Is >90%VO2max the only thing that matters when doing intervals?

In a nutshell, one develops physiological vo2max, while the other develops power at vo2max.

Sometimes we equate the two, but they are often decoupled (see traditional base -build strategies, lsd raises vo2max, but power @vo2 suffers until you really train it.

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Be careful when suggesting that >90% HRmax is a proxy for VO2max - it isn’t, although I know what you’re trying to say. It’s a good place to aim for for the best adaptations in these types of workouts.

Technically, we should be referencing percentage of HRpeak with respect to cycling. HRmax is absolute but in cycling you may never be able to achieve it due to less muscle recruitment etc. Exercise modality is important.

100% of HRpeak is a good proxy for VO2max and 90% HR peak is a good proxy for 90% VO2max but they don’t cross over - VO2max does not occur at 90% of HRpeak as a general rule.

Having said all of that, if you look at the VO2max studies, the aim of the workouts is not to get to 100% of VO2max as you’ll never be able to spend a significant amount of time there. Whether you favour the 4 x 8 minutes, 4 x 8 minutes with a hard start (my own favourite punishment), or the Bent Rønnestad 40/20 style of intervals, the aim is to spend as much time as you can at high percentages of VO2max - 90% is generally regarded as the sweet spot for getting the best adaptations.



One ‘yes’, one ‘no’ answer to this question.

FWIW, here’s what Coggan has to say about it:

Conversation not possible due to often ‘ragged’ breathing.

I guess you’ll know when you start bustin’ out the intervals.

I can see this exchange :

“Oh, so you do your 4x8 work without a hard start”?

Shakes head in disappointment and walks away…


I wouldn’t judge…

So i guess a 30/30 is a crap workout for me then. Damn, i feel that 4x8 is so much harder to do…

Gross, but what’s your protocol for this? :man_shrugging:

I use Xert’s constant XSS design.

Here’s a recent 4 x 5 minutes.

As you can see they start off pretty hard and end just above threshold. You get to spend a lot of time at high percentages of VO2max and accumulate a high amount of XSS (Xert’s TSS). I’m building the length at the moment and adjusting the intensity to get the perfect workout for me. The nice thing is that they don’t leave your legs feeling blasted even although they do feel hard at the time.



That’s groovy. At the end of 4th bout in a 4 x 8 I’m pushing above 90% Will have to try this approach

Thanks for posting the screen shot. That’s definitely stout work.

Yeah, I like them.

Here’s another one with a slightly harder single 9 minute effort (starts at 200% FTP) followed by some endurance work. Even although you tail off towards threshold heart rate is kept high all the way to the end.


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Funnily enough I’m trying to do a similar thing. My HR drops off quite markedly as it goes yellow so I’m messing about with constant power after a couple of minutes

(I skimmed all the responses)

I may be missing something but the 2 workouts you are citing are designed to do different things.
I think Taylor -2 is pure V02 development work (improving capacity), and Dick’s -2 is power threshold work (building and sustaining power at near your V02 max). My interpretation of your posted data indicates they are doing just that for you!

My non-authoritative, enthusiast understating is that Taylor is using slightly different muscles and technique to prioritize V02 conditioning, which maybe allowing for better recovery between intervals and better recovery overall between days in the plan. Dicks is what I call “pure power” intervals. Sustained and hard, but not maximum heart zone. So at 105% it is intended to be a manageable hard work giving high training stress in the context of a plan.

So really, it depends what your specific goals are. I think if you do all your internals like Tayor, you will not necessarily build sustained, higher power capability. But all Dicks, and you might not build V02 capacity as effectively. And remember that our bodies’ different systems for physical output are not binary so training across different aspect is necessary.

I assume this is why the Trainer Road programs incorporate both types, and when you get to specialty there is more of a particular type of conditioning.

Because I am not willing to ride the trainer 5 or 7 days a week, I have decided to “adjust” my training somewhat with the information from Watt/kg ( The short version of the info is that data indicates 4 x 8min workouts in a structured 12 weeks of training are most effective at building improvement. (not entirely new knowledge but this site explains it well and provides some citation to the data. I’m sure Chad and Nate are well beyond the simplistic version here)

I am doing a 6 day stage MTB race next year ( so my primary goal is to build sustained power over the winter. I want to be able to output higher power for longer periods. Last season I built my cadence from nominal 75-80rpm to now 85-100rpm which has substantially improved my climbing. The low-level riding I do when instructing has given me a higher base this summer so my endurance and recovery are improved. (I just don’t get tired day-to-day and I can easily do 4-6 hours MTB rides). My plan (already started) is to adapt a TR workout to incorporate specifically 4 x 8min workouts and very moderate recovery as per the Watt/kg plan. My first observation is that the lack of variety in the workouts makes things a little less interesting. (We’ll see what happens)

(Hope this helps)

My sample 4x8 data is shown below just for reference.
Weight: 90kg
FTP: 278 (Actually 285 but I run slightly low intentionally)


What is your LTHR and max?

Max is about 180/181 and LTHR I think is around 157ish. Reasonably sure about the max as the 2 times I’ve got there I’ve almost fallen off the bike and was almost blacking out. I’m not going to do it again. LTHR is where I think it might be based on efforts around ftp

based on the workout profile you posted its jumping right up to your maxhr during the first interval and tapering quickly down to your LTHR?

It went up to 166 then it came down more than I would have expected it to. Here’s the link to the workout
It’s also on TR

ah got it, curious why the durations are shifted? I use Xert but haven’t done any of the smart workouts yet

It’s the 2nd one that I cut short. I can’t remember whether it was because my HR had dropped too low or i was knackered and hadn’t got my 2nd wind so to speak. Anyway the others were all 5 minutes. Something went wrong with the turbo or Xert on the next to last interval as no matter how I pedalled the power would not increase. Switching erg on & off seemed to sort it.

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If your primary objective is to accumulate minutes in a VO2max condition then Dicks-2 (which is very much like a Seiler 4x8 workout) is going to be superior to Taylor-2 (which is basically a Billat 30/30 type of workout). However, if your goal is to prepare for a hotdog/hilly crit you might be better off with the Billat workout.

VO2max is a physiological condition, not a wattage. You can do a ‘hard start’ VO2max interval & reduce power to maintain VO2max for a very long time. Long enough to be chugging along in a physical VO2max state but turning the cranks at less than threshold power. Even Billat discovered that was a much better way to accumulate more minutes at VO2max.

On the other hand, if your goal is to really push the limits of steady state power, Dicks-2 is probably the better workout. It all depends on what your goal is. But if time @ VO2max is your goal consider a workout like Dorr+5. Hard start intervals get you into VO2max quicker and then you can maintain it longer at a lower power.