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The muscular system undergoes significant structural and functional changes during ontogenesis. Formation of muscle cells and muscle development as structural units of the muscular system occurs heterochronically, i.e. are first formed those skeletal ones muscles thatnecessary for the normal functioning of the child’s body at this age stage. The process of “rough” muscle formation ends by 7-8 weeks of prenatal development. After birth, the process of formation of the muscular system continues. In particular, intensive growth of muscle fibers is observed up to 7 years and during puberty. By the age of 14-16 years, the microstructure of the skeletal muscle tissue almost fully matured but the thickening of the muscle fibers (improvement of their contractile apparatus) can last up to 30-35 years.

The development of the muscles of the upper extremities is ahead of the development of the muscles of the lower extremities. In a one-year-old child, the muscles of the shoulder girdle and arms are much better developed than the muscles of the pelvis and legs. Larger musclesare always formed before small ones. For example, the muscles of the forearm are formed before the small muscles of the hand. The muscles of the arms develop especially intensively at 6-7 years of age. The total muscle mass increases very quickly during puberty: for boys - at 13-14 years old, and for girls - at 11-12 years old. Below are data characterizing the mass of skeletal muscles in the process of postnatal ontogenesis.

Much The functional properties of muscles also change during ontogenesis. Increases excitability and lability muscle tissue. Changes muscle tone. The newborn has increased muscle tone, and the flexor muscles of the limbs predominate over the extensor muscles. As a result, the arms and legs of infants are often in a bent state. They have a poorly expressed ability of muscles to relax (some stiffness in the movements of children is associated with this), which improves with age. Only after 13 - 15 years of age do movements become more flexible. It was at this age The formation of all sections of the motor analyzer ends.

In the process of development of the musculoskeletal system, the motor qualities of muscles change: speed, strength, agility and endurance. Their development occurs unevenly. First of all, speed and agility are developed.

Speed ​​(speed) of movements characterized by the number of movements that a child is able to produce per unit of time. It is determined by three indicators:

1) the speed of a single movement,

2) time of motor reaction and

3) frequency of movements.

Single movement speed increases significantly in children from 4-5 years of age and reaches adult levels by 13-15 years. By the same age, the adult level also reaches simple motor reaction time, which is determined by the speed of physiological processes in the neuromuscular system. Maximum voluntary frequency of movements increases from 7 to 13 years, and in boys at 7-10 years it is higher than in girls, and from 13-14 years the frequency of movements in girls exceeds this figure in boys. Finally, the maximum frequency of movements in a given rhythm also increases sharply at 7–9 years of age. In general, the speed of movement develops to its maximum by the age of 16-17 years.

Until the age of 13-14 years, most development is completed dexterity, which is associated with the ability of children and adolescents to carry out precise, coordinated movements. Therefore, dexterity is related to:

1) with spatial accuracy of movements,

2) with temporal accuracy of movements,

3) with the speed of solving complex motor problems.

The preschool and primary school periods are the most important for the development of dexterity. The greatest increase in movement accuracy observed from 4 - 5 to 7 - 8 years. It's interesting what sports training does beneficial influence on the development of dexterity and in 15-16 year old athletes the accuracy of movements is two times higher than in untrained adolescents of the same age. Thus, until the age of 6 - 7 years, children are not able to make subtle, precise movements in an extremely short time. Then spatial precision of movements gradually develops, A behind it is a temporary one. Finally, Lastly, the ability to quickly solve the engine is improvednew tasks V different situations. Agility continues to improve until age 17-18.

Largest strength gain observed in middle and high school age, strength increases especially intensively from 10 - 12 years to 16 -17 years. In girls, the increase in strength is activated somewhat earlier, from 10 - 12 years, and in boys - from 13 - 14 years. However, boys are superior to girls in this indicator in all age groups.

Endurance develops later than other motor qualities. characterized by the time during which it persists enough level performance of the body. There are age, genderhigh And individual differences in endurance. The endurance of preschool children is low, especially for static work. An intensive increase in endurance for dynamic work is observed from 11 to 12 years old. So, if we take the volume of dynamic work of 7-year-old children as 100%, then for 10-year-olds it will be 150%, and for 14-15-year-olds it will be more than 400%. From the age of 11-12, children also rapidly increase their endurance to static loads. In general, by the age of 17-19, endurance is about 85% of the adult level. Your maximum level it reaches 25 - 30 years.

Development of movements and mechanisms of their coordination It is most intense in the first years of life and adolescence. In a newborn, the coordination of movements is very imperfect, and the movements themselves have only a conditional-reflex basis. Of particular interest is the swimming reflex, the maximum manifestation of which is observed approximately 40 days after birth. At this age, the child is able to make swimming movements in the water and stay on it until 1 5 minutes. Naturally, the child's head must be supported, since his own neck muscles are still very weak. Subsequently, the swimming reflex and others unconditioned reflexes gradually fade away, and are replaced by motor skills. All basic natural movements characteristic of a person (walking, climbing, running, jumping, etc.) and their coordination are formed in a child mainly before 3 - 5 years. Wherein great importance The first weeks of life are necessary for the normal development of movements. Naturally, even in preschool age, coordination mechanisms are still very imperfect. Despite this, children are able to master relatively complex movements. In particular, it is V At this age they learn tool movements, i.e. motor skills and skills to use tools (hammer, wrench, scissors). From 6 to 7 years old, children master writing and other movements that require fine coordination. By the beginning of adolescence, the formation of coordination mechanisms is generally completed, and all types of movements become available to adolescents. Of course, improving movements and their coordination with systematic exercises is also possible in mature age(for example, athletes, musicians, etc.).

Improving movements is always closely related to the development of the child’s nervous system. In adolescence, coordination of movements is very often somewhat disrupted due to hormonal changes. Usually by 15 - ] 6 years this temporary deterioration disappears without a trace. The general formation of coordination mechanisms ends at the end of adolescence, and by the age of 18–25 they fully reach the level of an adult. The age of 18-30 is considered “golden” in the development of human motor skills. This is the age at which his motor abilities flourish.

From birth, your child begins to struggle for existence. On the path of evolution, the strongest wins. Nature helps in the development of your baby from a tiny creature into a full-fledged and strong member of human society in all respects. It may seem to you that your baby is wasting a lot of time - just lying there and doing nothing. But in reality this is not so - at this time the body grows and develops at a fast pace. And when the baby moves his arms and kicks his legs, he trains and develops his body. His muscles and bones get used to receiving stress and the child develops and becomes stronger. Muscle strength will help him hold his head, sit and hold his back, crawl, and hold heavier objects with his hands. And the vertebral muscles and legs that have grown and trained with such movements and movements will later help him take his first steps. Caring parents are interested in harmoniously and gradually making the child stronger, helping him in this with the help of a useful set of exercises recommended by pediatricians, described below. Become a personal trainer for your baby - help him become strong from the first months of life. These 4 simple exercises will help your baby become big and strong.

1. Tummy time

Usually the child spends most of the day on his back. And his muscles in this position are loaded and trained mediocrely. But when the baby is turned onto his tummy, muscle groups that have not previously received any load are immediately put into work, and the tone and load for the body muscles - the back, abdomen, neck and shoulders - increases many times over. Already in the first days after birth, you can use such exercises as approved by the Association of American Pediatricians. Start with several times for 3-5 minutes. Exercises are best done in a playful way; place the baby on his tummy on a blanket or rug. Lie down next to him and practice in an atmosphere of cheerful communication. Make a face, show the baby a toy, attract attention in another way so that the child moves and works different muscles. And the training he needs to develop strength will become a joyful game and entertainment for him.

By distracting the baby here and there, you force him to make more movements, therefore straining different muscle groups.

At first, during such activities, the child may perceive the exercises without enthusiasm. But after several sessions, the environment of training with dad or mom will become joyful and familiar for him, and strengthened muscles will allow him to enjoy both exercise and movement. After some time, the baby will be able to spend more and more time on his tummy (up to 20 minutes a day). Over time, he will begin to grab objects and become strong enough to crawl. Experts recommend not stopping such exercises, even after the baby begins to roll over from back to tummy on his own.

2. Pull-ups

Another important and useful exercise for muscle development in children is pulling up into a sitting position. This exercise helps strengthen the muscles of the shoulders, abdomen, arms and back. Even if you do all the work for the baby, pulling him up, the baby's abdominal muscles contract. And attempts to straighten the head help the baby gain a sense of balance.

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To perform this exercise correctly, you need to place the child on his back and securely grab him by the arms, carefully and smoothly lift him up. This exercise should be carried out no earlier than one and a half months after the birth of the baby. If the baby still has trouble holding his head, instead of pulling him by the arms, support him by placing one hand behind his back and the other under the back of his head.

You need to start the exercise by lifting the baby a few centimeters from the surface. The exercise will be more fun if your face is close enough to the baby's face, or it will be more fun for the baby if you kiss the baby every time he gets up.

3. Exercise “Bicycle”

You've probably already heard about one of the methods to relieve the suffering of newborns during colic - pulling the legs towards the tummy. This exercise has other bonuses - strengthening the muscles of the legs, knees, hip joints and abdominal muscles, increases flexibility.

Place your baby on his back and make circular movements with his legs, imitating riding a bicycle. Make jokes, smile, voice everything in a fun and joyful way of communication - the child should enjoy the activities. Repeat the movement 3-5 times - pause. Continue training until it is interesting and joyful for the child.

4. Weight lifting exercises

The baby by nature must have developed grasping movements. Grabbing objects is great way develop grasping skills, coordination of movements, and also helps to develop muscles in the shoulder, arms, and hands. After the baby begins to independently grab objects with his hands, select for him and use during such training objects that are safe for him and moderately heavy as weights. Motivate your baby to pick up objects, lift them and put them down.

FEATURES OF DEVELOPMENT OF THE CHILD'S MUSCULAR SYSTEM

In the embryo, muscles begin to develop at the 6-7th week of pregnancy. Until the age of 5, the child’s muscles are not sufficiently developed, the muscle fibers are short, thin, tender and can hardly be felt in the subcutaneous fat layer.

Children's muscles grow during puberty. In the first year of life they make up 20–25% of body weight, by 8 years – 27%, by 15 years – 15–44%. An increase in muscle mass occurs due to a change in the size of each myofibril. In muscle development, an age-appropriate motor regimen plays an important role; at older ages, playing sports.

Training, repetition, and improving quick skills play a big role in the development of children's muscle activity. As the child grows and muscle fiber develops, the intensity of muscle strength increases. Indicators of muscle strength determined using dynamometry. The greatest increase in muscle strength occurs at the age of 17–18 years.

Different muscles develop unevenly. In the first years of life, large muscles of the shoulders and forearms are formed. Motor skills develop up to 5–6 years; after 6–7 years, the ability to write, sculpt, and draw develops. From 8–9 years of age, the volume of the muscles of the arms, legs, neck, and shoulder girdle increases. During puberty, there is an increase in the volume of the muscles of the arms, back, and legs. At 10–12 years of age, coordination of movements improves.

During puberty, due to an increase in muscle mass, angularity, awkwardness, and abruptness of movements appear. Physical exercises during this period must be of a strictly defined volume.

In the absence of motor load on the muscles (hypokinesia), a delay in muscle development occurs, obesity, vegetative-vascular dystonia, and impaired bone growth may develop.

For various sports, there is an acceptable age for participating in competitions at a children's sports school.

At 7–8 years old, sports activities are allowed, rhythmic gymnastics, mountain views skiing, figure skating.

From the age of 9, trampoline classes, biathlon, Nordic combined, ski jumping, and chess are allowed.

At the age of 10 you are allowed to start playing volleyball, basketball, wrestling, rowing, handball, fencing, football, and hockey.

At the age of 12 – boxing, cycling.

At the age of 13 – weightlifting.

At the age of 14 - clay pigeon shooting.

STUDY OF THE MUSCULAR SYSTEM

The muscular system is examined visually and instrumentally.

The degree and uniformity of development of muscle groups, their tone, strength, and motor activity are assessed visually and palpation.

Muscle strength in children early age determined by an attempt to take the toy away. In older children, manual dynamometry is performed.

During an instrumental examination of the muscular system, mechanical and electrical excitability is measured using electromyographs and chronaximometers.

source: Directory of Children's Diseases.

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Muscle development in a child

.J Muscle growth after birth. Even in the first half of the intrauterine period of development, muscles acquire the characteristic giving them shape and structure^ Subsequently, their length and thickness quickly increase. They grow in length according to the growth of 1 volume of skeletal bones by lengthening muscle fibers and especially tendons, with the help of which “muscles are attached to bones.” Growth in thickness to a small extent occurs due to the formation of suture fibers from existing in the muscles there are remnants of "primary muscle tissue. However, mainly (approximately 90%) growth in thickness occurs by increasing the diameter of the fibers." In newborns it does not exceed 10-15 thousandths of a millimeter, and by 3-4 years it increases by 2-2 ,5 times. In subsequent years, the diameter of muscle fibers largely depends on the individual characteristics of the body, and mainly on motor activity.

In a newborn, muscles account for 20-22% of the weight of the entire body, i.e., approximately half as much as in an adult, whose muscles most often account for 35-45% body weight. Consequently, over the entire period from birth to adulthood, the increase in muscle weight should be twice as intense as the increase in total body weight. However, at first, until the child begins to walk, muscles grow even more slowly than

^^im^prgyanichm r. prdpm^ Thus, in the first 4 months of life, total body weight doubles, and muscle weight increases only by 60% and accounts for 16% of body weight. From the end of the first year of life, under the influence of training, muscle growth gradually becomes more intense^ and by 6 years to the share of muscles again accounting for about 22% of total body weight, and by 8 years - 27°/o. Muscles grow especially intensively in the period from 14-15 to 17-18 years. Thus, muscles account for an average of 30^_ body weight at 14 years old, and 40% at 18-20 years old.

"development of movements. By birth, the child’s motor system is sufficiently developed to perform a number of simple movements.

The ability of muscles to contract appears even earlier - already by the end of the second month of intrauterine life. Muscle tone gradually develops, and during prenatal development and infancy, the tone of the flexor muscles prevails over the tone of the extensor muscles, which is important for maintaining the natural position of the body in the uterus (Fig. 17).

By the end of the third month, the human fetus can clench its fingers into a fist in response to touching the hand. After another month, barely noticeable and very slow contractions of the muscles of the trunk and limbs, mainly extensors, begin to appear occasionally. These are the so-called movements. Gradually they become more frequent and so pronounced that the pregnant woman clearly feels them. Long before birth, respiratory movements appear, expressed in a slight alternating increase and decrease in the volume of the chest, as well as swallowing and sucking movements. The elementary coordination of movements necessary for flexion and extension of the limbs, for sucking, swallowing and breathing movements, for head movements, undoubtedly appears even before birth. However, the movements proceed extremely slowly.

Already in the first days of life, the child shows great motor activity. Basically, these are random movements of the limbs. When positioned on the stomach, the child turns his head to the side, then his torso and, as if rolling, lies on his back. If you hold it in a vertical position, the head tilts forward, since its center of gravity is in front of the fulcrum, i.e., the junction of the skull with the spine, and the tone of the posterior cervical muscles is insufficient to maintain the correct position of the head.

In the second month of life, the child turns his head towards the light and somewhat later towards the sound. When lying on his stomach, he raises his head, and by the end of the second month, leaning on his hands, he raises not only his head, but also his chest.

A three-month-old baby begins to roll over from his back to his stomach. The movements of his hands gradually become more varied

Rice. 19. The appearance of curves in the spine due to sitting and standing.

figurative. At the age of 4-5 months they begin to be well controlled by vision: seeing new item, the child reaches out to him, grabs him and, as a rule, drags him into his mouth.

By 7 months, the child maintains a sitting position well, and after another month he sits down independently and, holding on to various objects, rises to his feet. Gradually he begins to crawl on all fours, and by the end of the year or in the first months of the second of the year life, at first falling every now and then, and then more and more confidently walking around the room without outside help.

Mastering the vertical position of the torso or the whole body leads to a number of significant changes in the motor system: firstly, the tone and contractility of the extensor muscles sharply increases; Secondly, bends appear in the soil-_IPchnikP| i^vT-^r"t-"Q gn^gn^gt to maintain balance, have

springy ow and i nir pra_ hplbe, run.-jumping and facilitate muscle work while maintaining a vertical body position for a long time. the newborn's spine is weak along its entire length pronounced bulge facing posteriorly; in its lower part the convexity is more pronounced - this cross.pvp-k.opchikp.th bend. The cervical curve begins to form towards the end of the second month, when the tone of the posterior cervical muscles increases and the child begins to first raise his head while lying on his stomach, and then hold it with his body in an upright position. The forward-facing convexity of the cervical spine becomes well defined much later, when the child independently maintains a sitting position for a long time. At the same time, a backward-facing convexity of the middle part is clearly visible dialer - rough bend. Stagnant sitting position i~oSo"oen- But standing promotes education lumbar curve, addressed

convex forward. Usually this bend becomes noticeable only in the 2nd year of life (Fig. 19).

In preschool children, the curves are still developing and are highly dependent on the position of the body. After lying for a long time, for example after a night's sleep, the cervical curve and especially the lumbar curve may completely disappear, reappearing and intensifying towards the end of the day under the influence of sitting and walking. Even at primary school age, the curves flatten significantly during the night. The variability of the bends gradually disappears.

Preschool children are characterized by extreme flexibility of the body, which is explained by the large thickness and pliability of intervertebral cartilage and late ossification of the vertebral epiphyses. The curves of the spine are formed and subsequently strengthened under the influence of pressure from upper parts bodies. The direction of pressure depends on posture, i.e., sitting, standing and walking postures.

The muscular system is organically connected with the skeletal system, since they jointly provide human movement.

The muscular system in children is poorly developed. The weight of muscles in relation to the weight of the whole body in children is less than in adults, as can be seen from the following data:
- in a newborn - 23.3%;
- for a child 8 years old - 27.2%;
- for a 15-year-old teenager - 32.6%;
- for young men 17-18 years old - 44.2%.

The muscles of children differ in their structure, composition and functions from the muscles of adults. The muscles in children are paler and more tender in appearance, richer in water, but poorer in protein and fat, as well as extractive and inorganic substances. Only by the age of 15-18 does the amount of water in the muscles decrease, they become denser, and the content of protein, fat and inorganic substances in them increases. At this age, the mass of tendons also increases compared to muscles, and therefore their elasticity and elasticity increase.

Children's muscle development is uneven. They develop larger muscles, such as those in the shoulder and forearm, first, with smaller muscles developing later. Thus, a 4-5 year old child has relatively developed muscles of the shoulder and forearm, but the muscles of the hand are still far from developed, and therefore fine finger work at this age is not yet available to children. The qualitative function of the muscles of the hand develops sufficiently in a child at the age of 6-7 years, when children can already engage in work such as weaving, modeling and other exercises with low-resistance material. The development of the muscles of the hand at this age makes it possible to gradually teach the child to write. But writing exercises at this age should be short-term, so as not to tire the still far from strong muscles of the hand.

An increase in the rate of development of all muscles and an increase in muscle strength in children is observed after 8-9 years, when ligaments are also strengthened and a significant increase in muscle volume is noted. In subsequent years, muscle strength increases steadily. Muscle strength increases especially rapidly in adolescents at the end of puberty. During these same years, an intensive increase in muscle mass occurs.

At the end of puberty, not only does the strength of the arm muscles increase, but the muscles of the back, shoulder girdle and legs also develop powerfully. According to Dementyev's research, the greatest increase in dead strength occurs between the ages of 15 and 18 years. After 15 years, small muscles also develop intensively, due to which the accuracy and coordination of small movements are improved and economy of movements is achieved, which makes it possible to achieve the greatest results with the least expenditure of effort during physical (manual) labor. At the same time, movement technique is also improved.

In children and adolescents, fatigue of working muscles occurs more quickly than in adults. But at the same time, muscle fatigue in children goes away faster, since this is favored by faster metabolism and a more abundant supply of oxygen to them, which restores the excitability of the tired muscle and increases its temporarily weakened elasticity. All this suggests that when organizing and conducting physical exercise, sports activities and physical labor of children and adolescents, it is necessary not to overly burden their muscles, dose the load and conduct these activities at a slow pace with appropriate pauses for rest.

The development of motor skills in children and adolescents does not occur evenly, but spasmodically. By the age of 6-7, the child already has fluent control of his muscles, but precise movements are still difficult for him and are accompanied by great effort. When a child is forced to make precise movements, he quickly gets tired. Imperfect movements in children at this age depend on the insufficient development of coordination mechanisms in the central nervous system.

Coordination of movements, expressed in their accuracy and dexterity, becomes more perfect in children aged 8-12 years. At the same time, children’s mobility increases and their movements become more varied. However, children of primary and partly middle school age are still not capable of long-term productive physical work and to prolonged muscle tension. This circumstance must be taken into account when organizing physical education classes and labor activity children.

By the age of 10-13, the child already has some harmony of movements. But during puberty, this harmony is disrupted, since at this time the teenager’s motor apparatus is rebuilt. In this regard, primitive mechanisms (movements) are released from regulation by the higher parts of the central nervous system. Outwardly, in adolescents this manifests itself in an abundance of movements, awkwardness, some angularity, lack of coordination and impaired inhibition. By the end of puberty, these deficiencies in the adolescent’s motor skills are leveled out, and the development of the motor system is basically completed.

The above-mentioned features of the development of muscles and motor skills of children and adolescents put forward a number of hygienic requirements aimed, on the one hand, at protecting their muscular system, and on the other, at its development and strengthening. Considering the relatively rapid fatigue of muscles in children and adolescents and their lack of training, it is necessary to avoid prolonged and especially excessive physical stress, keeping in mind the possible dire consequences that can lead to crippling of a growing organism and a delay in its development. This applies not only to children of preschool and primary school age, but also to teenagers studying in high school high school and in vocational schools.

To ensure normal muscle development in children and adolescents, moderate physical exercise is necessary, be it sports, agricultural or other physical labor. When working, muscles receive a more abundant flow of blood containing nutrients and oxygen. The blood that flows into a muscle while working nourishes not only it, but also the bones to which it is attached, as well as ligaments. Muscle work has positive influence and on the process of formation of red blood cells in the bone marrow, thereby improving the composition of the blood. Muscular work has a beneficial effect on the entire body, in particular on organs such as the heart and lungs, and activates metabolic processes.

The activity of muscles is organically connected with the work of the brain and nerves, which mutually influence each other. As noted above, muscle exercise promotes core development cerebral hemispheres brain. The education of mental qualities, such as perception, memory, will, is associated with rational physical education. The work of the brain is more productive when its nutrition with blood delivered to it is enhanced. Thus, moderate physical exercise activates mental activity. However, with excessive muscle contractions, fatigue occurs not only in the muscles, but also in the nervous system.

Excessive muscle tension, especially when it occurs for a long time, has a harmful effect on the functioning of the entire body and can lead to serious diseases of the heart, lungs and other organs. With such excessive prolonged muscle tension, the heart works much more intensely, the heart muscle gets tired, as a result of which its contractions become slower. With prolonged tension in the muscles of the hands when playing the piano, sewing and writing, a disease known as writer's cramp sometimes occurs, which is expressed by severe pain in the muscles of the hand and the inability to continue working. All this must be kept in mind when conducting educational work with children and adolescents.

However, not only excessive prolonged muscle tension has an adverse effect on the body, but also insufficient work of individual muscle groups. The consequence of this is disorders in individual parts of the body, affecting the entire body. So, with a prolonged stationary sitting position without breaks for active rest in the form of movements of the whole body, blood circulation in the abdominal organs (stomach, intestines and liver) is disrupted, which can result in constipation. Therefore, it is so important during sedentary work to arrange breaks for rest, which should be accompanied by free movements of all the muscles of the body as much as possible. Such rest after prolonged stationary sedentary work will be much more effective if it is carried out in the fresh air.

The most important thing in the hygiene of the muscular system of children and adolescents is its exercise, training, which gradually involves individual muscle groups (in their mutual connection) in movements and thereby ensures the development of muscles and improves motor skills. Learning new movements, for example, during the initial training in writing, gymnastics, playing musical instruments, and certain types of physical labor, requires children not only to spend significant amounts of muscle, but also to experience considerable neuropsychic stress, which entails physical and mental fatigue. Systematic, gradually increasing, but at the same time strictly dosed training of individual muscle movements in the process of learning the above activities makes these movements familiar, easy and enjoyable. If these activities are not excessive in time and load, then they usually do not cause fatigue in a trained child and teenager. In connection with the above, the enormous hygienic and pedagogical importance of training the muscular system becomes obvious.

From a hygienic point of view, it is extremely important to ensure comprehensive development muscles of children and adolescents and avoid unilateral stress on one or another muscle group. With a unilateral load on any one muscle group, its excessive development occurs due to some underdevelopment of the remaining muscle groups, and this circumstance negatively affects the activity of the entire organism. Only comprehensive muscle exercise ensures the normal physical development of the growing organism as a whole and contributes to the improvement of the morphological and functional properties of individual organs and systems.

At primary school age, the main type of physical exercise is outdoor games. At this age, some strength exercises are already available, but only those that do not require strong tension. Gymnastic exercises at primary school age acquire higher value compared with preschool age, however, they are not yet the main type of physical education for children in this period. Only in middle and high school age do gymnastics and sports become the main types of physical education among adolescents, since at this age the muscular system has developed sufficiently for this kind of exercise.

When addressing issues of physical education among children and adolescents, it is not enough to take into account only the characteristics of the skeletal and muscular systems. In this regard, the features are of great importance of cardio-vascular system children and teenagers. Only taking into account all factors of organism development can ensure proper organization educational work among children and adolescents and carrying out activities among them in the field of individual hygiene.