Where does the energy for muscular activity
During the life of the body, whether it’s metabolic processes, muscle activity, etc. going on the energy consumption. ATP (adenosine triphosphate) is degraded to ADP (adenosine diphosphate), releasing energy that is used in all life processes.
ATP ADP + energy
The ATP content in muscle minor. During intense muscle activity, the ATP consumed in the 2C. However, within the muscles, there are several support systems that continuously regenerate ADP to ATP.
There are three main systems of resynthesis of ATP: phosphate, lactate and oxygen.
KrF + ADP → ATP + creatine
— creatine (ECOP), which reserves in the muscles are limited to 6-8 with intensive work.
At maximum load the phosphate system is depleted within 10 s. during the First 2 with ATP is consumed, and then within 6-8 with — KRF.
The phosphate system is important for racing (on the dash), Polo, Western, i.e. for all explosive, short-term, rapid and vigorous types of physical activity.
The rate of resynthesis ECOP after the cessation of physical activity is also very high. Reserves of high-energy phosphates (ATP and ECOP) expended during exercise, is replenished within a few minutes after its completion. Already 30, the ATP and KRF restored 70%, but after 3-5 min recover completely.
The phosphate system is called anaerobic because the resynthesis of ATP oxygen is not involved, and alactate, not because lactic acid is formed.
Oxygen system provides the body, particularly muscle activity, energy through the chemical interaction of nutrients (mostly carbohydrates and fats) with oxygen. Nutrients enter the body with food and deposited in the vaults for future use as needed. Carbohydrates (sugar and starches) are deposited in the liver and muscles as glycogen. Glycogen stores can be highly variable, but in most cases it lasts at least 60-90 minutes of work. This system is involved in equestrian sports like horse racing, hurdle racing, eventing, etc. At the same time the fat reserves in the body is practically inexhaustible.
The contribution of fats and carbohydrates in the energy supply of the load depends on the intensity of the exercises and the training level of the horse. The higher the intensity, the greater the contribution of carbohydrates in energosbytovaya. But at the same intensity aerobic exercise trained horse will use more fat and less carbohydrates compared to untrained horse.
The ratio of fats and carbohydrates (glycogen) in humans and horses are different. Provision of energy is one of the main limiting factors in exercise endurance. The liver glycogen is the carbohydrate reserve of blood glucose, it is about 0.2% of the total fat in humans (Newsholme E. A. (1976) Clinics in Endocrinology and Metabolism, No. 5, 543-578). Consequently, the body fat play a major role in providing the energy needed to work the muscles. The person maintaining the concentration of glucose in the blood at the expense of glycogen probably about 20 minutes (ibid.). The horse another picture, when running endurance, there is a tendency to a slight decrease of glucose after running compared to the state before him (distance 120 km at an average speed — 15 km/h). (R. J. Rose Changes in certain metabolic parameters in horses associated with food deprivation and endurance ckercise. — (1982) Researeh in Veterinary Science, No. 2, 198-202). The energy of the horse is produced by glycolysis rather than by fat metabolism, which is consistent with findings of some researchers that found in the muscles of the horse is very rich reserves of glycogen. (Straub R. Hoppeler H, Beurteilung der Trainierbarkeit und …? Sweiz. Arch. Tierheilk. 124(№11), 1982, 529-548)
Performance oxygen system depends on the amount of oxygen that is able to absorb the body. The greater the consumption of oxygen during the execution of a long work, the higher aerobic capacity (blood properties, namely the concentration of red blood cells, their biochemical ability to bind and release oxygen, and, of course, the quality of the respiratory system, namely, lung capacity, strength of respiratory muscles, elasticity of the lungs).
Under the influence of training aerobic capacity can increase by 50%, the horse much more. (Affectionate A. A. Afanas’ev A. V. O. A. Balakshin Pern E. M. Training and testing of racehorses. — M. Kolos, 1982. — 222 p.)
Fat oxidation for energy is as follows:
Fat + oxygen + ADP → carbon dioxide + ATP + water
Obtained in the course of the oxidation reaction of the carbon dioxide is excreted from the body through the lungs.
Breakdown of carbohydrates (glycolysis) occurs in a more complex scheme, which involved two sequential reactions:
The first phase:
glucose + ADP → lactic acid + ATP
lactic acid + oxygen +ADP → carbon dioxide + ATP + water
The first phase takes place without participation of oxygen, the second — with the participation of oxygen. In mild physical activity is a byproduct of the breakdown of carbohydrates – lactic acid is used directly in the second phase, so the final equation looks like this:
Glucose + oxygen + ADP → carbon dioxide + ATP + water
While consumed enough oxygen for oxidation of fats and carbohydrates, lactic acid will not accumulate in the body.
As you increase the intensity of the exercise, there comes a time when muscle work cannot be sustained through the aerobic system due to the lack of oxygen. Since then, the supply of physical work involved the mechanism of lactate resynthesis of ATP, the byproduct of which is lactic acid. With lack of oxygen, lactic acid is formed in the first phase of aerobic reactions, not completely neutralized in the second phase, resulting in its accumulation in the working muscles, leading to acidosis, or acidification, muscles.
The reaction of lactate mechanism is simple, and looks like this:
Glucose + ADP → lactic acid + ATP
With increasing acidosis the horse is not capable of supporting the same load level. Most often acidosis occurs in cases where the horse is taking acceleration. A horse that is able to delay the moment of acidosis longest are more likely to win the race.
Lactate system also supplies energy during short-term increase in intensity during normal aerobic exercise — in spurts, gradients, attempt to separate from his pursuers. The lactate system is involved in powering the finish of the throw after prolonged training (e.g., at the finish of the marathon).
High levels of lactate indicate that in the energy supply of the load connected to the lactate system, the byproduct of which is lactic acid.
The maximum lactate concentration can reach values up to 20 times greater than those during rest time.
The damage to the walls of muscle cells under the influence of acidosis are caused by leakage of substances from the muscle cells into the blood.
At high levels of lactate decreases the utilization of fat. This means that in the case of the depletion of glycogen reserves of the energy supply of the body will be jeopardized, since the body will not be able to use the fat.
Table of the relative contribution of aerobic and anaerobic mechanisms of energy production when performing maximum intensity of a single work of varying lengths (for people).