Features of the formation of biochemical mechanisms of energy supply in the process of endurance development female athletes in sports aerobics

The duration of the competitive program in sports aerobics is about 1.5 minutes, during which the athlete must perform highintensity complex coordination movements that are combined with acrobatic elements. The implementation of these exercises is necessarily subject to musical accompaniment, which sets the pace of exercise. With the athlete advanced training, the competitive program acquires changes and is saturated with more complex elements. In this regard, the trainers are constantly faced with the task of selecting exercises that would be able to solve the problem of developing the optimal level of endurance, which will allow more technically complete the given exercises. Since sports aerobics is a young sport that is gaining its development, today the basis for many years of training athletes has not yet been formed theoretically. The issues of developing endurance also remain uncertain, and it does not allow coaches to more fully build the training process of their pupils.

ISSN (English ed. Online) 2311-6374 2019 Kharkiv State Academy of Physical Culture, Kharkiv, Ukraine introduction Sports aerobics is a new, modern sport, which in the direction of motor activity is classified as complex coordination, acyclic sports. The competitive program in sports aerobics is represented by a continuous and high-intensity complex of exercises for musical accompaniment with acrobatic and choreographic movements of varying complexity, as well as exercises for strength and flexibility, which requires appropriate physical praparedness [3; 14; 15].
This is a very complex sport, which is an example of extreme physical activity in the zone of mixed (aerobic-anaerobic) energy supply [18].
Despite the fact that compositions in sports aerobics are marked by a complex coordination character, they must also be performed with great intensity and high pace throughout the entire competitive program. Therefore, when preparing athletes, the trainers are faced with the issue of selecting and including in the training process special exercises for the development of both general and special endurance of athletes.
The foundations of the physiological substantiation of the essence of endurance as the quality of motor activity and the identification of the features of its manifestation in various sports were laid in the works of Yu. According to V. N. Platonov [21], overall endurance should be defined as the ability to perform work of a nonspecific nature for a long and efficient time and creates a positive effect on the formation of specific components of sportsmanship due to increased adaptation to loads and the presence of "transfer" of training from non-specific specific activities. According to the same author, special endurance is the body's ability to perform work and overcome fatigue in conditions determined by the requirements of competitive activity in a particular sport.
The level of development of an athlete's endurance is determined by the energy potential of his body and how it meets the requirements of a particular sport. One of the most important factors affecting the development of endurance of athletes is the effectiveness of energy supply mechanisms, which are formed depending on the characteristics of competitive activity. The formation and dominance of various mechanisms is primarily affected by the duration and intensity of the competitive program.
purpose of the study: to find out the features of the formation of biochemical mechanisms of energy supply in the process of endurance development female athletes in sports aerobics.
Objectives. 1. To analyze the data of scientific and methodological literature on the development of endurance in sports aerobics. 2. Given the features of the competitive program, investigate the leading mechanisms that affect the energy supply of the body of female athletes with the development of endurance, and determine the rationality of including funds for its development.

Material and Methods of the research
The study was organized on the basis of the municipal out-ofschool educational institution "Center for Children and Youth Creativity" Dream "of the city of Krivyi Rig, in which 10 female athletes aged 14-15 years participated. In the process of the experiment, the following methods were used: theoretical analysis and generalization of scientific and methodological literature; study of documentary materials, video materials of competitions, pedagogical observation, pedagogical testing, methods of mathematical statistics.
For nine months, during the training sessions, athletes per-formed sports aerobics exercises that contribute to the development of the studied quality. We used the following methods: 1) continuous exercise methods (continuous standardized exercise method, continuous variative exercise method, continuous progressive exercise method, continuous regressive exercise method); 2) methods of interval exercise (the method of interval standardized exercise, the method of interval variative exercise, the method of progressive interval exercise, the interval regression exercise method); 3) combined exercise methods (the method of continuousinterval standardized exercises, the method of interval-standard progressive exercises, the method of repeated-interval standardized exercises, the method of circular exercises).
Training sessions were held 3 times a week for 90 minutes each.

results of the research
In the course of the study, the initial testing of the working capacity of the studied contingent by Ruffier samples and the Harvard step test was carried out, since these indicators are indicators of the development of endurance and reveal the athlete's ability to work of a different nature and form, the basis of which is endurance (Table 1).
According to the initial testing (Table 1), the results of the athletes were distributed by level. In both the IHST and the Ruthier Index, the average score in the study group indicates a good level. IHST=80,5 c. u., IR=6,8 c. u. A high level of uniformity of results can also be noted. (IHSTv=5%; ІRv=13%).
At the end of the experiment, re-testing was carried out and a comparative analysis of the results of the initial and repeated testing was done, which is reflected in tables 2 and 3.
Analyzing the data presented in Table 2, we can say that the average value of the Harvard step test index during repeated testing increased to an excellent level and amounts to 89,4 c. u. It can be noted that the IHST indicators increased in each athlete in the group. The significance of differences between the results of primary and repeated testing is also traced. р<0,01 (t=4,34).  Analyzing the results presented in table 3, we observe a decrease in the performance of the Ruffier index, which means an improvement in the results. The average index value is 5,46 c. u., which is interpreted as a good level. If we compare the individual results of athletes, we observe an improvement in the results in each of them. The indicators for this breakdown also have significant differences when р<0,05 (t=2,85).
Graphically, the improvement of the test results for the Ruffier test is presented in Figure 2.
After conducting the experiment, we revealed a change in the test results of varying degrees of reliability (in IGST, changes in the results took place with a degree of reliability of 99%, and in the Ruffier test the reliability of the changes was 95%). This is due to the different nature, structure and timing of the exercises in sports aerobics, therefore, to various energy supply mechanisms. When performing the Harvard step test, the main mechanism of ATP resynthesis is glycolytic, during which muscle glycogen, as well as glucose, are used mainly from the blood. When performing the Ruffier test, energy supply occurs mainly due to the creatine phosphokinase mechanism (within 10-15 s), and then glycolytic is gradually connected. That is, at the beginning of the Ruffier test, ATP resynthesis occurs mainly due to creatine phosphate, and the effectiveness of this process depends on its muscle reserves and the economy of its use.

conclusions / discussion
From the analysis of scientific and methodological literature it was established that today there is too little information that related to the peculiarities of training athletes in sports aerobics in the process of many years of training. Not an exception is the question of a rational combination of means in the process of developing endurance.
It has been established that during exercises aimed at developing endurance in sports aerobics, the leading mechanism that affects the energy supply of the body is glycolytic ATP resynthesis, as well as adaptation processes in the transition from creatine phosphate to glycolytic mechanisms. Therefore, in the process of training for the development of endurance, it is preferable to select funds that affect the increase in the effectiveness of these processes.
prospects for further research. Find out what methods can achieve the most effective impact on the formation of the leading mechanisms of energy supply to achieve a high level of development of special endurance of athletes in sports aerobics, taking into account the features of competitive activity.
conflict of interests. The authors declare that no conflict of interest. financing sources. This article didn't get the financial support from the state, public or commercial organization.