Fundamentals of sports biochemistry. The peculiarities of biochemical blood parameters in highly qualified athletes have been resolved. Ultra-thin muscle cell structure

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College physical culture

LECTURE COURSE

BASICS OF SPORTS BIOCHEMISTRY

Kucheryavyi Vsevolod Vladimirovich

Topic 1. Structure of proteins and enzymatic catalysis.

Topic 6. Protein metabolism

SECTION 3. WATER-MINERAL METABOLISM. VITAMINS. HORMONES

Topic 7. Exchange of water and salts. Vitamins

Topic 8. Hormones, biochemistry of urine and blood

PART 2. BASICS OF SPORTS BIOCHEMISTRY

SECTION 4. BIOCHEMISTRY OF MUSCLE ACTIVITY

Topic 9. Biochemistry of muscle contraction

Topic 10. Energy supply of muscle contraction

SECTION 5. GENERAL BIOCHEMISTRY OF SPORTS ACTIVITY

Topic 11. Biochemical changes during muscle work

Topic 12. Biochemical mechanisms of fatigue

Topic 13. Recovery from a biochemical point of view

Topic 14. General biochemical patterns of adaptation to muscular work

SECTION 6. SPORTS PERFORMANCE AND BIOCHEMISTRY

Topic 15. Biochemical basis of performance

Topic 16. Biochemical methods of increasing performance

APPENDIX 1. Biochemistry exam questions

PART 1. BASICS OF GENERAL BIOCHEMISTRY

SECTION 1. GENERAL CHARACTERISTICS OF METABOLISM

Topic 1. Protein structure and enzymatic catalysis

1. Biological role of proteins

2. Structure of a protein molecule

3. Classification of proteins

5. Structure of enzymes

Introduction. What does biochemistry do?

Biochemistry studies the chemical processes occurring in living systems. In other words, biochemistry studies the chemistry of life. This science is relatively young. She was born in the 20th century. Conventionally, the biochemistry course can be divided into three parts.

General biochemistry deals with the general laws of the chemical composition and metabolism of various living beings, from the smallest microorganisms to humans. It turned out that these patterns are largely repeated.

Particular biochemistry deals with the peculiarities of chemical processes occurring in certain groups of living beings. For example, biochemical processes in plants, animals, fungi and microorganisms have their own characteristics, and in some cases very significant ones.

Functional biochemistry deals with the peculiarities of biochemical processes occurring in individual organisms associated with the characteristics of their lifestyle. A branch of functional biochemistry that studies the influence physical exercise on the athlete's body is called sports biochemistry or sports biochemistry.

The development of physical culture and sports requires athletes and coaches to have good knowledge in the field of biochemistry. This is due to the fact that without understanding how the body works at the chemical, molecular level, it is difficult to hope for success in modern sports. Many training and recovery techniques these days are based on a deep understanding of how the body works at the subcellular and molecular level. Without a deep understanding of biochemical processes, it is impossible to fight doping - an evil that can ruin sports.

1. Biological role of proteins

The role of proteins in the body is difficult to overestimate. That is why our course begins with a description of the role and structure of this particular class of bioorganic compounds. Proteins in the body perform the following functions.

1. Structural or plastic function. Proteins are versatile building material, from which almost all structures of living cells consist. For example, in the human body, proteins make up about 1/6 of body weight. Moreover, trained people with good developed muscles this figure may be higher.

2. Catalytic function. Many proteins, called enzymes or enzymes, perform the function of catalysts in living systems, that is, they change the rate of chemical reactions (which will be discussed in detail below)

3. Contractile function. It is protein molecules that underlie all forms of movement of living systems. Muscle contraction is primarily the work of proteins.

4. Regulatory function. This function is based on the ability of protein molecules to react with both acids and bases, called amphotericity in chemistry. Proteins are involved in creating homeostasis in the body. Many proteins are hormones.

5. Receptor function. This function is based on the ability of proteins to respond to emerging changes in the conditions of the internal environment of the body. Various receptors in the body that are sensitive to temperature, pressure, and light are proteins. Hormone receptors are also proteins.

6. Transport function. Protein molecules are large in size and highly soluble in water, which allows them to easily move through aqueous solutions and transport various substances. For example, hemoglobin transports gases, blood albumins transport fats and fatty acids.

7. Protective function. Proteins protect the body, first of all, by participating in the creation of immunity.

8. Energy function. Proteins are not the main participants in energy metabolism, but they still provide up to 10% of the body’s daily energy needs. At the same time, it is too valuable a product to be used as an energy source. Therefore, proteins are used as a source of energy only after carbohydrates and fats.

2. Structure of a protein molecule

Proteins are high molecular weight nitrogen-containing compounds consisting of amino acids. Proteins contain hundreds of amino acid residues. However, all proteins, regardless of origin, are formed by 20 types of amino acids. These 20 amino acids are therefore called proteinogenic.

Amino acids contain a carboxyl group COOH and an amino group NH2. True, some proteins still contain very small amounts of amino acids that are not part of the proteinogenic ones. Such amino acids are called minor. They are formed from proteinogenic amino acids after the completion of the synthesis of protein molecules.

Amino acids are connected to each other by peptide bonds, forming long unbranched chains - polypeptides. A peptide bond occurs when the carboxyl group of one amino acid interacts with the amino group of another, releasing water. Peptide bonds are highly durable and are formed by all amino acids. It is these bonds that form the first level of organization of the protein molecule - the primary structure of the protein. Primary structure is the sequence of amino acid residues in the polypeptide chain of a protein.

The secondary structure of the protein is a helical structure formed mainly by hydrogen bonds.

The tertiary structure of a protein is a globule or ball into which the secondary helix in some proteins folds. Various intermolecular forces, primarily disulfide bridges, participate in the formation of a globule. Since disulfide bonds are formed by amino acids that contain sulfur, globular proteins usually contain a lot of sulfur.

Some proteins form a quaternary structure consisting of several globules, then called subunits. For example, the hemoglobin molecule consists of four subunits that perform a single function.

All structural levels of a protein molecule depend on the primary structure. Changes in the primary structure lead to changes at other levels of protein organization.

3. Classification of proteins

The classification of proteins is based on their chemical composition. According to this classification, proteins are divided into simple and complex. Simple proteins consist only of amino acids, that is, of one or more polypeptides. Simple proteins found in the human body include albumins, globulins, histones, and supporting tissue proteins.

In a complex protein molecule, in addition to amino acids, there is also a non-amino acid part, called a prosthetic group. Depending on the structure of this group, complex proteins are distinguished such as phosphoproteins (contain phosphoric acid), nucleoproteins (contain nucleic acid), glycoproteins (contain carbohydrates), lipoproteins (contain lipoid) and others.

According to the classification, which is based on the spatial shape of proteins, proteins are divided into fibrillar and globular.

Fibrillar proteins consist of helices, that is, predominantly of secondary structure. Molecules of globular proteins have a spherical and ellipsoidal shape.

An example of fibrillar proteins is collagen, the most abundant protein in the human body. This protein accounts for 25 - 30% of the total number of proteins in the body. Collagen has high strength and elasticity. It is part of the blood vessels of muscles, tendons, cartilage, bones, and vessel walls.

An example of globular proteins are albumins and globulins in blood plasma.

4. Physicochemical properties of proteins

One of the main features of proteins is their large molecular weight, which ranges from 6000 to several million daltons.

Another important physicochemical property of proteins is their amphotericity, that is, the presence of both acidic and basic properties. Amphotericity is associated with the presence in some amino acids of free carboxyl groups, that is, acidic, and amino groups, that is, alkaline. This leads to the fact that in an acidic environment proteins exhibit alkaline properties, and in an alkaline environment - acidic. However, under certain conditions, proteins exhibit neutral properties. The pH value at which proteins exhibit neutral properties is called the isoelectric point. The isoelectric point for each protein is individual. Proteins according to this indicator are divided into two large classes - acidic and alkaline, since the isoelectric point can be shifted either in one direction or the other.

Another important property of protein molecules is solubility. Despite the large size of the molecules, proteins are quite soluble in water. Moreover, solutions of proteins in water are very stable. The first reason for the solubility of proteins is the presence of a charge on the surface of protein molecules, due to which protein molecules practically do not form aggregates that are insoluble in water. The second reason for the stability of protein solutions is the presence of a hydration (water) shell in the protein molecule. The hydration shell separates the proteins from each other.

The third important physicochemical property of proteins is salting out, that is, the ability to precipitate under the influence of water-removing agents. Salting out is a reversible process. This ability to move in and out of solution is very important for the manifestation of many vital properties.

Finally, the most important property of proteins is their ability to denature. Denaturation is the loss of nativeness by a protein. When we scramble eggs in a frying pan, we get irreversible denaturation of the protein. Denaturation consists of permanent or temporary disruption of the secondary and tertiary structure of a protein, but the primary structure is preserved. In addition to temperature (above 50 degrees), denaturation can be caused by other physical factors: radiation, ultrasound, vibration, strong acids and alkalis. Denaturation can be reversible or irreversible. With small impacts, the destruction of the secondary and tertiary structures of the protein occurs insignificantly. Therefore, in the absence of a denaturing agent, the protein can restore its native structure. The reverse process of denaturation is called renaturation. However, with prolonged and strong exposure, renaturation becomes impossible, and denaturation is thus irreversible.

5. Structure of enzymes

Enzymes or enzymes are proteins that perform catalytic functions in the body. Catalysis involves both speeding up and slowing down chemical reactions.

Enzymes almost always speed up chemical reactions in the body, and they speed up tens and hundreds of times. In other reactions that take place under the control of enzymes, the rate in their absence drops to almost zero.

The region of the enzyme that is directly involved in catalysis is called the active site. It can be organized differently in enzymes that have only tertiary and quaternary structure. In complex proteins, as a rule, all subunits, as well as their prosthetic groups, participate in the formation of the active center.

There are two sections in the active center - adsorption and catalytic.

The adsorption site is the binding site. Its structure corresponds to the structure of reacting substances, called substrates in biochemistry. They say that the substrates and the adsorption site of the enzyme coincide like a key and a lock. Most enzymes have one active site, but there are enzymes that have multiple active sites.

It must be said that not only the active center of the enzyme, but also its other parts take part in the enzymatic reaction. The overall conformation of the enzyme plays an important role in its activity. Therefore, changing even one amino acid in a part of the molecule that is not directly related to the active center can greatly affect the activity of the enzyme and even reduce it to zero. Due to a change in the conformation of the enzyme, its active center “adapts” to the structure of the substrates participating in the reaction accelerated by the enzyme.

6. Mechanism of action of enzymes. Specificity

It must be remembered that when performing a catalytic function, the catalyst itself does not change its chemical nature. This statement is also true for enzymes.

In any catalytic reaction carried out by enzymes, there are three stages.

1. Formation of an enzyme-substrate complex. At this stage, the active center of the enzyme binds to substrates through weak bonds, usually hydrogen bonds. A feature of this stage is complete reversibility, since the enzyme-substrate complex can easily decompose into enzyme and substrates. At this stage, a favorable orientation of the substrate molecules occurs, which accelerates their interaction.

2. This stage takes place with the participation of the catalytic site of the active center. The essence of this stage is to reduce the activation energy and accelerate the reaction between substrates. The result of this stage is the formation of a new product.

3. At this stage, the finished product is separated from the active center, releasing the enzyme, which is again ready to carry out its function.

In cells, enzymes that catalyze multistage processes are often combined into complexes called multienzyme systems. Most often, these complexes are embedded in biomembranes or associated with cell organelles. This combination of enzymes makes their work more efficient.

In some cases, enzyme proteins contain non-protein components involved in catalysis. Such non-protein elements are called coenzymes. Most coenzymes contain vitamins.

The most important property of enzymes is their high specificity. In biochemistry there is a rule: one reaction - one enzyme. There are two types of specificity: action specificity and substrate specificity.

Specificity of action is the ability of an enzyme to catalyze only one specific type of chemical reaction. If a substrate can undergo various reactions, then each reaction requires its own enzyme.

Substrate specificity is the ability of an enzyme to act only on certain substrates.

Substrate specificity can be absolute or relative.

With absolute specificity, the enzyme catalyzes the transformation of only one substrate.

When relative, there may be a group of similar substrates.

7. What does the speed of enzymatic reactions depend on?

Chemical reactions are based on activation energy. If the activation energy is high, then the substances cannot react or the rate of their interaction will be low. Enzymes lower the activation energy threshold.

The speed of enzymatic reactions depends significantly on many factors. These include the concentrations of substances participating in the enzymatic reaction, as well as the environmental conditions in which the reaction occurs.

It has been shown that the higher the enzyme concentration, the higher the reaction rate. This is because the enzyme concentration is much lower than the substrate concentration.

At low substrate concentrations, the rate of reaction is directly proportional to the concentration of substrates. However, as the substrate concentration increases, it begins to slow down and, finally, reaching maximum speed, stops growing. This is because as the substrate concentration increases, the amount of free active cents becomes the limiting factor.

Temperature affects enzymatic reactions in a unique way. The fact is that enzymes are proteins, which means that at high temperatures (above 80 degrees), they completely lose activity. Therefore, for enzymatic reactions there is the concept of a temperature optimum. The optimum for most enzymes is a body temperature of 37 - 40 degrees. At low temperatures, enzymes are also inactive.

Another factor determining enzyme activity is the pH of the environment. Here, each enzyme has its own pH optimum. For example, gastric juice enzymes have a pH optimum in an acidic environment (pH - 1.0 to 2.0), and pancreatic enzymes prefer an alkaline environment (pH - 9.0 - 10.0).

In addition to the above factors, various substances - inhibitors and activators - affect the rate of enzymatic reactions.

Inhibitors are, most often, low molecular weight substances that slow down the reaction rate. The inhibitor binds to the enzyme, preventing it from performing its function.

Activators are substances that selectively increase the rate of enzymatic reactions.

Hormones can act as both activators and inhibitors of enzymes.

The speed of enzymatic reactions depends on a number of other factors:

· changes in the rate of enzyme synthesis;

· . enzyme modifications;

· change in enzyme conformation

8. Classification and nomenclature of enzymes

The modern classification of enzymes is based on the characteristics of the chemical reaction catalyzed by the enzyme. There are six main classes of enzymes.

1. Oxidoreductases are enzymes that catalyze redox reactions. Schematically it looks like this:

2. Transferases - enzymes that catalyze the transfer of chemical groups from one molecule to another

AB + C > A + BC

3. Hydrolases are enzymes that break down chemical bonds by adding water, that is, hydrolysis.

AB + H2O >A - H + B - OH

4. Lyases - enzymes that catalyze the cleavage of chemical bonds without adding water:

5. Isomerases are enzymes that catalyze isomeric transformations, that is, the transfer of individual chemical groups within one molecule:

6. Synthetases are enzymes that catalyze synthesis reactions that occur using the energy of ATP:

ATP + H2O > ADP + H3PO4

Each class is in turn divided into subclasses, and those into subsubclasses.

The name of the enzyme usually consists of two parts. The first part reflects the name of the substrate, the transformation of which is catalyzed by this enzyme. The second part of the name has the ending “-aza”, indicating the nature of the reaction. For example, an enzyme that removes hydrogen atoms from lactic acid (lactate) is called lactate dehydrogenase. And the enzyme that catalyzes the isomerization of glucose-6-phosphate into fructose-6-phosphate is called glucose phosphate isomerase. The enzyme involved in glycogen synthesis is called glycogen synthetase.

Topic 2. Metabolic stages and biological oxidation

3. Tissue respiration

1. general characteristics metabolism

Metabolism and energy is required condition existence of living organisms.

The body receives energy and building substances from the external environment, then these substances are processed and, finally, unnecessary waste products are released from the body into the environment. Thus, metabolism can be represented as three processes.

1. Digestion is a process during which food substances, usually high-molecular and foreign to the body, are broken down under the action of digestive enzymes and converted into simple compounds - universal for all living organisms. Proteins, for example, break down into amino acids exactly the same as the amino acids of the body itself. The universal monosaccharide glucose is formed from food carbohydrates. Therefore, the final products of digestion can be introduced into the internal environment of the body and used by cells for a variety of purposes.

2. Metabolism is a set of chemical reactions occurring in the internal environment of the body. True, sometimes the word “metabolism” is understood as a synonym for metabolism.

3. Excretion is the process of removing waste substances from the body. This process occurs both in the last stages of digestion and during metabolism. In the latter case, the excretion involves blood and special organs for excreting the breakdown products of nitrogenous substances - the kidneys.

Let us, however, take a closer look at metabolism itself.

Metabolism includes two processes, which are its two inseparable sides: catabolism and anabolism.

Catabolism is the process of breaking down substances, resulting in the extraction of energy and the production of smaller molecules. The end products of catabolism are carbon dioxide, water, and ammonia.

Catabolism in the human body and most living beings is characterized by the following features.

· In the process of catabolism, oxidation reactions predominate.

· Catabolism occurs with oxygen consumption.

· During catabolism, energy is released, approximately half of which is accumulated in the form of adenosine triphosphate (ATP) molecules. A significant portion of the energy is released in the form of heat.

Anabolism is a synthesis reaction. These processes are characterized by the following features.

· Anabolism is mainly a recovery reaction.

· During the process of anabolism, hydrogen is consumed.

· ATP serves as the energy source for anabolic reactions.

2. Structure and biological role of ATP

Adenosine triphosphate, or ATP for short, is the body's universal energy substance. ATP is a nucleotide, the molecule of which includes a nitrogenous base - adenine, a carbohydrate - ribose and three phosphoric acid residues.

A feature of the ATP molecule is that the second and third phosphoric acid residues are attached by an energy-rich bond, otherwise called a high-energy bond. Often compounds that have a macroergic connection (and we will encounter them in the process of studying the subject) are designated by the term “macroergies” or macroergic substances.

The structure of ATP can be reflected in the diagram

Adenine-ribose - F.K. - F.K. - F.K.

adenosine

When ATP is used as an energy source, it is usually eliminated by hydrolysis of the last phosphoric acid residue.

ATP + H2O > ADP + H3PO4 + energy

Under physiological conditions, that is, under the conditions that exist in a living cell, the splitting of a mole of ATP is accompanied by the release of 10 - 12 kcal of energy (43 -50 kJ).

The main consumers of ATP energy in the body are

· synthesis reactions;

· muscle activity;

· transport of molecules and ions through membranes.

Thus, the biological role of ATP is that this substance in the body is a kind of equivalent of the EURO or dollar in the economy. The main supplier of ATP in the cell is tissue respiration - the final stage of catabolism, which occurs in the mitochondria of most cells of the body.

3. Tissue respiration

Tissue respiration is the main method of producing ATP used by the vast majority of cells in the body.

In the process of tissue respiration, two hydrogen atoms are removed from the oxidized substance and transferred through the respiratory chain, consisting of enzymes and coenzymes, to molecular oxygen, delivered by blood from the air to all tissues of the body. As a result of the addition of oxygen and hydrogen atoms, water is formed. Due to the energy released during the movement of electrons along the respiratory chain, ATP is synthesized from ADP and phosphoric acid in mitochondria. Typically, the synthesis of three ATP molecules is accompanied by the formation of one water molecule.

As a substrate for oxidation in tissue respiration, various intermediate products of the breakdown of carbohydrates, fats and proteins are used. However, the intermediate products of the citric acid cycle, otherwise called the tricarboxylic acid cycle or the Krebs cycle, are most often subject to oxidation (isocitric, alpha-ketoglutaric, succinic, malic acids are substrates of the tricarboxylic acid cycle). The citric acid cycle is the final stage of catabolism, during which the oxidation of the acetic acid residue included in acetyl coenzyme A occurs to carbon dioxide and water. In turn, acetyl coenzyme A is a universal substance of the body into which, during its breakdown, the main organic substances - proteins, fats and carbohydrates - are converted. Tissue respiration is a complex enzymatic process. Tissue respiration enzymes are divided into three groups: nicotinamide dehydrogenases, flavin dehydrogenases and cytochromes. These enzymes make up the respiratory chain.

Nicotinamide dehydrogenases take away two hydrogen atoms from the oxidized substrate and attach it to the coenzyme molecule NAD (nicotinamide adenine dinucleotide). In this case, NAD transforms into its reduced form NAD.H2.

Flavin dehydrogenases remove two hydrogen atoms from NAD.H2 and temporarily attach them to FMN (flavin mononucleotide). This is a coenzyme that contains vitamin B2. Then two hydrogen atoms are transferred to flavin, which in turn transfers these atoms to the cytochromes.

Cytochromes are enzymes containing ferric iron ions, which, by adding hydrogen, become divalent. There are several cytochromes and they are designated by the Latin letters a, a-3 b, c. Cytochromes transfer hydrogen to molecular oxygen and water is formed.

When moving along the respiratory chain, energy is released, which is accumulated in the form of ATP molecules. This process is called oxidative or respiratory phosphorylation. At least 40 kg of ATP is produced in the body per day. These processes occur especially intensely in the muscles during physical work.

4. Anaerobic, microsomal and free radical oxidation

In some cases, the removal of a hydrogen atom from oxidizable substances occurs in the cytoplasm. These processes occur without the participation of oxygen. Therefore, the hydrogen acceptors here are different. Most often, hydrogen is added to pyruvic acid, which occurs during the breakdown of carbohydrates and amino acids. Pyruvic acid can add hydrogen and thus become lactate or lactic acid. This process, which occurs particularly in muscles when there is a lack of oxygen, is called anaerobic oxidation or glycolysis. Due to the energy released in the cytoplasm, ATP is also formed. The process of ATP formation in the cytoplasm is called anaerobic or substrate phosphorylation. This process is much less effective than tissue respiration.

In some cases, during oxidation, oxygen atoms are included in the molecules of the substances being oxidized. This oxidation occurs on the membranes of the endoplasmic reticulum and is called microsomal oxidation. Due to the inclusion of oxygen in the oxidized substrate, a hydroxyl group (-OH) is formed. Therefore, this process is often called hydroxylation. Ascorbic acid or vitamin C takes an active part in this process.

The biological role of this process is not related to ATP synthesis. It is as follows.

1. Oxygen atoms are included in the substance being synthesized.

2. Various toxic substances are neutralized, since the inclusion of an oxygen atom in the poison molecule reduces the toxicity of this poison, makes it water-soluble, and makes it easier for the kidneys to eliminate it.

In rare cases, oxygen entering the body from the air is converted into active forms (O2, HO2, HO+, H2 O2, etc.), called free radicals or oxidants.

Free oxygen radicals cause oxidation reactions affecting proteins, fats, and nucleic acids. This oxidation is called free radical oxidation.

This process has a particular effect on fatty acids. Lipid peroxidation (LPO) helps renew the lipid layer of biological membranes.

Free radical oxidation can also be harmful if it occurs too intensely. Therefore, the body has a special antioxidant system, the most important part of which is vitamin E (tocopherol).

SECTION 2. METABOLISM OF SEPARATE GROUPS OF SUBSTANCES

Topic 3. Structure and metabolism of carbohydrates

3. Pathways of carbohydrate catabolism. Hexose diphosphate pathway for the breakdown of glucose

1. General characteristics and classification of carbohydrates. Functions of carbohydrates in the body

Carbohydrates make up more than 80% of all organic compounds in the Earth's biosphere.

Glucose plays an exceptional role in the energy metabolism of the biosphere. It is this carbohydrate that is formed during photosynthesis. And it is precisely glucose that triggers energy metabolism in our body.

Carbohydrates are divided into three main classes: monosaccharides, oligosaccharides and polysaccharides.

Monosaccharides or simple sugars do not undergo hydrolysis and it is impossible to obtain simpler carbohydrates from them. Monosaccharides include: ribose, deoxyribose, glucose, fructose, galactose and others.

Oligosaccharides consist of several monosaccharides joined by covalent bonds. During hydrolysis, they break down into their constituent monosaccharides. An example of oligosaccharides are disaccharides, consisting of two molecules of monosaccharides. The most common disaccharides are sucrose (table sugar or cane sugar), consisting of glucose and fructose residues, lactose (milk sugar), consisting of glucose and galactose residues.

Polysaccharides are long, unbranched chains. Including hundreds and thousands of monosaccharide residues. The most famous of them - starch, cellulose, glycogen - consist of glucose residues.

The functions of carbohydrates in the body are very diverse.

1. Energy.

2. Structural function (part of cellular structures).

3. Protective (synthesis of immune bodies in response to antigens).

4. Anticoagulant (heparin).

5. Homeostatic (maintaining water-salt metabolism)

6. Mechanical (part of connective and supporting tissues).

2. Structure and biological role of glucose and glycogen. Glycogen synthesis and breakdown

The empirical formula of glucose is C6H12O6. It can have different spatial forms. In the human body, glucose is usually found in a cyclic form:

Free glucose in the human body is mainly found in the blood, where its content is fairly constant and ranges from 3.9 to 6.1 mmol/l.

Glucose is the main source of energy in the body.

Another carbohydrate typical for humans is glycogen. Glycogen consists of highly branched molecules big size containing tens of thousands of glucose residues. The empirical formula of glycogen is: (C6 H12 O5)n where n is the number of glucose residues.

The main glycogen reserves are concentrated in the liver and muscles.

Glycogen is a storage form of glucose.

Normally, 400 - 500 g of carbohydrates are supplied with food. These are mainly starch, fiber, sucrose, lactose, glycogen. Digestion of carbohydrates occurs in different parts of the digestive tract, starting with the oral cavity. It is carried out by amylase enzymes. The only carbohydrate that is not broken down in our body is fiber. All the rest are broken down into glucose, fructose, galactose, etc. and are involved in catabolic processes. A significant part of glucose is converted into glycogen in the liver. Between meals, some of the glycogen in the liver is converted into glucose, which enters the blood.

Glucose used for glycogen synthesis is pre-activated. Then, after a series of transformations, it forms glycogen. This process involves the nucleotide UTP (uridine triphosphate), which is similar in structure to ATP. During the reactions, an intermediate compound is formed - uridine diphosphate glucose (UDP-glucose). It is this compound that forms glycogen molecules by reacting with the so-called seed. The priming agent is the glycogen molecules present in the liver.

The reactions of glycogen formation are provided with energy by ATP molecules. Glycogen synthesis is accelerated by the hormone insulin.

The breakdown of glycogen in the liver occurs in the reverse order and ultimately produces glucose and phosphoric acid. This process is accelerated by the hormones glucagon and adrenaline. The breakdown of glycogen in muscles is stimulated by the hormone adrenaline, which is released into the blood during muscle work. At the same time, free glucose is not formed in the muscles and the path of glycogen breakdown is somewhat different.

3. Catabolism of carbohydrates. Hexose diphosphate pathway for the breakdown of glucose.

Glucose catabolism occurs in two ways.

· The main part of carbohydrates (up to 95%) undergoes breakdown along the hexose dinophosphate pathway. It is this path that is the main source of energy for the body.

· The rest of the glucose is broken down through the hexose monophosphate pathway.

The HDP pathway can occur in the absence of oxygen - anaerobically and in the presence of oxygen, that is, in aerobic conditions. This is a very complex chain of sequential reactions, the end result of which is the formation of carbon dioxide and water. This process can be divided into three stages, sequentially following each other.

The first stage, called glycolysis, occurs in the cytoplasm of cells. The end product of this stage is pyruvic acid.

1. The reaction is that glucose is converted to glucose-6phosphate.

Glucose + ATP > glucose-6-phosphate + ADP

2. Glucose 6-phosphate is converted to fructose 6-phosphate

3. Fructose-6-phosphate turns into frutose-1.6-phosphate

5. Then 1.3diphosphoglycerate is formed from phosphoglyceraldehyde

6. 1.3-diphosphoglycerate transforms into 3-phosphoglycerate,

7. which turns into 2-phosphoglycerate, and then

8 in phosphopyruvate, and that

9 in pyruvate (pyruvic acid).

The general equation for glycolysis looks like this:

Glucose + O2 + 8ADP + 8 H3PO4 > 2 Pyruvate + 2H2O + 8 ATP

The first stage of carbohydrate breakdown is practically reversible. From pyruvate, as well as from lactate (lactic acid) arising under anaerobic conditions, glucose can be synthesized, and from it glycogen.

The second and third stages of the GDP pathway occur in mitochondria. These steps require the presence of oxygen. During the second stage, carbon dioxide and two hydrogen atoms are split off from pyruvic acid. The separated hydrogen atoms are transferred through the respiratory chain to oxygen with the simultaneous synthesis of ATP. Acetic acid is formed from pyruvate. It attaches to a special substance, coenzyme A. This substance is a carrier of acid residues. The result of this process is the formation of the substance acetyl coenzyme A. This substance has high chemical activity.

Acetyl coenzyme A undergoes further oxidation in the tricarboxylic acid cycle. This is the third stage. The first reaction of the cycle is the interaction of acetyl coenzyme A with oxaloacetic acid to form citric acid. Therefore, these reactions are called the citric acid cycle. Forming a series of intermediate tricarboxylic acids, citric acid is again converted into oxalic-acetic acid and the cycle is repeated. The result of these reactions is the formation of separated hydrogen, which, passing through the respiratory chain (see the previous lecture), forms water with oxygen. As a result of all these reactions, 36 ATP molecules are formed. In total, the GDP pathway produces 38 ATP molecules per glucose molecule

Glucose + 6 O2 + 38 ADP + 38 H3 PO4 > 6CO2 + 6 H2O +38 ATP

The breakdown of glycogen adds another ATP molecule to the equation,

With a lack of oxygen aerobic pathway interrupted by the formation of pyruvate, which is converted to lactate. As a result of such transformations, only two ATP molecules are formed.

4. Hexose monophosphate pathway of carbohydrate breakdown

As already emphasized above, the HMP pathway of carbohydrate breakdown is a side one. This pathway is found in the adrenal glands, red blood cells, adipose tissue, liver and occurs in the cytoplasm of cells.

The GMP pathway of glucose breakdown has an anabolic purpose and provides various synthesis reactions with ribose and hydrogen.

The GMF pathway can be divided into two stages, and the first stage necessarily occurs, but the second does not always occur.

The first stage begins with the transition of glucose into the active form glucose-6-phosphate, from which a carbon dioxide molecule and two pairs of hydrogen atoms are then split off, attached to the coenzyme NADP (nicotinamide adenine dinucleotide phosphate). The end product of the first stage is ribose 5-phosphate.

NADP.H2 formed as a result of the first stage supplies hydrogen atoms to various synthesis processes, in particular for the synthesis fatty acids and cholesterol. Ribose 5-phosphate is used for the synthesis of nucleotides, from which nucleic acids and coenzymes are then formed.

The second stage occurs when ribose-5-phosphate is not completely consumed for synthesis. Unused molecules of this substance interact with each other, during which they exchange groups of atoms and monosaccharides with different numbers of carbon atoms, such as trioses, pentoses, tetroses, and hexoses, appear as intermediate products. Ultimately, from six molecules of ribose-5-phosphate, 5 molecules of glucose-6-phosphate are formed.

Thus, the second stage makes this method of glucose breakdown cyclical, which is why it is called the pentose cycle.

The pentose cycle is a backup pathway of energy metabolism, which in some cases can play a leading role.

Topic 4. Structure and metabolism of fats and lipoids

3. Fat catabolism

4. Fat synthesis

1. Chemical structure and biological role of fats and lipoids

Fats or lipids are a group of structurally diverse substances that have the same physical and chemical properties: they are insoluble in water, but highly soluble in organic solvents (benzene, toluene, gasoline, hexane, etc.)

Fats are divided into two groups - fats themselves or lipids and fat-like substances or lipoids.

The fat molecule consists of glycerol and three fatty acid residues connected by an ester bond. These are the so-called true fats or triglycerides.

Fatty acids included in fats are divided into saturated and unsaturated. The former do not have double bonds and are also called saturated, while the latter have double bonds and are called unsaturated. There are also polyunsaturated fatty acids that have two or more double bonds. Such fatty acids are not synthesized in the human body and must be supplied with food, as they are necessary for the synthesis of some important lipoids. The more double bonds, the lower the melting point of fat. Unsaturated fatty acids make fats more liquid. There are many of them in vegetable oil.

Fats of different origins differ in the set of fatty acids that make up their composition.

Fats are insoluble in water. However, in the presence of special substances - emulsifiers - fats, when mixed with water, form a stable mixture - an emulsion. An example of an emulsion is milk, and an example of an emulsifier is soap - sodium salts of fatty acids. In the human body, bile acids and some proteins act as emulsifiers.

In the body of animals and humans, three classes of lipoids can be distinguished.

1. Phospholipids, consisting of fatty acids, alcohol and necessarily phosphoric acid.

2. Glycolipids, consisting of a fatty acid, alcohol and some simple carbohydrate, most often galactose.

3. Steroids containing a complex sterane ring.

The importance of fats and steroids in the body is very high.

· Fats are an important source of energy. From one gram of fat, the body extracts about 9 kcal of energy, which is 2 times more than from 1 g of carbohydrates.

· Fats protect the body from hypothermia and mechanical stress (for example, shock).

· Fatty acids and lipoids are part of many hormones.

· Lipoids are the most important components of cell membranes.

· Under the influence of UV radiation, vitamin D is formed from lipoid cholesterol.

2. Digestion and absorption of fats

The daily diet usually contains 80-100 g of fat. Digestion of fat in the human body occurs in the small intestine. Fats are first converted into an emulsion with the help of bile acids. During the emulsification process, large fat droplets turn into small ones, which significantly increases their total surface area. Pancreatic juice enzymes - lipases, being proteins, cannot penetrate into fat droplets and only break down fat molecules located on the surface. Therefore, increasing the total surface area of ​​fat droplets due to emulsification significantly increases the efficiency of this enzyme. Under the action of lipase, fat is broken down by hydrolysis into glycerol and fatty acids.

Since there are a variety of fats in food, as a result of their digestion, a large number of varieties of fatty acids are formed.

Fat breakdown products are absorbed by the mucous membrane of the small intestine. Glycerin is soluble in water, so it is easily absorbed. Fatty acids that are insoluble in water are absorbed in the form of complexes with bile acids (complexes consisting of fatty and bile acids are called choleic acids). In the cells of the small intestine, choleic acids break down into fatty and bile acids. Bile acids from the wall of the small intestine enter the liver and are then released again into the cavity of the small intestine.

The released fatty acids in the cells of the wall of the small intestine recombine with glycerol, resulting in the formation of a fat molecule again. But only fatty acids that are part of human fat enter into this process. Thus, human fat is synthesized. This conversion of dietary fatty acids into your own fats is called fat resynthesis.

Resynthesized fats through the lymphatic vessels, bypassing the liver, enter the systemic circulation and are stored in fat depots. The main fat depots of the body are located in the subcutaneous fatty tissue, the greater and lesser omentum, and the perinephric capsule.

3. Fat catabolism

The use of fat as an energy source begins with its release from fat depots into the bloodstream. This process is called fat mobilization. Fat mobilization is accelerated by the action of the sympathetic nervous system and the hormone adrenaline.

In the liver, fat is hydrolyzed to glycerol and fatty acids.

Glycerol easily transforms into phosphoglyceraldehyde. This substance is also an intermediate product of carbohydrates and therefore is easily involved in carbohydrate metabolism.

Fatty acids combine with coenzyme A to form acyl-coenzyme A (acyl-CoA). these processes occur in the cytoplasm. Next, acyl-CoA transfers the fatty acid to cornetin. Cornetin carries the fatty acid inside the mitochondria and again gives it to coenzyme A, but this time to the mitochondria. In mitochondria, fatty acid oxidation occurs in two stages.

The first stage is β-oxidation. The carbon atom of the fatty acid located in the “beta” position undergoes oxidation. From the fatty acid bound to CoA, two hydrogen atoms are split off twice, which are then transferred through the respiratory chain to molecular oxygen. As a result, water is formed and five molecules of ATP are formed. This process is repeated many times until the fatty acid is completely converted to acetyl-CoA.

The second stage of oxidation is the tricarboxylic acid cycle, in which further oxidation of the acetic acid residue included in acetyl coenzyme A occurs to carbon dioxide and water. When one molecule of acetyl coenzyme A is oxidized, up to 12 molecules of ATP are released. Thus, the oxidation of fatty acids to carbon dioxide and water provides a large amount of energy. For example, from one molecule of palmitic acid (C15 H31COOH) 130 molecules of ATP are formed. However, due to the structural features of fatty acids (too many carbon atoms compared to oxygen), their oxidation is significantly more difficult compared to carbohydrates. Therefore, fat provides the body with energy during work of average power, but for a long time. Hence the conclusion that in order to burn fat you need to carry out work of medium power, but for a long time.

Beta oxidation scheme

With prolonged physical activity and excessive formation of acetyl coenzyme A, a condensation reaction of acetic acid occurs with the formation of ketone bodies. In muscles, kidneys and myocardium, these bodies again turn into acetyl coenzyme A. Thus, ketone bodies play an important role during long-term sports training. However, when overtrained, they can form acetone in the blood, which is released in sweat, urine and exhaled air.

Activation of the synthesis of ketone bodies during fasting. Dotted lines - the speed of metabolic pathways is reduced; solid lines - the speed of metabolic pathways is increased. During fasting, as a result of the action of glucagon, lipolysis in adipose tissue and 3-oxidation in the liver are activated. The amount of oxaloacetate in mitochondria decreases, since it, having been reduced to malate, enters the cytosol, where it is again converted into oxaloacetate and used in gluconeogenesis. As a result, the rate of TCA cycle reactions decreases and, accordingly, the oxidation of acetyl-CoA slows down. The concentration of acetyl-CoA in mitochondria increases, and the synthesis of ketone bodies is activated. The synthesis of ketone bodies also increases in diabetes mellitus

4. Fat synthesis

Fats are synthesized from glycerol and fatty acids

Glycerol in the body occurs during the breakdown of fat (food and own), and is also easily formed from carbohydrates.

Fatty acids are synthesized from acetyl coenzyme A. Acetyl coenzyme A is a universal metabolite. Its synthesis requires hydrogen and ATP energy. Hydrogen is obtained from NADP.H2. The body synthesizes only saturated and monosaturated (having one double bond) fatty acids. Fatty acids that have two or more double bonds in a molecule, called polyunsaturated, are not synthesized in the body and must be supplied with food. For fat synthesis, fatty acids can be used - products of hydrolysis of food and body fats.

All participants in fat synthesis must be in active form: glycerol in the form of glycerophosphate, and fatty acids in the form of acetyl coenzyme A. Fat synthesis occurs in the cytoplasm of cells (mainly adipose tissue, liver, small intestine). The pathways for fat synthesis are presented in the diagram.

It should be noted that glycerol and fatty acids can be obtained from carbohydrates. Therefore, with excessive consumption of them against the background of a sedentary lifestyle, obesity develops.

Topic 5. Structure and metabolism of nucleic acids

1. Structure of mononucleotides

3. Digestion of nucleic acids. Catabolism

4. Nucleotide synthesis

5. Nucleic acid synthesis

1. Structure of mononucleotides

By their structure, nucleic acids are polynucleotides, consisting of mononucleotides or nucleotides.

A nucleotide is a complex organic compound consisting of three parts: a nitrogenous base, a carbohydrate and phosphoric acid residues.

Nitrogen bases are heterocyclic organic compounds belonging to two classes - purines and pyrimidines. Among the purines, nucleic acids include adenine and guanine

And among the pyrimidines, cytosine, thymine (DNA) and uracil (RNA).

The carbohydrate components of nucleotides can be ribose (RNA) and deoxyribose (DNA)

The nitrogenous base bound to a carbohydrate is called a nucleoside.

Phosphoric acid is attached by an ester bond to the fifth carbon atom of ribose or deoxyribose. The nucleotides that make up nucleic acids have one phosphoric acid residue and are called mononucleotides. However, di- and trinucleotides are found in the cell.

For example, a nucleotide consisting of adenine, ribose and one phosphoric acid residue is called adenosine monophosphate or AMP, and a nucleotide consisting of cytosine and one phosphoric acid residue is called cytosine monophosphate or CMP.

2. Structure of nucleic acids

From a chemical point of view, nucleic acids are irregular polymers consisting of rather complex monomers called nucleotides.

There are two classes of nucleic acids in cells - DNA and RNA. DNA is deoxyribonucleic acid and RNA is ribonucleic acid.

The structure of DNA is very complex and unique. Each nucleotide that makes up DNA is made up of a deoxyribose sugar unit, a phosphoric acid unit, and a nitrogenous base. There are four types of nitrogenous bases: adenine, guanine, cytosine, and thymine. Nucleotides are linked into long chains using phosphorus-diester bonds.

In 1953, researchers James Watson and Francis Crick proposed a model that explained the structure of the DNA molecule. According to their theory, DNA consists of two helical chains connected by hydrogen bonds. The nitrogenous bases of both chains are located inside the helix and form hydrogen bonds. These bonds connect DNA strands not randomly, but according to the principle of complementarity or correspondence. The essence of this principle is as follows: if thymine is in one chain, then in the opposite chain it corresponds to adenine, and cytosine always stands opposite guanine. This means that when DNA is doubled, another can be completed on each of its chains, and instead of one molecule you get two at once.

The principle of complementarity underlies all processes associated with the implementation of genetic information: DNA replication (DNA doubling), transcription (RNA synthesis on DNA templates), and translation (protein biosynthesis based on RNA templates).

The diagrams below demonstrate the structure of DNA and the principle of complementarity.

DNA structure

Principle of complementarity

In addition to DNA, there are three types of RNA in cells: messenger RNA (i-RNA), transport RNA (t-RNA) and ribosomal RNA (r-RNA). They all differ from DNA in a number of features. Firstly, instead of the nitrogenous base thymine, they contain uracil. Second, instead of the sugar deoxyribose, they contain ribose. Thirdly, they are usually single-stranded.

3. Digestion and absorption of nucleic acids. Catabolism

About 1 g of nucleic acids enters the body with food per day.

Digestion of nucleic acids occurs in the small intestine. First, nucleic acids received from food are converted into mononucleotides under the action of pancreatic juice enzymes - nucleases. Then, under the influence of enzymes of the small intestine, phosphoric acid is cleaved from mononucleotides, and nucleosides are formed. Some of the nucleosides are then broken down into nitrogenous bases and carbohydrates.

The products of nucleic acid digestion enter the blood, and then the liver and other organs.

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Biochemical research in sports practice is carried out either independently or as part of a comprehensive medical and biological control of the training of highly qualified athletes.

MAIN TASKS OF BIOCHEMICAL CONTROL:

Assessing the level of general and special training of an athlete (it should be noted that biochemical studies are more effective for characterizing general training, i.e. physical training athlete. Special training largely depends on the technical, tactical and psychological preparation of the athlete).

Assessing the compliance of the applied training loads with the functional state of the athlete, identifying overtraining.

Monitoring recovery after training.

Assessing the effectiveness of new methods and means of developing speed and strength qualities, increasing endurance, accelerating recovery, etc.

Assessing the athlete’s health status, detecting the initial symptoms of diseases.

METHODS OF BIOCHEMICAL CONTROL

A special feature of biochemical research in sports is its combination with physical activity. This is due to the fact that at rest the biochemical parameters of a trained athlete are within normal limits and do not differ from similar indicators of a healthy person.

However, the nature and severity of biochemical changes that occur under the influence of physical activity significantly depend on the level of training and functional state of the athlete. Therefore, when conducting biochemical studies in sports, samples for analysis (for example, blood or urine) are taken before the testing physical activity, during its implementation, after its completion and at different periods of recovery.

Physical activity used for testing can be divided into two types: standard and maximum.

Standard physical activity is strictly dosed. Their parameters are determined in advance. When conducting biochemical control in a group of athletes (for example, players of one team, members of one sports section, etc.), these loads must be accessible to all subjects and well reproducible.

Such loads can include the Harvard step test, work on a bicycle ergometer and other exercise equipment, or running on a treadmill. When using the Harvard step test (climbing onto a bench with a height of 50 cm for men and 40 cm for women), the height of the bench, the frequency of ascension are pre-set (the height of the bench and the pace of the load determine the power of the work performed) and the execution time this test.

When performing standard work on a bicycle ergometer and other exercise equipment, the force with which the pedals are rotated, or the weight of the weight, the pace of the load (in the case of a bicycle simulator, the cadence of the pedals) and the duration of the load are set.

When working on a treadmill (“treadmill”), the angle of inclination of the track, the speed of the belt and the time allotted for performing the load are regulated.

As standard work, you can also use cyclic exercises such as running, race walking, rowing, swimming, skiing, cycling, skating, etc., performed by all subjects at the same speed for a predetermined time or at the same distance.

Of all the described standard loads, work on an exercise bike is still more preferable, since in this case the volume of work performed can be determined with great accuracy and depends little on the body weight of the subjects.

When assessing the level of fitness using standard loads, it is advisable to select groups of athletes of approximately the same qualifications.

Standard load can also be used to evaluate the training effectiveness of a single athlete. For this purpose, biochemical studies of this athlete are carried out at different stages training process using the same standard loads.

Maximum, or extreme, physical activity (work “to failure”) does not have a predetermined volume. They can be performed at a given intensity for the maximum time possible for each subject, or for a given time, or at a certain distance with the maximum possible power. In these cases, the volume of load is determined by the athlete’s fitness.

As maximum loads, you can use the Harvard step test described above, the bicycle ergometer test, and running on a treadmill, performed “to failure.” “Failure” should be considered a decrease in a given pace (frequency of climbing onto a bench or rotating pedals, running speed on a treadmill).

Working “to failure” also includes competitive loads in a number of sports (for example, gymnastics and track and field exercises, race walking, rowing, swimming, cycling, skiing and skating).

Standard and maximum loads can be continuous, stepped and interval.

To assess general fitness (general physical fitness - GPP), standard loads that are non-specific for a given sport are usually used (to exclude the influence of the technical and tactical training of the athletes being examined). An example of such a non-specific load would be a bicycle ergometer test.

Assessment of special training is most often carried out using exercises characteristic of the corresponding sports specialization.

The power of testing loads (standard and maximum) is determined by the tasks of biochemical control.

To assess anaerobic performance, loads in the zone of maximum and submaximal power are used. The aerobic capabilities of an athlete are determined using loads in the zone of high and moderate power.

GENERAL DIRECTION OF BIOCHEMICAL SHIFT IN THE BODY AFTER PERFORMING STANDARD AND MAXIMUM LOADS, DEPENDING ON THE FITNESS LEVEL

The biochemical changes that occur after performing a standard load are usually greater, the lower the athlete’s level of training. Therefore, standard work of the same volume causes pronounced biochemical changes in poorly trained subjects and has little effect on the biochemical indicators of well-trained athletes.

For example, a significant increase in lactate content in the blood after a standard load indicates a low capacity for aerobic energy formation, as a result of which the muscles had to rely heavily on glycolytic resynthesis of ATP to provide energy for the work performed. Athletes with a high level of training have a well-developed aerobic energy supply (tissue respiration), and when performing a standard load it is the main source of energy, and therefore the need for the glycolytic method of ATP formation is small, which ultimately manifests itself in only a slight increase in blood lactate concentration.

Hydrogen index (pH);

Alkaline blood reserve;

Plasma protein concentration;

Glucose concentration;

Lactate concentration;

Concentration of fat and fatty acids;

Urea concentration.

The biological significance of the listed biochemical indicators, their values ​​at rest, as well as their changes under the influence of physical activity are described above in Chapters 12 “Blood Biochemistry” and 16 “Biochemical changes in the body during muscle work.”

It must be emphasized once again that when interpreting the results of biochemical studies, it is necessary to take into account the nature of the physical work performed.

Urine

Due to the possibility of infection during blood collection (for example, infection with hepatitis or AIDS), urine has recently become the object of biochemical control in sports.

To conduct biochemical studies, daily urine can be used (i.e., urine collected during the day), as well as portions of urine obtained before and after physical activity.

In daily urine, the creatinine coefficient is usually determined - the excretion of creatinine in urine per day per 1 kg of body weight. In men, creatinine excretion ranges from 18-32 mg/day-kg, in women - 10-25 mg/day-kg. The creatinine ratio characterizes the reserves of creatine phosphate in the muscles and correlates with muscle mass. Therefore, the value of the creatinine coefficient allows us to assess the possibilities of creatine phosphate resynthesis of ATP and the degree of muscle development. Using this indicator, you can also evaluate the dynamics of an increase in creatine phosphate reserves and an increase in muscle mass in individual athletes during the training process.

To carry out biochemical analysis, portions of urine taken before and after exercise are also used. In this case, immediately before performing testing loads, subjects must completely empty their bladder, and urine collection after the load is carried out 15-30 minutes after its completion. To assess the course of recovery processes, urine samples obtained the next morning after performing the testing load can be examined.

Research carried out at the Department of Biochemistry of St. Petersburg State Academy of Physical Culture named after. P.F. Lesgaft, revealed a clear correlation between changes in biochemical parameters of blood and urine caused by physical work, and a higher increase in these parameters was observed in urine. As an example in Fig. Figure 22 shows data on the effect of bicycle ergometric load in a high-power zone on indicators of free radical oxidation - diene conjugates, TBA-dependent products, Schiff bases (see Chapter 17 “Molecular mechanisms of fatigue) and the level of blood and urine lactate.

Before load

After load

Mochadiene TBA-dependent Schiff bases lactate conjugates products (arbitrary units/l) (μmol/l) (arbitrary units/ml) (mmol/l) Fig. 22. Changes in biochemical parameters of blood and urine under the influence of bicycle ergometric load. As can be seen from the figure, for all studied indicators, except for Schiff bases, significantly greater changes under the influence of physical activity are found in the urine. For example, blood lactate levels increased slightly more than 2-fold, while urine lactate levels increased 11-fold.

This difference may be due to the fact that in the urine during physical activity there is a gradual accumulation (cumulation) of chemical compounds coming from the blood, leading to a significant increase in their content in the urine after completion of the work. In addition, physical activity causes not only a change in the content of its ingredients in the urine, but also leads to the appearance in it of substances that are absent at rest - the so-called pathological components (see Chapter 16 “Biochemical changes in the body during muscle work").

In sports practice, when analyzing urine obtained before and after performing testing loads, the following physicochemical and chemical indicators are usually determined:

Volume (diuresis);

Density (specific gravity);

Acidity (pH);

Dry residue;

Urea;

Indicators of free radical oxidation (diene conjugates, TBA-dependent products, Schiff bases);

Pathological components (protein, glucose, ketone bodies).

The listed biochemical parameters of urine were discussed in detail in chapters 13 “Biochemistry of the kidneys and urine” and 16 “Biochemical changes in the body during muscular work.” When assessing detected changes in urine samples after performing testing loads, it is necessary to proceed from their nature. In well-trained athletes, standard loads lead to a slight change in the physicochemical properties and chemical composition of urine. In those with little training, on the contrary, these changes are quite significant. After performing maximum loads, more pronounced changes in urine parameters are found in athletes highly qualified.

Separately, we should dwell on the features of urea excretion in the urine after completion of muscular work. The literature provides data on both an increase and a decrease in urea excretion after physical exercise. This inconsistency is due to different times of urine sampling. At the Department of Biochemistry of St. Petersburg State Academy of Physical Culture named after. P.F. Lesgaft studied in detail the dynamics of urea excretion after performing standard high-power loads. It turned out that in portions of urine taken for analysis 15-30 minutes after performing the load, the urea content is usually lower compared to its excretion before the start of work, and this is more pronounced in poorly trained subjects.

The discovered phenomenon can be explained by the fact that when performing work, the excretory function of the kidneys deteriorates (in Chapter 16 “Biochemical changes in the body during muscular work” it was noted that when performing prolonged physical work, the level of urea in the blood can increase several times , which is evidence of a decrease in renal excretion). In urine samples taken in the morning the day after exercise, an increased urea content is found compared to the resting level.

Here, too, the dependence of urea excretion on the level of training can be traced: in poorly trained individuals, large amounts of urea are excreted, and in highly qualified athletes, its content only slightly exceeds the pre-working level. Recently, express diagnostic methods are increasingly used in urine analysis. These very simple methods (mainly using indicator paper) make it possible to quickly conduct a urine test in any conditions, and this can be done not only by biochemist specialists, but also by coaches and the athletes themselves.

Using express methods, you can quickly determine the concentration of urea, the presence of protein, glucose, ketone bodies in urine portions, and measure the pH value. The disadvantage of express control is the low sensitivity of the methods used. Express control methods also include the color sediment reaction according to Ya.A. Kimbarovsky (TSORK). This reaction is carried out in the following way: A solution of silver nitrate is added to a portion of the urine being tested. Upon subsequent heating, a colored precipitate forms.

The intensity of the Kimbarovsky reaction is expressed in conventional units, based on the color and color saturation of the resulting sediment, using a special color scale. The values ​​of CORC correlate with the depth of biochemical and physiological changes that occur under the influence of physical activity, including changes in the urea content in the blood. Therefore, with the help of CORK, one can indirectly judge the concentration of urea in the blood.

When studying the topic “Biochemistry of Athlete Nutrition”, the student must know :

1. Basic principles of athlete nutrition;
2. Factors that determine the value of food.

Be able to:

1. Make a diet in accordance with the stage of the training process;
2. Properly use biologically active food supplements to improve sports performance.

Own:

Basic concepts of the topic (nutrition, diet, calories, vitamins, basal metabolism, daily energy expenditure).

Nutrition - this is the entry of food into the body, its transformation in the digestive system, the absorption of the main components of food into the blood and their assimilation by the tissues of the body. To achieve high sports results it is necessary correct program nutrition, which should take into account the specifics of the sport, gender, age of the athlete, as well as training conditions and the schedule of the training process.

Proper nutrition athlete helps to increase physical performance, accelerating recovery, adapting to stress, relieving stress, etc. Rational nutrition requires adherence to the principle: the amount of energy received must correspond to the amount of energy expended.

Human food contains many chemical compounds, both organic and mineral. In addition to useful ones, food may also contain substances that are unnecessary for the body, as well as harmful to it. The main share of organic substances consists of proteins, fats, and carbohydrates. Some of the organic substances are vitamins, which are required by the body in small concentrations.

Nutrients can be replaceable or irreplaceable. Replaceable - those that can be formed in the body from other substances. For example, fats can be formed from carbohydrates, carbohydrates from amino acids, some amino acids from other amino acids and carbohydrates. Essential nutrients are not synthesized in the body and therefore must be supplied with food.

Essential amino acids include: valine, leucine, isoleucine, threonine, methionine, phenylalanine, tryptophan, lysine. If the body does not receive at least one essential amino acid, then the processes of protein biosynthesis stop. The content of these amino acids determines the nutritional value of any protein. The nutritional value is high if the protein contains all the essential amino acids in the proportions required by humans. Many animal proteins satisfy this requirement. In plant proteins, there is often a lack of methionine, tryptophan, and lysine.

The most important nutritional problem is meeting human protein needs, which consists of the need for total nitrogen and essential amino acids. A successful combination of products of plant and animal origin allows you to fully satisfy the body's need for protein.

Protein malnutrition leads to serious disruptions in the functioning of the body. The processes of tissue renewal, the synthesis of enzymes and hormones of protein-peptide nature are reduced, and immunity is reduced. Children may experience impairments in physical and mental development.

Essential fatty acids. Most of the fatty acids needed by humans can be synthesized in the body from carbohydrates. Essential ones include linoleic and linolenic acids. Linoleic acid is a precursor of arachidonic acid, from which tissue hormones - prostaglandins are synthesized. The combination of the above acids is called vitamin F. The main food sources of polyunsaturated fatty acids are vegetable oils. Phospholipids, which are involved in the construction of cell membranes, deserve special attention. Phospholipids are found in unrefined vegetable oils and egg yolk. Products of plant and animal origin contain sterols, the most important of which is cholesterol. Bile acids and sex hormones are synthesized from cholesterol in the body; in addition, it is a precursor of vitamin D. About 20-30% of cholesterol comes from food, and the main part of it is synthesized in the human body. The richest foods in cholesterol are eggs, cheeses, butter, and offal.

A sharp decrease in the intake of fats from food can lead to adverse events: dystrophy, weakened immunity, a decrease in fat-soluble vitamins, and a deterioration in the condition and functions of cell membranes.

Vitamins – most important group essential nutrients. About two dozen vitamins are known. Based on solubility, they are divided into water-soluble and fat-soluble. Fat-soluble ones include A, D, E, K; all others are classified as water-soluble. In addition to vitamins, there is a group of substances that, according to the mechanism of participation in metabolism, are not classified as vitamins. These are so-called vitamin-like substances. A condition in which the level of vitamins in the body is reduced is called hypovitaminosis, and excessive consumption of vitamins is called hypervitaminosis.

Many athletes use not only natural food products, but also special ones - the so-called ergogenic substances that increase the level of physical performance, as a rule, ergogenic substances are biologically active substances that affect the processes of energy formation or the mechanisms of their regulation. The most commonly used are: carnitine, creatine, creatine phosphate and phosphates, as well as some organic acids.

Nutrition helps increase physical performance, speed up recovery processes, improve adaptation mechanisms to systematic physical activity, relieve stress, etc. Therefore, it is important to take into account the type of sport, as well as the stages of preparation or competition, and the conditions for their holding. Thus, when compiling an athlete’s diet, it is necessary to take into account:

· energy expenditure of athletes;

· component composition of the diet;

· selection of products of increased biological value;

· vitamin intake by athletes;

· deterioration of the digestive system during physical activity, etc.

Calorie content A person's daily diet varies depending on the amount of energy consumed. When there is insufficient energy intake from food, the body uses up reserve substances, mainly fats and complex carbohydrates, and over a long period of time, it also begins to break down proteins, which leads to a decrease in body weight, muscle atrophy, anemia, growth retardation, and a decrease in physical performance.

With excess energy intake, its consumption decreases, so some of the carbohydrates and fats are deposited in the tissues as fat, which can lead to obesity.

The daily energy expenditure of the human body includes:

· BX (the minimum amount of energy required to maintain basic body functions and biosynthetic processes in a state of relative rest),

· specific - dynamic effect of food, or energy expenditure on digestion and absorption of food (with a mixed diet - on average 10-15% of daily energy expenditure),

· energy consumption for various types of activities.

Basic metabolism depends on:

· age;

· body weight;

· external conditions;

· individual characteristics of a person.

On average, for an adult man weighing 65 kg it is 1600-1800 kcal, and for women weighing 55 kg it is 1300-1400 kcal. In children, per unit of body weight, the basal metabolism is 1.5 times higher than in adults, and in older people, it is correspondingly lower.

The average energy expenditure of athletes is presented in Table 1.

Table 1.

An athlete's daily energy requirement (kcal)

Nutrition during competitions and at a distance has a number of features. Before starting, it is very important to increase the level of carbohydrates and vitamins in the body. This problem can be solved by drinking small amounts of drinks containing glucose, sucrose and other substances.

If the athlete faces a very long load, then the athlete is provided with nutrition during the distance. Food must meet the following requirements:

• quickly replenish energy reserves;
• eliminate the feeling of thirst and dry mouth;
• do not increase diuresis;
• should taste familiar;
• should not burden the gastrointestinal tract.

Self-test questions

1. Give the concept of “athlete nutrition”.
2. What determines the value of food?
3. What components determine a person’s daily energy expenditure?
4. What determines the basal metabolic rate?
5. Justify the different caloric content of the diet in different sports.
6. What are the features of nutrition during the race and before the start?

Conclusion

Studying the biochemistry of muscle activity allows the coach and athlete to build sports training at a high scientific and methodological level, taking into account the biochemical patterns of development of adaptation to physical activity.

The development of sports qualities presupposes knowledge of the mechanisms of energy generation and energy supply to muscle activity. Increasing stress in sports highest achievements must be adjusted in a certain way to prevent the development of overtraining.

Each athlete, having the necessary knowledge of anatomy, physiology and biochemistry of sports, is able to competently organize his activities, speed up recovery processes, and increase the level of performance.

Test options for part-time students

Option 1.

1. Biochemical composition of living organisms. The concept of macro-, micro-, ultra-microelements.
2. Steroid hormones. Mechanism of action. Features of the use of steroids in sports practice.
3. Glycolysis and its regulation during muscle activity.

Option 2.

1. General characteristics of amino acids. Properties, classification, biological significance.
2. Bioenergetics of muscle activity. Aerobic and anaerobic mechanisms of ATP resynthesis.
3. Dynamics of biochemical processes during the rest period after muscular work.

Option 3.

1. Squirrels. Classification. Properties, structure, elemental composition, biological role.
2. Energy in the cell. Biological role of high-energy compounds.
3. Biochemical characteristics of fatigue. Features of the development of fatigue when performing exercises of varying power and duration.

Option 4.

1. Enzymes. Classification of enzymes. The mechanism of action of enzymes in the body.
2. Metabolism in the body. Types, stages and regulation of metabolism.
3. Oxygen transport and consumption during muscle activity. The concept of oxygen debt and oxygen deficiency.

Option 5.

1. Protein biosynthesis and factors influencing the rate of this process
2. Exchange of water and minerals during muscle activity
3. Basic principles of athlete nutrition. The role and ratio of proteins, fats, carbohydrates in an athlete’s diet.

Option 6.

1. General characteristics of carbohydrates and their classification. Biological role of carbohydrates.
2. ATP resynthesis and its features when performing exercises of varying power and duration.
3. Structure and functions of muscle fiber. Chemical composition of muscle tissue

Option 7.

1. General characteristics of lipids. Classification of lipids. Biological role of lipids.
2. Energy transformation in living organisms. Biological oxidation as the main mechanism for releasing energy in living organisms.
3. Training. Patterns of biochemical restructuring of muscles under the influence of training.

Option 8.

1. Peptide hormones. Structure, mechanism of action.
2. Lipid metabolism. Lipid metabolism disorders. The influence of muscle activity on lipid metabolism.
3. Doping control and the effect of doping on the human body.

Option 9.

1. General characteristics of vitamins. The role of vitamins in human nutrition. Vitamin-like substances. Antivitamins.
2. Free oxidation. Conjugate oxidation. Oxidative phosphorylation.
3. Patterns of development of adaptation during physical activity. Principles of training.

Option10.

1. Characteristics of fat-soluble vitamins.
2. Biological oxidation. Types of oxidative reactions (direct addition of oxygen, abstraction of hydrogen, electron transfer, respiratory chain)
3. Biochemical characteristics of recovery processes during muscle activity

Option 11.

1. Characteristics of water-soluble vitamins.
2. Interrelation and regulation of metabolic processes.
3. Biochemical foundations of speed-strength training methods for athletes.

Option 12.

1. Metabolism of carbohydrates in the body during muscle activity.
2. The most important muscle proteins. Molecular structure of myofibrils.
3. Biochemistry of speed-strength qualities of an athlete. Methods of speed-strength training.

Option 13.

1. Protein metabolism, nitrogen balance. Speed ​​dependence metabolic processes by age, gender, muscle activity.
2. Adaptation and training effect. Specificity and reversibility of adaptation.
3. Biochemical characteristics of a trained organism. Biochemical processes in the body during overtraining.

Option 14.

1. Using the features of recovery processes during construction sports training.
2. Factors limiting sports performance. Aerobic and anaerobic performance of athletes.
3. Molecular mechanism of muscle contraction.

Option 15.

1. Biochemical factors of endurance. Training methods that promote endurance development.
2. The phenomenon of super-recovery (supercompensation). Using the features of recovery processes when constructing training.
3. Biochemical changes in various organs and tissues during muscular work.

Option 16.

1. The concept of alactic, glycolytic and aerobic components of endurance.
2. Biochemical control in sports.
3. Features of an athlete's nutrition.

As part of studying the course “Biochemistry”, students studying in the correspondence department master a large amount of information independently. They learn to analyze the material, master the content, identify features of the problem being studied, evaluate phenomena, use the acquired knowledge in practice, be able to compare, correlate, and juxtapose.

Performance test work in biochemistry of sports requires students to know basic (school) courses in biology and chemistry, as well as sections of biochemistry:

1. Static biochemistry, in which the student gains an understanding of the elemental and molecular composition of the human body.
2. Dynamic biochemistry, which studies the characteristics of metabolism and energy in the human body.

The quality of the written test is assessed according to the following criteria:

Unity of content (clear formulation of the main idea, unidirectionality of the material used to reveal it);

Clarity of composition (connection between all sections, parts);

Use of specific facts (to support the main idea);

Grammatical correctness.

When performing work, follow the following rules:

1. the work is prepared in accordance with the requirements for tasks of this kind;

2. for teacher comments, leave the fields on the left;

3. pages must be numbered, the headings of questions and subparagraphs are clearly highlighted in accordance with the plan;

4. in the text, be sure to make footnotes to the literature used in accordance with the requirements of GOST;

5. a list of references used is given at the end of the work in alphabetical order; this is an integral part of the work, to a certain extent reflecting the degree to which the student has studied the problem.

Literature

Main:

1. Biochemistry / Ed. Menshikova V.V., Volkova N.I. – M.: Physical culture and sport, 1986.
2. Volkov N.I., Nesen E.N., Osipenko A.A., Korsun S.N. Biochemistry of muscle activity - Kyiv: Olympic literature, 2000.
3. Dynamic biochemistry: educational and methodological manual for FFKiS students/ Comp. A.A. Govorukhina. – Surgut: RIO SurGPI, 2003
4. Static biochemistry: educational and methodological manual for students of FFKiS / Comp. A.A. Govorukhina. – Surgut: RIO SurGPI, 2002.

Scientific and practical journal "Medicine of extreme situations"
№3 (61) / 2017

Key words: sports medicine, biochemistry, clinical laboratory, physical activity, elite sports.

Keywords: sports medicine, biochemistry, clinical laboratory, exercise stress, sport of highest achievements.

Abstract: The article presents the results of studies of biochemical blood parameters in highly qualified athletes in comparison with similar indicators in untrained people based on an analysis of Russian and foreign studies. The paper presents the characteristics and features of the dynamics of the results of the main markers of functional systems. A comparative analysis was carried out, the features of the dynamics of biochemical parameters under the influence of physical activity in various sports were shown. The basic principles for interpreting the results of biochemical examinations in athletes are summarized. Based on the analysis of literary sources, conclusions were drawn in which the authors emphasize the importance and relevance of this issue in the field of sports medicine.

Abstract: This article presents the results of studies of biochemical blood parameters in highly skilled athletes in comparison with similar indicators in untrained people on the basis of the analysis of Russian and foreign studies. The paper presents the characteristic and feature of the dynamics of the results of the main markers of functional systems. The comparative analyze is carried out, we can see features of physical dynamics of biochemical indicators depends active in various kinds of sports. Basic principles of interpretation of the results of biochemical examination in athletes are summarized. Conclusions are drawn based on the analysis of literature sources, in which the authors emphasize the significance and relevance of this topic in the field of sports medicine.

Introduction

One of the main tasks of a sports medicine doctor working with highly qualified athletes is to assess their health status and identify organic and functional pathological changes that can develop against the background of regular intense physical activity. To assess the functional state of athletes and their level of adaptation to physical activity, a regular in-depth medical examination is carried out, in which hematological parameters and biochemical markers of metabolic processes are studied.
Any physical work is accompanied by a change in the speed of metabolic and biochemical processes in the body, working muscles, internal organs and blood. The depth of biochemical changes that occur in muscle tissue, internal organs, blood and urine during physical activity, depends on its power and duration. The living conditions of an athlete differ significantly from those observed among people who do not engage in sports. This includes adherence to a strict daily routine, stressful conditions during competitions, frequent travel, changing time zones and climate zones, subordination to the demands of the coach, and finally, the need to systematically perform heavy physical activity.
Based on the order of the Ministry of Health of Russia dated March 1, 2016 No. 134n “On the Procedure for organizing the provision of medical care to persons involved in physical education and sports (including during the preparation and conduct of physical education events and sporting events), including the procedure for medical examination of persons wishing to undergo sports training, engage in physical education and sports in organizations and (or) fulfill the standards of testing (tests) of the All-Russian Physical Culture and Sports Complex "Ready for Labor and Defense" systematic monitoring of the health status of persons involved in physical education and sports (including during preparation and conduct physical education events and sports events), carried out by a sports medicine doctor constantly for the purpose of operational monitoring of their health and the dynamics of the body’s adaptation to training and competitive loads and includes preliminary and periodic medical examinations, including an in-depth medical examination program, staged and ongoing medical examinations, medical and pedagogical observations. Based on Appendix N2 to this order, a list of mandatory biochemical blood parameters has been established during an in-depth medical examination (IME) of athletes from Russian national teams.
Traditionally, biochemical markers have been of interest in sports science to determine the athlete’s level of performance or overtraining. IN last years is given Special attention to the relationship of biochemical blood parameters with the level of intensity of physical activity. In elite sports, biochemical markers are key parameters for assessing the impact of physical exercise on various organs and systems of an athlete. The values ​​or concentrations of biochemical parameters of blood serum depend on many factors. This includes the level of physical fitness of the athlete, the level of his psycho-emotional stability, age, gender, and, of course, state of health. The main problem of correct interpretation of biochemical parameters in athletes is the lack of reference values ​​for them.
In our article, we tried to identify whether the norms of biochemical blood parameters in highly qualified athletes differ from the same indicators in untrained people, and also to highlight the most important biochemical markers in athletes that must be taken into account in the work of a sports medicine doctor.
The most significant biochemical blood parameters in athletes based on the analysis of Russian and foreign studies are lactate, creatine phosphokinase (CPK), creatinine, lactate dehydrogenase (LDH), uric acid, urea, BNP, pro-BNP, alpartate aminotransferase (AST), alanine aminotransferase (ALT) , bilirubin, myoglabin, troponin, cystatin C, iron.

Liver parameters

One study determined the concentration of aminotransferases (ALT, AST) and body mass index (BMI) in professional athletes out of 7 various types sports (rugby, triathlon, football, swimming, cycling, basketball, skiing) before the start of training and the competitive season. There were no statistically significant differences in concentrations between athletes and the control group (people not involved in professional sports), and there were no significant differences in the concentrations of ALT and AST in the blood serum between athletes (runners, hammer throwers, wrestlers, weightlifters) and age-matched control group. AST activity increases significantly immediately after exercise and decreases to normal values ​​one hour after exercise in hockey players. . Accurate assessment and interpretation of ALT and AST concentrations in elite athletes is essential for the diagnosis of pathological conditions and the prevention of overtraining. A study was conducted among football players. The average AST values ​​before and after training were higher than in the control group. ALT levels remained within normal limits. The mean GGT value was higher than normal only after training. Regarding bilirubin metabolism, its levels in the blood plasma of athletes were similar before and after the race, regardless of gender. . It was also found that among athletes, an increase in bilirubin concentration is in second place after an increase in AST. In a study of 10 elite football players, blood samples were taken at the end of the season, after a recovery period, and then after the following pre-season training. Mean bilirubin values ​​increased significantly at the end of the recovery period and then returned to baseline levels before the start of the new season.
Lactate dehydrogenase is a catalytic enzyme that is found in most tissues of the human body, and in particular in the heart, liver, kidneys, muscles, blood cells, brain and lungs. During acute stress reactions, there is an increase in the level of LDH activity in the blood serum. There is a connection between the level of LDH activity and the body's performance. Increased LDH activity is observed in athletes at rest and after intense physical activity. The results of the study revealed a decrease in LDH activity at rest in athletes of the second group, which is associated with a more energy-efficient mode of operation of the muscle tissue of athletes training speed-strength qualities.
Levels of LDH, AST, and ALT were significantly higher after completing a 100 km race than in marathon runners and significantly higher after completing a 308 km race than in marathon runners or a 100 km race.

Muscle indicators

Creatine phosphokinase is used as a marker of damage muscle fibers. Blood concentration increases in response to continuous muscle contractions. A study of track and field athletes found that the increase in creatine kinase during exercise was dependent on the intensity of the exercise. Although CPK concentrations have mainly been studied in individual sports, it is also interesting to evaluate this parameter in team sports, which are characterized by severe and intensive training and competitions. Rugby is considered one of the most physically demanding team sports in the world. In a study by B. Cunniffe, CPK was measured in 10 rugby players during international tournament. It was found that the CPK values ​​after the game were significantly higher than the values ​​of this indicator before the game. In a study conducted on wrestlers in Turkey, creatine kinase levels were found to be significantly higher than the normal range for the general population. Swiss scientists conducted a study aimed at studying the level of muscle markers in the biochemical analysis of the blood of elite floorball players. A significant increase in creatine phosphokinase and myoglobin was found after exercise. A study of markers of muscle damage conducted in Brazil among tennis players found a slight increase in myoglobin and CPK 24-48 hours after play. However, in blood samples taken immediately after the game, a significant increase in the level of these indicators was found.

Heart indicators

Brain natriuretic peptide (BNP) is synthesized by cardiomyocytes and released into the bloodstream. The cleaved form of BNP's precursor, NT-proBNP, can also be measured in the blood and is a marker for assessing and monitoring pathological cardiac conditions. This hormone, being an antagonist of the renin-angiotensin system, reduces the effect on the myocardial wall due to natriuretic, vasodilating and sympathoinhibitory effects. It is also a regulator of heart cell growth. Exercise causes an increase in pro-BNP, troponin, but serum concentrations are rarely above the upper limit of normal for the general population. In 15 mountain marathon runners, the average pro-BNP concentration after the race was more than 2 times higher than that before the race. Pro-BNP was measured in 15 male athletes participating in a marathon under extreme conditions (distance 246 km, temperature 5-36 C and humidity 60-85%). Blood tests were taken before the start of the race, within 15 minutes after the end of the race, and 48 hours later. A sharp increase in Pro-BNP was found after the marathon compared to normal, but 48 hours after the end of the race the concentration decreased by almost half. . In athletes with left ventricular hypertrophy, increased pro-BNP concentrations are a symptom of hypertrophic cardiomyopathy. However, elevated serum concentrations of myocardial markers should not be interpreted as a danger signal, but rather as a physiological response to intense cardiac activity. In addition, NT-proBNP values ​​must be correctly interpreted in relation to glomerular filtration rate (GFR).
There is evidence that CPK-MB levels increase in hockey players. Moreover, the concentration of the indicator an hour after exercise is lower than before exercise.

Kidney indicators

In sports medicine, creatinine levels are used to assess the overall health of an athlete, for whom water and electrolyte balance plays an important role. Serum creatinine concentration is the most widely used and accepted indicator of renal function. There are no athlete-specific baseline creatinine values. And the values ​​that are used are typical for the population as a whole. However, studies have been conducted that indicate that the concentration of creatinine in the blood serum of athletes is higher than in the population. Based on the results of the studies, it was revealed that the type of sport and the associated anthropometric data of athletes can affect the concentration of creatinine in the blood serum. Creatinine levels in cyclists are stable during the competitive season, while they can be altered in athletes competing in other sports. It is also important to consider differences in training regimen and athletic performance to interpret creatinine values.
Uric acid can be elevated when muscles contract continuously during intense exercise. At the same time, the concentration of uric acid in runners is at long distances was minimal during low training intensity and highest during intensive training and competition. Giovanni Lombardi et al. monitored 18 alpine skiers from the Italian national team for four seasons. Blood samples were collected before the start of training, at the end of training, before the start of competition and at the end international competitions. According to the study, high-intensity training did not lead to significant changes in serum uric acid.
Cystatin C is an alternative to creatinine in terms of studying the dynamics of biochemical parameters in athletes. It is a low molecular weight protein that is freely filtered by the glomeruli and is a qualitative marker of renal excretory function. This indicator does not depend on age, gender and body mass index, unlike creatinine. The differences between these two markers were clearly demonstrated in a study of marathon runners. Serum cystatin C and creatinine concentrations in runners were increased after the marathon by 26% and 46%, respectively. The mean increase in cystatin C was half that of creatinine. Studies have shown that cystatin C values ​​in rugby players were within normal limits, while creatinine concentrations were in many cases higher than the upper limits of normal.

Lactate

Blood lactate levels are closely related to the intensity of physical activity. At a certain intensity of physical activity, lactate increases exponentially. Determination of lactate levels in athletes is used throughout the world. It can be considered as the current “gold standard” for determining the intensity of physical activity and the adaptation of the athlete’s body to it.
I. P. Sivokhin and co-authors conducted a study to study the dynamics of changes in lactate concentration in the peripheral blood of highly qualified weightlifters. The study showed that biochemical control over the dynamics of changes in lactate is a sensitive indicator of the athletes’ body’s response to the training load and can be used to manage the educational and training process in weightlifting.
O.P. Petrushova and co-authors conducted a study to study the mechanisms of adaptation of the acid-base balance of the blood of swimmers during the training and competitive process. The results of the study showed that before physical exercise, the level of lactate in the blood of athletes corresponds to the physiological norm, and when performing a test load, a significant increase in lactate level was found in the blood of athletes. It should also be noted that the return of swimmers’ blood acid-base balance to physiological norms occurs quite quickly, which indicates a high level of training of athletes.

Iron

In studies of iron metabolism in athletes, it was shown that intense physical activity leads to an increase in the synthesis of hepcidin, which, in turn, leads to a block in iron absorption, disruption of the transfer of iron from macrophages to erythroblasts and can cause iron deficiency.
Due to the enormous functional role of iron, disorders of its metabolism in highly qualified athletes have Negative consequences regarding professional opportunities. In iron deficiency conditions, inhibition of aerobic energy production in cells is noted from the early stages. It is obvious that the complex of physiological changes caused by iron deficiency can sharply limit the professional capabilities of an athlete and the possibility of achieving high athletic results.
Free iron in blood serum is highly variable depending on the time of day and the individual biological rhythm of the athlete. Morning values ​​are more than twice the values ​​measured 12 hours later and therefore cannot be used to determine body iron levels. In addition, free serum iron decreases in inflammatory reactions and increases in cases of hemolysis after blood collection. Currently, free iron is an outdated marker and should only be used to calculate transferrin saturation or in acute intoxications.
When interpreting the results obtained, doctors use standard indicators defined for a population of people who are not highly qualified athletes. The demands placed on the body of professional athletes differ significantly from the lifestyle of an ordinary person and consist not only in systematic intense physical activity, but also in regular psycho-emotional stress, frequent changes in time zones and climatic zones, and a certain, sometimes severe restriction of the diet in some sports. sports The main changes that develop with systematic physical activity affect the musculoskeletal system, endocrine and cardiovascular systems. To adequately assess the functioning of these systems in professional athletes, it is not correct to use general population normative indicators.
Thus, the development and scientific and methodological justification of normative ranges of biochemical and hematological parameters for highly qualified athletes is an urgent task of sports medicine. It is on the indicators of the norm established for athletes that the criteria for admission to sports should be based, and time restrictions and exemptions from physical activity should be justified.

conclusions

1. It must be remembered that alanine aminotransferase (ALT) is released mainly from the liver, and aspartate aminotransferase (AST) from muscles during intense physical activity.
2. The level of total bilirubin may be increased due to constant hemolysis (red blood cells), which is typical for intense physical activity.
3. Serum CPK concentrations tend to increase after exercise. Incomplete recovery of CPK concentrations is a sign of injury or overtraining. CPK concentrations can be used to monitor the return to activity of athletes with muscle injury.
4. NT-pro-BNP, a marker of heart wall breakdown, increases after exercise. Increased concentration serum NT-pro-BNP in athletes should not be interpreted as a signal of cardiac damage, but rather as a sign of myocardial adaptation to exercise.
5. Creatinine concentrations should be interpreted taking into account the BMI of the athletes and the phase of the competitive season. Creatinine concentrations measured during the season should not be interpreted in relation to reference intervals for the general population. It should be remembered that creatinine values ​​fluctuate during the training and competition season.
6. Cystatin C level is a significant alternative to creatinine level. Uric acid is the main antioxidant in the blood and increases in response to intense exercise.
7. The concentration of uric acid is stable throughout the competitive season.
8. Athletes have been diagnosed with high levels HDL compared to the control group. The positive effect of physical activity on an athlete’s lipid profile persists throughout life, even after cessation. sports career, If former athlete continues physical exercise.
9. Monitoring of biochemical parameters in highly qualified athletes allows us to identify the level of adaptation of various functional systems to physical activity. Establishing standard reference values ​​for biochemical parameters in highly qualified athletes is necessary for effective assessment of the functional state of athletes, because in progress sports activities the athlete’s body acquires functional characteristics that go beyond population norms. Taking into account these features can improve the quality of medical care at all stages of medical and biological support.

Bibliography:

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2. Ganeeva L.A., Skripova V.S., Kasatova L.V. and others. Assessment of some biochemical parameters of energy metabolism in student athletes after prolonged exercise // Uchen. zap. Kazan. un-ta. Ser. Natural Sciences. 2013. T. 155. Book. 1. pp. 40–49.
3. Nikulin B.A., Radionova I.I. Biochemical control in sports. // Soviet sport. 2011. pp. 9-24.
4. Pervushina O.P., Mikulyak N.I. Biomedical chemistry. 2014. T. 60. Issue 5. P. 591-595.
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Institute of Physical Culture (branch)

FSBEI HE "UralGUFK"

B1.V.10 SPORTS BIOCHEMISTRY

Educational and methodological manual

for practical classes and independent work of students,

students in the direction 49.03.01 “Physical Education”

UDC 577.1 (075)

BBK 28.072 ya73

Methodological recommendations for practical training and independent work of students in the discipline “Sports Biochemistry” / .- Ufa: Bashkir Institute of Physical Culture (branch) of the Federal State Budgetary Educational Institution of Higher Education “Ural State University of Physical Culture”, 2015.- 88 p.

Reviewer: Ph.D. biol. Sci., Associate Professor, Department of Physical Means

rehabilitation -

The proposed publication is compiled in accordance with the Federal State Educational Standard for Higher Education in the discipline “Sports Biochemistry”. Intended for the preparation of bachelors in the direction 49.03.01 – “Physical Education”.

The manual covers the main topics related to the study of the discipline “Sports Biochemistry”. The content of each topic is considered both in theoretical terms and in terms of practical use in the process of independent study of the discipline. Literature is recommended for a deeper study of the material.

© Bashkir Institute of Physical Culture (branch) of the Federal State Budgetary Educational Institution of Higher Education "Ural State University of Physical Culture"

CONTENT

Independent work of students 70

Topic 10. Biochemical foundations of rational nutrition

athletes 72

1. Introduction

Biomedical disciplines, in particular biological chemistry, occupy a large share in modern sports practice. Effective management of the training process is not possible without knowledge of sports biochemistry and the laws of metabolic regulation during physical exercise.

In accordance with the requirements for a highly qualified specialist in the field of physical culture and sports, students studying the course of sports biochemistry are faced with the following tasks:

Deepening knowledge about the medical and biological laws of sports training, fatigue and recovery after work;

Introduction to the basic methods of biochemical control in sports;

Illustration of the main theoretical principles with specific practical works;

Acquiring the skills necessary to work with scientific literature, allowing you to quickly use information to set and solve professional problems.

It is advisable to begin preparing for each lesson presented in this manual with a careful study of the lecture material and a brief theoretical introduction explaining the significance of the work performed. Questions for the lesson focus students' attention on the key sections of the topic under consideration.

The questions in the proposed homework options include all sections of the relevant topic, and completing them allows you to consolidate theoretical material. To self-test your mastery of the material, at the end of each topic, questions of programmed knowledge control are given in the form of tests with multiple-choice answers, one of which is correct.

The appendix includes: a list of key terms in sports biochemistry, a list of abbreviations.

The list of references includes a bibliography recommended for more in-depth preparation on the proposed topics.

Topics 1, 2.

CHEMICAL COMPOSITION OF MUSCLE TISSUE.

Ultra-thin structure of the muscle cell.

MECHANISM OF MUSCLE CONTRACTION

Muscle tissue in the human body accounts for 40-45% of the human body weight. In women, muscle mass is usually lower than in men, which is associated with gender differences in the manifestation muscle strength and level of physical performance. Muscles, thanks to their contractile function, provide movement processes. Manifestation of various motor qualities human performance, especially strength and speed, depends on the morphological structure of the muscles, their chemical composition, the characteristics of the biochemical processes occurring in them, as well as on the regulatory effects of the nervous system.

Muscle fiber is structural unit skeletal muscles, representing a large multinucleated cell, or more precisely, an acellular formation - symplast, which is formed by the fusion of many myoblasts in the embryonic period.

The muscle cell membrane is electrically excitable and is called the sarcolemma. On the sarcolemma there are places of contact with the endings of motor nerves - synapses (neuromuscular junctions). Like other membranes, the sarcolemma is selectively permeable to various substances. High molecular weight substances do not pass through it, but water, glucose, lactic and pyruvic acids, amino acids, ketone bodies and some other low molecular weight compounds do. The sarcolemma also has transport systems, with the help of which the difference in concentrations of Na+ and K+ ions, as well as Cl- ions inside the cell and the intercellular fluid is maintained, which leads to the appearance of a membrane potential on its surface. The formation of a membrane action potential under the influence of a nerve impulse is a necessary condition for the excitation of muscle fibers. On the surface of the sarcolemma there are tortuous collagen fibers, giving it strength and elasticity. The internal fluid of a muscle cell is called sarcoplasm. Inside the sarcoplasm there is a system of longitudinal and transverse membrane tubes and vesicles, called the sarcoplasmic reticulum (SR). SR regulates the concentration of Ca2+ ions inside the cell, which is directly related to the contraction and relaxation of muscle fiber. As in any actively working cell, muscle fiber has a large number of mitochondria. About 80% of the fiber volume is occupied by long filaments - myofibrils.

Myofibrils- these are contractile elements, the number of which in a muscle fiber can reach several thousand. Under a microscope, it is noticeable that the myofibrils have transverse striations in the form of alternating dark and light areas - discs. Dark disks are birefringent and are called A-disks (anisotropic), while light disks are not birefringent and are called I-disks (isotropic). In the central part of disk A there is a light area - the H-zone. In the middle of the I disk there is a Z-membrane that permeates the entire fiber, as if holding and ordering the arrangement of the A and I disks of many myofibrils. The area of ​​myofibril between two Z-membranes is called sarcomere. This is the smallest functional, that is, contractile unit of muscle. Sarcomeres follow each other along the myofibril, repeating every 1500-2300 nm. A myofibril may contain several hundred sarcomeres. The speed and force of muscle contraction depend on their length and quantity in the myofibril. Most muscle cells are lined up so that their sarcomeres are located parallel to each other, and the A- and I-disks of all muscle cells in the fiber coincide accordingly, which gives the resting muscle a cross-striped appearance (Fig. 1).

According to electron microscopy data (Fig. 1), myofibrillar structures are aggregates consisting of thick filaments of about 14 nm and thin filaments with a diameter of 7-8 nm located between them. Thick filaments or threads are found in A-disks and are composed of the contractile protein myosin. Thin filaments are found in I-discs and contain the contractile protein actin, as well as the regulatory proteins tropomyosin and troponin. The filaments (threads) are arranged in such a way that the thin ends fit into the spaces between the thick ones (Fig. 2).

Thus, discs-I consist only of thin filaments, and discs-A consist of two types of filaments. At rest, zone H contains only thick filaments, since thin filaments do not reach there. Thick and thin filaments of myofibrils interact with each other during contraction through the formation of cross bridges between them.

Types of muscle fibers and their involvement in muscle activity

In skeletal muscles, there are two main types of muscle fibers: slow-twitch (MS) or red and fast-twitch (FT) or white, differing in contractile and metabolic characteristics (Table 1).

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