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



@tofel: Wow! This is perfect. It really nicely shows sensitivity and the axis you need to work on to get to the next step…from a marginal gain perspective.


@tofel: just a remark: if you want to push it even further, you could invert the y-axis so that improvements go from right to left and bottom to top. And not everybody will start at 50Vo2max. Don‘t get me wrong, there is no need for any changes, just if you are striving for perfection…


I’m a triathlete. So if I want to maximize my performance on the bike I should focus on getting my VO2max as high as possible, and VLAmax as low as possible.

Without knowing my actual VO2max and VLAmax, I should still be able to monitor progress by performing the following test every 6 to 8 weeks :

  • 15s power test (~VLAmax)
  • 4min power test (~VO2max), should this be overpaced ? If yes, why ?
  • 20min power test (~FTP)

What I would want to see as a triathlete or time trialist in consecutive tests is :

  • 15s power should drop ( this would mean VLAmax is decreasing), is this correct ?
  • 4min power should go up (this would mean VO2max is increasing)
  • 20min power should get closer to 4min power (this would mean VLAmax is decreasing)

Furthermore, if the gap between 20min power and 4min power is big (how big ?), I should focus on decreasing VLAmax (lots of tempo and sweetspot work, maybe with low cadence). If the gap between 20min power and 4min power is small (how small ?) I should focus on raising VO2max (long endurance rides or VO2max workouts).

Is this correct, or am I oversimplifying things ?


Let’s say as a die hard TrainerRoad user I want to try to lower my VLaMax. How would I even effectively do that following TR plans? Just do Sweet Spot Base repeatedly? I mean even Sustained Power Build appears to be too heavy on intensity and too light on Sweet Spot.


If I’m being honest I don’t think you’re too far off here. Keep in mind though that there are several popular ways of doing sweet spot training that don’t look anything like a TR plan. Sweet spot riding as it was originally envisioned was not “intervalized”.

I think the more difficult pill for dedicated TR riders to swallow is that their FTP is probably significantly higher than MLSS/anaerobic threshold/lactate curve inflection point thingie. It’s been hinted at already but for many folks a sweet spot interval session on TR is probably more like threshold intervals. Whether or not you buy into that is certainly up for debate (and has been, ad nauseam, elsewhere). But the fact remains that their is a TON of intensity you’re subjecting yourself to in a very short period of time.


Pretty much, but I’d recommend starting with an FTP based on a longer test protocol (at the very least 20min) and working towards being able to ride longer durations than those prescribed by TR.


Yep. I think this is pretty much it.

This part, on best training to reduce VLaMax, I,m not fully clear on. My understanding is that long endurance rides reduce VLaMax as this trains slow twitch muscle fibers, and improves fat metabolism - which produce less lactate than fast twitch, and carbs.

And SS rides differentially improve lactate removal (in concept, the inverse of VLaMax). Logic here being that SS is at an intensity where more fast twitch fibers are being employed, more carb being used for fuel, more lactate being produced - which then needs to be removed in order to sustain your pace - improving power at MLSS.

So both endurance and sweet spot are needed. But I could be wrong on this.


Maybe. I agree with @DaveWh but I want to point out that these are not max power tests. The are (intentionally) over-paced. What that tells me is that the software might account for the rate of decay in power output. When they give you instructions for the Critical Power test, you are required to over-pace…by A LOT. As in, tomorrow I’m going to start the 20min test at about 400w. <–thats not a typo. I can’t hold 400w to save my life. It will rapidly decay and I will suffer at a trillion percent RPE for the next 19mins.

If they simply wanted mean max power you would want to pace them “correctly”.


Agree. Overpaced needed for the INSCYD analysis algorithms. You probably don’t need to do overpaced tests for yourself to measure progress. Just do regular paced tests.


From my notes in this, I have:

  • Make sure you’re engaging your fast twitch fibers. If intensity is too low, you won’t be training them at all.
  • Threshold and sweetspot rides should work well. My notes say 2-4 weekly sweet spot rides.
  • High torque, subthreshold rides. Basically low cadence work. This works, because you’re pushing hard enough on the pedals to engage fast twitch fibers, even when at a power that wouldn’t normally engage them. But because cadence is low, you have plenty of time to clear lactate from each pedal stroke.
  • Fasted riding, because training in a glycogen depleted state can help teach the body not to prefer carbs as a fuel, which is effectively teaching it to produce less lactate, which lowers vlamax. This one is hard, because if you under-fuel for some workouts, you’ll just bonk, and get off the bike early. You still need to be able to finish the workouts, or riding low carb isn’t worth it.

What’s less clear, is how high you can take intensity/duration, before your fast twitch fibers start to increase Vlamax. Particuarly, some short and intense Vo2max rides get up to 150% or so. I have no idea if that’s too high, or where the line is on this.

But a lot of that, you can fit into a normal training plan. Adding low cadence and fasted riding can be done in pretty much any plan. If you want more ss/threshold, that’d be plan dependent. Avoiding sprints and other anaerobic efforts is also somewhat plan dependent, although you can pretty easily modify some plans, especially non-specialty plans, to simply not do the sprints that’d otherwise be in some of these workouts.


This is a part I don’t understand about reducing VLaMax. Makes sense to train for clearing lactate - as fast twitch, higher intensity (more carbs) rides produce more lactate that then needs to be cleared.

Ditto. I see how this might train your body to clear lactate, but not reduce VLaMax.

Agreed. I understand how this kind of training reduces VLaMax.

Maybe it’s a combination of fasted (or, more specifically, glycogen depleted) rides, and sweet spot rides that work best? Eg a couple hrs endurance pace, followed by some sweet spot intervals?


My understanding is that lactate production can either be stimulate by riding around and above threshold or by increasing torque at levels below threshold. I understand that both lead to same effect while for the latter you can do the same at a lower Intensity Factor (having an impact on overall training volume/capacity).


Responding to my own comment.

I think I’ve misunderstood the VLa measurement. I’ve been interpreting this as rate of lactate production

Whereas I think it’s actually the rate of lactate accumulation in the blood. Which is the net of lactate production and lactate removal.

So training the body to improve lactate removal also improves VLaMax.

@roflsocks the training you describe above makes a lot more sense to me now :+1:t3:


I think your original understanding was correct.

The rate of lactate removal is dependent on your Vo2max. Training to lower Vlamax is all about generating less lactate at a given intensity. Thus training to improve lactate removal would improve Vo2max, but wouldn’t have much of an impact on Vlamax.

FTP is simply where the two meet, such that the rate of production and removal balance. You can then improve FTP by either increasing Vo2max, or lowering Vlamax, or both. You could alternatively keep FTP the same, but raise both, and have the same sustainable power output with more anaerobic capacity.


This is also where I’m trying to wrap my head around . The part that I need to listen about again is when he discusses lactate clearing. Biochemically, this is an aerobic process as lactate is converted to pyruvate->acetyl coA and is then metabolized just like fats in the presence of oxygen. Clearing (reducing lactate concentrations) is an obviously aerobic process, so I think when he’s talking about glycolytic pathway, he’s talking about just producing lactate anaerobically and not the second half of what is generally instructed as glycolysis in biochemistry.

Looks like VlaMax is just discussing lactate production rate, not the equilibrium/balancing.

I recently did a lab study with a 20s wingate, got my lactate up to between 8-9mmol/l from a baseline of about 2 mmol/l . I wonder if it is just easy enough to divide the delta by the 20s to get VLamax. That would put it at about .3 to .35. and confirms that I have little kick beyond my VO2 max efforts.


There’s a good webinar I found on this that discusses some of the physiology on the different energy pathways. The relevant bit starts around 15 minutes in. Does a fantastic job of explaining glycolysis, and how oxygen and fat are used to process lactate.


Yes but isn’t it about production of lactate at steady state? The “equilibrium/balancing” are just a factor of being at steady state. No?

I guess I’m trying to make sure we’re not confusing production with levels. Levels is how we normally think of it. 2 mmol/l this, 4 mmol/l that.

The curves you normally see for lactate tests are measures of lactate levels in the blood, usually plotted against a measure of speed or power. This is an estimate of lactate production not lactate levels and it is in the muscle fiber itself. Notice the measures are different. The left axis is lactate production, not lactate levels. The unit of lactate production is lactate mmols per minute per liter. It is a rate such as miles per hour or meters per second. The total lactate production capability for this athlete is 42 mmol per minute per liter based on the estimated maximum production level of .7 mmol/sec/l. So this chart indicates that the athlete will never get close to the maximum production level.

This is what I was trying to get at with @DaveWh. When @DaveWh said “production” I thought he meant what would be “levels” in the above quote.

@Bioteknik Is this what you’re saying?

Never mind. Lower down in the thread it’s cleared up. I was fixated on what happens at steady state and that’s not really the point.


VLaMax is the maximum rate at which lactate concentration can increase in your blood. Tests usually involve a 15s all-out sprint followed by lactate measurements every minute. You take the peak lactate concentration and divide it by 15s - (time it took to hit peak power). I think that time correction is done to account for the 3-5s where energy is created from creatine phosphate instead of glycolysis.


Good discussion above. What do y’all think of the following:

Seems like there are 2 possible definitions for VLa

  1. Rate of lactate production
  2. Rate of lactate accumulation (which is the net of production and removal)

As far as I know, most lab tests measure #2 - rate of lactate accumulation in the blood. I’ve not read of any test that measures rate of lactate production in the muscle.

My origianal interpretation was #1. Then I reassessed and thought it was #2. And now I am just confused - don’t know if it’s #1 or #2. :grin:.

If it’s #1, how is it measured in the lab? Also, I don’t see how SS training (higher intensities, carb burning, lactate producing) train your body to lower VLaMax (unless it’s glycogen depleted training). Endurance training better.

If it’s #2, then to lower VLaMax, it’s equally important to train to lower lactate production, and increase lactate removal. Hence both endurance training and SS training helpful.

Or maybe VLaMax is measured over short enough duration (eg 15 sec test) where lactate removal is negligible, and hence #1 and #2 yield the same value?

Then lactate removal does not impact VLaMax. But increasing lactate removal does improve power at MLSS because more lactate can be removed, as a result allowing more lactate to be produced, which in turn allows riding at a higher power output. Which would lead back to a mix of endurance training and SS - endurance to train a lower VLaMax (lower lactate production), SS to improve lactate clearing. This logic hold?