Basic knowledge about physiological mechanisms of energy supply of muscular activity
This knowledge is necessary in order to better understand the essence and meaning of different training effects.
Any human activity associated with energy expenditure. The immediate source of this energy in the body is adenosine triphosphate (ATP). It was during her breakdown and there is a release necessary for energy. It is very important to know that the current stock of ATP in the muscles is
very small. In the conditions of powerful muscle contractions it can last only for a few seconds. From this it follows that consumed in the process, the ATP must be immediately replenished, otherwise the muscles will lose the opportunity to decline. Such reversal is called the resynthesis of ATP, and occurs due to the reactions of two kinds: (a) aerobic walking with the participation of oxygen and b) anaerobic, occurring in anoxic conditions.
Possible aerobic mechanism of energy supply can be traced by measuring the amount of oxygen consumption during operation. The maximum amount (volume) of oxygen that is able to consume people 1 minute. characterizes his aerobic capacity and is denoted by the index – IPC (maximum oxygen consumption). Under certain values of the intensity of the provision of oxygen occurs within this indicator, meaning the body gets it as much as he needs.
However, very often there are situations when oxygen demand exceeds IPC. Work in such conditions may continue, but it begins to accumulate an oxygen debt. There are already effective mechanisms of anaerobic energy supply.
Anaerobic capacity of the person characterised by the critical value of oxygen debt, at which he can no longer continue. The need to include anaerobic mechanisms can occur in the first seconds of work, for example, when running at 60, 100 meters maximum speed. Despite the brevity of this work, it also requires active regeneration of ATP. Moreover. its resynthesis occurs in the absence of oxygen, which “the transport system is” the body simply does not have time for such a short period of time to deliver to working muscles.
In these circumstances, the action takes the first mechanism of anaerobic energy supply – creativestate. . He got this name because of the special energy substance phosphocreatine (ECOP). Splitting, it transfers its phosphate groups adenosine acid (ADP), resulting from the collapse of ATP and, thus, is the resynthesis of the latter.
However, creatine phosphate is also quite a bit in working muscles. Practically it only lasts for 10-15 seconds. powerful work. This, in fact, lies the answer to the question, why can’t sprint pace to run, for example, 800 meters.
Power supply when running middle-distance (800, 1000, 1500 m) is at the expense of power sources operating in the anaerobic mode. But here comes into action for the second mechanism of anaerobic energy supply – glycolytic.. The body now produces the energy for work due to the breakdown of carbohydrates, which occurs again in the resynthesis of ATP.
In the process of this reaction (glycolysis) is used glucose contained in the blood and glycogen found in muscle and liver. It is important to emphasize that as a result of glycolysis in the blood occurs end rapid accumulation of acidic degradation products – lactic and pyruvic acids. Reaching a certain concentration, they negatively affect the efficiency of the muscles and body in General. For this reason, and also because of limited glycogen stores, this mechanism of energy supply also operates a relatively short time – within 2-5 minutes.
The main source of energy, providing work for tens of minutes and several hours is the aerobic mechanism of energy supply, that is, when the necessity of the organism for oxygen is fully satisfied. In this mode, the body extracts energy 20 times more than when glycolysis.
Aerobic and anaerobic capabilities together characterize the “functional ceiling” energy metabolism in an individual, i.e. its total energy capabilities. While aerobic capacity is determined by the totality of those properties of the organism. which provides the supply of oxygen to the tissues:
* the performance of the circulatory system (stroke and minute volume of the heart, heart rate, blood flow velocity, etc.);
* the performance of the respiratory system (vital capacity(VC), respiratory minute volume, maximum pulmonary ventilation, etc.);
* the blood (hemoglobin);
* coherence of the activities of all these systems.
Anaerobic capacity determined.
* reserves of energy substances in the tissues;
* the body’s resistance to hypoxia (lack of oxygen);
* buffer capabilities of the blood, i.e. its ability to neutralize decomposition products formed in the process of glycolysis.
All of these features in different people is highly individual. Their input parameters (the power and the capacity of each of the described mechanisms) each person due to natural inclinations (genetically).
However, the range of each of the levels of energy can be expanded through specifically targeted training. Its influence is directed, first of all, existing in every cell of the body a kind of energy substation – the mitochondria. It is in them and there is a continuous process of regeneration of ATP. With increasing training loads of requests to all ATP increase. To support them in cells increases the number of mitochondria and speeding up the rate of their renewal. This enhances the energy capacity of the body, fitness and health.
Thus, during intense muscular work different mechanisms of energy supply. creationfactory, glycolytic and respiratory, have a different take:
* creativestate reaction reaches its maximum already at 3 seconds of work and immediately starts to decline rapidly as supplies KRF in cells small;
* glycolysis, developing more slowly, reaches a maximum intensity at 2 minutes of work and energy enough only for a few tense minutes work;
* respiratory processes are fully deployed only by 3-5 minutes of work, which is very often associated with the onset of the so-called “second wind”.
Aerobic and anaerobic capacity. defined by the value of the IPC (maximum oxygen consumption) and MCD (maximum oxygen debt). are a leading determinant of endurance during intense muscular work. There is another important indicator, referred to as PANO – the threshold of anaerobic metabolism. He, too, all people are different and characterizes the power level of operation at which the switch from aerobic to anaerobic mechanism of energy supply, and Vice versa. In the process of targeted training indicators PANO also increase.