14 Sep 2007
After the allocated supply of stored ATP is exhausted, the body must find another fuel source in order for activity to continue. After the first 30 seconds the next available fuel source will come from the lactic acid system.
Technically, the lactic acid system, is known as anaerobic glycolysis. While glycolysis refers to the breakdown of sugar (carbohydrate), anaerobic glycolysis is the breakdown of (sugar) carbohydrates without oxygen.
In this system the breakdown of sugar supplies the necessary energy required to re synthesize ATP. However, when carbohydrate is only partially broken down, one of the end products is lactic acid. (Hence the name lactic acid system).
When a high level of lactic acid accumulates in the muscle and blood the result is temporary muscular fatigue and soreness.
You have probably experienced this. It often occurs after extended anaerobic exercise. Activities such as weight lifting, tennis, basketball, football, etc. draw energy from sugar in the blood and muscles (glucose) to rebuild and resynthesizes ATP.
The lactic acid system, like the ATP system, is extremely important because it provides a rapid supply of rebuilt ATP energy. Exercises that are performed at maximum rates between 1 and 3 minutes depend heavily upon the Lactic Acid System for ATP energy.