Khankeldiev Sh. Kh. Regional features of the physical status of youth students fergana 2022 Reviewer

2.4. ENERGY EXCHANGE DURING NATURAL LOCOMOTION
As it was shown above, the determination of optimal loads of motor activity is of great importance both for the practice of physical education and for the shift sciences dealing with improving the training of the younger generation. However, there are still no uniform norms for the proper number of movements, which is explained by the use of different evaluation criteria for this. The most acceptable criterion, on the basis of which it is possible to more or less objectively assess the nature of muscular activity, is the energy assessment of the exercises performed and their comparison with the daily energy expenditure or with the basic metabolism. And if these energy costs when performing movements correspond to the optimal solution, then such loads create conditions in the body for indicating excess energy /14/ and provide high social activity, readiness for labor, defense and sports activities. All this points to the need for in-depth consideration of issues related to determining the energy performance of the body of children and adolescents and the energy cost of the exercises they perform.
Determining the "energy cost" of muscle work is very important in solving many issues of motor activity. The intensity of energy metabolism, in turn, during muscular activity is determined by several factors. First of all, this is the initial level (the level of relative rest), the energy capabilities of the body when performing maximum loads, the energy costs of the body system for the production of specified exercises.
The level of basic metabolism depends on many reasons and may vary in the same person. With age, the intensity of metabolic processes decreases. In younger children, it is the highest (2. 16 kcal-kg), and then it decreases in 15-17 years and is equal to 1.35 on average. As a rule, overweight children have a lower intensity of metabolic processes, which is due to the presence of a significant part of the fat mass that is inactive in oxidative metabolism and respiratory rate – children with high metabolic rate have more frequent breathing and vice versa. The amount of exchange is significantly influenced by climatic conditions, national peculiarities of nutrition and lifestyle, genetic factors.
The morphological structure of the body and, above all, the development of the muscular system is of great importance for the characteristics of the basal metabolism. Muscle contraction affects the basic metabolism even when they do not produce any work. An increase in energy consumption is observed even with a slight change in posture.
When assessing the energy capabilities of an organism in extreme conditions, first of all, its aerobic performance is evaluated, that is, the criteria of power, capacity and efficiency.
The maximum oxygen consumption (MPC) is an indicator of the power of aerobic processes. Therefore, when assessing the physical performance of children and adolescents, along with anthropometric and morphological measurements, the definition of IPC and its components is of great importance. Much attention has been paid to this indicator in recent years in connection with the proposal within the framework of the International Biological Program to standardize the definition of physical performance.
Currently, the maximum aerobic capacity is determined in all countries, not only in adults, but also in children. According to most authors, it follows that the MPC increases with age in children, but in terms of 1 kg of weight, the MPC kg tends to decrease. Most authors have defined the average value of MPC as 40-53 ml/min/kg. Along with these indicators, a number of researchers obtained relatively low values of this indicator – 30-35 ml/min/kg. Sex differences do not have a significant effect on BMD levels, in women by 5-10 ml.
The age-related change in MPC/kg is characterized by the following changes. In boys and boys, this indicator, according to most authors, practically remains at the same level – 46-48 ml/min/kg. In girls, it is reliably preserved until the age of 13, then its decrease is observed. A number of authors have found that individuals of both sexes have an increase in the relative maximum oxygen consumption from 6 to 9 years, and then changes occur. The opinions of researchers also differ in the age limits at which the highest values of the MPC values are reached. It is believed that the maximum indicators of aerobic capacity in children and adolescents are 16-19 years old.
In adolescent children, there are significant fluctuations in absolute and relative BMD within each age group. This fluctuation, respectively, can be from 1.9 l/min. up to 4.8 l/min. and 35 ml./min./ kg and 77 ml./ kg, however, in the majority (more than 60%) of the surveyed, these indicators are about average values. Such individual fluctuations indicate that aerobic performance depends on many components and, above all, on body weight, its active mass, heredity, environmental conditions.
Many studies indicate the relationship of BMD with the motor activity of children and adolescents. A.A.Guminsky, A.G.Sukharev showed a greater value in young athletes of MPC / kg compared to their peers who are not engaged in sports. A comparison of schoolchildren with high and moderate motor activity shows that the aerobic capabilities of the former are better than the latter, and their adaptation mechanisms to maximum loads are higher. A high correlation between motor activity and relative BMD was established in schoolchildren of grades I-III in winter. K. Cooper considers MPC/kg and the body's ability to complete running work as mutually dependent human data. Based on this, he suggests the following estimated values of relative aerobic capacity: poor – 25-33.7 ml/ min/ kg, satisfactory – 33.8 – 42.5, good – 42.6-51.5, excellent – 51.6 and above.
Recently, when assessing aerobic performance
much attention is paid to hereditary factors. The literature provides data when the use of training still did not significantly increase the value of MPC / kg, at the same time, some people have high working capacity and without the use of special exercises to improve it. At the same time, there are works in which the hereditary conditionality of the manifestation of MPC / kg is questioned.
An informative indicator of the functional state of the oxygen supply system is also the oxygen pulse (0 -2 – pulse). In children, this indicator increases with age. Thus, V.M.Volkov noted its increase from 11 to 20 years in parallel with the load. There is a high correlation of this indicator with the volume of the heart, the stroke volume of blood. In children 7-9 years old, the 0-2 pulse is 8.4 ml, and in 16-18-year-olds it reaches an average of 18.2 ml. At the same time, the 0 -2 pulse is higher in boys than in girls by an average of 1.4 ml at 12 years old and by 6.9 ml at 16 years old, averaging 7.2 ml/ud in the first. At 8 years and 16.1 ml/ud. At the age of 16, the second - 4.7 and 9.2 ml / ud. accordingly.
With muscular work requiring the same oxygen consumption in children and adolescents, the level of functioning of the cardiovascular system is higher than in adults. Boys of 9-14 years of age consumed 2-3 times less oxygen for each pulse beat than adults, the results of determining the MPC allow us to judge a person's physical performance. At the same time, a number of authors characterize physical performance by indicators of the cardiovascular system only. Other researchers took the levels of functioning of the external respiration and gas exchange systems, the state of the central nervous system and the state of the neuromuscular apparatus as the criterion of the state of general and special working capacity. This led to difficulties in identifying the main link of the study - working capacity during physical exertion. In recent years, it has been proposed to determine performance by the amount of work performed at a pulse of 170 beats/min (PWC 170).
With this pulse, the most optimal level of performance of the circulatory apparatus is observed. The simplicity of this technique makes it suitable for mass studies of PWC 170 both in absolute and relative values and calculated for 1 kg of body weight, higher in boys than in girls, and these differences increase with age. The PWC 170 index is subject to biological rhythmic fluctuations during the day, week, and school year. This indicator is also due to climatic, social, genetic, and other factors.
When carrying out strenuous sports activities, the energy resources of the body increase many times. Energy expenditure when walking is studied by many authors. According to the gradation of muscle work, walking refers to light physical exercises, in which the energy consumption is 3 kcal / min., oxygen consumption is 0.6 l / min. When walking on flat terrain at a speed of 4 km/h, energy costs are approximately 3.5 to 4 kcal/min. The energy consumption is proportional to the walking speed, the weight of the moving body. Moreover, individual fluctuations in energy consumption at the same speed of movement can deviate only up to 155. However, the energy cost of walking also changes under the influence of the technique of performing the exercise (torso tilt, foot position, repulsion efficiency), shoe weight, soil features. The energy costs are not the same during the execution of all the specified work. They are larger at the very beginning of walking and gradually decrease as they enter the work. Thus, energy costs when walking on a treadmill for 0.5, 1.3 and 7 minutes. decreased as the duration of movement increased; the whole process of getting into work lasts 3-7 minutes.
The difference in energy costs when walking for boys and girls aged 8-15 years has been established. It is shown that the intensity of metabolic processes in boys of all ages, as a rule, is 15-25% higher than in girls, both in conditions of basic metabolism and with various kinds of physical exertion. Walking (70 steps per minute) it causes an increase in gas exchange and an increase in heat production by more than 250-340% in relation to the main exchange. With age, the absolute values of energy consumption increase, but when converted to 1 kg of body weight, a pronounced tendency to decrease the intensity of metabolism is revealed. The literature data concerning the energy consumption for walking are contradictory. Thus, the increase in energy consumption for walking in relation to the level of rest is fourfold. It is claimed that walking increases the basal metabolism by 313% in girls and by 238 % in boys. According to N.A.Palnau, walking at a pace familiar to children increases energy consumption per minute in boys by 2.9 and in girls by 2.6 times compared to the level of rest; the energy cost of 1000 steps increases significantly with age, because walking becomes more economical with age. In addition, it was found that second-grade children spent 430.68 kcal on walking per day, grades 5-6 - 486.12 kcal.
Thus, the study of literary sources has shown that the energy cost of natural locomotion increases with age, which is probably due to an increase in the body weight of children and adolescents. A number of authors point to the presence of a high correlation between motor activity and maximum aerobic capabilities of schoolchildren. There are data in the literature on the so-called proper values of the relative maximum oxygen consumption, which can become starting points for calculating the optimal values of motor activity.
Based on the above, it can be concluded that the proper values of motor activity requires clarification based on energy criteria and taking into account the climatic and national characteristics in which children live, the means and methods that need to be applied to implement the problem of increasing motor activity are not clear. All this gives the basis for our research on this problem.