VO2 max in running

Those who practice running often hear about the famous MAS, or Maximal Aerobic Speed. This value is unique to each individual, changes with physical condition, and knowing it allows you to evaluate yourself and then follow precise training plans.

By Guillaume Judas – Photos: New Balance / Neo / DR

Maximal Aerobic Speed (MAS) is the equivalent of Maximal Aerobic Power in cycling, which is the speed (on flat ground) at which your oxygen consumption is maximal. Above this very critical speed, the body is no longer able to supply the necessary oxygen for the breakdown of glycogen as an energy substrate. You therefore enter the anaerobic pathway, with or without lactic acid production, for a very limited period of time. However, MAS is a critical pace that you can only maintain for around five minutes. It is directly related to the famous VO2Max (Maximum Volume of Oxygen Consumption), the level of which is influenced by genetics, training, age, and lifestyle. Suffice it to say that we are not all equal in this area, at least for two out of four factors. Nevertheless, independently of VO2Max, MAS can be optimized with quality stride.

The benefit of MAS

MAS is one of the basic data in running, as it is used to determine running paces and time goals for reference distances. We know that a 10 km runner should be able to maintain the distance at a pace close to 90% of their MAS. For a half-marathon, it’s more like 85%, and 80% for a marathon. The notion of endurance also comes into play, because depending on the distance and race time, what matters is your ability to sustain a certain percentage of this MAS. Working on MAS is therefore essential for progress, by pushing maximum capacities upwards, but it is important not to neglect lower paces in order to be able to benefit from them whatever the distance.

MAS is one of the basic data in running, as it is used to determine running paces and time goals for reference distances.

MAS is associated with the notion of performance, and you may not care about it if you only run for pleasure. However, even without a time goal, working on MAS significantly improves your performance, whether it’s to increase distances or to gain ease and better sensations once you return to your usual paces. Since MAS is directly linked to the notion of VO2Max, specific training can also make it easier for you to climb hills and generally handle elevation changes better.

Measuring MAS

Since we’re talking about speed, or pace (in minutes per kilometer), the simplest way is to test yourself by running as fast as possible for four to six minutes, and measure the distance to then calculate the corresponding speed. Obviously, such a test should only be performed after a very good progressive warm-up of at least twenty minutes. To obtain a consistent and reference value, this test must be performed on a flat course, or better yet, on a track. Even if we talk about four to six minutes “all out”, there is still a notion of effort management. As we mentioned above, it is always possible to run faster than MAS, but by using the anaerobic pathway, which risks leaving you out of breath and with tired legs after a few hundred meters. The MAS test must therefore be performed at a very high pace, but as consistently as possible throughout the test. Beginners can settle for four minutes of effort, or even test themselves over a full 1000 meters. The six-minute test is reserved for experienced runners, but it offers a significant advantage in terms of calculation, as it is then sufficient to multiply the distance covered by 10 to know the MAS in km/h.

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MAS and heart rate

At the end of such a test, you will probably be at your maximum heart rate. But the same can happen during a 10 km race or in the latter part of a half-marathon, because during prolonged high-intensity effort, what is called cardiac drift occurs, due in part to external factors such as an increase in body temperature or dehydration. Heart rate is an indirect measure of effort intensity, and it is especially useful for all sub-maximal exercises, or for managing long rides. On the other hand, it is not very significant for short but high-intensity exercises like interval training, when intense effort is interspersed with recovery periods.

Improving MAS

Regardless of your physiological limits, you can improve your MAS by running at paces close to it, between 90 and 105%. But since this is a speed you cannot maintain for very long (beyond 4 to 6 minutes), exercises are performed by breaking up efforts, so that you can accumulate more time around the target pace during the same training session.

Exercises are performed by breaking up efforts, so that you can accumulate more time around the target pace during the same training session.

To improve MAS, you must first run in very short effort segments at a slightly higher pace (around 105%), with series such as 20 seconds of effort alternated with 20 seconds of jogging, or 30/30 second intervals. With two sets of 8 x (30/30) at 105% of MAS, for example, you accumulate a total of eight minutes of quality work, which would be impossible continuously. For longer intervals, such as one to two minutes, or 300 to 600 m, you work on sustaining your MAS, at a pace close to 90 to 95% of it. The number of sessions per week, the number of repetitions, and the recovery times between sets depend on your level and the preparation phase based on your goals. However, MAS training is advantageously placed to build a solid foundation for physical condition, well before working on specific paces.

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