Optimising VLAmax for Time Trials

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Being a time trial enthusiast, when I first heard Sebastian Weber talk about this it was really eye-opening. I’d spent most of my cycling time trying to increase my threshold power without knowing this very important detail! How frustrating!! However, like always, the opportunity to improve is something that is hard to resist.

The picture above shows my metabolic test results from the beginning of the block of training I was. planning to lower it


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What is VLAmax?

VLAmax is basically your glycolytic power, it’s how fast you can metabolise glucose and therefore proportional to the rate of lactate accumulation. So the higher your VLAmax, the more quickly you accumulate lactate. Conversely, the lower the VLAmax the slower you will accumulate lactate.

Time Trialing Requires a relatively low VLAmax

What Should Your VLAmax be?

Like any time you are training and racing you have to match what you are working on to your goals. Training has to be individualised, but that’s exactly what metabolic testing allows for.

If your goals are around sprinting, track sprinting, crits you will need your glycolytic power to make the high power efforts involved in those kinds of events. Again, exactly how high is depends on how much aerobic power you also need for your event.

However, if you are into your time trials then a high VLAmax will actually hold you 

back. This is because for a given power output the person with the higher VLAmax will accumulate more lactate, which ultimately leads to lower power at threshold.

As you can see from the top picture my VLAmax is actually quite high at 0.69. This test came after a period of de-training.

Why my VLAmax was high I’m not sure. I have a history of doing well in sports that require speed and agility, so it could be that? Or it could be genetic? Either way, for my time trial ambitions it needs to come down. In the podcasts/seminars I’ve done with Sebastian Weber, he recommends a VLAmax 0.30 for a TT specialist, so there’s a long way to go.


How do You Change It?

It doesn’t matter if you know you are doing it or not, your VLAmax is like any other training parameter and will adapt to the type of training you do.

However, if you know what it is from testing and you know what you want to achieve you can plan to change the VLAmax to suit your cycling goals.

Since we are talking about time trial here we are going to talk about lowering it.

What did I Do?

Mine was quite high, so I put a 3-4 week plan in place to lower it. During that time I planned to keep easy-riding really easy, targeting the FATmax zone (160-170 Watts),  then on the hard days, I would do long sustained intervals at Sweet Spot (235-240 Watts). The sweet spot efforts were to be completed at low cadence high torque (55-60 rpm).

The low cadence work is particularly good for bringing down VLAmax because it forces the bigger, faster twitch fibres to get involved in producing the power for pedalling. This combined with the long nature of the intervals means that the faster twitch fibres are given a stimulus to work more aerobically. This triggers more aerobic adaptation in these fibres and reduces your glycolytic power…perfect

My Training Block

During the block I did:

  • 15 Training Sessions
  • 6 Sweet Spot Over Geared Sessions
  • 4 Fasted Sessions
  • The rest were easy rides

The reason for the fasted rides is to help with the lowering of VLAmax. By doing fasted rides you are encouraging fat metabolism above the glycolytic pathway, which is what we wanted in. my case.

If you do an easy ride before breakfast you will be glycogen depleted, particularly the liver, so you have to take it very easy. If you want to deplete the muscle glycogen in your legs you need to either train twice in one day (I did that twice) or train hard in the evening and then fasted in the morning (again, did that twice). I’d caution against diving into a lot of fasted training, it can be a powerful tool and you need to know what you are doing. I’m not a nutritionist, so you should get some professional advice before getting yourself in a mess with it.

See the Results Below

The first test was on 16-9-21 and the re-test was on 4-10-21 – Results below

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The Results

Though it wasn’t a long time between tests it was a really nice improvement. You. can see the VLAmax has come down from 0.69 to 0.53….great result!! You can also see the large effect the training had on the other parameters too. FATmax improved up to nearly 200 Watts from 168! With Critical Power up to 294 from 261.

This is a cracking result from a relatively short training block, but you can clearly see that a block of very specific, targeted training can have a relatively rapid change in your performance. I’m very happy to have the extra 30 watts to time trial with. The good thing about the re-test is that it completely updates your zones, so the next block can be just as targeted as the previous one as there are still room to improve, which is really exciting!

Would you Like to do a Metabolic Test?

THE BEST THING about this metabolic testing is it is very affordable and can be done at home with the power meter on your bike/turbo trainer. Previously, this level of testing required a lab visit and a big cost…not any more.

If you are interested get in touch,  now is a great time to set your zones for training in preparation for next season

If you want to be fast next season you have to do the right training now!!



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