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What is VLamax, how to fine tune it and what does it mean for your anaerobic capacity.

Although you might have never heard of it, VLamax. It is the single most important measurement to enhance your performance. VLamax is the maximum production of lactic acid in your blood and gives you a complete understanding of your anaerobic metabolism.

So in this post we are looking at how to increase and decrease the VLamax (V= volume, La= lactate, max= maximum), otherwise known as the anaerobic capacity or lactate building rate.

Let's talk about it in a different way. V02Max and VLamax and why they matter. The two are related, though too often VLamax is overlooked. V02Max is the maximum amount of oxygen your body can use during exercise to create energy. It’s a measure of your aerobic power. VLamax, on the other hand, is the ability of your cells to burn glycogen to reduce power resulting in lactate which then feeds the aerobic system.

It is like two production belts: One takes glycogen and transform it into lactate, defined by VLamax, and the second belt takes this lactate to make energy for locomotion out of it defined by VO2max.

The glycolysis (or the glycolytic process) is in fact at work within the human metabolism when an athlete is working-out at lower intensities. Therefore, the more your body activates the glycolytic process, the more it burns carbohydrates during the exercise and this will trigger a higher lactate production (so, a higher VLamax too).

On the other hand, if your VLamax is lower, it means that your glycolytic system is less active and your body burns less carbohydrates. And carbs are a such precious fuel you want to save as much as possible during endurance events: because if in long events you mainly burn carbs, then you also burn less fat. Fat very rich in energy and it contains roughly 9 kcal per every gram (against the approx. 4 kcal per gram of the carbs), but its storage is virtually infinite, whilst the carbohydrate one is limited.

While you want to have a high V02 max number, a high VLamax number may be problematic for say an Ironman athlete. What the body uses to produce lactate is glucose. So the more lactate you produce, the more glucose you’re burning. For a sprinter who wants to burn glucose like crazy in a 15-second race, that’s great. But torching your glucose stores in the first four hours of an Ironman is less than ideal.

First off all though, we will look at developing your Anaerobic capacity.

Increasing your VLamax

As mentioned athletes who compete in short duration, high intensity events require a strong, by that I mean high, VLamax number to facilitate the rapid production of ATP, the body’s energy currency. This is particularly suited to any event that is short in distance but high in effort, such as ITU racing, TT’s. 100m sprint or track cycling.

In these events, athletes need a high rate of glycolysis (break down of glycogen, the body’s storage form of glucose) to keep up with this high energy demand. More accurately a very significant portion of the total energy produced throughout is provided by the anaerobic glycolytic system.

A common misconception is that VO2 is important for very short-duration events. The reality is that the fractional utilisation of the VO2, i.e. the percentage of the aerobic capacity where an athlete steps over their lactate threshold, is not the primary determinant of performance. That is not say that it is not important but to reiterate it does not determine your performance.

Any athlete that competes in longer duration disciplines (e.g. IRONMAN 70.3, IRONMAN, Marathon races, multi day stage races e.g. Tour De France) where the aerobic system is the biggest contributor to total energy production, the fractional utilisation IS one of the key predictors of success.

In any of these examples, you can use the following training methods to increase the VLamax to the required level:

Ensure that you have high glycogen availability.

The body uses the most easily accessible substrate available to it, and so training with topped off muscle glycogen gives it ready access to this fuel source for the purposes of energy production. This allows for high power efforts to be produced and trains the body to metabolise carbohydrate more effectively.

High output sustained efforts.

Very short sprints less than 5 seconds will primarily use the phosphocreatine system, which is a different anaerobic pathway to the glycolytic anaerobic system, but sprint efforts longer than this, like 10-30 second all-out bursts will encourage a very high rate of glycolysis and train the body’s ability to produce energy via this pathway.


If you include explosive and very very fast, strength training into a program will help to activate a greater number of Type II (fast twitch) muscle fibres will encourage greater anaerobic energy production. Such movements should be repeated quickly and recovery time kept low to avoid replenishment of creatine phosphate and its contribution to energy production.

Specific gym sessions

If you have specifically designed strength training in the gym, then it can also promote the use of glycolysis effectively. You will need sets that use relatively high weight (not so heavy to cause complete failure), feature no significant in-set recovery time and use relatively short set durations (long enough not to only involve the phosphocreatine anaerobic system, but not so long as to let aerobic metabolism take too much of the strain) are ideal.

Very high-power efforts

Training sessions that feature a series of intervals in the neighbourhood of 45-90 seconds each will also serve to raise glycolytic activity and train the production of lactate. There will be a greater contribution of the aerobic system in these longer efforts, but this will remain a very effective workout design for development of the anaerobic capacity.

The ultimate goal for the endurance athlete - Decreasing your VLamax

In any endurance sport, it is always advantageous to have the highest aerobic capacity possible, and there isn’t a single situation where a lower VO2max would be to your advantage. The same isn’t true for the VLamax though, in almost all metabolic testing of athletes that I have completed who compete in endurance events, their anaerobic capacities is almost always too strong.

The reason is an athlete likes to ‘feel’ as though they are working hard to have a ‘benefit’ from training. The downside of this approach is that they are almost always training their anaerobic system and not developing the change needed to lessen their dependency on glycogen as a primary fuel.

Another way to look at this is to say that endurance athletes need a lot of energy spread over a lot of time. Such endurance events can be long distance triathlons (half and full-distance Ironman), marathons and also bike races.

In these types of events (performed at low intensities for a very long time), a different energy production system takes place. It is called the aerobic pathway (a different way of saying “with oxygen”) and in this process energy is produced using oxygen, fatty acids and lactate as the main fuels.

However, VLamax (the max production rate of lactate) affects the performance of an athlete in long events too. How?

That is easy to understand: if your lactate production rate is high at max conditions (sprints), it’s also relatively high at sub-max conditions (endurance events). Vice versa, if your maximum lactate production is low at max conditions, it’s also relatively low at sub-max conditions.

It is also important to note that a very key difference between the aerobic and anaerobic pathways is the nature of the by-products that are created during energy production.

The aerobic system’s by-products are non-fatiguing (HO2 - absorbed by the body, CO2 - exhaled, heat - which only becomes a problem in extreme climatic environments). The more energy produced via aerobic metabolism, the greater the energy yield without fatiguing consequences.

The anaerobic glycolytic system’s by-products, principally the production of hydrogen ions alongside lactate which lower the ph of the muscles and create an acidic environment that hinders contraction and enzyme activity, cause fatigue very rapidly when production of lactate outstrips the aerobic system’s ability to metabolise pyruvate. The more ATP is produced via anaerobic metabolism then, the quicker the path to fatigue, despite faster short-term energy.

This is fine if your events are very short and but becomes a huge problem as the duration increases. So, compared to the aerobic system, anaerobic energy production needs to be finely balanced so that it’s strong enough to provide the required energy, but necessarily weak enough so as not to hinder the aerobic system’s much larger contribution to longer duration exercise.

A VLamax of an athlete that is too strong will result in more lactate at a given power output (your enemy in endurance), thus lowering the lactate threshold/fractional utilisation of the VO2, which we now know is a key fitness parameter in any endurance event.

With this in mind we will look at the key training approaches, workout designs and nutritional strategies needed to build a training program that can develop or suppress the anaerobic energy system as needed in order to achieve the optimal aerobic-anaerobic balance for the specific demands of a particular event or discipline. When the VLamax needs to be reduced, the main training methods that can be used to result in these adaptations are:

The elephant in the room. Don’t train at a percentage of FTP

Don’t train at a percentage of FTP. Yes I did just say that. When you train at a percentage of your FTP, you cannot understand how much stress you put on your aerobic system or your glycolytic system. If you don’t understand the stress, then you cannot train effectively to reduce your VLamax. This is the problem with basing your training on your FTP. It is not a clear link to just one metabolic system. For example, if you put 10 people on the same training programme based on % of FTP, 5 people will develop in one direction, and 5 in the other. This is because the actual training of their aerobic and glycolytic systems will be completely different. 

Low Glycogen availability.

It is no surprise that ensuring you have a low glycogen status before training is one of the best means of training the body to utilise your aerobic metabolism. This also means that at higher intensities you can restrict its availability to glycogen and force the combustion of fat as the primary fuel for energy production. Performing low intensity rides on a weekly basis in a fasted state is a simple but very effective way to tip the aerobic-anaerobic balance favourably.

You can maximise this approach by utilising a low carbohydrate dinner preceding the mornings exercise session to maximise this adaptation. When carbohydrate is restricted, enhanced training adaptations are reported, which has been given the term “train low.” In conjunction with the correct cadence range and power value (more on this below), which will help develop your VLamax.

Since the goal is to change your reliance on glycogen it is important to remember that full glycogen replenishment mostly happens within 48 hours, with 60% happening in the first 24 hours. Therefore, by utilising the approach above you are ensuring that you are making the most of the session designed to change your metabolic cart.

You can also help this with your nutrition plan. If you're trying to lower lactate production and glucose consumption, you don't want to feed yourself a high glucose diet. If you complete the above sessions but then consume a diet very high in carbohydrates or glycose then you are negating the training effects.

Consistency and repetition

When there are long periods between training sessions, such as with those athletes who can only train around the weekend, the tendency is for the aerobic system to degrade and the anaerobic systems to become more dominant. Therefore, consistent training day after day is one of the best ways to keep the VLamax low, assuming you are doing the right type of training that is. It can take months to see the changes, repetition and consistency are critical to this type of training.

SweetSpot Training

The balance of the two capacities is interlinked with the athlete’s muscle fibre type composition. The greater the use of Type IIx (fast twitch glycolytic fibres), the higher the anaerobic contribution will be. By training at intensities just below the lactate threshold, it is possible to recruit the body’s Type IIa fibres (fast twitch oxidative) and turn them into muscle fibres that possess qualities more akin to the Type I (slow twitch) fibres than the Type IIx, making them more aerobically capable and thus reducing the lactate production during exercise at low to middle intensities.

High Torque/Low cadence

By increasing your force production you will recruit the Type IIa muscle fibres and make them more aerobically capable. Muscle fibres work on a continuum, where a necessary level of demand is needed before the next fibre type in line can be activated. This means that if a particular demand is not reached, there will be no activation and therefore no adaptation. Intensity (discussed above) is one method to increase the demand, and force/torque is another, so utopia is to use both for the purpose of lowering the VLamax.

To finish, here are a few pointers that may help

It is important not to lose sight of the need for a perpetually strong aerobic capacity. The higher the VO2max, the more aerobic, non fatigue-producing energy can be contributed to an effort, even a short burst of power that many would call an “anaerobic effort”.

The stronger the aerobic capacity, the greater its ability to “mop up” the byproducts of anaerobic metabolism, meaning that any anaerobic efforts can be sustained for longer and longer periods (also known as improving “anaerobic power”).

Seeing meaningful increases in aerobic capacity can take months and even years, and this fact means that it is something to work on constantly throughout the training cycle. Be patient, be consistent and test regularly to ensure that you are on the right path.

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