Motor activity of the child: regularities of formation

The development of the child's motor sphere is one of the most striking and amazing in its richness transformations of age-related development phenomena - from the apparent motor limitations and helplessness of the fetus and newborn to the highest levels of sports technology, musical and artistic creativity. It is with the help of motor acts that a person exercises his transformative influence on nature, technology and culture, but at the same time, motor activity itself is the most powerful stimulus for individual development.

Already in the intrauterine period, when motor activity, it would seem, has no special significance, there is an exceptionally rapid formation of motor reflexes. At present, it is known that the motor activity of the fetus is one of its fundamental physiological characteristics, ensuring normal intrauterine development and childbirth. Thus, irritation of the proprioceptors and receptors of the skin ensures the timely emergence of a specific intrauterine position, which is the position of the smallest volume with minimal internal pressure on the walls of the uterus. Due to this, pregnancy is carried to term already at a fairly large size of the fetus. Labyrinthine motor reflexes of the fetus contribute to strict maintenance of the position optimal for future childbirth, i.e. cephalic presentation. Intrauterine respiratory and swallowing movements help to swallow amniotic fluid, which is an important component of fetal nutrition, a factor in the formation of the enzyme-forming capacity of the mucous membrane of the gastrointestinal tract and ensuring the exchange of amniotic fluid. Finally, a number of motor reflexes formed in utero provide great assistance to both the fetus and its mother during a critical period for them - childbirth. Reflexive turns of the head, body, pushing off the bottom of the uterus with the legs - all this, of course, contributes to the successful course of labor. Immediately after childbirth, hypertonicity of the flexors of the limbs is very important for maintaining sufficient heat production, activating the activity of the respiratory and vasomotor centers. In all subsequent age periods, the child's motor activity, along with his senses, the entire sum of external impressions and emotions, constitutes that general stimulation complex, under the influence of which further development of the central nervous system itself, and, above all, the brain occurs. Finally, motor activity is a direct activator of skeletal growth and maturation, it integrates metabolism in cells with the function of the respiratory and cardiovascular systems, ensuring the formation of high physical performance of the child and maximum economization of all his physiological functions. This is, according to the leading Russian specialist in age physiology, Professor I. A. Arshavsky, the key to human health and longevity.

It is extremely important for a doctor that the formation of various motor reflexes and capabilities at an early age is carried out in strict correlation with the maturation of certain neural structures and connections. Therefore, the spectrum of a child's movements very clearly indicates the degree of his neurological development. In the first years, a child's motor skills can serve as one of the reliable criteria of his biological age. Delay in motor, and therefore neurological development, and, especially, its reverse dynamics always indicate the presence of severe nutritional disorders, metabolism or chronic diseases in the child. Therefore, each pediatrician's record of the results of an examination of a healthy or sick child should contain information about motor functions.

The importance of motor activity for the development of health and physical performance explains all the great attention that health authorities and the government pay to the development of children's physical education and sports.

The most primitive form of motor response is muscle contraction upon mechanical stimulation. In the fetus, such contraction can be obtained starting from the 5th-6th week of intrauterine development. Very soon, from the 7th week, the formation of reflex arcs of the spinal cord begins. At this time, muscle contractions can already be obtained in response to skin irritation. The skin of the perioral region becomes the earliest such reflexogenic zone, and by the 11th-12th week of intrauterine development, motor reflexes are evoked from almost the entire surface of the skin. Further complication of motor activity regulation includes the formation of elements located above the spinal cord, i.e., various subcortical formations and the cerebral cortex. N. A. Bernstein called the level of movement organization following the spinal level the rubrospinal level. The development and inclusion of the function of the red nucleus ensures the regulation of muscle tone and motor skills of the trunk. Already in the second half of pregnancy, a number of subcortical structures of the motor analyzer are formed, integrating the activity of the extrapyramidal system. This level, according to N. A. Bernstein, is called thalamo-pallidal. The entire motor arsenal of the fetus and the child of the first 3~5 months of life can be attributed to the motor skills of this level. It includes all rudimentary reflexes, developing postural reflexes and chaotic or spontaneous movements of the newborn child.

The next stage of development is the inclusion of the striatum with its various connections, including the cerebral cortex, into regulation. At this stage, the formation of the pyramidal system begins. This level of movement organization is called pyramidal-striatal. Movements at this level include all the main large voluntary movements that form in the 1st-2nd years of life. This includes grasping, turning over, crawling, and running. The improvement of these movements continues for many years.

The highest level of movement organization, and, moreover, inherent almost exclusively to humans, was called by N. A. Bernstein the level of object action - this is a purely cortical level. According to its localization in the cortex, it can be called parietal-premotor. The development of this level of movement organization in a child can be traced by observing the improvement of finger movements from the first finger grasping at the age of 10-11 months to the improvement of the child, and then of an adult, in writing, drawing, knitting, playing the violin, surgical technique and other great human arts.

Improvement of motor activity is connected not only with the formation of the corresponding regulatory links, but also largely depends on the repetition of actions, i.e. on motor education or training. Self-training of a child in movement is also a powerful stimulus for the development of nervous regulation of movements. What does the level of a child's mobility depend on? Several reasons can be named.

For a newborn and a child in the first weeks of life, movements are a natural component of emotional arousal. As a rule, this is a reflection of a negative mood and a signal to parents about the need to satisfy his will by eliminating hunger, thirst, wet or poorly placed diapers, and perhaps pain. Further distribution of motor activity largely reflects the formation of sleep and wakefulness. If a newborn has relatively low motor activity, then its distribution during the day and in connection with wakefulness and sleep is practically uniform. Starting from the 2-3 month of life, there is a general increase in motor activity, and a much more contrasting distribution with maximum concentration in the hours of active wakefulness. Some physiologists even believe that there is some daily minimum of motor activity, and if the child could not gain it during wakefulness, then his sleep will be restless and rich in movements. If we quantitatively characterize the ratio of a child's mobility during wakefulness and falling asleep, then in the first 4 months the ratio will be 1:1, in the second 4 months of the first year it will already be 1.7:1, and in the last months of the first year - 3.3:1. At the same time, the overall motor activity increases significantly.

During the first year of life, several peaks of motor activity are noted. They occur in the 3rd-4th month, the 7th-8th month, and the 11th-12th month of the first year. The emergence of these peaks is explained by the formation of new capabilities of the sensory or motor sphere. The first peak is a complex of excitement and joy at the first experience of communication with adults, the second peak is the formation of binocular vision and the activation of crawling (mastery of space), the third is the beginning of walking. This principle of sensorimotor connections is preserved subsequently.

The general mobility of a child is largely determined by his constitutional features, level of liveliness or temperament. We have to observe children who are lazy and sedentary from the first days of life, and the group of hyperactive children with increased nervous excitability (hypermotor, hyperkinetic children) is also very numerous. Extreme forms can be caused by various diseases. Many acute and chronic diseases of children affect motor activity, often in two phases - at first they increase anxiety and mobility, later they decrease.

Motor skills and reflexes of the intrauterine period

The doctor must be familiar with the motor skills and reflexes of the intrauterine period due to the fact that when immature and premature babies are born, special conditions for their care and observation must be created.

Fetal heart contractions are probably the first motor reaction of normal intrauterine development. They occur in the 3rd week at a total fetal length of about 4 mm. Tactile sensitivity reactions with muscle reactions are observed from 6-8 weeks. Gradually, zones of particularly high tactile sensitivity are formed, which will already be the perioral zone, especially the lips, from 12 weeks, then the skin of the genitals and the inner thighs, palms and feet.

Spontaneous worm-like movements of the fetus are observed from the 10th to 12th week, opening of the mouth due to the lowering of the lower jaw - from the 14th week.

Around the same time, elements of respiratory movements begin to be noted. Independent regular breathing occurs much later - from the 25th to 27th week. Generalized motor reactions to shaking, a sharp change in the position of the pregnant woman's body can be noted from the 11th to 13th week, swallowing movements with swallowing of amniotic fluid - from the 20th to 22nd week. Already from the 18th to 20th week, finger sucking is noted in photographs and film frames, but sufficiently pronounced movements of the sucking reflex are formed only by the 25th to 27th week. Around this time, the fetus or newborn immature child can sneeze, cough, hiccup and emit a quiet cry. Also, after the 5th to 6th month of intrauterine development, the intrauterine position is especially well maintained, and complexes of movements to ensure and stabilize the cephalic presentation arise. Starting from the 14th to 17th week, the pregnant woman begins to feel individual movements of the fetus. After 28-30 weeks, the fetus reacts with movements to sharp, unexpected sounds, but after several repetitions it gets used to it and stops reacting.

Postnatal development of motor skills and reflexes of the child

The motor activity of a newborn child consists of the following main components: maintaining muscle tone, chaotic spontaneous movements and unconditioned reflexes, or automatisms.

Increased tone of the limb flexors in a newborn is associated with the action of gravity (irritation of proprioceptors) and massive impulses from sensitive skin (air temperature and humidity, mechanical pressure). In a healthy newborn, the arms are bent at the elbows, and the hips and knees are pulled up to the stomach. An attempt to straighten the limbs meets some resistance.

Chaotic spontaneous movements, which are also called choreic, athetosis-like, impulsive movements, are characterized by a relatively slow rhythm, asymmetry, but bilaterality, connection with large joints. Often, throwing back the head and straightening the trunk are observed. These movements are not reflexive in nature and, according to most physiologists, reflect the periodicity of the functional state of the subcortical centers, their "recharging". The study of the structure of spontaneous movements made it possible to find in them elements resembling certain locomotor acts, such as stepping, climbing, crawling, swimming. Some believe it is possible to develop and consolidate these primitive movements as a basis for early learning of movements, in particular swimming. There is no doubt that spontaneous movements of a newborn are a normal and necessary phenomenon for him, reflecting the state of health. I. A. Arshavsky notes the positive effect of spontaneous movements on breathing, blood circulation and heat production. It is possible that spontaneous movements are the primary motor arsenal from which purposeful voluntary movements will subsequently be selected.

The reflexes of a newborn child can be divided into three categories: stable lifelong automatisms, transient rudimentary reflexes that reflect specific conditions of the level of development of the motor analyzer and subsequently disappear, and reflexes, or automatisms, that are just appearing and therefore not always detected immediately after birth.

The first group of reflexes includes the corneal, conjunctival, pharyngeal, swallowing, tendon reflexes of the extremities, and the orbital-palpebral, or superciliary, reflex.

The second group includes the following reflexes:

• spinal segmental automatisms - grasping reflex, Moro reflex, support, automatic reflex, crawling, Talent reflex, Perez reflex;
• oral segmental automatisms - sucking, searching, proboscis and palmar-oral reflexes;
• myeloencephalic postural reflexes - labyrinthine tonic reflex, asymmetrical cervical tonic reflex, symmetrical cervical tonic reflex.

The third group includes mesencephalic adjusting automatisms - adjusting labyrinthine reflexes, simple cervical and trunk adjusting reflexes, chain cervical and trunk adjusting reflexes.

Throughout the year, the activity of the reflexes of the second group fades. They are present in the child for no more than 3-5 months. At the same time, already from the 2nd month of life, the formation of reflexes of the third group begins. The change in the pattern of reflex activity is associated with the gradual maturation of the striate and cortical regulation of motor skills. Its development begins with a change in movements in the cranial muscle groups and then spreads to the lower parts of the body. Therefore, both the disappearance of physiological hypertonicity and the emergence of the first voluntary movements first occur in the upper limbs.

The result of motor development in the first year of life is the emergence of finger grasping of objects, manipulation with objects and movement in space (crawling, sliding on the buttocks and walking). After the first year, all types of movements are improved. The final development of walking on fully straightened legs with manipulation of the arms occurs only at 3-5 years. The technique of running, jumping, and various sports games is improved even longer. The development of perfect forms of movement requires persistent repetition, training, which in early childhood and preschool age occur in connection with the natural restless mobility of children. This mobility is also necessary for the physical, neurological and functional maturation of the child in general, as well as proper nutrition and natural gas exchange.

Average terms and possible limits of development of motor acts in children aged 1 year

Movement or skill	Average term	Time limits
Smile	5 weeks	3-8 weeks
Cooing	7»	4-11 »
Holding the head	3 months	2-4 months
Directional movements of the handles	4 »	2.5-5.5 >»
Turning over	5 »	3.5-6.5 »
Sitting	6 »	4.8-8.0 »
Crawl	7»	5-9»
Voluntary grasping	8»	5.75-10.25"
Getting up	9"	6-11 »
Steps with support	9.5 »	6.5-12.5"
Standing independently	10.5"	8-13»
Walking independently	11.75"	9-14»

Grasping development

In the first weeks of life, the baby is more adapted to grasping with the mouth. When touching the skin of the face with any object, the baby will turn his head and stretch his lips until he grasps the object with his lips and begins to suck it. Oral touch and cognition of objects is an essential moment of all motor activity of the baby in the first months of life. However, due to the presence of a developed grasping reflex, the newborn can firmly hold an object or toy placed in his hand. This reflex has no relation to the subsequent formation of grasping.

The first differentiated movements of the hands appear in the 2nd - beginning of the 3rd month of life. This is bringing the hands closer to the eyes and nose, rubbing them, and a little later - raising the hands above the face and looking at them.

From 3-3 1/2 months, the baby begins to feel his hands, finger the blanket and the edge of the diaper.

The stimulus for the grasping reaction is the emergence of interest in the toy, the desire to possess it. At 3 months, when seeing a toy, there is simply joy and general motor excitement, sometimes a motor impulse with the whole body. From 12-13 weeks, the child begins to stretch his hands to the toy and sometimes, reaching for it, immediately clenches his hand into a fist and pushes the toy with his fist, without grasping it. When putting a toy in his hand, he will hold it for a long time, pull it into his mouth and then throw it.

Only from the 5th month of life does the reaching out of the hand and grasping of an object begin to resemble similar movements of an adult with a number of features indicating the immaturity of the motor act. First of all, this is the abundance of accompanying irrational movements. The grasping movements of this period are accompanied by parallel movements of the second hand, due to which we can talk about two-handed grasping. Finally, during grasping, movements occur in both the legs and the body, and opening of the mouth often occurs. The grasping hand makes many unnecessary, searching movements, grasping is carried out exclusively with the palm, i.e. the fingers are bent so as to press the toy to the palm. Subsequently, the interaction of the motor and visual analyzers improves, which by 7-8 months leads to greater precision of the grasping hand movement.

From 9-10 months, scissor-like grasping occurs by closing the thumb and II-III fingers along the entire length.

From 12-13 months, grasping is pincer-like, using the distal phalanges of the first and second fingers. Throughout the entire period of childhood, various associated irrational movements gradually fade away. The most persistent are the associated movements of the second hand. Only long-term training contributes to their disappearance. In most people, complete suppression of movements by the second hand is noted only by the age of 20. Obvious and persistent right-handedness of grasping and taking develops only after 4 years.

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Moving in space

A. Peiper identifies four sequentially emerging forms of locomotion: crawling on the stomach, crawling on all fours, sliding on the buttocks and vertical walking. Other authors count a larger number of forms. This is due to the great individuality of the development of locomotion forms in connection with the peculiarities of the child's constitution (excitability, mobility), individual motor experience, collective motor experience of peers in the same playpen or in the same room, and the conditions of stimulation of motor education. However, the differences concern mainly the intermediate stages - crawling on all fours and sliding on the buttocks. The initial and final phases are quite similar in all children.

The beginning of this chain of motor development is rolling over, from the back to the stomach. A newborn baby can roll over from the back to the side with the help of gravity and spontaneous motor activity. Further development of rolling over is associated with the formation of mesencephalic adjusting reflexes. A few weeks after birth, the spinal extension phase begins: the infant turns his head to the side and back. The shoulder on the side where the back of the head turns rises. Gradually, the entire spine is involved in the turn. With further development, the arm and leg on the parietal side rise and move to the jaw side. First, the shoulders turn, then the pelvis, and the child ends up on his side. Such motor automatism develops gradually from 3 1/2-4 months of life, usually immediately after the disappearance of flexor hypertonicity of the lower extremities. This automatism reaches its highest development by 6-7 months. After this, the development of voluntary rolling over occurs.

The position on the stomach with the shoulder girdle and head raised, the gaze directed forward, is the optimal starting position for the development of crawling. If this is accompanied by a lively interest in a toy located very close, then an attempt to move forward is sure to arise. It is possible that there is a desire to grab the object not only with the hand, but also with the mouth. If the child fails to grab the toy by stretching the arms forward, the body is gradually pulled up by the arms and the arms are thrown forward again. The lack of alternation in the throwing of the arms, the initially disordered movements of the legs often result either in turning over on the side or even in crawling back.

A fairly mature crawling with cross-movement of arms and legs is established by 7-8 months of life. Relatively quickly after this, the abdomen rises, and then the child already prefers to move in space exclusively on all fours. Sliding on the buttocks with a leg tucked under itself is formed in cases where there is a particularly smooth, slippery surface of the arena, and is not typical for all children.

Walking begins when a child stands in a crib or playpen and steps with his legs along the back of the crib or a barrier, this is observed at about 8-9 months. Later, the child steps with support from both hands, one hand, and finally, at about a year, takes his first independent steps. Significant variations in the timing of walking have been described. Some children can already run at 10-11 months, others begin to walk at about 1 1/2 years. The formation of a mature gait occurs in several more years. A one-year-old child walks with his legs wide apart, the feet are directed to the sides, the legs are bent at both the hip and knee joints, the spine is bent forward in the upper part, and bent back in the remaining sections. The arms are first extended forward to reduce the distance, then they balance to maintain equilibrium or are bent and pressed to the chest for insurance in case of a fall. After 1 1/2 years, the legs straighten and the child walks almost without bending them. The improvement of the basic characteristics and structure of walking occurs up to 10 years. By 4 years, the structure of each individual step is formed, although the system of steps still remains arrhythmic and unstable. The process of walking is not automated. From 4 to 7 years, a series of steps is improved, but the relationship between the pace of walking and the length of the step may be absent up to 7 years. Only by 8-10 years do the indicators of the structure of the step and walking approach those of adults.