ATP is stored in small amounts in the muscle fibres and when one of its phosphate bonds is broken, , is formed together with energy and heat production (this is why people get hot when exercising).ATP → ADP energy for contraction Muscle stores of ATP are limited.
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.
It is used when there is a plentiful supply of oxygen for the muscles to use while working. This system starts to ‘kick-in’ after about 3 minutes and theoretically will go on for ever.
The ADP formed during energy production uses energy from glucose/glycogen (carbohydrates), fat or protein breakdown to reform ATP.
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.Although the aerobic energy system is far more efficient than the anaerobic systems, it is much slower to take effect.The energy needed for different activities varies considerably.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 .These three energy systems do not provide energy for physical activity – only ATP can do this – they provide energy to restore ADP into ATP.(anaerobic = without oxygen) These systems produce energy when muscles need to move quickly or forcefully, but do not need to keep going for very long.The energy system used is determined by the: Some activities use 1, 2 or even all 3 energy systems at different times during the activity, with the emphasis changing according to the intensity relative to fitness levels.When anaerobic energy systems are used, an oxygen deficit is produced – muscles need more oxygen than they can get at that time.It takes some time for oxygen to get into the blood and then to working muscles.The lactic acid system of energy production is used when oxygen is not available and when stores of creatine phosphate run out (after approximately 10 seconds).