Answer:
The energy systems are three: ATP-PC system, Anaerobic glycolysis system and Aerobic system.
ATP stands for Adenosine Triphosphate, when a molecule of ATP is broke down, the energy is released. It depends on simple and short chemical reaction, it makes a huge contribution to anaerobic exercises, which are intense.
During the anaerobic system we have the lactic acid production, which is activated when we do intense exercises. It has more complex chemical reactions than ATP, and provides energy when the muscle is under intense pressure or anaerobic exercises when oxygen is not present like aerobic activities.
At last, the aerobic system depends on the oxygen to provide energy to the body an fulfil this lower intense activities. An important fact is that this system provides more energy than the anaerobic system, that's why it's better to longer activities, it gives more endurance.
After knowing a little of each type of system, we see that all of them are important. So, the best way to optimize our whole energy system is to using these three in the best context possible. Doing activities that improve each of them, that way we will always feel energize.
