That Triathlon Show | EP#169 - FTP, VO2max and VLaMax


These are measurements of lactate accumulation in the blood, not measurement of lactate production.

Maybe in such short durations, lactate removal in negligible, and lactate production = lactate accumulation?


VLaMax is a measure of maximum lactate production in the blood and has nothing to do with your ability to clear it. That is why tests involve short sprints; there is zero aerobic contribution, and for an effort that short there is little to no lactate removal. VO2max provides all the information about your body’s ability to clear lactate at different intensities, and VLaMax provides information about your body’s ability to produce it.

Low cadence SS training can help convert fast-twitch Type IIx fibers to Type IIa (I think), which limits peak lactate production rate and also lactate production at lower intensities. It is also still very aerobic in nature (true SS is not high intensity at all).

I think 20s may be too long of a test to measure VLaMax, because you could potentially hit peak lactate concentration after only 10-15s of work, and the extra 5-10s would throw off the measurement considerably. Testing this metric seems to be tricky which is one of the benefits of INSCYD.


Option 1 is correct. Option 2 mixes up both the production of lactate (anaerobic) and the clearing of lactate (aerobic).

The rate of lactate accumulation is absolutely important, but it’s simply a function of how your aerobic and anerobic energy systems interact.

I’m not clear yet on how this is measured in a lab. I’ve got a decent high level view of what types of adaptations you get from different training, but I still have a long way to go to understand why training in X zone causes Y adaptation. I think it’s easier to understand why Y adaptation improves either vo2max or vlamax.

And on your last paragraph, I think you’ve got the right idea on mechanisms. Keep in mind “removal” is essentially converting lactate into actual power output. So the more lactate the aerobic system processes, the faster you can go aerobically. But yes, your assertion that removing more lactate would result in a higher threshold is spot on.

On the training to do, I think you have it backwards. Endurance to improve your Vo2max, and SS to lower Vlamax. There’s some overlap on some of the training effects. Here’s a screencap from the webinar I linked earlier in the thread about expected adaptations in each zone.


It was measured prior to the test, directly after the 20s test, then 1 minute afterwards with passive rest.

The goal was not for VLaMax, but to also resopond to @madman2, the first test was not to saturation… after 5 more 30s ones I peaked at almost 18 mmol/l. I nearly threw up the first time there. It was brutal.


I think it’s what @madman2 said. Over a short duration sprint, lactate removal is not significant, hence lactate accumulation in the blood = lactate production.

Thx for the screen grab on training approaches. Appreciated. Have not yet watched that webinar.


(Hopefully) quick side question: I screen grabbed that slide when I listened to that talk and have been trying to make sense of the rows that have “up” and “down” arrows. I think it just means conflicting responses? Or is there more to that (to your knowledge). The “High intensity intervals” row is really what prompted my very first question in this thread (which has been addressed, but there are others with up/down arrows).


The impression I got, was that those rows were “it depends.” Which I took as might go either way depending on the athlete. I don’t recall that they really went into detail on that though.

I also really want more specifics on high intensity. Most any workout I do above threshold feels pretty high intensity, but I feel like there’s a huge difference between intervals at 105%, and 200%, and everything between. I want to know how high I can go for VO2max intervals, without impacting Vlamax. Or at least, how I can best optimize it.


Can we infer anything from the shape of a lactate curve regarding lactate accumulation rates?

For example would athlete two in the example below have lactate accumulation rate higher as the curve gets steeper? Is it a maximum rate of accumulation that is important or an average over the times of the various tests? Or is the ‘traditional’ lactate curve data not useful in this context because of the ‘go hard and decay’ nature of the VLaMax testing protocol.

That was the impression I got too. Training effects would depend on where the current VLaMax is.


Exactly, and whats more the INSCYD defined “aerobic maximum” zone is pretty wide. So I really couldn’t infer from that.


I would think that anything that is highly repeatable would at worst be neutral for VLaMax. Whatever method you use that has you at the highest O2 uptake for a reasonable amount of time to boost VO2max. I really like the build/specialty progression for short power in to XCO, starts with shorter ones, builds up to 3 minute VO2 sets, and then throws in some longer 108% ones.


As I recall - and honestly this is a podcast I would listen to again just to be sure - it depends on two factors. The first is that the muscle fibers that are used are the muscle fibers that experience stress, and then have an opportunity to adapt. Since your fast twitch muscle fibers are the ones contributing the most to your VLaMax, making changes in them is important, and therefore doing training that engages them is important.

The second factor is giving the muscle fibers you want to adapt an aerobic workload, so that they adapt to doing aerobic work. This is where the duration and rest interval comes in. I think there are a few factors here; during longer intervals with shorter recoveries, the muscle fiber will be relatively glycogen-starved, so the glycolytic pathway won’t be exercised and the oxidative pathway will be. Of course being able to do long intervals then influences what a realistic power target can be. And note that you don’t have to be glycogen depleted, you just need to be producing enough power for a long enough duration that there’s a big gap between what the muscle fiber can produce with the available glycogen and what you are making the muscle fiber produce.


So the key part of that is that as I read it is to change the way the muscle fibre functions the work needs to be

  1. Hard enough that the fast twitch fibres are engaged
  2. Not so hard that they increase their fast twitch functioning abilities.

Am I reading that correctly?


I agree. I feel that you negatively impact VLaMax when you “burn matches” - attempts that you can only repeat a couple of times during a longer period.

There is a very good explanation in this podcast @29:26min where they describe how keep the high intensity intervals aerobic (and thus not impacting VLaMax)


Yes, basically. Some of the descriptions of the value of really long long rides are similar - you ride until the slow twitch muscles are all exhausted and the fast twitch muscles are forced to participate, and do so oxidatively.


This correctly answers a lot of the discussion going on before it. On SS training, exactly, this intensity is required to engage type IIx fibers, and when we place them under “endurance stress” (SS intervals being very long durations for these fibers) some of them will adapt and become type IIa, with better oxidative capacities and endurance capabilities.

On a practical note, for this reason I think that a common training mistake is too often bumping up the intensities at which they do SS intervals (typically as a result of bumping up FTP) rather than focusing on increasing duration at SS. Why not wait until we can do 4 x 20’ until we increase the intensity?

It takes 5-8 minutes typically before you can actually measure peak lactate in the blood, even though it occurs almost instantly in the muscles. So the way a lab test like that should be performed is proper warm-up, let lactate stabilise at baseline level, then 15-s sprint (not longer), then sample lactate every minute until peak lactate is found (so when one reading is lower than the previous one - then the previous one was peak lactate) and lactate production equals peak lactate minus baseline lactate. Several people mentioned correctly that for a 15s sprint change in lactate concentration more or less equals lactate production rate.

IIRC, you are correct.

There’s no set percentages for obbvious reasons, everybody will be slightly different. And it’s not just about intensity either. Interval duration, recovery interval duration, recovery interval intensity and some other factors also play a very big role. If you want to increase your chances of not triggering a VLaMax response when doing VO2max intervals for example, shorten recovery durations and increase recovery intensity.

Just quickly looking through some of the data I have from athletes, it seems that the zone for glycolytic stimulus (increasing VLaMax that is) varies from starting at 125% of anaerobic threshold (remember, this probably means 115-120% of TR FTP) to 132% of anaerobic threshold.

When it comes to VO2max workouts, I’m partial to intervals in the 2-4 minute range, and the fitter the athlete gets, the more the focus turns to 3-4 minute intervals. I don’t know for sure, but until I see evidence otherwise I’m pretty sure these will be neutral from a VLaMax perspective. And this is despite the fact that I still typically keep a 1:1 work:rest ratio.

-I also like the longer 5-8 minute intervals that are a bit lower intensity than VO2max (ie. slightly lower than 90% of pVO2max). There is definitely much less research around these than 1-5 minute intervals at 90+ % pVO2max, but there is some (Seiler’s 8-minute intervals would fall in this category) and anectdotally they also seem to work well.

I looked at this with some data I have.
Athlete A: VO2max 57.6, VLaMax 0.30
Athlete B: VO2max 57.3, VLaMax 0.39

Beyond threshold, lactate concentration increases more quickly in athlete A, with a lower VLaMax. Up until threshold, athlete A has a lower lactate concentration.

But here VO2max is almost identical. If we don’t know VO2max, I don’t think we can infer anything from the shape of the lactate curve.

Not entirely correct, but I think your thinking is right. But we can do repeatable intervals of 30s at e.g. 140% of anaerobic threshold, recover for 4.5 minutes and go again. Not the same as sprint interval training which is all out. This is repeatable AND a stimulus to increase VLaMax.

Yes. Type IIa fibers start contributing more significantly around ~60% of VO2max and IIx around 75% of VO2max (SS/low threshold zone).


Not sure if this has been mentioned in this thread or not:

I don’t know if this relationship between VO2max and VLaMax was understood back then, but sounds like Armstrong’s training followed this prescription pretty closely.


I am going from memory, but I am pretty sure that the first measurement was the highest, but I have requested my data from the study author


From where was the lactate sampled?


Thanks Mikael. Really useful information :+1:

In all the things I’ve read and listened to regarding VLaMax figures they are often quoted as 0.3, 0.6 and 0.9. Is that for just for modelling convenience or are they typical high/low/medium values that are achievable?

Edit to add: Hope you’re feeling better, you sounded grim on the last podcast🤧


I think one thing that isn’t discussed, but looking at this chart it appears that until you get to more elite levels, improvements in VO2Max will lead to more FTP gains than reductions in VlaMax.