T.G. Petrova, Ph.D  
T.V. Chelyshkova, Ph.D
N.N. Khasanova, Ph.D
Adyghe state university, Maikop

Key words: nervous system, neurophysiological status, body’s aerobic abilities, competitive judokas, competitive track and field athletes.

 Introduction. Nowadays promotion and protection of students' health transforms into an essential factor of ideological, social, cultural, economic state policy. Under these conditions sport as an element of a healthy way of life of young students becomes an important component that characterizes the social development in modern conditions [1, 4, 5, 12].

The problem of the influence of systematic physical exercises on the functional status of nervous system is among the central problems in the study of the natural laws of human adaptation to sports activity and keeps attracting the researchers’ attention [2, 9, 11]. The central nervous system is primary in the hierarchical structure of functional systems ensuring the body’s adaptation [10]. Several researchers consider the properties of the nervous system as a limiting factor of sports activity that defines functional and psychological fitness of athletes, the model of their motor abilities. Adaptation to training and competitive activity has significant differences in efficiency and physiological value depending on the functional status of the central nervous system. Trainer should take into account the features of the neurophysiological status of persons engaged in physical culture and sport when determining the volume and intensity of loads. The special features of physiological processes in the central nervous system - lability of nerve centers and mobility of nervous processes [3] and reserves of development of body's aerobic abilities underlie the physiological mechanisms and natural laws of development of such physical qualities as speed and endurance [7, 9, 11, 12]. In this regard, the definition in students of the aerobic power indices, reflecting the overall endurance of the body, along with the neurophysiological status suggests an integrative approach to the analysis of the functional status and adequate characterizing of the mechanisms of development of the body’s adaptive capacities, revealing the basic components involved in their formation; prioritizing solution of the problems to get some neurofunctional model characteristics in case of different forms of organization of physical activity in a higher school. Considering of the current functional status of the nervous system and physical working capacity of the body will help to build an effective concept of correction and regulation of physical loads, which often exceeds in the amount functional and adaptive abilities, reduces students' physical culture and sports motivation, forming their active-negative attitude [12] .

The purpose of the study was to determine the influence of sports physical loads on the functional status of the nervous system and overall endurance of students’ body.

Materials and methods. The cross-sectional study was conducted with the students of the Institute of Physical Culture and judo of Adyghe state university. The young men involved in judo (35 persons) and track-and-filed athletics (30 persons) were the subjects of the study and were included in the experimental group (EG). 35 2-4-year students of the department of natural science of Adyghe state university with a traditional motor mode (2 hours of physical education per week) were involved in the control group (CG).

To standardize the conditions all researches were conducted in the first half of the day (at 9-12 o’clock), in the conditions of a comfortable temperature (18-20 ^оС) on the basis of the laboratory “Physiology of child’s development” of the Scientific research institute of complex problems of Adyghe state university.

Student-track and field athletes (middle distance runners: 800 and 1500 m) had the sports qualification of the first grade - 20 persons and CMS - 10 persons, trained year-round 5 times a week for 1,5 to 3 hours a day and had an experience in track-and-filed athletics of 3 to 5 years.

Student-judokas had the sports qualification of CMS - 29 persons and MS - 6 persons, trained year-round ащк 10 hours per week, their sport experience of judo classes ranged from 3 to 5 years.

The study was conducted in the preliminary period of the training cycle, mainly intended to improve the overall physical fitness of athletes.

The features of neurodynamic processes of athletes were studied using a software-hardware complex "NS-PshycoTest” produced by Neurosoft, Ivanovo town.

We studieв the indices of simple visual-motor reaction, tapping test, which represent variants of classical methods of chronoreflexometry, characterize the overall tone, lability, mobility, power of central nervous system and are among the most common indices in testing of the reaction rate. In addition, there were determined the indices of reaction to a moving object (RMO) and critical flicker fusion frequency (CFFF). Psycho-emotional state was estimated using the method of static tremometry.

Overall endurance was assessed by the indices of maximum oxygen consumption. MOC was calculated automatically using the program "Poly-Spectrum".

The findings were statistically processed using the statistical package Statistica 6.0 and the built-in function of analysis in the program Microsoft Excel (2007).

Results and discussion. The basic characteristics of neural processes (power, lability, mobility, balance), the level of their functional tension, state of psycho-emotional sphere of the organism largely determine the specific features of adaptation to sports activity, its effectiveness and physiological value [6].

Proceeding from the analysis of the time of simple visual-motor reaction (SVMR), the lowest values ​​of in the reaction time were observed in judokas in comparison with track and field athletes, and especially with students not doing sports (Tab. 1), indicating better development of speed in qualified judokas and good functional status of their central nervous system. This can be due to the fact that sport activity of representatives of martial arts is associated with decision-making in alternative situations and they need to have a high level of sensory correction. Deterioration of runners’ time of SVMR must be caused by the fact that during training sessions runners primarily react to a sound signal, but not to a visual one. However, in judokas, just as in track and field athletes, the time of SVMR is much shorter compared to the students not involved in sports (Tab. 1). This testifies to a significant improvement of the current functional status of the central nervous system of the qualified athletes. Now it has been proved that the reduction of simple sensorimotor reaction time among qualified athletes compared to students not involved in sports is assumed to be due to shorter time of "central delay", because it largely reduces the latency time of the reaction as a result of speed training.

One of the integral indices of the speed characteristic of nervous system is the maximum frequency or movements or tapping, which also indicates the power of nervous system. The individual features of the course of physiological processes in the nervous and muscular systems, such as the rate of the course of excitation in neurons and muscle cells (liability), mobility of nervous processes, the ratio of fast and slow muscle fibers underlie the displays of the speed quality in conditions of a tapping test [11].

The maximum rate of movements (8,1 ± 0,3 Hz), indicating the strong type of the nervous system, was observed in the overwhelming majority of track and field athletes (63,5% versus 28,6% in judokas and 30% for non-athletes ).

Table 1. Indicators of simple visual-motor response in qualified athletes and students not involved in sport, M±m

The judokas' tapping rate was 7,7 ± 0,4 Hz, which indicates the prevalence of the contingent with the average type of the nervous system (51,4% versus 23,3% in track and field athletes and 55.0 % of students not involved in sports). The average type of the nervous system was dominating among the students not involved in sport, since the rate of the tapping test was 7,1 ± 0,3 Hz, which was significantly lower (p <0.05) compared with the track and field athletes. Higher tapping values ​​in track and field athletes can be caused by the fact that a great number of sport exercises in athletics require the maximum development of speed and rate of movements under time pressure.

The data of the tapping test results are confirmed in the study of CFFF, showing lability and power of the nervous system. The highest values ​​of CFFF were marked in track and field athletes - 43,2 ± 1,4 Hz ( p <0,05) (Tab. 2), which indicates the prevalence in this group of persons with high lability of the nervous system. As for judokas, the index of CFFF comprised 40,1 ± 1,5 Hz (p> 0.05). This indicates the average level of lability of the nervous system. The CFFF index in the students not engaged in sport - 37,4 ± 1,4 Hz. In practice this means optimal absorption only of the information that is given at moderately. Thus, the results of CFFF confirm the high lability of nervous processes among track and field athletes along with higher speed and accuracy of visual perception.

Table 2. Indicators of the critical flicker fusion frequency in qualified athletes and students not involved in sport, M±m

* to the right – significance of differences (р<0,05) between athletes from different sports, ** to the left – significance of differences (р<0,001) between athletes and students not involved in sport.

Reaction to a moving object underlies the manifestations of quickness of athlete’s action, which is a rather delicate indicator of the state of CNS, reflecting its status and the degree of fatigue. The indicators of RMO suggest the effectiveness of athlete’s behavior in alternative sports situations, to react in time to opponents’ movements, providing fast response. Reaction to a moving object has a special meaning in situational sports, being a measure of lability and mobility of nervous processes, the degree of their balance. The comparative analysis showed the majority with accurate reactions and an optimal balance of nervous processes in judokas. This is especially important for athletes involved in martial arts, who are constantly in a situation of rapid response to changing conditions of competitive environment, the complexity of which is determined by the multiplicity of alternative choices and the rigid framework of the limited time available for decision-making.

Proceeding from the studies of RMO and response strategies, in the group of judokas 37.2% had an antedating response as dominating, 11.4 % - deferred; exact reactions were observed in 51.4%, but regarding competitive track and field athletes 36.6 % responded exactly to a signal; 43.4% used the antedating strategy and 20.0 % - deferred. As for students not involved in sport, 37,2% used the antedating response, 54.2 % - deferred response and only 8.6 % accurately responded to the signal. The presence of subjects with antedating response indicates the predominance of excitation and deferred responses suggest that the body joins the work gradually, but it provides a relatively high duration of the optimum performance that has previously been shown in studies of E.P. Il’in [6].

Proceeding from the analysis of the dynamics of static tremorometry, the minimum number of touches was typical for track and field athletes and amounted to 19.2 1.5 per s, and the time of touches - 1,2 0,6 ms. As for judokas, the indicators of the number of touches and time of touches amounted to 21,1 1,4 per sec and 1,3 0,8 ms respectively, which did not have fundamental differences with track and field athletes (p>0,05). In the students not engaged in sports the number of touches was 31,2 ± 1,7 per sec and time of touches - 2,94 ± 1,7 ms. The tremorometric data testify to the stability of the neuromuscular apparatus and lack of significant mental and emotional stress among qualified athletes, whereas students not involved in sport had reduced resistance of the neuromuscular apparatus on a background of bigger mental and emotional stress.

Proceeding from the analysis of the experimental findings, the MOC level in qualified track and field athletes reached 65,2 ± 3,0 ml/min/kg. Higher values ​​of MOC in qualified track and field athletes enable to develop significant power of movement and show high sports results. The individuals with high MOC have good endurance to prolonged cyclic aerobic work.

It is known that a well-developed muscular system of wrestlers is adapted to work primarily in the anaerobic mode. In addition, the moments of breath holding and straining during a fight when holding, getting ready to throw and throwing, are typical for judokas. This explains their relatively low MOC indices.

MOC of students not involved in sport was 47,1 ± 0,9 ml/min/kg, indicating the reduction of body's aerobic abilities on the background of lack of motor activity and a large volume of training loads.

The differences in the structure of the physical fitness of athletes of different specializations are a natural result of the long-term process of the process of the morphofunctional specialization of the body. Consideration of the regularities of such a specialization is an indispensable condition of the optimal control of the adaptation to physical loads and should be displayed in the appropriate selection of training exposures, determining the strategy of using rehabilitation means and naturally - defining markers in monitoring and evaluation of athletes' functional fitness.

Conclusions

1. The studies revealed the principal differences in the basic neurophysiological characteristics of the functional status of students’ central nervous system in respect to sports specialization and qualification: quicker persons (63,5%) at step test with stronger nervous system and high lability are more frequent among qualified track and field athletes rather than qualified judokas.
2. The highest speed of sensomotor response to a moving object, relatively lower temporal characteristics of simple visually-motor reaction showing mobility of nervous processes and dominant number of accurate responses are specific for qualified judokas in 71,4 % cases. The latter indicates to optimization of the balance of nervous processes at judo classes, which is a precondition of success of competition. It expands the potentials of extrapolation and facilitates better forecasting of possible movement of opponents on the tatami.
3. The highest levels of development of aerobic abilities and body's overall endurance are marked among qualified track and field athletes (runners) compared to qualified judokas and students not going in for sports, indicating to various influence rendered by the manner of training process on the body's physical fitness. Hereby, in accordance with the indicators of maximum oxygen consumption the level of physical fitness is estimated as high for qualified track and field athletes and judokas and above average - for non-athletes.

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Author’s contacts: tatyana.petrowa-golubencko@ya.ru