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Energy System Usage


The human body needs energy to function and to fuel physical activity. That energy comes from the food we consume: carbohydrates, protein, and fats. Carbohydrates are broken down into glucose and converted into energy (ATP) for immediate use, stored for later later use in the form of glycogen, or converted to body fat. Both protein and fat can be broken down and used to create energy (ATP), but in more complex metabolic pathway. The majority of energy (ATP) is metabolized from the food we eat, however the body does store a minimal amount.

Food is made up of carbohydrates, fats, and proteins and breaks down to its simplest form glucose, fatty acids and amino acids during digestion. Once broken down, they will either be used or stored. Before the food we eat can be utilized to produce work for exercise, it needs to be transformed into the primary energy source of the body, ATP. And that ATP is created from ADP and free phosphate molecules (ADP + Pi).

There are 3 primary energy systems. Each system is constantly being used, however each plays a different role depending on the availability of energy and the specific demands placed on them.

ATP-PC (adenosine triphosphate-phosphocreatine)



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