When the supply runs low phosphocreatine (this happens in 6-8 seconds), the body goes back to the synthesis of atp by aerobic or anaerobic. Anaerobic metabolism – glycolysis anaerobic metabolism, or glycolysis, only synthesizes atp from carbohydrates. A byproduct of this metabolism is lactic acid. When glycolysis energy is released as a result of partial digestion of glucose, and it does not require oxygen. Anaerobic metabolism produces energy for short, intense exercise, lasting no more than a few minutes. A few minutes later the accumulated lactic acid reaches a certain limit, the so-called lactate threshold, and thus the person feels fatigue, pain and burning sensation in your muscles. Aerobic metabolism Aerobic metabolism produces energy for prolonged exercise. For the synthesis of atp from nutrient substances – proteins, fats and carbohydrates – used oxygen.
This path is slower than the anaerobic, it involved the circulatory system, which supplies the working muscles with oxygen at a time until an atp synthesis. Aerobic metabolism is mainly used during prolonged exercise of low intensity. During the training sessions of aerobic and anaerobic metabolism replace each other. At the beginning of exercise, atp is produced by scheme of anaerobic metabolism. As soon as the increase in breathing and heart rate, body receives more oxygen and the body moves to the aerobic type of metabolism. Under this scheme, the body continues to work as long as reach lactate threshold. When this limit is reached, the oxygen is no longer enters the body quickly enough for the synthesis of atp, so once again "turn on" anaerobic metabolism.
But this mechanism is designed for a short period time, so the athlete must reduce the intensity of exercise to prevent the formation of lactic acid. Restores the energy reserves of the body depending on the intensity and duration exercise, as an energy source are the carbohydrates or fats. Fats are a good source of energy for long workouts, but under extreme stresses, such as Sprint, they are not used organism. If exercise intensity is low (when the heart rate less than 50 percent of the maximum), the body can use stored fat as an energy source for many hours, until the organism will do enough oxygen needed for the process of fat metabolism. When the intensity of the load starts carbohydrate metabolism. It is more efficient than fat metabolism, but can produce a limited amount of energy. Carbohydrates are stored in the body as glycogen can provide energy for intense exercise for two hours. But after as the body runs out of their carbohydrate reserves, the athlete rapidly losing strength. Training can continue after the replenishment of carbohydrates in the body. That is why it is important to consume rapidly digestible carbohydrates during long training. If you do not replenish their carbohydrate stores, you will have to reduce the intensity of the workout, the body began to use fat as an energy source. With increasing intensity workout efficiency of carbohydrate metabolism is reduced, and the case enters the anaerobic metabolism. This is due to the fact that the body does not do enough oxygen for fat or carbohydrate metabolism. In fact, from the grams of carbohydrates you can get 20 times more energy in sufficient amounts of oxygen than in circumstances where the body is not received sufficient quantity, that just happens, and the anaerobic metabolism. If properly distributed loads, energy exchange mechanisms in the body work for us, allowing you to make your workouts and longer and more intense.