The CP system remakes ATP as quickly as the muscle stores use it up.
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.
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.
The ADP uses energy formed from the breakdown of carbohydrates (glycogen or glucose) to produce ATP. As lactic acid accumulates in the muscle, muscular contraction becomes more difficult.
ATP → ADP P energy (for movement) Carbohydrate → lactic acid energy (to resynthesize ATP) ADP P energy → ATP This energy system does not last long and will sustain energy production for intense activities that last up to 3 minutes.