Training practice part 2: VO2max TRAINING.

Frank Vandewiele

SITUATION

Since time immemorial, the attention of sports scientists and coaches has been on VO2max, the maximum oxygen uptake ability. Rightly so, because the endurance performance and the amount of oxygen that the muscles can use per unit of time are closely linked. Over the years, the debate about the extent to which this important trait can be increased through training has also continued. The heredity factor is still a very important factor, but new insights into training methodology support the theory that the training factor may play a more prominent role than originally thought. The VO2max training in particular would be responsible for this because they respond to a more efficient functioning of the mitochondria and therefore to a better movement economy.

The lack of time of many cycling fanatics and the emergence of increasingly better electronically controlled trainers gave this form of training a 4-star status in no time. However, let there be no doubt about it, classic endurance training is still the best way to improve the maximum oxygen supply to our muscles. Endurance athletes will therefore have to build in a lot of long and easy training sessions in their program to allow the mitochondria to increase in number and therefore to produce more energy (ATP).

In part 4 “Training Intensity Distribution - TID” we take a closer look at this dichotomy.

Time @ VO2max.

Like all training, the VO2max training will only have an optimal effect if the training protocol can be composed in such a way that the rider can ride at the necessary intensity for as long as possible: T@ VO2max. Depending on the study, the necessary intensity is at least 90 to 95% of the maximum oxygen uptake ability. This implies – as will become clear from the definition of our zones – that there are two zones in which “VO2max workouts” can be performed and that the active time he or she spends in those zones is no less important. A first important constraint to optimize T@ VO2max is the anaerobic input. The fact that athletes can only perform at VO2max for a handful of minutes is due to the rising acidification. The term VO2max is therefore a rather confusing term, in any case one that does not exactly reflect what it means. It gives the impression that an effort that is made at the VO2max is 100% aerobic.

On an app – used by thousands of cycling enthusiasts – this observation led to the following definition: “With the VO2max training you train your anaerobic system and you cycle above your threshold”. It is added: “This training is especially useful for tough small climbs”.

We can join the authors in speaking understandable language, but with this description they are going very short, even out of the corner.

AN INNOVATIVE APPROACH.

In part 1 of our series on training practice, we already referred to Professor C. Dauwe who, thanks to hundreds of analyzes of power values of both World Tour professionals and amateur cyclists, designed the Extended Critical Power concept. His mathematical approach to endurance performance has an extraordinary practical significance. After all, it enables the coach to approach VO2max training from a more substantiated point of view. Thanks to this concept - only on the basis of some maximal power data and time to exhaustion - the lowest power eliciting the VO2max can be calculated, as well as the percentage anaerobic input for all performances above the limit, defined by him as Recovery Threshold. For those who want to learn more about this innovative approach, we refer to his website www.typhooncycling.org .

To set up a targeted VO2max training, the following items are important:

·     The knowledge of the Recovery Threshold RT or the power above which the anaerobic reserve is used (read “where acidification starts”).

·     The knowledge of SCP or Super Critical Power or the power necessary to elicit the VO2max.

·     The Slow Death Zone, defined by RT and SCP. The anaerobic system does not yet contribute very much to the total energy supply because the aerobic contribution can still increase. On SCP, VO2max is reached and the anaerobic contribution is typically between 5 and 8%. This SD zone is extremely important for climbers and time trialists, so it goes without saying that the power values for their VO2max training are chosen from this. The Time @ VO2max – even if intensities close to SCP are chosen – is quite extensive thanks to the limited anaerobic input. Note that although this zone is not called a VO2max zone, it can be used to improve maximal oxygen uptake capability. Interval workouts of long (8' - 20') and medium (2' - 8') duration can be used.

The traditional “VO2max zone” is in our approach a subzone of the “Fast Death zone” and defined as the zone between SCP and P5, the power that can be sustained for 5'. Since the aerobic component can no longer increase from SCP on, the anaerobic reserve is now responsible for all additional energy supply, which therefore strongly limits the duration of exercise. The riders with a talent for short "explosive"climbs will rather get their training intensities out of this zone. Interval training sessions of short duration (< 2') are suitable.

CONTROL OF THE GOAL

In addition to the fact that interval training must be physiologically substantiated, it must also be possible to monitor its effect. After all, what is the load effect of, for example, 300 W if the exercise duration is 4' or 8'? What is the effect if the effort/rest ratio changes?

In the previous section, we described in detail the modules developed for this purpose, as well as the SuperCycle bicycle application. Thanks to these practical applications, the rider can monitor all important parameters both in "preview" and during the execution of the training. Our special attention goes to the “% VO2max widget” with which the rider can check whether he is delivering enough power to meet the necessary percentage load: at least 90% and preferably 95%. It should be noted that this widget does not indicate the current oxygen consumption, but the consumption that you would have if you continue to drive at this intensity for a sufficient period of time. The widget is therefore particularly useful for VO2max training in the Slow Death zone.
To also control the dynamics of the anaerobic system, use the anaerobic widget.

Power values selected from the VO2max zone – i.e. above SCP – load the aerobic system by definition by 100%. The % VO2max widget is therefore not useful in this zone, the anaerobic widget on the other hand is indispensable.

TIME TO REACH VO2max.

The second factor that can negatively affect T@ VO2max is oxygen kinetics. Depending on the individual, single efforts “to the limit of tolerance” can take more than 1:30” to reach VO2max. It is precisely for this reason and as already indicated in the paragraph above that we do not use the % VO2max widget for interval efforts of less than 2'. So be careful with interval training of short duration because they do not always reach the intended goal. This is clearly illustrated in Figure 1.

Fig. 1: the effect of different interval formats on VO2max achievement.

With an interval combination of only 15” effort and the same amount of rest, a maximum of 75% of the VO2max is reached, even after a lot of repetitions. The combination 30”/15” seems to be the best choice, but we note that 90% of the VO2max is only reached after about ten minutes!

Short intervals may be fun to do, but they don't seem to be as efficient. In addition - and this is often overlooked - the peak power must be taken into account when starting each new interval. Especially for road training, it is impossible to develop stable power within 15”, which means that the “average” power is also a poor benchmark (figure 2).

Fig. 2: the peak power at start-up and the questionable “average” power.

In our next blog we will discuss some “artificial tricks” to optimize the Time @ VO2max even at high intensities selected from the VO2max zone.