ERG mode for VO2 max intervals?

I think my point is valid, as increasingly research is saying that VO2 max session need to be very short. This seems to be the core issue with ERG trainers, ie, their reliability for short intervals is suspect. If these very short intervals do become a more significant component of TR workouts it will require attention.

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I don’t know whether I’d consider I’ve experienced reliability issues with short intervals in erg - even 5 or 6 second sprint intervals. Any off target issues I’ve had have been user generated - ramping up the cadence at the start of the interval rather than before (then I get the spike, and it settles down). I don’t really see much variance to when I’ve done them on hybrid rollers (with no erg) to be honest.

I have successfully hit even Anaerobic and Sprint level workouts with short, 10-12 second intervals in ERG. Subject to the rider and trainer, these ARE possible.

For anyone that struggles with them in ERG, they can swap to RES/STD modes as needed, simple.

I assume it still works like this but when I used the TR app it would ramp the resistance on 1-2 seconds before the intervals, I would find when doing 10-30s spikes the power would be correct for all but 1-2s of the effort. Close enough if you want to stay on ERG and not switch over to resistance.

Yes, TR still sends the trainer resistance adjustment instruction early. Considering that the rider loses and then regains that time on the trainer lag, the physiologic load on the rider is good regardless of the actually timing. That early send is meant to try and align the actual resistance load with the target load block, so the Interval Summaries at the end are more “correct”. But if you ignore those entirely, the rider gets the work they are supposed to get, even with some of the slower acting trainers. It just may be time shifted to later in the workout timing, which is not a real problem.


Hey @craigmanning! Let’s see if we can figure this out with you.

I took a look at the background recording of the VO2 max Workout you shared with us. Based on what I saw, I’d like to make sure that you have a strong connection to your trainer.

Optimal erg mode function relies on a strong connection between your trainer and the TrainerRoad app.

Strengthening the connection between TrainerRoad and your trainer:

With that said, here’s what I’d like you to try:

  • Turn off battery saving settings:
  • On Android, we can do this via the following:
  1. Open Settings
  2. Go to “Battery” (it may be named differently, depending on the model of the device).
  3. Turn off Battery Saving
  • Make sure Battery Optimization settings are turned off for TrainerRoad -This is something we’ve discovered recently- which is a bit different from the phone’s basic battery saving settings. Instead, these are individual settings for each app- which are actively managed by the phone in order to keep apps from using too much of the phone battery. For more information on these settings, I would check the article on this here: Turn Battery Optimization On / Off - Android 6.x and higher (Google) | Verizon

I’ll also go ahead and include the steps here:

  1. From the Home screen, swipe up to view the Apps List.

  2. Navigate to: :gear: Settings > Apps & notifications > Advanced.

  3. Tap “Special app access”.

  4. Tap “Battery optimization”. (Note: Apps/services unable to be optimized appear grayed out.)

  5. Tap the ‘Not optimized’ dropdown menu (located at the top).

  6. Tap “All apps” .Tap “TrainerRoad”, tap “Don’t optimize”, and tap “Done*”.

On iOS, we can do this via the following:

  1. Open :gear: “Settings”
  2. Scroll down to “Battery”
  3. Make sure Low Power Mode is turned off.
  • Closeout of all other apps/programs that may be running in the background - This will make sure there are no apps that could be interfering with TrainerRoad. Additionally, we’ll want to make sure our devices are completely unpaired from any other fitness app.

  • Turn off all other wireless devices in the room including speakers, headphones, keyboards, computer mice, etc.

Erg mode tips:
In addition (as some of you guys have already suggested) here are some of our tips for using Erg mode:

Yuuuuup, this can help!

  • Cadence can directly change your output power during your workout if you’re changing your RPMs significantly (e.g. >10-15 RPM). When increasing your cadence, your power will attempt to rise; to counteract this, your trainer will lower the resistance. The opposite will occur when lowering your cadence; an increase in resistance will be felt.

@mcneese.chad’s advice might worth a shot! It is worth experimenting with your cadence to figure out what works for you and your set up.

  • Set your gearing- In order to maintain smooth, even power across all of your power zones, you should maintain a mid-ring gearing in the rear cassette, and either a mid (if you have three) or inner (if you have two) front chainring. Your chain should follow a straight path from rear to front.

  • Maintain your gearing - In most cases, you should not change gears once you’ve set your gearing. Changing your gears may confuse your smart trainer and can result in a temporarily uneven delivery of resistance

Give these steps a shot, and let us know if there is any improvement!


Ok ERG experts…what happened here? Second clearing effort had no resistance then all the intervals took 7 seconds to come up to the correct wattage…I tried to hold cadence and let the resistance build but ended up short on every interval…also in the ride report the target wattage showed 286 when it was actually 293?

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I flagged this to review on PC tomorrow’s morning, but other than a few small issues, this looks quite good to me via quick phone review.

That second early effort does look odd. Not sure other than to have TR review the logs we can’t access.

But I think you pretty much nailed this one.

Thanks Chad…kinda weird the difference between the target wattages.

Sounds like the trainer didn’t receive the command, and stayed at the recovery wattage.

Lol, when I experimented with ERG for VO2max intervals it was usually the other way for me, it would hang at circa 125% when it was supposed to be a recovery. #SodsLaw :joy: I’ve been experimenting with it again but only for the other zones (non VO2max) and I’ve to the conclusion it just isn’t for me. I had a calf spasm when it went from high resistance/ low cadence to low resistance/ high cadence too fast. I cant really recall an injury in resistance mode but I’ve had a similar injury a few time with ERG :neutral_face: Its maybe the quality of my suito and my low power but it doesn’t work for me :neutral_face: :neutral_face:

I agree with Chad that it looks ok. I might also add that if you reached 90-95% of your maximum heart rate within the first couple of minutes in each set I would consider it a success. Power is just a guide to the appropriate intensity. Contrary to popular beliefs there is no point in exceeding about 95% HR as it only adds unnecessary fatigue. If you didn’t reach 90% HR you could probably finish an even harder version of that workout.

Recently I saw that Jan Hoff claimed that 85-95% was an appropriate intensity so basically; as long as you reach 85-95% you are good regardless of any power deviation.

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I agree…when its goes from hi to low resistance the increase in cadence isnt good for my knees at all…I usually start to slow down with about 2 seconds left.

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So this really illustrates the benefit of doing VO2 max type in Resistance mode. You really want to be pushing as hard as possible and ERG can often hold you back. Here you showed as the workout went on that you had capability to push it harder and you reach a higher HR in the third set where you really got after it. I suspect you were getting close to that “near death” feeling by the end of the third set that VO2 max work should bring on when done correctly.

Actually wasnt that hard…my max hr is 187 so I was only about 85%.

Based on third set, you did hold back in the first two and then gradually ramped up in the third. This is off topic for this thread, but it would be interesting to see what you could do going fully in on all three sets in Resistance mode.

Can you explain what do you mean you want to be going “hard as possible?” VO2 pace is very hard but not an all out max effort. I get why you’d want control of the pace but ERG can be helpful in controlling your pace?

Where ERG might be restricting you, you may only be pushing your HR to say 85% MHR for a 120% power. Whereas an uncapped power (non ERG) may allow you to push your HR to 90-95% . In the first case you are not really training your VO2Max which is an oxygen state not a power state, where as the latter case does. Like a lot of things though it depends upon an individuals system what is best for them. This is a quite good podcast on the subject.
Watts Doc #23: Training Your VO2max, and Why Not Rønnestad 30/15 Intervals - Empirical Cycling


ERG will control the power. Depending on how hard you’re working, that might mean your heart rate goes from 90% of HR Max 2 minutes or so into the interval to 98% of HR Max over the course of the interval as you fatigue. That’s going to make it very hard to complete multiple intervals. You might get two and then pop.

That’s not what you want.

What you want is for power to decline slightly as required during each individual interval so that your heart rate rises from 90% of HR Max 2 minutes in to at most 95% of HR Max over the course of that interval. That way you should be able to knock out interval after interval without a big drop off in power between the first and last intervals.

Of course, at the other extreme, if the intervals are too easy you might never reach 90% of HR Max, and you’ll not be achieving the intention of the workout.

If you have no idea roughly how hard to go, take 95% of your best effort for the interval length.

Oh, and Hard Starts might be a good option. Or not. YMMV.


The goal is to burn off the anaerobic contribution in the first few efforts and get you body working at its maximum aerobic capacity during the rest of the interval. You anaerobic system will recharge a little during the rest between sets, but then you can quickly burn it off again at the start of the next one. The effort is not 10/10, but pretty close - like 9 or 9.5/10. The idea with going hard early in a set is to quickly get that heart rate up and get to the point where you are working at your aerobic max for a long a possible.

This explains it similarly in a little more detail:

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