Energy Systems
Energy is the capacity or ability to do work. Without energy, muscle contraction cannot occur, thus resulting in not having the ability to perform general day-to day tasks and participate in physical activity. Energy is produced by a molecule called Adenosine Triphosphate, otherwise known as ATP (Amezdroz, 2010).
What is ATP?
ATP is an energy rich molecule, found in all cells. Without ATP, the majority of the functions of the human body cannot be performed. ATP is made up of Adenosine and three Phosphate groups. It is synthesised in the mitochondria of our cells. When energy is required for muscular work, a chemical reaction takes place, in which the third phosphate group splits off, resulting in the release of chemical energy. This chemical energy then turns into mechanical energy, so work can be performed. To resynthesis ATP from Adenosine Di-Phosphate and Phosphate the Creatine Phosphate system is required.
The Three Energy Systems
There are two general energy systems present in the human body; the Anaerobic and Aerobic Systems. The Anaerobic Energy system does not resynthesise ATP in the presence of oxygen, unlike the Aerobic system. There are two systems that are used to anaerobically convert energy in the body, and one system that converts energy in the body aerobically (Amezdoz, 2010);
Anaerobic System: ATP-CP (Creatine Phosphate) and Lactic Acid Systems
Aerobic System: Aerobic System
Anaerobic System: ATP-CP (Creatine Phosphate) and Lactic Acid Systems
Aerobic System: Aerobic System
How the Energy Systems Work Together
The graph below demonstrates the interrelationship of the three energy systems. The three systems work in conjunction with each other to provide energy to the body. The Creatine Phosphate System provides energy for maximal effort activities, that last up to 10 seconds, until the Creatine Phosphate stores become depleted. At this the point the Creatine Phosphate System line in the graph below, intersects with the Lactic Acid System line, and the Lactic Acid System takes over. This system can maintain moderate to high intensity exercise, until it cannot provide enough ATP due to the lack of oxygen present. This is generally at the 2-3 minute mark. Then the line intersects with the Aerobic System line, and it takes over. The Aerobic System is needed to provide the body with energy in the presence of oxygen. After a period of time, a constant submaximal activity can be performed, at a lower intensity, for a prolonged period of time (Amezdroz, 2010). When describing an activity it is not which energy system is present, but which one dominates.