Energy systems


Energy systems refer to the specific mechanisms in which energy is produced and used by your body. All three energy systems are engaged during all forms of physical activity. However, the extent to which each one is involved varies depending on the duration and intensity of the activity. To train effectively, an athlete engages specific energy systems relevant to the activity of choice.

Anaerobic Alactic

ATP-PC (Adenosine TriPhosphate - PhosphoCreatine) or Phosphagen system.
This system does not use oxygen, is stored in muscle cells, the amount is small, does not produce lactic acid.
Using this system is typical for very short duration (10-30 seconds) on a high intensity.

Anaerobic Lactic

Glycolyptic system.
This system does not use oxygen, the capacity can work longer than ATP-PC, produces lactic acid, uses carbohydrate.
Using this system is typical for durations of 30-180 seconds on a high intensity.


Oxidative system.
This system requires oxygen, the amount is large, does not produce lactic acid, uses carbohydrate; protein; fat.
Using this system is typical for long duration (3 minutes - several hours) on a low or moderate intensity.


Adenosine TriPhosphate is the usable form of energy for muscular activity. At any given time, each (or a combination) of the 3 energy systems transform their energy sources into ATP.
ATP is stored into the muscle cells and can be used on the next contraction.

Our philosophy

The big question is, which energy system should you train. The answer in our philosophy is simple: All of them!

Should you train them equally in time: Well: that depends on your goals, your ambition, periodization.

Why should you train all of them: When you start your workout, the oxidative system is not fully active, it takes about 3 minutes to activacte. So you do your WarmUp on a low intensity and you use your anaerobic system. Since it is low intensity, you only produce a little lactic acid which you won't notice.
So when you start your WarmUp you will use all 3 systems ATP-PC for your first 30 seconds, then anaerobic until 3 minutes and after 3 minutes your oxidative system take over.

If you do a race, you have done a proper WarmUp, but when the startsignal goes, you (hopefully) start on your race-pace. The first seconds ATP-PC, Anaerobic (perhaps even with lactic acid) for 2-3 minutes (sometimes even longer) and only then your oxidative system kicks in. You are racing on the limit, sometimes even a little above your lactate threshold. As soon as you go above, you will start producing lactic acid. Don't worry, the amount is low, perhaps you don't even feel it. Perhaps there is a small gap to the group in front of you and you decide to do a little sprint. At that direct moment ATP-PC is taking over.

So you see, during a race all systems are required, sometimes more than you think and therefore you need to train all of them. Besides the purpose of using them, your body never only uses one of them at any given time. Even on a easy long run, there is never 100% Aerobic only.

Training effects

Anaerobic (both ATP-PC and Glycolyptic)
- The ability to maintain a higher intensity for a longer period.
- Reducing the amount of lactic acid building up.
- Prolonging the time when lactic acid is building up.

- Enhancing the ability to use oxygen.
- Prolonging a higher intensity before anaerobic starts.

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