Endocrine Phsysiology-Computer Stimulation

The aerobic system is the oxidation of foodstuffs in the mitochondria to provide energy ( 2001). As shown in the table, glucose, fatty acids/fats, and amino acids from the foodstuffs – after some immediate processing – combine with oxygen to release tremendous amounts of energy that are used to convert AMP to ADP into ATP.

The phosphagen system is the one used by the muscle for power surges of a few seconds, and the aerobic system is required for prolonged athletic activity. In between is the glycogen-lactic acid system, which is especially important for giving extra power during intermediate races as the 200- to 800-meter runs ( 2000).

In anaerobic glycolysis, the process converts glycogen or glucose to lactic acid and regenerate energy stores of ATP. However, if lactic acid is allowed to build up, muscle contraction is compromised. This buildup of lactic acid is thought to be a component of muscle fatigue ( 1997).

The fuels or substrates used during exercise are primarily carbohydrates and fats ( 1997). Carbohydrates (CHO) are largely used by muscles during exercise and other sports activities. In addition to the large usage of CHO by the muscles, large amounts of fat in the form of fatty acids and acetoacetic acid are also used. To a much less extent proteins in the form of amino acids are also used. In fact, even under the best conditions, in those sports events that last longer than 4 to 5 hours, the glycogen stores of the muscle become almost totally depleted and are of little further use for energizing muscle contraction. Instead, the muscle now depends on energy from other sources, mainly from fats ( 2000).