Hitting VO2 30s/1m power with ERG

I’m using a Tacx Neo 2T with an MTB and finding it hard to match the interval power for short durations.

It seems that the power doesn’t rise up fast enough at the start of the interval and because the duration is short, the average power is lower than the target. Does anyone have a workaround or VO2max sessions should be completed using resistance mode instead?

Thank you for the insights!

Can you share a link to your workout (assuming your TR account is “Public”) or at the very least, a picture of the intervals so we can see the power and cadence of your efforts?

Outside of that, I will try to find my prior post, but be aware that the lag you see at the start of an interval is often similar at the end. Functionally, your are likely getting most of the loading desired, but it may be “shifted” on the timeline. As a result, the Interval Summary may show you are “missing” the values, while you are actually getting the right loading, just delayed.

Some search results that may help:

And to add one of my tricks, I often slow my cadence about 5 rpm in the 10-15 seconds before these kicks. Once the interval applies the trainer resistance, I ramp up my cadence to whatever I aim for (100-120 rpm depending on the power target and duration). This “slow start” helps kick up the measured power a bit as I quickly increase my cadence for the work interval.

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I echo what chad says. This lag works both ways - resistance comes in late but also drops off late, I still hit the power but the interval is offset from the interval ‘window’ in the workout so TR reports it low - do you find that at the start of the rest interval the power is still high?

yes, I see that the rest interval average comes off higher which kind of averages the drop in the power segment average.

Not sure if it’s public but link here to trainer road: Log In to TrainerRoad

Will give that slowing of cadence before the power section a try. Thank you!

Your account is Private, so the link is a dead end.

I have a 2T and the delay is typical It can be partially mitigated by using the small ring (easier gears). I think you will find that your normalized power is accurate for the ride as a whole, which just means that some of the interval is spilling over into the subsequent rest. It’s ok. I wouldn’t pay attention to the in-ride interval power summary if you are using erg mode.

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I have the strava link public if that helps at all:

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Yeah, quick look at that and I see no problems here. That power looks solid and predictable to me.

As I experience, the first one is a bit of a surprise / learning curve. Your latter ones within each set and pretty much all of them are functional from what I see. Just ignore the Summary data and you are fine IMO.

The only suggestion I have is my typical one for ERG use. Ignore power and focus only on your cadence. Let the trainer and TR sort out the power. Once you do this, this picture may look even better.

ok here is the interval with highest power, as per the on/off defined by TR:

Average power of 304W.

but if you offset the start by 2 seconds

Average power of 309W.

Not that it really matters in the big picture. Don’t get caught up thinking you have to hit precise power targets.

Out of curiosity, what was the TR target power? If your intervals are off by a significant % then we might have something to talk about. But if its just the starting/ending edges, and getting ocd about not “getting full credit” then its not worth discussing / obsessing / chasing.

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I made a post about this a few weeks ago, having difficulty hitting 30/30s some suggestions were using the little ring instead of the big ring, I tried this for a bit and it did smooth out the power but found with calibrating the trainer, in the little ring with a straightish chain line it wouldn’t hit the 38.6, without shifting into the big ring and wasn’t sure on the effects of shifting while calibrating so have moved back to using the big ring.

Since having issues at the start of August I feel like I have accomplished a few workouts with 30/15s like Sleeping Beauty +3, not sure if I have just matured into the FTP a bit better or gotten more skilled at winding up fast at the start of the interval and then keeping the power up.

Before I took some time off for vacation, where I immediately got Covid, I failed Spanish Needle -3 with its 15/15s which I figured I would, coming out of covid I attempted Tyndall -5 a few weeks ago and made it half way and then ditched as I felt like shit, I had done a couple weeks of endurance following my covid symptoms going away and it was my first attempt at a higher intensity than endurance workout. I thought I was really missing the avg power targets but was within 5 watts so probably should have kept going, might have accomplished it.

Before I do another ramp test or AI FTP I would like to accomplish Spanish Needle -3 and Tyndall -5, have my last A race in 10 days and a recovery week of endurance after that, then my AT plan ends so may insert Spanish Needle and Tyndall in there before inserting my CX races (calendar isn’t out yet) and my hypothetical XCO or Road race for in the spring to keep AT running.

Thanks @WindWarrior , The target power was 308W
Screenshot 2022-09-08 at 1.00.03 PM

Thanks, I’m still working on making my cadence more stable because at the moment when it gets hard I just try to spin faster to lower the resistance

  • You can calibrate in any gear you’d like. Using the big ring is common for this purpose and is not a problem even if you use a small ring or any other gear in ERG mode.
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IMHO you’ve got nothing to be concerned about.

The specificity concept should not apply to Erg (IMHO). If you did that Bluebell workout outside, in perfect conditions, it would make your indoor workout on Neo 2T look unnatural with ‘perfect’ power. After buying a Wahoo Kickr I went thru a phase looking for this level of power perfection, and in retrospect it was a silly exercise. To each their own, but don’t expect any real return on time invested in pursuing a pedaling style that doesn’t translate to anything you do outside (or better performance).

Yeah, I wouldn’t be using cadence as a “crutch” to sneak your way through a workout. I generally recommend using cadences (and functional cadence ranges) that make sense for how you plan to use your fitness outside or otherwise.

Generally speaking, people are better off to apply higher cadences for higher power efforts. Lots of nuance hiding within that oversimplified statement, but it is worth considering. Think about the efforts in front of you, how they might translate to your actual needs and then choose and apply your cadence (and range) accordingly in workouts.

This concept applies regardless of trainer mode. It’s possible apply a range of cadences within ERG, but also in Resistance/Standard/Level/Slope modes via shifting within the trainer’s non-ERG resistance unit range.

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Good to know, what if you shift during calibration does that mess it up? Calibrating in the big ring with my H3 feels like its the end of a ramp test it must be like 400W+ for those first few pedal strokes to get things moving.

  • No, not a problem to shift. I am almost always starting my calibration in the small ring, and shift to the big once I get above 100rpm cadence. Then I just plug along until I hit the calibration speed.
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okay good to know, have been treating the calibration like its super fragile when it hits the 38.6 and starts the spin down I just freeze and am like okay nobody move, try not to back pedal or unclip or move my feet as all as I don’t want to throw artifact in there.

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There is some wiggle room in there from what I see. I do what’s needed to get the wheel to the speed identified. And then like you, I also just sit “coasting” without backpedaling or unclipping until the process is complete. May well be unnecessary, but it’s a minor delay so not a bother.