090 THE OXYGEN SYSTEM

THE AEROBIC  SUPPLY OF ENERGY

A permanent form of energy, so in fact re synthesis of ATP, is provided by assistance systems that use combustion of nutrients. This involves the burning of carbohydrates and fats, with the aid of oxygen. These nutrients are with the food contained in the body and stored in depots to be used when it is needed. The stock of fats, viewed as an energy supplier, is virtually unlimited. The carbohydrates – sugars, starch and glucose – it is different. They are stored in the liver and in the muscles in the form of glycogen. The glycogen can vary greatly, but is usually sufficient for at least 60 to 90 minutes sub maximal exercise at a high level.

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ENERGY STOCKS IN THE BODY: The amount of ATP is exhausted after 2-3 seconds of a maximum effort. CP is consumed totally after 6-9 seconds maximum effort. The phosphate battery is totally exhausted after an explosive maximum effort of 12 seconds. The glycogen stores are consumed after 60 to 90 minutes sub maximal exercise. The amount of fat as an energy source is unlimited.

The breakdown of fats proceeds schematically as follows:

Fats + ADP + oxygen → carbon dioxide + water + ATP

The formed carbon dioxide is exhaled through the lungs.

The conversion of carbohydrates, also known as glycolysis, is more complicated. This occurs in two successive reactions.

Schematic:

1st phase: glucose + ADP →  lactic acid + ATP

2nd phase: lactic acid + oxygen + ADP → carbon dioxide + water + ATP

The first stage does not use oxygen; in contrast, the second does. During a light effort, lactic acid that is formed as an intermediate product, also known as lactate, is directly converted via the second phase, so that the final result is:

Glucose + oxygen + ADP → carbon dioxide + water + ATP

 If the oxygen system is not overloaded during exercise, there is plenty of oxygen available, so the accumulation of lactic acid does not take place. The fuels which are mainly used are the carbohydrates and the fats and the proteins in certain circumstances. The aerobic energy needs time to come on stream. At the start of an effort it takes two to three minutes prior to the transport of oxygen by the heart, lungs and circulatory system, is well under way. Therefore, a good warm-up for example, before a time trial is so important. After a good warm-up the transport of oxygen, at a next effort, started more quickly.

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At the beginning of the effort, even at low intensity, the energy supply is anaerobic. Formation of lactic acid or lactate (L) is the result. If after a few minutes, the aerobic system was under way, the lactic acid concentration decreases.

The stock of carbohydrates is limited, fat supply practically speaking unlimited. Both systems work simultaneously, but their share in the total energy supply process is different and also depends on the intensity of the effort and the level of training.

Fat burning occurs mainly during exercise of low intensity. The carbohydrate combustion becomes more important as an energy source if the intensity of the effort increases. After a period of training of the oxygen system, the supply of energy runs more economically. That means, the trained athlete longer burn fats and in this way he saves his supply of carbohydrates.

The proportion of fat oxidation and carbohydrate burning depends on the intensity of the effort. At intensity at the level of the VO2 max 90% of the energy is provided by the breakdown of glucose and 10% due to the degradation of fats. At the level of the FTP, so less intense, 74% of the energy is supplied by the breakdown of glucose and 26% by the fats.

The oxygen system is into old age to train outstanding. The aerobic capacity can be increased through training to 50%.

From the above it follows that people who want to lose weight, by moving more, a low intensity and a high volume are desired.

A rider with sufficient carbohydrate reserves is more likely to do well in the final of a race than its competitor whose carbohydrate stocks are exhausted.

The workers in the team who keep their leader out the wind consume early in the race, their carbohydrate reserves. The leader who sits in the wheel and is brought to the final in a seat will be mainly burns fat and saves his carbohydrates to the final.. Gerrie Knetemann former world champion: “you should be smart, eat first the plate of your teammates and your servant and your opponents to be the strongest in the final of the race.”