Regular aerobic training increases the size and number of mitochondria making the body more efficient at burning fat.
By improving the utilisation of fatty acids, the body is able to use less glycogen which is in much shorter supply.
This system allows the body to work in a steady state – the muscles work below maximal effort and keep this going for a long period of time.
Carbon dioxide and water are produced as by-products.
With continued high intensity exercise, there is a build-up of lactic acid in the working muscles.
If the rate of build-up is greater than the rate of removal then the muscles become fatigued and muscle contraction becomes impaired.There are 2 anaerobic systems: (also called the creatine phosphate or PC or phosphocreatine system) Muscular contractions need ATP (stored in muscles).Energy is immediately available but stores are very small and will only give enough energy for a few seconds.The CP system remakes ATP as quickly as the muscle stores use it up.ADP is turned back into ATP by using another chemical found in the muscle fibres called .ATP → ADP P energy (for movement) Carbohydrate/fat/protein → carbon dioxide water energy (to resynthesize ATP) ADP P energy → ATP The aerobic system yields a large amount of ATP and is used for all light continuous exercise and activities.This system produces energy at a much slower pace than anaerobic systems, and is much too slow for intensive or explosive activities.The aerobic process takes place in mitochondria – specialised structures within the muscle cell.They are like factories containing special enzymes which work on the oxygen.CP is also stored in the muscle fibres in small amounts, and although ATP can be reformed very quickly using this method, it cannot be kept up for very long, as the stores of CP are used up in 6-10 seconds.ATP → ADP P energy (for movement) CP → C P energy (to resynthesize ATP) ADP P energy → ATP The CP system is used for activities that need bursts of explosive speed or power such as sprinting, jumping and throwing.