VO2max training in TR effective? – power vs heart rate

I’m not sure what you specifically refer to in that large post, but note for example that breathing is going to lag similarly as HR does. It takes a bit for oxygen to deplete in the lungs, blood, but that doesn’t mean the uptake in the muscles isn’t already maximal.

Transport or uptake? That’s the difference right? Uptake goes up faster than transport, I’d think? It’s like a chain of connected events with lag.

Yes this is true but over a full set of short shorts you should still see the elevated HR. Maybe not after the first or second interval, but by the end of the sets you definitely should. If youre still in sweetspot HR for example at the end of a 6 or 8 minute set it kind of shows you aren’t actually working close to VO2 max.

1 Like

I’m not sure, the efforts might just being flattened out and buffered when looking at the HR/breathing angle.

If you do a 30 second effort and HR/breathing doesn’t go up to VO2Max levels, but does when you do 120 seconds at the exact same power, don’t we thus confirm that the power level and uptake were right all along? Unless for some reason we believe it’s possible for uptake to lag, but then you’d fail the power level after seconds already?

Edit: What I mean is, your muscles must be taking something up to produce that power. We know anaerobic stores last only for seconds, so what else could maintain 30 second of that effort except increased oxygen uptake?

1 Like

I’m just going to pop in and recommend looking at cadence as well. I don’t respond much to short/short VO2 either, and find 2-3 minute intervals to be the best, but I will say, after listening to Kolie Moore’s podcast on VO2 training, I upped my cadence in these intervals from 98-100 to about 110 and my breathing and HR at a given power went up significantly. I still have to do 2 minutes at a little more than 120% though generally.


No, I don’t think so, I don’t see why that should be the case. The power targets for the interval is inherently related to the duration.

This is why a lot of the TR VO2max short:shorts have the on intervals significantly above VO2max power zones - 140% or higher. It’s about stimulating oxygen uptake not any specific power number. And yes, uptake.

There’s an AACC on this which covers what I said: VO2 Max Training: How To Do It Right (Ask a Cycling Coach 349) - YouTube - it’s been discussed on here a bunch of times as well. A lot of people on here argue for going for the hardest “on” intervals you can manage for the full sets, which I think might be going a bit too far the other way (you don’t need all workouts to feel like death…).

I am definitely not suggesting that your HR needs to be through the roof from the start of the intervals, but if by the end of the sets in short:shorts you’re still able to chat, that’s not working as intended. “If it feels easy it’s not VO2 max” - Amber Pierce in that video…

1 Like

Good point.

I am also definitely above 100 in these intervals. Just checked, for yesterday’s workout/data posted at the top it was 105 for the intense intervals throughout.

I just did a 5x3.5’ v02 hat I made custom

You can see I do hard starts and just go as hard as I can. There is some heart rate lag but my max gets to 95% which is about as good as I can do on the trainer (also on third week of this v02 block so I’m tired as hell).


No because you have made a number of incorrect assumptions, specifically about Anaerobic contribution and W’ or FRC

Well yeah, if you’re in VO2Max, you’re accumulating lactate, so that immediately follows regardless of the other aspects discussed here. But exactly that lactate accumulation supports being above threshold, regardless of HR/breathing.

There’s several aspects that can make something feel “not easy”, so that’s not very useful here. A 10s max sprint doesn’t feel easy but won’t get my HR up immediately either. Edit: And 1h at FTP doesn’t feel “easy” either, but that doesn’t make it VO2Max!

I’m talking about anaerobic store depletion, which is part of W’, the other is lactate accumulation, which is also part of that. So maybe you can be more specific what you actually disagree with rather than this completely nonconstructive dismissal.

W’ is a just a number that summarizes anaerobic processes (or really, above threshold processes…) in a simplified power model. I detailed the components above.

So a few things here.

  1. Never do VOs max workouts in ERG mode, as others have mentioned. For 30/30s you should be going as hard as you can. The first couple 30 second intervals will have a fairly large anaerobic contribution and it is not until later in the sets that you really will be taxing the aerobic system. As such, you should expect your power to fade the further you get into a set.

  2. The workout you picked is on the lower end for VO2 efforts, and I think is more appropriate for someone who is not used to going hard or doing this type of work. For instance, the Ronnestad protocol was 30/15s for 13 reps for 3 sets, which means that you are doing your efforts over 9.5 minutes.

  3. Everyone reacts differently to VO2 work. Some people respond really well to the traditional intervals such as 5x5. Other people react better to the microburst intervals. Some people do really well with hard starts at the beginning. In the TR catalog there are also the float sets as well. Personally, I’ve found for myself that microbursts (30/15s, 40/20’s etc.) and float sets give me a ridiculous amount of time over 90% Max HR, and usually have me bent over the handlebars on the verge of puking by the end. However, I know some people that find the traditional ones far more effective.

  4. I would also suggest trying to do VO2 work outdoors. I think it is easier to just go deeper outside than inside.

  5. Lastly, you will know if you are doing VO2 work right if you feel like there is not enough oxygen in the room, or you are doubled over on the bike at the end of the set struggle for air. If you don’t have that sensation, then you probably aren’t going hard enough.


Thank you for the summary!

It’s the workout(s) that TrainerRoad picked/picks for me!

… which probably goes along with a HR well above THR – as I was assuming but asking for support in my original post – not?

So from the first discussion here I take it that the workouts that TR suggests for improving my VO2max are too easy! It also seems as if my assumption that HR should not stay “low” for VO2max workouts is alright.
There are some indications here (and more so elsewhere) that VO2max efforts go along not only with hard breathing but also very high HR.

I’ll guess I’ll do some traditional 5 x 3 or 4 x 4 workouts, which I used to do last winter before starting with TrainerRoad, for the next VO2max sessions, and in the following block maybe see how sets of 30/15, 60/30 can work for me instead if done at sufficiently high intensity.
In any case, will make sure that I spend significant time at HR > THR in any of these workouts;-)

I think it is generally recommended that if you want an effective short-short VO2Max workout, you should probably be looking at 30/15s (eg. Sleeping Beauty +5) or 20/10s, with their shorter recovery intervals, before trying different power levels.

Shortening the recovery interval means your HR will remain pretty high throughout, rather than dropping slightly as it does in your posted graphs. In fact, you look very carefully at your graphs, you can see peak HR actually occurs after each effort interval, and at 15s into recovery, it has barely dropped.

1 Like

I was going to make this point, too. I find getting my cadence up to within, say, 5 rpm of my comfortable maximum achieves the double whammy of upping breathing and HR while also reducing leg fatigue, and thus RPE for those of us who are more leg-limited than lung-limited.

I think the three options have been covered

  1. Longer Intervals (6x 4’, 5x 5’ etc, as stated at the begining)
  2. Change the ratio of work to rest. i.e 2:1 work:recovery
  3. Do 30/30s at a higher power (or max for each set), the issue with this is some people will be using high anaerobic powers over 150%, increasing VlaMax which might not be a desired outcome.)

I tend to prefer option 1 and 2


The hard part with adaptive training and VO2 is it will start you with fairly easy workouts that get someone used to this feeling but for someone who is used to training with structure they’re far too easy. If you’ve done true VO2 work in the past you can just go for it with longer intervals and pace them appropriately.

These custom workouts I made are rated 6.6 PL or so and I did them coming off 1.0 PL (I had done a SST block before this and an FTP block before that). And I was able to do a 6.6 workout as “not recommended” because I’ve done V02 work in the past and it’s not rated against my FTP (according to how I do them).

So just go for a hard workout that fits your needs (for V02, I wouldn’t just go for a PL 5.0 threshold being a 1.0 - because that is a way different beast)

1 Like

I struggle with VO2 max in ERG mode but mostly because of the death spiral. I was absolutely getting my oxygen uptake to maximum but just cracked today cuz couldn’t hold the power.

Is that why you shouldn’t do these in ERG mode or is it more that you want to be able to EXCEED the power target (wow, which I couldn’t do this morning)

Exactly - look at the workout I posted form this morning. By the 5th set I couldn’t hold the “target” (which was fake when I made the custom workout) and ended up averaging 111% rather than 120/118% (I can’t remember which one I made the target) and in erg mode I would have had to quit that interval - but my HR was in the right place for the workout. I expect this fatigue by the last set.