Fast Talk Episode 67: What is VLamax? with Sebastian Weber

In Fast Talk Episode 67: What is VLamax? With Sebastian Weber, Trevor and Chris take a close look at the concept of VLamax developed by @Sebastian-Weber and how it can improve your training.

In this episode, we discuss:

  • First, we define FTP, and why it may not be the be-all-end-all of training. If you have an FTP of 350 watts, you should be proud. But the more important consideration, particularly for how you train and where you may excel as a cyclist, is how you produce those 350 watts.
  • What are VO2max and VLamax, and why is the cross-over point of lactate production and lactate clearance so important.
  • The issues with lab testing: Yes, it’s inconvenient, it disrupts training, and it hurts. We’ll also explain why finding ways to get the same information out on the road is important to an athlete’s training.
  • How to determine VLamax since it can’t be measured as easily as VO2max.
  • Then we get to the crux: how to apply the concepts of VLamax and VO2max to training. Weber makes the very important point that developing one system generally comes at the cost of the other.
  • Finally, we address how this has different implications depending on if you are a time trialist or a sprinter. Weber gives great advice to both styles of riders on how to direct their training.

We recently reposted this episode on Twitter, and it sparked a conversation that we think would be a lot more useful to share and continue here on the Fast Talk podcast Forum. We’ll invite those Twitter users to join this Forum conversation. And we hope Sebastian is willing to chime in here, too!

To catch you up, here’s how the conversation has flowed on Twitter:

Fast Talk Labs: What is VLAmax – and what does it reveal about your sprinting? Find out.

Twitter user nfkb: What is VLAmax ? a marketing tool I guess :wink:

Fast Talk Labs: It’s interesting because our staff and many of our athletes have taken the test and VLAmax is corresponding closely with expected performance and rider profiles.

nfkb: Hope to see a peer reviewed publication then :wink: big bonus if the recipe to move VLaMax in the direction you want works

Fast Talk Labs: @INSCYD INSCYD team, can you point us to any peer-reviewed research relating to VLamax? This would be a fun exploration for many!

nfkb: And I have already read Mader’s papers.

Twitter user skier_ib: Can you really measure VLamax? If it is glycolitic capacity, then you have to exclude alactic PCr mechanism and aerobic component (granted, it contributes very little in 15s max sprint) in any testing protocol. Otherwise, a 15s max sprint is still a combination of three energy systems.

Trevor Connor: … interestingly, Sebastian’s issue with W’ is exactly what you are asking about with VLamax - W’ is a combination of anaerobic and aerobic energy contributions. VLamax, unlike W’, isn’t a capacity, it’s a rate of anaerobic contribution.

skier_ib: Yes, Mader (upon which all Vlamax models are based) defines VLamax as “maximal rate of glycolysis” and it’s a function of “concentration of glycolytic enzymes”. In a real field test, you don’t know what level of glycolysis is active.

So that’s where we are now.

What do you think? Can you measure VLamax? What are the considerations?

my understanding is that you do not measure VLamax… you estimate VLamax…
Is it a marketing tool? For sure it is! Does it work? We do not have much literature avaiable showing results or even showing how to manipulate VLamax, but that does not mean that it does not work in my opinion… people from Cologne use this methodology for years with good results…
I use the model myself to guide my training (I did an spreadsheet for myself after read Mader’s papers… it is not rocket science) and I think it helps a lot to understand if I am going in the right direction…

What I did notice though, lots of people keep discussing about VLamax but do not get how the model really works… I even took the test last year and I did not find that it helped me a lot as I got the results and the “coach” that have selled the test clearly did not know what to do with that…

Finally… in my opinion it is just a tool… much better that most of the tools avaiable but you got to know how to use the tool… otherwise is useless…


Couldn’t agree more.

All testing is valuable.

All testing is a tool to help us understand what direction we are going.

Knowing how to change the next test the way you want is the secret.

I can say in my experience there are a lot of North American mtb and cross riders thinking that vlamax of .7 is ok.

It is ok to win in North America…but .5 is necessary to be one of the top of the world.

Sometimes when you are winning on one level you think that is what it takes.

I love testing of all types to help me stay heading in the right direction with my athletes. If I have someone at .67 and I tell them I need .5, I best know how to make that happen (or I might have to blame the testing…which is NOT fair)


For people who are trying to RAISE vlamax and not lower it, the training itself seems straightforward (basically train like an elite 400m runner rather than an elite marathoner), about how long does the training normally take to have an impact? Probably some happens quickly but some takes a long time, right?

Question : In the litterature, I read that low VlaMax is good for time trial and high VllaMax is good for short time trial. Whate defines short time trial ? Thanks

Exactly, you should start to see improvements in as little as ~6 weeks. Of course, longer term training will continue those improvements and make them more significant.

Not sure what the papers would define short time trial as exactly. Do you have any links to some of those?

I would think that if we’re talking about TT’s with a consideration of a high VLamax being beneficial, I would think that “short” would be in terms of maybe less than 3-4 minutes, but don’t have any studies to back that up at the moment.

@ryan “littérature” was a bit exaggerated… that was more on the internet, on different web sites. But your answer reassures me. Already for 10 miles TT it is important to have a lower VLamax ? Thanks

You’re welcome. I would think that even by 10 mile TT’s you would want a relatively lower VLamax since the aerobic contributions are quite high over that type of duration. What’s the starting point though? Are we talking 0.88 mmol/l/min, or more like 0.30?

@ryan thanks. I don’t know my VLamax yet… never tested. But I was thinking that despite the fact that I didn’t test I could already go in direction of training lowering VLamax as a global idea. Not so smart I know…

Honestly, it’s probably not a bad idea to generally focus on some of those approaches that lower it. All of those aerobic adaptations tie nicely to health maintenance and improvements anyway. It’s just a matter of knowing if what you’re doing is actually causing change, and to what degree. Good luck with the training! :muscle:

@ryan That’s what I’m doing while waiting to do an INSCYD test. Currently my training is based on 4DP and is pretty general fitness. Since I want to focus on TT in January, I will do an INSCYD test and then the question of the training program will arise.

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