an interval at something like 110 rpm cadence, I actually roll into the final 30 seconds or so before that with something around 95 rpm cadence. When I feel the ERG resistance kick in at about 1 second before the “official start” of the interval, I kick fast and hard to hit that 110 rpm goal (or even a tad more). This has the effect of “ramping” up the actual power faster than holding a single, steady cadence.

  • Outside of that, if you are questioning training impact, it’s a non-issue. Consider that the lag you get on the front end is usually similar on the back end. Meaning your actual loading at the target power is very close to the total time. The only “issue” is that the interval summary in TR may show you missed it because it is looking at the discrete start/stop times, not the actual “time at power” value. Close counts here and you will be getting all the benefit even if you miss a bit on either end.

And even further outside of the above, feel free to experiment with Resistance or Standard modes. These manual modes require you to shift and set cadence to hit power targets. But because of of this, it places the control more directly in your hands, which is one reason some around here prefer those modes.


Short/shorts in standard/slope mode. This is the way.

Sure, for some. I am happy with ERG for my S/S intervals. Different strokes… so always worth a test and pick what each one prefers.

Then we get into philosophical differences about how to program workouts above threshold and we just don’t wanna go there. :blush:

I never do get into those. Not worth my time.


What I read is that you power was delayed by 1-3 seconds - and the key thing now is that ‘analyzing’ segments can’t be done by simply reviewing the TR interval segments.

My opinion - for 30/30s the Kickr v5’s standard mode is a better choice than erg. Because its more like doing the workout outside, and learning to use cadence/power to cover small gaps that open up (or short changes in gradient).

However Erg can be perfectly fine, it just requires some practice to quickly ‘dump’ extra power at the start and then back off and keep cadence the same. More of a special skill for erg.

When it comes to adaptations in your legs, prescribed power is an interesting topic and I wrote something about it here:

and be sure to read the linked article about some of the research and potential adaptations. From that TrainingPeaks blog post, the basic idea is that the higher target power of 30/30s (versus 3-min or 4-min classic vo2 intervals) can result in greater adaptations in leg muscles.


Something like 30-30s are the nightmare of any trainer in erg mode. Usually trainers take a while to stabilize and they take longer if the difference in power is large — just the setup you have with 30-30s and its variations.

There are a few things you can do:

  • Make sure you are in a very easy gear, i. e. you are in the small chainring in the front (if you are on 2x or 3x) and in either the easiest or the second-easiest gear.
  • If you keep your cadence steady, then the averages are what they are, you are putting in the right work. It is a non-issue. (Basically, whenever I am in erg mode, I don’t look at power numbers after my workout. They are what they are.)
  • Try resistance/standard mode. By far this is my go-to, I only use erg mode for endurance workouts and for longer endurance or recovery valleys. For me, this is the solution, not least because it matches the experience outdoors: if I stay in the same gear and the grade is constant, then increasing power just means increasing cadence. With erg mode, this doesn’t work, increasing cadence can put quite a bit of additional strain on you.

I use this trick also - albeit I drop to 90 then ramp to 100 as I feel the trainer ‘bite’

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