Fast Talk, ep. 67: What is VLamax? With Sebastian Weber

In episode 67, we explore VLamax, a measurement of an athlete's maximal rate of lactate production, and how it affects training and rider type.

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The VeloNews Fast Talk podcast is your source for the best training advice and most compelling insight on what it takes to become a better cyclist. Listen in as VeloNews managing editor Chris Case and our resident physiologist and coach, Trevor Connor, discuss a range of topics, including sport science, training, physiology, technology, nutrition, and more.

In this era of training data, one number reigns supreme for many athletes: FTP. It’s a badge of pride, or maybe an obsession, and many cyclists pay coaches good money to improve it.

But is FTP the only number we should be looking at — or even the most important one? Our energy systems can be divided into two key categories: aerobic and anaerobic. And both our total strength as an endurance athlete and our rider type are a function of the relative balance between these two systems. How they interact may tell us more about our FTP or threshold strength than a simple power number.

For years, we have used VO2max to measure the maximal rate of our aerobic system. But how do we measure the rate of our anaerobic system? Over the past two decades, renowned physiologist and coach Sebastian Weber has developed the anaerobic equivalent to VO2max, which he calls VLamax, or the maximal rate of lactate production.

Today we take a close look at this sometimes complicated concept, but be patient as there are several points that we address that could have a significant impact on how you train, and how quickly you progress.

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.

Our primary guest today is the head physiologist and scientific brain behind INSCYD, Sebastian Weber. Weber has also coached some of the best riders in the world including Tony Martin, Andre Greipel, and Peter Sagan. INSCYD is currently used by several WorldTour teams, including Bora-Hansgrohe and Jumbo-Visma.

Along with Sebastian, we talked with Armando Mastracci, the owner and founder of Xert. While that system’s approach is very different from INSCYD, the two tools are similar in that each uses on-the-road data to analyze a rider’s physiology with remarkable accuracy. Mastracci talks about this balance of anaerobic and aerobic power and also the potential issues with outliers in the formulas.

Finally, we’ll touch base with coach Neal Henderson and mountain bike and gravel racer Rebecca Rusch to get their thoughts on VLamax and how the type of rider you are can influence how you view it.

So, put on your nerd cap. Let’s make you fast!

Fast Talk is available on all your favorite podcast services, including iTunesStitcherGoogle Play, and Soundcloud. If you enjoy the podcast, please take a moment to rate and comment on iTunes after listening.


  1. Hauser, T., J. Adam, and H. Schulz, Erratum to: ‘Comparison of calculated and experimental power in maximal lactate-steady state during cycling’. Theor Biol Med Model, 2016. 13(1): p. 18.
  2. Hauser, T., J. Adam, and H. Schulz, Comparison of calculated and experimental power in maximal lactate-steady state during cycling. Theor Biol Med Model, 2014. 11: p. 25.
  3. Dudley, G.A., W.M. Abraham, and R.L. Terjung, Influence of exercise intensity and duration on biochemical adaptations in skeletal muscle. J Appl Physiol Respir Environ Exerc Physiol, 1982. 53(4): p. 844-50.

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