Physiology, Podcast, Technology, Training

Physiology, Training, and INSCYD with Sebastian Weber (part 2) | EP#238

 June 15, 2020

By  Mikael Eriksson


In this Episode you'll learn about:

  • Block periodisation vs. mixing different types of training
  • Time-course of adaptations for VO2max and VLaMax
  • The challenges of increasing VLaMax
  • Potential issues of high-intensity training when your VLaMax is low
  • Differences between VLaMax and VLaMax training between cycling, running, and swimming
  • Training zones
  • Training stress/load and recovery, and using carbohydrate combustion rates to figure out how much intensity is feasible to do
  • Differences between testing in the aero position compared to sitting up
  • How world tour cycling teams are using INSCYD

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Training strategies

05:15 - 

  • Generally I would recommend a block approach when it comes to improving one physiological parameter (i.e. for instance VO2max or VlaMax).

    In concrete, this would mean that one should focus on such training that improves the given parameter for a certain time, but one must do so in a way so other parameters are not affected.

    For instance, if one targets to improve VO2max, then VlaMax may increase and then FTP may remain roughly the same and can hence not be used as a measurement tool for if the training block has been successful or not.

Improving VO2max and VlaMax

07:40 -

  • The first improvements in VO2max can be seen already after a few weeks, however, these changes may be so small so that it is hard to determine if any improvements actually have occurred or if it is just day to day fluctuations.

    However, after 6-8 weeks of focused VO2max training, a significant increase can normally be seen.
  • When it comes to VlaMax, it generally takes longer time until improvements can be seen.

    The VlaMax component can, however, be divided into two parts, structural and functional.

    The functional part responds quicker to VlaMax focused training and/or diet (for instance one can see a fairly quick decrease in VlaMax by switching diet to more fats and protein), but these changes are also much less stable and the VlaMax easily ”bounce back” to the original level once the training and/or diet is changed back.

    The structural changes in VlaMax take both longer time to achieve but they also stick longer, here we are talking about a time perspective of months to years.

    My recommendation is therefore to work with your VlaMax while you have the time, for instance during the build up towards the season.

    How ”easy” VlaMax changes in one direction or the other is also highly dependent on genetics, if an athlete is more of a ”slow twitch muscle fibre kind of a guy” and wishes to raise his or hers VlaMax, this is going to be much more difficult to achieve than if the athlete naturally was more of a ”fast twitch muscle fibre guy”.
  • To improve (reduce) VlaMax for cycling, high torque (i.e. low cadence) and medium intensity (sweet spot) training is what is what is recommended in the first hand.
  • Generally, it is easier to lower your VlaMax when running compared to cycling since the intensity for most people is higher when running, which tends to lower VlaMax.

    But if one wishes to specifically lower VlaMax on the run, the same principles apply even though it may be a bit difficult to achieve that in practice.

    The high torque on the bike would be similar to running uphills, and otherwise medium intensity is recommended as well as lowering the carbohydrate intake a little bit.
  • I wouldn’t care about the VlaMax in the swim since working economy is such a massively much more important factor in swimming than VlaMax.

Balancing training load in regards to VO2max and VlaMax

15:10 -

  • How much different training tear on the body is highly dependent on the athlete’s VO2max and VlaMax.

    Generally, low intensity training does not put any major strain on the body for athletes regarding of their VO2max and VlaMax.

    High intensity on the other may put very high strain on the body, but how much depends on ones VlaMax and VO2max, an athlete with a high VO2max and a slightly higher VlaMax could tolerate high intensity training very well since the glycolytic system (which is represented by the VlaMax) does not get overloaded.

    But if the athlete instead would have a lower VlaMax, then during for instance VO2max intervals, the glycolytic system gets overloaded and this puts great strain on the body.

    Generally speaking, one could estimate the strain a session puts on the body by how high of a percentage of each system you go (and this is particularly applicable to the glycolytic system).

    Consequently, when you do training of how high percentage of your VO2max or (and particularly) VlaMax, this puts great load on the body, and this is something you need to have in mind when planning training.

Training zones

23:40 -

  • I am aware of that the training zones have created plenty of confusion among athletes and coaches.

    The training zones are merely ranges of intensities where some physiological processes are taking place and these are not black and white but more like ”ballparks”.
  • In the next weeks and months to come, we at INSCYD will update our approach to communicating training zones and how they can be applied.
  • I would also like to understate here that the most important part is to see the big picture and not get to hung up on specific power ranges, because that does actually not really matter.

Training dosage

34:15 -

  • The total volume of training should in my opinion be determined of how much actual time there is available to training and recovery, and in this everyday stress from regular life plays an important part here.

    Generally, low intensity endurance training does not put much strain on the body and most people can tolerate plenty of volume.

    When it comes to intensity, this is in my opinion more about actual time in the high intensity zones than percentage of the total volume of training.
  • When planning training I use to look at the carbohydrate combustion and the ability to refill carbohydrate stores between sessions when putting together a training plan.

    The ability to recover from a session and in the next step be fresh for the next one is highly determined by the degree of depletion of carbohydrates during the first session and the ability to replenish until the next one, if one training session would deplete the carbohydrate stores, then it is not wise to go on and do another hard session the next day without making sure to fuel properly before (increases risk of accumulated fatigue, infection, injury etc.).

Differences between aero vs sitting up position

39:40 -

  • In terms of VO2max, when wearing a mask we often see slightly higher values in the aero position compared to sitting up while the power output may decrease a little bit.

    However, someone who is extremely adapted to the TT position may produce the same wattages in aero than sitting up (except for sprinting).
  • When it comes to testing, it is very important to be as specific as possible for what you’re training for, so if you do long distance triathlon, then you should do the testing in the aero position.

How the professional cycling teams use INSCYD

42:45 -

  • Several professional cycling teams regularly use INSCYD as a training tool for assessing performance but how they do so varies massively.

    Some teams base their whole training on the results of the INSCYD tests while other use it one part of the puzzle.
  • The VlaMax of a GC rider should typically not be lower than 0.3 even though it is a little bit depending on the VO2max (with a high VO2max, the VlaMax could be slightly higher), but what one also needs to point out is that the VlaMax should not be too low going into a stage race like the Tour the France since such a race lowers the VlaMax and one should not have a too low VlaMax towards the end, which could make it hard to counter attacks in the hills.

    VlaMax of classic riders typically range between 0.4 to 0.6 and for sprinters it could almost not be too high (it is going to be very difficult to win a sprint in professional cycling races with a VlaMax lower than 0.7).

Estimating VO2max and VlaMax without doing an INSCYD test

50:30 -

  • It is hard to estimate VlaMax without doing an INSCYD test, but one can say that if the training volume is rather high, then VlaMax is typically rather low.

    The same thing applies to VO2max, a big training volume generates a high VO2max and with a low training volume one simply cannot anticipate a VO2max higher than 40-50 ml/kg/min.

INSCYD in the future

55:00 -

  • Currently, all our webinars are free and available on our website and we are also looking at increasing our educational material.
  • Also, we are working on improving and develop new tests for running, which I am excited to launch.


Mikael Eriksson

I am a full-time triathlon coach, founder of Scientific Triathlon, and host of the top-rated podcast That Triathlon Show. I am from Finland but live in Lisbon, Portugal.

Please contact me if you have feedback on the podcast or want to make suggestions for improvement or send in a question for a Q&A episode.

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