What is energy system development?
Traditionally, energy system training has been described as cardiovascular development – conditioning or endurance work, the focus of which is to build the capacity and efficiency of the body’s three main energy systems.
Here are the three main systems:
ATP-PC System (Alactic Anaerobic Energy System)
Short duration
The fuel source (ATP) is stored in small amounts in the working muscles and is used for short intense efforts lasting up to 10-15 seconds. This energy system doesn’t require the use of oxygen (anaerobic) and no lactate is produced (alactic).
Glycolytic System (Lactic Anaerobic Energy System)
Medium duration
Used in bouts of exercise ranging from 10-120 seconds. The energy substrate is muscle glycogen (glucose) and is broken down to produce ATP. At the onset of lactic acid (the anaerobic threshold) the body will need to cease such intensity and begin to slow down, therefore sufficient recovery is needed – or a switch to the third energy system as the dominant.
Aerobic System
Long duration
This system is constantly working to facilitate the above systems. Typically, training will be of moderate intensity and range anywhere from 3-90 minutes. Here, the body uses oxygen to fuel the breakdown of carbohydrates first, then to free fatty acids, and (if duration is long enough) eventually proteins.
In addition, ESD addresses the varying demands of training, allowing you to build the metabolic infrastructure required to train and perform at a multitude of intensities. It’s important to recognize that training energy systems are not black and white – all three systems work interdependently.