There are three sections in the aerobic system:
- Glycolysis
- Krebs Cycle
- Electron Transport Chain (ETC)
Glycolysis is an ATP generating metabolic process that occurs in nearly all living cells in which glucose is converted in a series of steps to pyruvic acid.
Krebs cycle is a series of enzymatic reactions in aerobic organisms involving oxidative metabolism of acetyl units and producing high-energy phosphate compounds, which serve as the main source of cellular energy.
Electron transport chain is a group of compounds that pass electron from one to another via redox reactions coupled with the transfer of proton across a membrane to create a proton gradient that drives ATP synthesis.
This anaerobic energy system relies on the release of energy from the food stores in the body. This system provides 45-70 seconds of high power. The system provides energy when there isn’t any oxygen. This is used in the first few minutes of exercise, before there is enough oxygen available at the muscles for aerobic metabolism. This system is also used for fast, powerful bursts of energy, for which the aerobic system is lacking. An example of their use in sport is weight lifting.
There are two systems within anaerobic metabolism:
- ATP-PC System
- Lactic Acid System
The ATP-PC system is a high energy molecule that can be broken down quickly to form ADP. Phosphocreatine is another high energy molecule which is found in the muscle fibres. The phosphate system is useful for short single or continuously bursts of energy around 10 seconds. Javelin is a good example of an event this system would be used for and long jump is also another example. There is only 120g of creatine in the human body, so the human body will have to breakdown PC so that it can produce energy to resynthesise ATP. This is temporary and can only last approximately 10 seconds. Therefore the ATP-PC system is used mainly for short bursts.
The lactic acid system is also known as anaerobic glycolysis because the process is the same as aerobic glycolysis only this is used without oxygen. To prevent an increase in acidity the pyruvic acid lets the hydrogen form lactic acid. If oxygen was present the hydrogen would be transported to the mitochondria for use in the kerbs cycle. Lactic acid provides energy for a long duration, between 10-90 seconds this would be required for an 800m run or a 100m swim.
