VLamax: Elite Coaches Secret Weapon

Are you a cyclist looking to sprint faster than Wout van Aert? Or a triathlete dreaming of racing with Jan Frodeno at the next Ironman World Championships? These may be hard goals, but a good way to start working towards them is to understand a very important metric of human performance: VLamax (also: glycolytic power). During both a sprint and a triathlon, VLamax plays a crucial role.

Never heard of VLamax and this all sounds like blasphemy to you? Read on and you’ll understand.

Table of Contents

What is VLamax

Before we start, let’s first talk about the definition. VLamax stands for the maximum production rate of lactate in your muscles. Let’s break it down:

  • is volume over time. Just like in VO2max it’s about the flux rate
  • La is an abbreviation of lactate
  • Max is an abbreviation of maximum

Since lactate is produced in the muscle, we say VLamax is the maximum (max) production rate (V̇) of lactate (La) in the muscles.

“I use VLamax as the main parameter to prepare the training."
Dan Lorang
Coach of Jan Frodeno, Anne Haug and Bora Hansgrohe pro cycling team

Why should you care

You probably wonder why you should care about the maximum lactate production. And that’s a good question! To answer that question, let’s look at the 3 energy systems of the human body:

  1. Phosphocreatine (PCr) energy system
  2. Glycolytic (anaerobic) energy system
  3. Aerobic energy system

If you want to better understand your sports performance, you need to know how well those energy systems are performing. Especially because they are almost always working together, whether you are sprinting or running a marathon.

Energy contribution 800m run
Example: energy contribution of a 800m run in 1:43: blue = aerobic, red = creatine phosphate, green = glycolytic

Performance Aerobic energy system

Let’s first talk about the VO2max because often the VLamax is best understood by comparing it with its wellknown brother: VO2max.

We all measure the aerobic performance, using the VO2max. VO2 max is about the maximum (max) oxygen (O2) volume uptake over time (V̇). This is proportional to the amount of energy (or power) produced aerobically. Therefore, VO2max is a valid marker of the aerobic energy system’s performance.

Performance Glycolytic energy system

VLa max is about the maximum lactate production rate. This is proportional to the amount of energy (or power) produced via the glycolysis. Therefore, VLamax is a valid marker of the glycolytic (anaerobic) energy system’s performance.

Do you see the similarities between VO2max as a performance metric for the aerobic energy system, and VLamax as a performance metric for the anaerobic (glycolytic) energy system?

As some call the VO2max, the aerobic capacity or aerobic power – you can also call the VLamax , the glycolytic capacity, or better: glycolytic power.

Watch the summary of this article via this video:

To answer the question “why should you care?”. Because it tells you how well the glycolytic energy system is performing. Unlike the VO2max (which is the higher the better), having a high VLamax can be an advantage or a disadvantage. This depends on the type of sports performance you want to be good at. Let’s learn more about that.

There are two sides of VLamax

The glycolytic energy system produces energy fast. Therefore:

  • On the one hand, a high VLamax increases the energy available for short efforts: a 200m swimming race, a 400m run, an attack, a sprint.
How glycolytic power depends on VLamax
The higher the VLamax, the higher the Glycolytic power

However, the glycolytic energy system also produces lactate and burns a precious fuel: carbohydrates. Therefore:

  • On the other hand, a high VLamax decreases the anaerobic threshold and fat combustion and lengthens recovery time from hard efforts. 
How anaerobic threshold depends on VLamax
The higher the VLamax, the lower the Anaerobic threshold (all other things equal)

This should make clear that all athletes benefit from knowing their glycolytic power, so they can adjust it to their race demands! But how do you know what your VLamax is?

VLamax test: how to measure it

There is no such thing as a VLamax calculator based on certain efforts. To get an accurate value, there are two VLamax test protocols: one that includes a 15 second sprint and one that includes several sub-maximal tests. 

INSCYD is the only tool that provides you a scientifically validated VLamax . Even more important: it also allows you to understand how it influences your performance and what your optimal VLamax is.

The INSCYD VLamax test can be performed in a lab environment, but you can also do a VLamax field test and even a remote Zwift test. Athlete’s can do their test via one of our INSCYD coaches. Coaches can start offering these tests by becoming an INSCYD coach:

VLamax training

Once you know your glycolytic power, it’s time to start training. The question about “how to train VLamax” is a bit more difficult than “how to train VO2max”. Why? Because, as mentioned, a highly active anaerobic energy system has both advantages and disadvantages. However, once you know your VLamax and your goal, you know whether to increase or decrease VLamax. Here’s how you can start doing that.

“You really know what you need to work on if you know your VLamax.“
Dan Lorang
Coach of Jan Frodeno, Anne Haug and Bora Hansgrohe pro cycling team

How to increase VLamax

If you want to increase your VLamax, start by making sure you do nothing that decreases it. Next, think about short intervals like sprint training with a lot of recovery in between intervals. Strength training could also be a part of your trainingplan. Get 5 training tips on how to increase glycolytic power via our free whitepaper:

How to decrease VLamax

Even though it’s a marker for the performance of an energy system, we often receive questions about “how to lower VLamax“. Reducing VLamax often comes down to making sure glycolytic muscle fibers fatigue, and therefore become more aerobic. Get 5 training tips on how to decrease glycolytic power via our free whitepaper:

VLamax normative data

As said: some athletes benefit from reducing their glycolytic power while others will benefit from increasing it. That depends on the sport you perform: cycling, running, triathlon, swimming, XC skiing etc. It also depends on the type of athlete that you want to be. A sprint runner needs a different VLamax than a marathon runner.Interested in whether you should increase VLamax or decrease VLamax? National Champion coach Ben Tilus shares how you can find out whether you should increase or decrease VLamax.

Here’s an example of some values:

VLamax values typically range from 0.2 mmol/l/s to 1.0 mmol/l/s.

For comparison: world class marathon runners have a VLamax in the ballpark of 0.3 mmol/l/s. But if you want to run 100m in sub 10sec it needs to be more in the ballpark of 1.0 mmol/l/s.

Scientific literature showed that a female world record marathon runner had a VLamax of 0.31 mmol/l/s.

Cycling Team Jumbo Visma head coach Mathieu Heijboer shares VLamax values of his riders in this webinar.

In the book DER KONA CODE, Sebastian Weber recommends (KONA) triathletes to aim for a VLamax below 0.3 mmol/l/s for women and below 0.4 mmol/l/s for men.

You can use this normative data to understand what you need to work on to get the ideal metabolic profile.

"It’s interesting to know my VLamax, whether that’s an area of strength, or an aspect I need to train more.”
INSCYD user Sepp Kuss wins stage Tour de France 2021
Sepp Kuss
Professional Cyclist at Team Jumbo Visma

The ideal VLamax for sprinters

Sprinters need a lot of energy very quickly. For such short, hard efforts, a high-energy production in a small amount of time is needed.

The glycolytic energy system is the solution, because it produces energy much faster than the aerobic energy system.

With VLamax being a measure of performance of the glycolytic/anaerobic energy system, it will come as no surprise that a high VLamax increases glycolytic power and therefore the possible sprint power.

Here’s an example of how the VLamax determines glycolytic power and 12 second sprint power in cycling:

VLamax and sprint power
Table: example of how VLamax determines glycolytic power and sprint power

However, always keep in mind that in some sports, the sprint takes place after a long endurance race. For instance in cycling. That’s why some sprinters – like Wout van Aert – still feel the need to decrease their VLamax for better performance. Watch the video to hear what Wout van Aert has to say about it:

The ideal VLamax for endurance athletes

Endurance athletes need a good amount of energy for a long time. Examples of endurance events are: long distance triathlons (half and full-distance Ironman), marathons and also bike races. In these kind of events, the key is to go as fast as possible without:

  1. Running out of energy. You rather burn fat (“infinite” source of fuel) than carbohydrates (scarce source of fuel).
  2. Building up lactate and fatigue early in the race.

Having a high VLamax does quite the opposite. Even at sub-maximal intensities.

How FatMax depends on VLamax
The higher the VLamax, the lower the FatMax (all other things equal)

Learn more about the role of VLamaxin endurance performance via our free white paper:

Wrap up

Finally, it doesn’t matter if you’re Wout van Aert or Jan Frodeno. In both cases – but especially in your case – basing your training on VLamax will bring your performances to peaks they’ve never reached before.

Dr. Hellard of the french swimming federation on the importance of VLamax in swimming.

Dan Lorang – coach of Jan Frodeno – on the importance of VLamax in Ironman races.

VLamax podcasts

Is there any INSCYD podcast that does not mention VLamax? Probably not. But if you want to learn everything about it via a podcast, we highly recommend starting with these two.

VLamax white paper

Want to learn more? Get our FREE whitepaper full of practical tips:


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