As discussed in the last blog, we are a bit like a clever hybrid car, and combine 3 different types of energy systems to make energy for movement, growth and all the other things that keep us alive and breathing. Understanding energy systems underpins the study of exercise and the effect it has on the human body. Whether it’s during a 26-mile marathon run or one explosive movement like a tennis serve, skeletal muscle is powered by one and only one compound… adenosine triphosphate (ATP) . However, the body stores only a small quantity of this ‘energy currency’ within the cells and it’s enough to power just a few seconds of all-out exercise . So the body must replace or resynthesize ATP on an ongoing basis. Understanding how it does this is the key to understanding energy systems. An ATP molecule consists of adenosine and three (tri) inorganic phosphate groups. When a molecule of ATP is combined with water (a process called hydrolysis), the last phosphate group splits away and releases energy. The molecule of adenosine triphosphate now becomes adenosine diphosphate or ADP .
The most powerful of these systems that re-synthesises this ATP is the creatine phosphate or CP system. It is also the one that gets exhausted the most rapidly.This is the system that would be used in a golf swing or a shot putt. This system does not need oxygen, fat or carbohydrate but uses chemical energy, and so it’s called anaerobic. We use this energy system for activity at 95-100% of our maximum exertion, and it lasts only for 10 to 15 seconds. Remember that we use all these systems together, always as a combination, but one system is dominant. A good example of this is blinking. While you are sitting at the computer at work you will be using the oxygen system (more on this later) but every time you blink you are using this powerful CP system.