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Factors influencing anaerobic performance. Energy supply for muscle activity. Aerobic and anaerobic factors of sports performance. Factors Determining Aerobic Performance

Rubric "Biochemistry". Aerobic and anaerobic factors of sports performance. Bioenergetic criteria for physical performance. Biochemical indicators of the level of development of aerobic and anaerobic components of sports performance. Correlation in the levels of development of aerobic and anaerobic components of sports performance in representatives of various sports. Features of biochemical changes in the body under critical conditions of muscle activity.

Among the leading biochemical factors that determine sports performance, the most important are the bioenergetic (aerobic and anaerobic) capabilities of the body. Depending on the intensity and nature of the support, it is proposed to divide the work into several categories:

anaerobic (alactate) load power zone;
anaerobic (glycolytic) zone;
zone of mixed anaerobic-aerobic supply (anaerobic processes predominate);
zone of mixed aerobic-anaerobic supply (aerobic processes predominate);
aerobic energy supply zone.

Anaerobic work of maximum power (10-20 sec.) is performed mainly on intracellular reserves of phosphagen (creatine phosphate + ATP). The oxygen debt is small, has an alactic nature and must cover the resynthesis of spent macroergs. There is no significant accumulation of lactate, although glycolysis may be involved in providing such short-term loads and the lactate content in working muscles increases.

Operation of submaximal powers depending on the pace and duration, it lies in the zones of anaerobic (glycolytic) and anaerobic-aerobic energy supply. The leading contribution is from anaerobic glycolysis, which leads to the accumulation of high intracellular lactate concentrations, acidification of the environment, development of NAD deficiency and autoinhibition of the process. Lactate has a good, but finite, rate of penetration through membranes and the balance between its content in muscles and plasma is established only after 5-10 minutes. from the start of work.

When working high power prevails aerobic pathway of energy supply (75-98%). Work of moderate power is characterized by almost complete aerobic energy supply and the possibility of long-term performance from 1 hour. up to many hours depending on the specific power. There are a significant number of indicators used to identify the level of development, aerobic and anaerobic mechanisms of energy conversion.

Some of them provide an integral assessment of these mechanisms, others allow us to characterize their various aspects (speed of deployment, power, capacity, efficiency) or the state of any individual link or stage. The most informative are the indicators recorded when performing testing loads that cause close to maximum activation of the corresponding energy conversion processes. It should be taken into account that anaerobic processes are highly specific and are included to the greatest extent in the energy supply only for the type of activity in which the athlete has undergone special training. This means that to assess the possibilities of using anaerobic processes to provide energy for work, bicycle ergometer tests are most suitable for cyclists, running for runners, etc.

Of great importance for identifying the possibilities of using various energy supply processes are the power, duration and nature of the testing exercise performed. For example, to assess the level of development of the alactic anaerobic mechanism, the most suitable are short-term (20-30 seconds) exercises performed with maximum intensity. The greatest changes associated with the participation of the glycolytic anaerobic mechanism of energy supply to work are detected when performing exercises lasting 1-3 minutes. with maximum intensity for this duration. An example would be work consisting of 2-4 repeated exercises, lasting about 1 minute, performed at equal or decreasing rest intervals. Each repetition exercise should be performed with the highest possible intensity. The state of aerobic and anaerobic processes of energy supply to muscle work can be characterized using a test with a stepwise increase in load until “failure”.
Indicators characterizing the level of anaerobic systems are the values of alactic and lactate oxygen debt, the nature of which was discussed earlier. Informative indicators of the depth of glycolytic anaerobic shifts are the maximum concentration of lactic acid in the blood, indicators of the active blood reaction (pH) and the shift of buffer bases (BE).

To assess the level of development of aerobic mechanisms of energy production, the determination of maximum oxygen consumption (MOC) is used - the highest oxygen consumption per unit of time that can be achieved under conditions of intense muscular work.
MIC characterizes the maximum power of the aerobic process and is integral (generalized) in nature, since the ability to produce energy in aerobic processes is determined by the combined activity of many organs and systems of the body responsible for the utilization, transport and use of oxygen. In sports where the main source of energy is the aerobic process, along with power, its capacity is of great importance. The holding time of maximum oxygen consumption is used as an indicator of capacity. To do this, together with the MPC value, the value of “critical power” is determined - the lowest power of the exercise at which the MPC is achieved. For these purposes, a test with a stepwise increase in load is most convenient. Then (usually the next day) athletes are asked to perform work at the critical power level. The time during which the “critical power” can be maintained is recorded and oxygen consumption changes. The operating time at “critical power” and the MIC retention time correlate well with each other and are informative regarding the capacity of the aerobic pathway for ATP resynthesis.

As you know, the initial stages of any fairly intense muscular work are provided with energy due to anaerobic processes. The main reason for this is the inertia of aerobic energy supply systems. After the aerobic process has developed to a level corresponding to the power of the exercise being performed, two situations may arise:

aerobic processes fully cope with the energy supply of the body;
Along with the aerobic process, anaerobic glycolysis is involved in energy supply.

Research has shown that in exercises whose power has not yet reached “critical” and, therefore, aerobic processes have not developed to the maximum level, anaerobic glycolysis can participate in the energy supply of work throughout its entire duration. The lowest power, starting from which glycolysis takes part in energy production throughout the entire work, along with aerobic processes, is called the “threshold of anaerobic metabolism” (PANO). The power of ANNO is usually expressed in relative units - the level of oxygen consumption (as a percentage of MIC) achieved during operation. Improved fitness for aerobic exercise is accompanied by an increase in PANO. The value of PANO depends primarily on the characteristics of aerobic mechanisms of energy production, in particular, on their efficiency. Since the efficiency of the aerobic process can undergo changes, for example, due to changes in the coupling of oxidation with phosphorylation, it is of interest to assess this aspect of the functional readiness of the body. The most important are the individual changes in this indicator at different stages of the training cycle. The effectiveness of the aerobic process can also be assessed in a test with a stepwise increase in load when determining the level of oxygen consumption at each step.
So, the participation of anaerobic and aerobic processes in the energy supply of muscle activity is determined, on the one hand, by the power and other features of the exercise being performed, and on the other hand, by the kinetic characteristics (maximum power, maximum power retention time, maximum capacity and efficiency) of energy generation processes.
The considered kinetic characteristics depend on the joint action of many tissues and organs and change differently under the influence of training exercises. This feature of the response of bioenergetic processes to training loads must be taken into account when drawing up training programs.

FUNDAMENTALS OF ANAEROBIC PERFORMANCE ANALYSIS When assessing the operating performance of various energy generation systems, it is important to understand the difference between system capacity and power. Energy capacity is the total amount of energy that is used to perform work and is produced in a given energy system. The energy power of a system is the maximum amount of ATP energy that is generated under load per unit time by a given energy system.

METABOLIC PROCESSES OF ENERGY FORMATION AND THEIR INTEGRATION □ Creatine phosphokinase (alactate) - an instantaneous mechanism for replenishing ATP (ATP-Cr. F system); regeneration of ATP from the ATP-Cr system. F through the creatine kinase and adenylate kinase pathways does not lead to the formation of lactate and is called alactic. □Glycolytic, lactate (glycogen to lactate conversion system) represents the phosphorylation of adenosine diphosphate (ADP) through the glycogenolysis and glycolysis pathways, leads to the production of lactate and is called lactate. The generation of ATP energy in these processes occurs without the use of oxygen and is therefore defined as anaerobic energy production.

High-intensity anaerobic work can cause a 1000-fold increase in the rate of glycolysis compared to the resting state. ATP replenishment during maximal sustained exercise is never achieved solely by one energy production system, but rather is the result of a coordinated metabolic reaction in which all energy systems contribute differently to power output.

PRACTICAL APPROACHES It is more feasible to measure peak operating performance over periods ranging from a few seconds to almost 90 seconds. With such a duration of work, ATP resynthesis depends mainly on the alactic and lactate anaerobic pathways. Simple estimates of anaerobic energy expenditure can be obtained from test results, supplemented if possible by biochemical or physiological

1. Muscle ATP reserves are assumed to support only a few contractions and are better assessed by muscle strength and maximum instantaneous power measurements. 2. It is assumed that maximal exercise of several minutes or longer is primarily aerobic and requires information about aerobic metabolism. If it is necessary to collect data on the anaerobic components of the special performance of athletes performing in sports in which the duration of maximum effort is about 2 minutes or a little more, it is necessary to take into account the interaction

SHORT-TERM ANAEROBIC WORK CAPACITY This component is defined as the total work output during a maximum power exercise duration of up to 10 s. It can be considered as a measure of alactic anaerobic performance, which is provided mainly by muscle ATP concentration, the ATP-Cr system. F and slightly anaerobic glycolysis. Highest working productivity per second in process

INTERMEDIATE ANAEROBIC WORK PERFORMANCE This component is defined as the total work output during a maximum exercise period of up to 30 s. Under such conditions, working performance is anaerobic with a major lactate (about 70%), significant alactic (about 15%) and aerobic (about 15%) components. The work power during the last 5 s of the test can be considered an indirect assessment of lactate anaerobic power.

CONTINUOUS ANAEROBIC WORK PERFORMANCE Defined as the total work output during a maximum workload of up to 90 s. Characterizes the limit of the duration of work, which can be used to assess the anaerobic capacity of the energy supply system of athletes. The advantages of these tests are that they allow the overall operating performance of anaerobic systems to be assessed at maximum demands on them and to quantify the decrease in operating performance from one part of the test to the next (for example, the first 30 s versus the last 30

AGE, GENDER AND MUSCLE MASS Anaerobic performance increases with age during growth in boys and girls. The maximum values of this type of performance are achieved at the age of 20 to 29 years, and then its gradual decrease begins. The decline with age is the same in men and women. This decline appears to be almost linear with age, amounting to 6% per decade. Men perform better than women on 10-, 30-, and 90-second maximal tests, and the work output per kilogram of body weight in women is approximately 65% of the work output per kilogram of body weight in men. Similar

Maximum performance is associated with: anaerobic body size especially lean mass muscle mass. Some age- and sex-specific differences in maximal anaerobic performance are more related to changes in muscle mass than to other factors.

STRUCTURAL AND FUNCTIONAL FACTORS AFFECTING ANAEROBIC PERFORMANCE. Muscle Structure and Fiber Composition Muscle structure plays a significant role in the level of power and amount of work it can generate. The degree of polymerization of actin and myosin filaments, their arrangement, sarcomere length, muscle fiber length, cross-sectional area of the muscle and total muscle mass are structural elements that contribute to muscle performance under anaerobic conditions, especially for absolute work performance. The relationship between muscle fiber composition and anaerobic performance is not simple. Athletes who specialize in sports that are anaerobic in nature or sports that require high anaerobic power and capacity exhibit a higher proportion of fast-twitch fibers (FTFs). The more BS fibers or the larger the area they occupy, the higher the ability to develop 1

2. SUBSTRATE AVAILABILITY The energy output for maximal exercise of very short duration is explained mainly by the breakdown of endogenous energy-rich phosphagens, but it appears (at least in humans) that the generation of maximal exercise even for very short periods of time is provided by the simultaneous breakdown of CP and glycogen. Depletion of reserves of Kr. F limit anaerobic performance under loads of maximum power and very short duration. But the main role of Kr. Ph in muscle is the role of a buffer between the concentrations of ATP and ADP.

3. ACCUMULATION OF REACTION PRODUCTS Anaerobic glycolysis unfolds with a very short delay after the onset of muscle contraction and is accompanied by the accumulation of lactate and, accordingly, an increase in the concentration of hydrogen ions (H+) in body fluids. Muscle lactate concentrations increase significantly after short-term exercise and can reach values of about 30 mmol kg-1 wet weight during exhaustion. Muscle buffer systems create a partial buffer for hydrogen ions. For example, muscle bicarbonate concentration decreases from 100 mmol L-1 liquid media

However, the muscle cannot buffer the hydrogen ions produced for long, and p. The muscle H decreases from 7.0 before the load to 6.3 after the maximum load, causing exhaustion. Decrease in river Sarcoplasmic H disrupts the interaction of Ca 2+ with troponin, which is necessary for the development of contraction and is explained by the competition of hydrogen ions (H+) for calcium-binding sites. Thus, the frequency of formation of actomyosin cross-bridges decreases with decreasing p. H and also the rate of synthesis and breakdown of energy is reduced (according to the feedback principle and due to disruption of the activity of catalysts and enzymes) The ability to resist acidosis increases

EFFICIENCY OF METABOLIC PATHWAYS Determined by the speed of deployment of the energy process. The rate of the creatine kinase reaction is determined by the activity of creatine kinase. The activity of which increases with a decrease in ATP in the muscle and accumulation of ADP. The intensity of glycolysis can be stimulated or delayed by various signals (hormones, ions and metabolites). The regulation of glycolysis is largely determined by the catalytic and regulatory properties of two enzymes: phosphofructokinase (PFK) and phosphorylase. As mentioned above, high-intensity exercise leads to an excessive increase in H+ and a rapid decrease in p. N muscles. The concentration of ammonia, which is a derivative of the deamination of adenosine 5"-monophosphate (AMP), in skeletal muscle increases during maximal exercise. This increase is even more pronounced in subjects with a high percentage of BS fibers. However, ammonia is recognized as an activator of PPA and can create buffer for some changes in intracellular pH. In vitro studies have shown that phosphorylase and PPK are almost completely inhibited when pH levels approach 6.3. Under such conditions, the rate of ATP resynthesis should be greatly reduced, thereby impairing the ability to continue performing. mechanical work due to the anaerobic pathway

Depends on the quality and quantity of muscle fibers: BS fibers are rich in ATP, CK and glycolytic enzymes compared to slow-twitch fibers. From this summary, it is clear that training maximizes anaerobic performance because most of the limiting factors adapt in their interaction in response to high-intensity training.

CHARACTERISTICS OF MUSCLES NECESSARY TO ACHIEVE A HIGH LEVEL OF ANAEROBIC PERFORMANCE AND THE RESULTS OF THE IMPACT OF HIGH-INTENSITY TRAINING ON THE INDICATORS THAT DETERMINE IT Characteristics of muscles Factors of anaerobic performance Value of ATP CP Glycogen Bu Ferment capacity Maximum lactate p. N in case of exhaustion Proportion of BS fibers Recruitment of BS fibers CK activity Phosphorylase activity FFK activity Yes Probably no Probably yes Probably no Yes Yes Yes Probably yes Yes Effect of training = or = or ↓ = = or

OXYGEN DELIVERY SYSTEM All other factors being equal, oxygen delivery and utilization systems probably make a very significant contribution to peak operating performance during load durations of 90 seconds or longer. Obviously, the longer the load, the higher the importance of the oxidative system. Under conditions of shorter duration maximum loads, the oxygen delivery system will not function at its maximum level, and oxidative processes in the final part of the work

During work with a load of maximum intensity lasting from 60 to 90 s, the oxygen deficiency associated with the beginning of work will be overcome and the oxidation of substrates in mitochondria at the end of work will lead to an increase in the share of aerobic processes in the energy supply of work. In this case, individuals who are able to quickly mobilize oxygen delivery and utilization systems and have a correspondingly high aerobic power will have an advantage in conditions of intermediate duration and

INHERITANCE It is now established that an individual's genotype largely determines the prerequisites for high aerobic power and endurance capacity, as well as a high or low level of response to training. We know much less about the heredity of anaerobic performance. Short-term anaerobic work performance (based on 10-second maximal work performance on a bicycle ergometer) had a significant genetic influence of approximately 70% when data were expressed per kilogram of lean mass. Recently, several studies of sprinting involving twins and their families, conducted in Japan and Eastern Europe, were analyzed. Heritability estimates for sprint performance ranged from 0.5 to 0.8. These data suggest that an individual's genotype has a significant effect on short-term anaerobic work performance. There is no reliable evidence yet regarding the role of heredity in long-term anaerobic work performance. On the other hand, we have recently obtained evidence of genetic influences on the distribution of fiber types and

TRAINING Training increases power and capacity during short-term, intermediate and long-term anaerobic work. Variations in training response (trainability) to a specific anaerobic training regimen have been studied extensively. The response to short-term anaerobic performance training was not significantly dependent on the genotype of individuals, whereas the response to long-term anaerobic performance training was largely determined by genetic factors. Trainability for overall 90-second work performance was characterized by genetic influence accounting for approximately 70% of the variation in response to training. This data is of great importance for coaches. Based on test results, it is easier to find talented people for short-term anaerobic work than for long-term anaerobic work. WITH

From an energy point of view, all speed-strength exercises are anaerobic. Their maximum duration is less than 1-2 minutes. For the energy characteristics of these exercises, two main indicators are used: maximum anaerobic power and maximum anaerobic capacity (capacity). Maximum anaerobic power. Maximum work power for a given person can only be maintained for a few seconds. Work of such power is performed almost exclusively due to the energy of anaerobic breakdown of muscle phosphagens - ATP and KrP. Therefore, the reserves of these substances and especially the rate of their energy utilization determine the maximum anaerobic power. Short sprints and jumping are exercises whose results depend on maximum anaerobic power,

The Margarine test is often used to assess maximum anaerobic power. It works as follows. The subject stands at a distance of 6 m in front of the stairs and runs up it as quickly as possible. On the 3rd step he steps on the stopwatch switch, and on the 9th step on the switch. Thus, the time it takes to travel the distance between these steps is recorded. To determine power, it is necessary to know the work performed - the product of the mass (weight) of the subject’s body (kg) by the height (distance) between the 3rd and 9th steps (m) - and the time to overcome this distance (s). For example, if the height of one step is 0.15 m, then the total height (distance) will be 6 * 0.15 m = 0.9 m. If the subject weighs 70 kg and the time to cover the distance is 0.5 s. the power will be (70 kg*0.9 m)/0.5s = 126 kgm/a.

In table Table 1 shows “normative” indicators of maximum anaerobic power for women and men.

Table 1 Classification of indicators of maximum anaerobic power (kgm/s, 1 kgm/s = 9.8 W)

Classification	Age, years



mediocre


excellent


mediocre


excellent

Maximum anaerobic capacity. The most widely used value for assessing the maximum anaerobic capacity is the maximum oxygen debt - the largest oxygen debt, which is detected after work of the maximum duration (from 1 to 3 minutes). This is explained by the fact that the largest part of the excess amount of oxygen consumed after work is used to restore the reserves of ACP, CrP and glycogen, which were consumed in anaerobic processes during work. Factors such as high levels of catecholamines in the blood, elevated body temperature, and increased O 2 consumption by the rapidly contracting heart and respiratory muscles may also cause an increased rate of O 2 consumption during recovery from heavy work. Therefore, there is only a very moderate relationship between the value of the maximum debt and the maximum anaerobic capacity.

On average, the maximum oxygen debt in athletes is higher than in non-athletes and is 10.5 liters (140 ml/kg body weight) for men, and 5.9 liters (95 ml/kg body weight) for women. For non-athletes, they are equal (respectively) to 5 l (68 ml/kg body weight) and 3.1 l (50 ml/kg body weight). Among outstanding representatives of speed-strength sports (400 and 800 m runners), the maximum oxygen debt can reach 20 liters (N. I. Volkov). The amount of oxygen debt is very variable and cannot be used to accurately predict the outcome.

By the size of the alactic (fast) fraction of the oxygen debt, one can judge that part of the anaerobic (phosphagen) capacity that provides very short-term speed-strength exercises (sprints).

A simple determination of the alactic oxygen debt capacity consists of calculating the oxygen debt value for the first 2 minutes of the recovery period. From this value we can isolate the “phosphagen fraction” of the alactacid debt by subtracting from the alactacid-oxygen debt the amount of oxygen used to restore the reserves of oxygen associated with myoglobin and located in tissue fluids: the capacity of the “phosphagen”

(ATP + CP) oxygen debt (cal/kg body weight) = [ (O 2 -debt 2min - 550) * 0.6 * 5 ] / body weight (kg)

The first term of this equation is the oxygen debt (ml), measured during the first 2 minutes of recovery after work of a maximum duration of 2-3 minutes; 550 is the approximate amount of oxygen debt in 2 minutes, which is used to restore the oxygen reserves of myoglobin and tissue fluids; r 0.6 is the efficiency of paying for the alactic oxygen debt; 5 - caloric equivalent of 1 ml O 2.

The typical maximum value of the “phosphagen fraction” of oxygen debt is about 100 cal/kg of body weight, or 1.5-2 l O2. As a result of speed-strength training, it can increase by 1.5-2 times.

The largest (slow) fraction of oxygen debt after work of a maximum duration of several tens of seconds is associated with anaerobic glycolysis, i.e. with the formation of lactic acid during speed-strength exercise, and therefore is designated as lactic acid oxygen debt. This part of the oxygen debt is used to eliminate lactic acid from the body by oxidizing it to CO2 and H2O and resynthesising it to glycogen.

To determine the maximum capacity of anaerobic glycolysis, you can use calculations of the formation of lactic acid during muscle work. A simple equation to estimate the energy produced by anaerobic glycolysis is: anaerobic glycolysis energy (cal/kg body weight) = blood lactic acid (g/l) * 0.76 * 222, where lactic acid is the difference between its highest concentration at 4-5 minutes after work (peak lactic acid content in the blood) and concentration under resting conditions; the value of 0.76 is the constant used to correct the level of lactic acid in the blood to the level of its content in all fluids; 222 - caloric equivalent of 1 g of lactic acid production.

The maximum capacity of the lactic acid component of anaerobic energy in young untrained men is about 200 cal/kg body weight, which corresponds to a maximum concentration of lactic acid in the blood of about 120 mg% (13 mmol/l). In outstanding representatives of speed-strength sports, the maximum concentration of lactic acid in the blood can reach 250-300 mg%, which corresponds to a maximum lactic acid (glycolytic) capacity of 400-500 cal/kg body weight.

Such a high lactic acid capacity is due to a number of reasons. First of all, athletes are able to develop higher work power and maintain it for longer than untrained people. This, in particular, is ensured by the inclusion of large muscle mass (recruitment), including fast muscle fibers, which are characterized by high glycolytic ability. The increased content of such fibers in the muscles of highly qualified athletes - representatives of speed-strength sports - is one of the factors providing high glycolytic power and capacity. In addition, during training sessions, especially with the use of repeated interval exercises of anaerobic power, mechanisms appear to develop that allow athletes to “tolerate” (“tolerate”) higher concentrations of lactic acid (and correspondingly lower pH values) in blood and other body fluids, maintaining high athletic performance. This is especially true for middle distance runners.

Strength and speed-strength training cause certain biochemical changes in the muscles being trained. Although the content of ATP and KrP in them is slightly higher than in untrained ones (by 20-30%), it does not have much energy value. A more significant increase in the activity of enzymes that determine the rate of turnover (cleavage and resynthesis) of phosphagens (ATP, ADP, AMP, KrF), in particular myokinase and creatine phosphokinase (Yakovlev N.N.).

Maximum oxygen consumption. A person’s aerobic capabilities are determined, first of all, by his maximum rate of oxygen consumption. The higher the VO2 max, the greater the absolute power of maximum aerobic exercise. In addition, the higher the MOC, the relatively easier and therefore longer the aerobic work.

For example, athletes A and B must run at the same speed, which requires both of them to consume the same oxygen - 4 l/min. Athlete A has an MPC. is equal to 5 l/min and therefore the remote consumption of O 2 is 80% of its MIC. For athlete B, the MOC is 4.4 l/min, therefore, the remote consumption of O 2 reaches 90% of his MOC. Accordingly, for athlete A, the relative physiological load during such running is lower (the work is “easier”), and therefore he can maintain a given running speed for a longer time than athlete B.

Thus, the higher the athlete’s MPC, the higher the speed he can maintain over a distance, the higher (all other things being equal) his athletic result in exercises requiring endurance. The higher the MPC, the greater the aerobic performance (endurance), i.e. the greater the amount of aerobic work a person can perform. Moreover, this dependence of endurance on MOC is manifested (within certain limits) the greater, the lower the relative power of aerobic exercise.

This makes it clear why, in sports that require endurance, the IPC of athletes is higher than that of representatives of other sports, and even more so than that of untrained people of the same age. If in untrained men 20-30 years old the MOC is on average 3-3.5 l/min (or 45-50 ml/kg * min), then in highly qualified runners-stayers and skiers it reaches 5-6 l/min (or more than 80 ml/kg * min). In untrained women, MOC is on average 2-2.5 l/min (or 35-40 ml/kg * min), and in skiers it is about 4 l/min (or more than 70 ml/kg * min).

Absolute MIC indicators (l O 2 /min) are directly related to body size (weight). Therefore, rowers, swimmers, cyclists, and speed skaters have the highest absolute MOC indicators. In these sports, absolute MPC indicators are of greatest importance for the physiological assessment of this quality.

Relative indicators of MOC (ml O 2 /kg * min) in highly qualified athletes are inversely related to body weight. When running and walking, significant work is performed on the vertical movement of body weight and, therefore, other things being equal (the same speed of movement), the greater the weight of the athlete, the greater the work he does (O2 consumption). Therefore, long-distance runners tend to have a relatively low body weight (primarily due to a minimal amount of adipose tissue and a relatively small skeletal weight). If in untrained men 18-25 years old adipose tissue makes up 15-17% of body weight, then in outstanding stayers it is only 6-7%. The highest relative MOC indicators are found in long-distance runners and skiers, the lowest in rowers. In sports such as track and field running, race walking, cross-country skiing, an athlete’s maximum aerobic capacity is more accurately assessed by relative VO2 max.

The level of MIC depends on the maximum capabilities of two functional systems: 1) the oxygen transport system, which absorbs oxygen from the surrounding air and transports it to working muscles and other active organs and tissues of the body; 2) oxygen utilization systems, i.e., the muscular system that extracts and utilizes oxygen delivered by the blood. In athletes with high VO2 max, both of these systems have greater functionality.

Restoration (resynthesis) of ATP is carried out due to chemical reactions of two types:

- anaerobic, occurring in the absence of oxygen;
- aerobic (respiratory) in which oxygen is absorbed from the air.

Anaerobic reactions do not depend on the supply of oxygen to tissues and are activated when there is a lack of ATP in cells.

However, the released chemical energy is used for mechanical work extremely inefficiently (only about 20-30%). In addition, when a substance decomposes without the participation of oxygen, intramuscular energy reserves are consumed very quickly and can only provide motor activity for several minutes.

Consequently, with the most intense work in short periods of time, energy supply is carried out primarily through anaerobic processes.

The latter include two main sources of energy: the creatine-phosphate reaction, associated with the breakdown of energy-rich CrP, and the so-called glycolysis, which uses the energy released during the breakdown of carbohydrates into lactic acid (H3PO4).

In Fig. Figure 4 shows the change in the intensity of creatine phosphate, glycolytic and respiratory mechanisms of energy supply depending on the duration of the exercise (according to N.I. Volkov). It should be emphasized that, in accordance with the differences in the nature of the energy supply of muscle activity, it is customary to distinguish aerobic and anaerobic components of endurance, aerobic and anaerobic capabilities, aerobic and anaerobic performance.

Anaerobic mechanisms are of greatest importance in the initial stages of work, as well as in short-term efforts of high power, the value of which exceeds the TANO.

Rice. 4. - Change in the intensity of creatine phosphate, glycolytic and respiratory mechanisms depending on the duration of the exercise:

An intensification of anaerobic processes also occurs with all kinds of changes in power during the exercise, if the blood supply to the working muscles is disrupted (straining, holding your breath, static tension, etc.).

Aerobic mechanisms play a major role during prolonged work, as well as during recovery after exercise (Table 2), and characterize the functional energy potential of a person - his general energy capabilities.

Table 2. - Sources of energy supply for work in individual zones of relative power and their restoration (according to N.I. Volkov):

In connection with these main sources of energy, some authors (N.I. Volkov, V.M. Zatsiorsky, A.A. Shepilov, etc.) identify three components of endurance:

- alactic anaerobic;
- glycolytic anaerobic;
- aerobic (respiratory).

In this sense, various types of “special” endurance can be considered as combinations of these three components (Fig. 5).

During intense muscular activity, the creatine phosphate reaction first develops, which reaches its maximum after 3-4 s. But the small reserves of CrF in the cells are quickly exhausted, and the reaction power drops sharply (by the second minute of work it is below 10% of its maximum).

Rice. 5. - Relative energy contribution of anaerobic (An) and aerobic (Ae) mechanisms in ensuring running over different distances:

Glycolytic reactions unfold more slowly and reach maximum intensity in 1-2 minutes. The energy released in this case ensures activity for a longer time, since in comparison with KrF, the reserves of myoglobin in the muscles prevail much more. But during work, a significant amount of lactic acid accumulates, which reduces the ability of muscles to contract and causes “protective-inhibitory” processes in the nerve centers. Respiratory processes develop in full force by 3-5 minutes of activity, which is actively facilitated by the breakdown products of anaerobic metabolism (creatine-lactic acid), which stimulate oxygen consumption during the breathing process. When characterizing endurance, along with our knowledge of how their components change depending on the power and duration of motor activity, it is necessary to reveal the individual capabilities of the athlete for aerobic and anaerobic performance. For this purpose, in the practice of physiological and biochemical control, various indicators are used that reveal the features and mechanisms of muscle energy (A. Hill, R. Margaria, F. Henry, N. Yakovlev, V. Mikhailov, N. Volkov, V. Zatsiorsky, Yu Verkhoshansky, T. Petrova with co-authors, A. Sysoev with co-authors, V. Pashintsev and others). Anaerobic performance is a set of functional properties of a person that ensures his ability to perform muscular work in conditions of inadequate oxygen supply using anaerobic energy sources, i.e., in oxygen-free conditions.

Basic indicators:

- the power of the corresponding (intracellular) anaerobic systems;
- total reserves of energy substances in tissues necessary for ATP resynthesis;
- the possibility of compensating for changes in the internal environment of the body;
- level of tissue adaptation to intensive work in hypoxic conditions.

From the above, it becomes obvious that depending on the intensity, duration and nature of motor activity, the value of endurance will increase (Table 3).

Table 3. - The ratio of aerobic and anaerobic processes of energy metabolism when running at various distances (according to N.I. Volkov):

Aerobic capacity is determined by the properties of various systems in the body that ensure the “delivery” of oxygen and its utilization in tissues. These properties include efficiency:

- external respiration (minute volume of respiration, maximum pulmonary ventilation, vital capacity of the lungs, the rate at which gases diffusion occurs, etc.);
- blood circulation (pulse, heart rate, blood flow speed, etc.);
- utilization of oxygen by tissues (depending on tissue respiration);
- consistency of activities of all systems.

The main factors determining the IPC are presented in more detail in Fig. 6.

Rice. 6. - The main factors determining the IPC:

Aerobic performance is usually assessed by the level of MOC, by the time required to achieve the MOC, and by the maximum time of work at the MOC level. The MOC indicator is the most informative and is widely used to assess the aerobic capabilities of athletes.

By using the MIC you can find out how much oxygen (in liters or milliliters) the human body can consume in one minute. As can be seen in the figure, the functional systems that provide high MIC values include the external respiration apparatus, the cardiovascular system, the circulatory system and tissue respiration.

Here we note that the integral indicator of the activity of the external respiration apparatus is the level of pulmonary ventilation. At rest, the athlete performs 10-15 breathing cycles, the volume of air exhaled at one time is about 0.5 liters. Pulmonary ventilation in one minute in this case is 5-7 liters.

When performing exercises of submaximal or high power, i.e., when the activity of the respiratory system is fully developed, both the respiratory rate and its depth increase, the amount of pulmonary ventilation is 100-150 liters. and more.

There is a close relationship between pulmonary ventilation and BMD. It was also revealed that the size of pulmonary ventilation is not the limiting factor of BMD.

It should be noted that after reaching the maximum oxygen consumption, pulmonary ventilation still continues to increase with increasing functional load or duration of exercise.

Among all the factors that determine BMD, the leading place is given to cardiac performance. The integral indicator of cardiac performance is cardiac output.

With each contraction, the heart pushes 7-80 ml from the left ventricle into the vascular system. blood (stroke volume) and more. Thus, in a minute at rest the heart pumps 4-4.5 liters. blood (minute blood volume - MOC). With intense muscle load, heart rate increases to 200 beats/min or more, stroke volume also increases and reaches values at a pulse of 130-170 beats/min.

With a further increase in the frequency of contractions, the heart cavity does not have time to completely fill with blood, and the stroke volume decreases. During the period of maximum cardiac performance (at a heart rate of 175-190 beats/min), maximum oxygen consumption is achieved.

It has been established that the level of oxygen consumption during exercise with tension causing increased heart rate (in the range of 130-170 beats/min) is linearly dependent on the cardiac output (A.A. Shepilov, V.P. Klimin).

Experimental studies in recent years have shown that the degree of increase in stroke volume during muscle work is much less than previously thought. This makes it possible to consider that heart rate is the main factor in increasing cardiac performance during muscle work. Moreover, it has been established that up to a frequency of 180 beats/min, heart rate increases with increasing severity of work. There is no consensus on the maximum heart rate values during the greatest (maximum) loads. Some of the researchers recorded very large values. Thus, N. Nesterenko obtained a heart rate result of 270 beats/min, M. Okroshidze and others give values of 210-216 beats/min, according to N. Kulik, the pulse during competitions fluctuated in the range of 175-200 beats/min, in A. Shepilov’s studies, the pulse only sometimes exceeded 200 beats/min. The most optimal heart rate, allowing to achieve maximum cardiac performance, is considered to be a heart rate of 180-190 beats/min. A further increase in heart rate (above 180-190 beats/min) is accompanied by a clear decrease in stroke volume. During the recovery period, the change in heart rate depends on the power of the exercise and the duration of its implementation, on the degree of training of the athlete. You should always remember that the oxygen capacity of the blood is essential when determining MP K. Normally it is 20 ml. per 100 ml. blood. The level of MOC depends on the body weight and qualifications of the athletes. According to P. O. Astrand, the strongest wrestlers in Sweden had an MOC of 3.8 to 7 l/min. For a wrestler, this is a unique indicator. The “king” of skis, S. Ernberg, who competed in the 1960s, had an MOC value of 5.88 l/min. However, in terms of 1 kg. body weight S. Ernberg had an MOC of 83 ml., Dmin/kg) (a kind of world record at that time), and the MOC of the Swedish heavyweight wrestler was only 49 ml., Dmin/kg). It should be taken into account that the level of maximum aerobic capacity depends on the qualifications of the athletes. For example, if in healthy men who do not engage in sports, the MOC is 35-55 ml., Dmin/kg), then in athletes of average qualification it is equal to 56-65 ml., Dmin/kg). For particularly outstanding athletes, this figure can reach 80 ml., Dmin/kg) or more.

Table 4. - Average MPC values for representatives of various sports:

To confirm this, let us turn to the MOC indicators of highly qualified athletes specializing in various sports. It should be noted that aerobic performance indicators change significantly under the influence of training that involves exercises that require high activation of the cardiovascular and respiratory systems.

Many researchers have shown that the level of VO2 max under the influence of training increases by 10-15% of the initial level within just one season. However, when training aimed at developing aerobic performance is stopped, the level of VO2 max decreases quite quickly.

As you can see, a person’s energy capabilities are determined by a whole system of factors, which in their totality are the main (but not the only) condition for achieving high sports results. In practice, there are many cases where athletes with high anaerobic and aerobic capabilities showed mediocre results. Most often, the reason lies in poor technical (in some cases, volitional and tactical) training. Perfect coordination of motor activity is an important prerequisite for the full use of an athlete’s energy potential.

The described bioenergetic factors of endurance by no means exhaust the problem of the structure and mechanisms of this basic human motor property.

The role of the nervous system is extremely important for the processes of fatigue and physical performance. Unfortunately, its leading position is still poorly understood. Regardless of this, the influence of a number of factors is no longer in doubt.

For example, it is considered proven that maintaining the impulse flow at a certain level (corresponding to the required speed of movement) is one of the main conditions for prolonged motor activity. In other words, the primary link and the most general factor characterizing endurance is the neural systems of higher levels of control. This is evidenced by a number of factors. For example, the connection between the hypothalamus - pituitary gland - endocrine glands becomes unstable in mediocre long-distance runners (most of them have a weak nervous system).

And vice versa, 1200 highly qualified middle and long distance runners - skiers, skaters, cyclists, etc. (with a strong nervous system) - have a high functional stability of the system: hypothalamus - pituitary gland - adrenal glands

1. Aerobic and anaerobic performance. Criteria for its evaluation

2. Physiological characteristics of the body’s states during sports activity. Pre-launch states

3. The role of emotions in sports activities

1. Aerobic and anaerobic performance. Criteria for its evaluation

In table Table 1 shows “normative” indicators of maximum anaerobic power for women and men.

Table 1 Classification of indicators of maximum anaerobic power (kgm/s, 1 kgm/s = 9.8 W)

Classification	Age, years
Classification	15-20	20-30
Men:
bad	Less than 113	Less than 106
mediocre	113-149	106-139
average	150-187	140-175
good	188-224	176-210
excellent	More than 2-24	More than 210
Women:
bad	Less than 92	Less than 85
mediocre	92-120	85-111
average	121-151	112-140
good	152-182	141-168
excellent	More than 182	More than 168

By the size of the alactic (fast) fraction of the oxygen debt, one can judge that part of the anaerobic (phosphagen) capacity that provides very short-term speed-strength exercises (sprints).

(ATP + CP) oxygen debt (cal/kg body weight) = [ (O 2 -debt 2min - 550) * 0.6 * 5 ] / body weight (kg)

The typical maximum value of the “phosphagen fraction” of oxygen debt is about 100 cal/kg of body weight, or 1.5-2 l O2. As a result of speed-strength training, it can increase by 1.5-2 times.

2. Physiological characteristics of the body’s states during sports activity. Pre-launch states

When performing a training or competitive exercise, significant changes occur in the athlete's functional state. In the continuous dynamics of these changes, three main periods can be distinguished: pre-start, main (working) and recovery.

The pre-start state is characterized by functional changes preceding the start of work (exercise).

In the working period, a distinction is made between rapid changes in functions in the very initial period of work - the working-in state and the following relatively unchanged (or rather, slowly changing) state of the basic physiological functions, the so-called steady state. In the process of performing the exercise, fatigue develops, which manifests itself in a decrease in performance, i.e., the inability to continue the exercise at the required level of intensity, or in a complete refusal to continue this exercise.

Restoration of functions to the original, pre-working level characterizes the state of the body for a certain time after stopping the exercise.

Each of these periods in the state of the body is characterized by special dynamics of the physiological functions of various systems, organs and the entire organism as a whole. The presence of these periods, their characteristics and duration are determined primarily by the nature, intensity and duration of the exercise performed, the conditions for its implementation, as well as the degree of training of the athlete.

Pre-launch state

Even before the start of muscular work, in the process of waiting for it, a number of changes occur in various functions of the body. The significance of these changes is to prepare the body for the successful performance of upcoming activities.

Pre-launch state

The pre-start change in functions occurs during a certain period - several minutes, hours or even days (if we are talking about a responsible competition) before the start of muscle work. Sometimes a separate starting state is distinguished, characteristic of the last minutes before the start (beginning of work), during which functional changes are especially significant. They go directly into the phase of rapid function change at the beginning of operation (run-in period).

In the pre-launch state, a variety of changes occur in various functional systems of the body. Most of these changes are similar to those that occur during work itself: breathing becomes more frequent and deepens, i.e., LV increases, gas exchange increases (O2 consumption), heart contractions become more frequent and intensified (cardiac output increases), blood pressure increases ( blood pressure), the concentration of lactic acid in muscles and blood increases; body temperature, etc. Thus, the body seems to move to a certain “working level” even before it begins; activity, and this usually contributes to the successful completion of work (K.M. Smirnov).

By their nature, pre-launch changes in functions are conditioned reflex nervous and hormonal reactions. Conditioned reflex stimuli in this case are the place and time of the upcoming activity, as well as secondary signal and speech stimuli. Emotional reactions play a major role in this. Therefore, the most dramatic changes in the functional state of the body are observed before sports competitions. Moreover, the degree and nature of pre-start changes are often in direct connection with the significance of this competition for the athlete.

O 2 consumption, basal metabolism, drugs before the start can be 2-2.5 times higher than the normal resting level. For sprinters (see Fig. 7) and alpine skiers, heart rate at the start can reach 160 beats/min. This is due to increased activity of the sympathoadrenal system, activated by the limbic system of the brain (hypothalamus, limbic lobe of the cortex). The activity of these systems increases even before the start of work, as evidenced, in particular, by an increase in the concentration of norepinephrine and adrenaline. Under the influence of catecholamines and other hormones, the processes of breakdown of glycogen in the liver and fats in the fat depot are accelerated, so that even before work begins, the content of energy substrates in the blood - glucose, free fatty acids - increases. Increased sympathetic activity through cholinergic fibers, intensifying glycolysis in skeletal muscles, causes dilation of their blood vessels (cholinergic vasodilation).

The level and nature of pre-start shifts often correspond to the characteristics of those functional changes that occur during the exercise itself. For example, the heart rate before a start is, on average, higher the shorter the distance of the upcoming run, i.e., the higher the heart rate during the exercise. In anticipation of a middle-distance run, the systolic volume increases relatively more than before a sprint run (K.M . Smirnov). Thus, pre-start changes in physiological functions are quite specific, although they are quantitatively expressed, of course, much weaker than those occurring during work.

Features of the pre-start state can largely determine sports performance. Not in all cases, pre-race changes have a positive impact on athletic performance. In this regard, three forms of the pre-start state are distinguished: a state of readiness - a manifestation of moderate emotional arousal, which helps to improve athletic performance; the state of so-called starting fever - a pronounced excitement, under the influence of which both an increase and a decrease in athletic performance is possible; too strong and prolonged pre-start excitement, which in some cases gives way to depression and depression - starting apathy, leading to a decrease in athletic performance (A. Ts. Puni).

3. The role of emotions in sports activities

Various psychological, nervous and humoral mechanisms take part in the regulation of functional states, which are the basis of human motor activity: needs, main sources of activity; motives that encourage the satisfaction of these needs; emotions that support activity; speech regulation (self-organization and self-mobilization); hormonal influences - release of hormones from the pituitary gland, adrenal glands, etc.

THE MEANING OF EMOTIONS.

Sports activity, and, first of all, performances at competitions, causes two types of stress in the athlete’s body.

Physical stress associated with exercising muscular work;

Emotional and mental stress caused by extreme stimuli (stressors).

The latter includes 3 factors:

A large amount of information coming to the athlete, which creates information overload (especially in team sports, martial arts, downhill skiing, etc.);

The need to process information under time pressure;

High level of motivation - the social significance of the decisions made by the athlete.

In carrying out these processes, the role of emotions is enormous.

Emotions represent a person’s personal attitude towards the environment and himself, which is determined by his needs and motives. Their significance in behavior lies in the evaluative influence on the activity of specific body systems (sensory and motor). Emotions ensure selective human behavior in a situation with many choices, reinforcing certain ways of solving problems and methods of action.

In sports, they constantly accompany athletes who experience “muscular joy,” “sports anger,” “the bitterness of defeat,” and “the joy of victory.” Emotions are clearly manifested in the pre-start state, as well as during wrestling, and are an important component in the process of tactical thinking. The emotional mood increases the maximum voluntary strength and speed of locomotion.

PSYCHOPHYSIOLOGICAL MECHANISMS OF EMOTIONS.

Emotions are divided into lower (also present in animals) and higher, associated with the social aspects of human life (intellectual, moral, aesthetic), his conscious behavior and cognitive activity - interests, conscious and unconscious motives (impulses, drives), feelings, searches for information . They arise when needs are not sufficiently met, when there is a discrepancy between necessary and real information.

Some parts of the cerebral cortex and subcortical formations of the lower and inner surfaces of the cerebral hemispheres (cingulate gyrus, hippocampus) - some nuclei of the thalamus, hypothalamus, network-like formation of the median parts of the brain stem - are involved in the emergence of emotions. These formations represent the so-called limbic-reticular complex, which, together with the higher parts of the cortex, forms human emotions.

Emotional reactions include motor, autonomic and endocrine manifestations: changes in breathing, heart rate, blood pressure, activity of skeletal and facial muscles, release of hormones - adrenocorticotropic hormone of the pituitary gland, adrenaline, norepinephrine and corticoids secreted by the adrenal glands.

There are positive and negative emotions. During electrical stimulation in experiments on animals and during medical procedures in the clinic, centers of pleasure (in the hypothalamus, midbrain) and displeasure in some areas of the thalamus were discovered in humans). When these centers were irritated, patients experienced “causeless joy,” “pointless melancholy,” and “unaccountable fear.”

Involved in complex mental processes, emotions participate in decision-making and provide so-called heuristic thinking during sudden discoveries in a person, reinforcing his “insight.” In children 2-3 years old, unlike adults, the emotional connotation of words is more important than their semantic component.

Emotions are a mechanism for regulating the intensity of movements, causing the mobilization of the body's functional reserves in extreme situations. This is especially evident in competitive conditions, when the performance of an athlete exceeds his achievements in training sessions. Doing work alone, with normal motivation, always takes less time and is less effective than when competing with other people, with increased motivation. The ability to mobilize functional reserves with increased motivation is most characteristic of experienced, qualified athletes, while at the same time, untrained individuals most often exhaust their body’s reserves even with normal motivation.

Significant neuropsychic stress during sports activities leads to a sharp increase in emotional reactions, causing emotional stress in athletes, and with excessive exposure they cause negative manifestations of emotions - distress (deterioration of the functional state and activity of the body, decreased immunity).

A special class of biological regulators - neuropeptides (enkephalins, endorphins, opiate peptides) - are involved in the formation of emotions and emotional stress. They are fragments of protein molecules - short amino acid chains. Neuropeptides are distributed widely and unevenly in different parts of the brain and spinal cord. Acting in the area of contacts between neurons, they are able to enhance or inhibit their functions, providing an analgesic effect, improving memory and the formation of motor skills, changing sleep and body temperature, relieving severe conditions of alcoholism - withdrawal. Their concentration in the nervous system decreases with restrictions on motor activity and increases with emotional reactions and stress. It was found, in particular, that in athletes under competitive conditions the concentration of neuropeptides is 5-6 times higher than their usual content in untrained individuals.

Bibliography

1. KOTS Y.M. - Sports physiology, http://www.natahaus.ru

2. D. Wilmore, D. Costill. – Physiology of sports and motor activity., “Olympic Literature”, Kyiv

3. Solodkov A.S., Sologub E.B. Human physiology. General. Sports. Age: Textbook. - M.: Tera-Sport, Olympia Press, 2001.

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