V.I. Frolov, associate professor, Ph.D.
Russian state university of physical culture, sport, youth and tourism (SCOLIPC), Moscow

Key words: dialectics, body systems, motor unit, physical qualities, motor abilities.

A great deal of research materials in the sports sphere, especially on the verge of physiology and biochemistry of muscular work requires its immediate theoretical synthesis in view of dialectics.

The purpose of the study was the theoretical approval of the conceptual interaction of athlete’s body systems and physical qualities.

Materials and methods. The research methods involved were as follows: theoretical synthesis based on philosophic principles of the dialectic and materialist analysis of living systems.

The dialectic-materialist approach to the analysis of human body development in sports activity makes us consider this question, abstracting away from numerous other systems, first of all, at the level of functioning of central nervous system (CNS), motor, cardiovascular and respiratory systems (Fig. 1). The main theoretical premise is that all body systems are given to us as something tangible that exists objectively, independently of our consciousness, we are given historically as a part of nature, as a product with brain being psychophysiological substrate of consciousness and as the top produce of this nature. Naturally, at the level of integral body systems interact closely with each other on the principle of mutual assistance to get some specific adaptive result [1].

We also have every reason to say that muscles are the moving force of man, especially in sports activity. The fuel for the moving force is supplied by CNS, respiratory and cardiovascular systems, as well as those energy substrates, which are in muscles themselves.

Speaking further, we again can confidently state that development of human body as a whole since very early childhood is determined by the motor system, because he has to constantly overcome the terrestrial gravitational field with the help of muscle contractions, motor system of a certain level of organization. Whatever man is doing during his development, interacting with the environment, he is doing it through muscle contraction. It was continuously indicated by Ch. Darwin, I.M. Sechenov, I.P. Pavlov and many other prominent scientists.

Let us see how the terrestrial gravitational field is overcome in sport, using the construction of movements in five levels of N.A. Bernstein: A, B, C, D, E [6]. Below is the interpretation of levels according to sports terminology and terminology of N.A. Bernstein.

      А – lowest background level. This level is characterized by taking and holding a pose in a particular sport. Here, the basic background is arranged providing the chance of whatever motion, the background of flexible reactive tone of all muscle mass. The afference of the level takes place by the mechanism of "reflex circuit".

      В – the level of muscle synergies and stereotypes. Relatively slow, standard simulation motions are “built” at this level, involving the coordinated work of many dozens of muscles. The main task is to eliminate (reduce) the impact of reacting forces within a motor act and turn the athlete's multilink kinematic chain into a controlled system. There is no explicit start and end of motion here. Afference of the level - mainly via the mechanism of "reflex circuit".

      С – the level of spatial field. Motions at this level are primarily targeted with a strongly expressed beginning and end of a motor act. Here the skills to use reacting forces are developed. In the aspect of theory of physical education this is the level of skills. In the afference of this level a cortical component is being actively involved, but only in the form of "sites of entry and exit".

      D – cortical, subject, level of actions. This is a subject, skill, competitive level of automated execution of motor actions. Subject is the major afference of the level. The subject is considered not as it is as a geometric shape, as something with a certain mass, consistence etc., but as a conceptual aspect of action with a subject – it makes no difference if the subject in this action operates as an object or as an implement as well. The afference systems of the described level are the functional systems, which sensitively comprehend the declared subject and determine, what and in which order can and is to be done with this subject.   

      E – a group of levels above the level of actions. At these levels control of motor actions is being developed and improved, especially in situational sports, and they define at a higher degree of the human intellectual activity (goal setting, selection of means, programming, etc.)

Dialectics is clearly visible: every upper level is built on the top of the lower one, determined by it, and starting from the subject level of CNS and motor system represent a single solid system, and their distribution is rather purely conditional, speculative. J.H. Jackson [5], considering the hierarchical structure of nerve centers relative to motor system in accordance with the concept of evolution, marks: "Nervous system is a system of projections, body parts are presented even in the centers of "mind". The concept of evolution rejects all schemes in which the differentiation is carried out into ideomotor and other centers, on the one hand, and motor and sensory - on the other; all the centers are sensory or motor or both together. Within the framework of this scheme, motor centers are not divided into movements and motor coordination centers; coordination and presentation are actually the same. The whole nervous system in general represents some kind of sensor mechanism, system of coordinations top-to-bottom… Upper centers are only extremely complex and specific sensomotor formations, representing and coordinating activity of the whole body in general”. So when analyzing sports activity, one might need to speak not so much on the motor system itself in general, as on its peripheral executive neuromuscular apparatus (NMA), functioning at some sports activity. It means, of course, that this specific functioning of NMA occurs within the central-nervous control of motion systems of a certain level of organization. Besides, motor unit (MU), made of motoneuron, axon and muscle fibers it is innervating, is the basic structural unit of the motor system.

Hence, MU itself “in miniature” represents a solid mass of CNS and NMA.

      Historically, human NMA and motor system in general started to be characterized in respect to development of mainly three basic motor (physical) qualities: strength, speed and endurance. Later various methodological approaches to development of these qualities arose, in the form of first their separate, but then complex development. Such a scholastic attitude to motor qualities in their isolation from substrata – body systems, naturally, was rather harmful and impeded the development of useful scientific-methodological recommendations for practice. Thereby, it is long past time to consider the conceptual framework related to athlete’ physical qualities from dialectic and materialist points of view, as “in the situations when we deal with concepts, dialectic thinking, – as F. Engels emphasized, – brings, at least, the same fruitful results as mathematical manipulations” [12].

Firstly, the definition itself of strength as human ability to overcome external resistance or oppose it by muscle tensions or efforts [7] brought a practitioner to understanding it only as development of absolute force. It turned out that, due to its excessive increase an athlete could not implement force in motion, as any motor competitive act is limited by the amplitude and time of its performance. Moreover, athletes who are not able to show explosive force due to genetic muscle contraction features were often found in the sports where high level of its manifestation was required [2, 8]. So when estimating athlete’s physical qualities one is to speak, first of all, on the contractive features of NMA, on what nature has given to a man – on strength and speed of voluntary muscle contraction. As we can see on the scheme (Scheme 1), both of these characteristics are derivatives from motor and central nervous systems, determined by these systems and characterize one process of evolved in time voluntary muscle contraction in the form of the “strength-time” curve. It has been clarified [16], that one can calculate the coefficient of speed of voluntary muscle tension and indirectly judge on the ratio of quick and slow MU in the athlete’s NMA by the parameters of this curve in the standard test in the isometric mode. The studies specially conducted by Y.V. Verkhoshansky [4] have shown that the instrumental method of registration of the strength-time” curve of explosive effort is very reliable, informative and resolving. So it is recommended for laboratory researches associated with the studies of speed and strength characteristics of human muscles and for teacher’s control of athlete’s status dynamics within sports practice [16].

Much experimental data have been accumulated by now showing that human and animals’ physical abilities are largely determined by the ratio of slowly and rapidly contracting fibers, the ratio of fast and slow MU in muscles [2]. The first (red) fibers were called type 1 fibers, the second (white) – type 2 fibers. It turned out that the red muscle fibers contain a big amount of myoglobin and evolutionarily more adapted to endurance work. Type 2 muscle fibers are devoid of myoglobin, but contain more phosphocreatine, have higher glycolytic capacities and thus evolutionary adapted to anaerobic work. They mainly provide rapid and large amplitude motions. White muscle fibers compared with red, in addition, have a higher adenosine triphosphate activity, which influences greatly the manifestation of the strength quality, as a large number of MU can be involved in muscle contraction at the same time.

Thus, the speed and force of muscle contraction ​​are largely determined by the genetic ratio of fast and slow MU, which can range from 20 to 80 % [2]. Ultimately, the results in any kind of sports activities will be determined by the mechanisms of energy supply of the motor system. The more perfect these mechanisms are, the higher, figuratively speaking, the quality of the fuel supplied to the working muscles is.

Man has such a motor system that has been formed during the millennia long adaptation to the environment, which enabled him to solve different in complexity motor tasks, both related to high-speed motor reaction, when small and big muscle efforts were to be displayed in the shortest period of time, and the ones requiring long, cyclically recurring functioning of NMA with a certain level of intensity. This was especially necessary at early phases of phylogenesis, when human life depended on the level of development of the motor system, muscle contraction force and speed in various conditions of their operation. Therefore, the nature endowed his motor system with various neuromotor units (fast, slow and intermediate) with quite definite, specific systems of their energy supply.

From the evolutionary point of view the dialectic unity of physiological and biochemical mechanisms of life support of the human body at the level of motor system is seen very clearly. Moreover, different chemical reaction chains at the cellular, subcellular, organ and organism levels in the ontogenesis of an individual determined his morphofunctional development. The identical environmental conditions having been repeating billions of times, the man has been coping with, determined the chemistry of metabolic processes in the body’s internal environment, which at the level of NMA has led to certain muscle morphological structure. N.N. Yakovlev notes about it: "... the morphological changes, as well as biochemical ones, are adaptive changes that contribute to better implementation of a particular function. The only difference is that the biochemical changes occur earlier than morphological ones" [19].

In view of the above, it is important for us to qualify to "standard", acyclic and cyclic short-term sports the contingent of persons with NMA with as many as possible fast MU and then improve the mechanisms of their energy supply by using relevant methods of development of both NMA contraction force and speed, thereby creating the necessary preconditions for the synthesis of proper substrates for this energy supply.

When characterizing muscle contraction force and speed as a motor quality, one is to define them as athlete's ability to cope with external resistance or to oppose it via muscle efforts, based on specific motor task. Here the latter should take a definite place in the chain of settlement of key training missions.

It would seem that the given definition suits better to strength, but it fully applies to muscle contraction speed, as proceeds from a specific motor task and describes one process of development of strength in time. Some abstract manifestation of strength beyond time and space is simply impossible, as well as muscle contraction speed, not provoking any force indices.

It should be noted that pure speed is found, perhaps, only in the latent time of motor reaction, as a generalized property of the CNS, which development opportunities are limited and largely genetically predetermined [4]. This must explain to some extent the fact that the latent time of motor reaction is relatively independent of other accepted forms of speed display: speed of single movement (at small external resistance) and rate of movements [4, 16]. In all cases where the fact of muscle contraction is already present, speed becomes identical with muscle contraction speed. However, one extremely important fact should be considered to explain the framework of concepts relative to motor qualities.

The fact is that the main source of energy of muscle contraction - adenosine triphosphate (ATP) does not change in any type of sports activity in muscles. The same amount of ATP is enough for trained muscles as they have an increasing chance of decomposition and anaerobic and aerobic resynthesis of ATP, as in such muscles ATP is not only faster and better consumed, but faster and more completely resynthesized [19]. Therefore, muscle contraction force will be determined in addition to central nervous mechanisms of innervation primarily by the capacities of energy substrates in muscles themselves. The higher capacity they have, the greater number of MU can be involved in the work at the same time, the faster the necessary strength values ​​as biodynamic characteristics for solving a motor task will be achieved. In this case, the concept of muscle contraction velocity is not identical to muscle contraction speed, which is inversely related to the contraction force.

This dependence according to A.V. Hill [18] as a methodologically starting one is adduced almost in all scientific and methodical publications involving the analysis of the muscle contraction mechanism. But in sports practice the operation of any single muscle and moreover single MU is not common. We always deal with the muscle groups and a huge number of MU. Therefore, speaking of muscle contraction speed, we mean not the inner mechanism of slipping in the sarcomeres of myofibrils of thin and thick filaments relative to each other, but some required quantity of simultaneously recruited MU to obtain the desired biodynamic structure of sports movement.

Moreover, in everyday life, and especially in sports practice, we constantly deal with reversing muscle work, which is characterized by switching them from the inferior mode to the surmounting one. It is present in practically all routine and sports motor acts: walking, running, jumps, football, boxing, etc.

In the inferior mode of work active muscle stretching occurs which results in accumulated potential energy of elastic strain in it. Then during the transition to the surmounting mode this potential energy can transform into kinetic energy of the moving unit [4]. Thus, usually, maximum muscle efforts are marked at the moment of changing from inferior work to surmounting one [4]. Yu.V. Verkhoshansky named this athlete's ability to rapidly switch their muscles from the inferior mode to the surmounting one in the maximal dynamic load being developed at this moment the reactive ability of the neuromuscular apparatus [4]. It was found that the faster changing from the inferior muscle work mode to the surmounting one contributes to higher strength values ​​and higher sports results [4, 17].

In view of the above mentioned objective requirements of sports activity it can be concluded that on the basis of the laws of the motor system energy supply, muscle contraction force and speed are closely interrelated and are characterized by the same definition.

      Such a physical quality as endurance needs special consideration. Again, let’s start with the same definition, where endurance is commonly interpreted as mainly the ability to resist fatigue in any activity [18]. Here a practitioner is willing to hear that an athlete must always get ready for coping with fatigue during training and competitive activities, where endurance is especially significant.

Endurance as a physical quality can not be called directly motor quality, unlike muscle contraction force and speed. It is only a derivative characteristic, result of specific functioning of NMA and generally determines the body’s abilities at the level of all systems (see diagram) to provide energy, "fuel", primarily oxygen needed for the ATP resynthesis, for the working muscles. Endurance is especially important in motor cyclic locomotions, in overcoming long distances in athletics, swimming, skiing and skating, etc. But most importantly, no matter what sport we take, it is created and completely determined by the conditions of functioning of NMA, a system of movements of certain level of organization. Mastering some new progressive system of movements, we thereby create a more progressive, more releasing mechanisms of muscle energy supply. If we develop endurance only at the level of utilized locomotor acts by overcoming different distance parts, coping with arising muscle fatigue, ultimately, we shall get good endurance only regarding respiratory and cardiovascular systems, i.e. at the level of maximum oxygen consumption (MOC). And in this case, the standard mode of functioning of NMA will turn into the factor limiting athlete's special working capacity, for the body will stop responding with a positive adaptive response to the same stimuli at the level of motor system.

This mode of endurance development is required at the early phases of sports specialization during stimulation of the natural development of respiratory and cardiovascular systems. We do this with children, offering them the mode of functioning of NMA at the level of various action-oriented and sports games, running and swimming different distance parts. And at this phase of ontogenesis, this approach is justified, since the main task here is to improve total body endurance, its overall performance at the level of respiratory and cardiovascular systems, as the last two, if not developed to the required level, may become a limiting factor in increasing special performance in the future. Moreover, respiratory functional system makes the greatest contribution to MOC at the initial stage of adaptation to muscle loads. Then, at the second, more long-term, phase a further increase of efficiency of the cardiovascular system occurs, ensuring achievement of the maximum amount of blood circulating in the body. At the third phase of the long-term adaptation to strenuous physical loads the increase of the ability of muscles to utilize oxygen acts as the leading mechanism of improvement of aerobic capacity [9]

Thus, at the final stage of the long-term adaptation, which is usually the phase of elite sports skills, body’s aerobic fitness (as the most economical) will be determined by the anaerobic threshold (AT), the threshold beyond which blood lactate starts exceeding 4 mmol/l, 36 mg%.

Increase of blood lactate concentration, indicating the occurrence of AT, is observed at the intensity of work when oxygen consumption reaches approximately 50% of MOC and can vary within a wide range (40-80% or more of MOC).

I.P. Ratov and V.A. Kryazhev [15], analyzing the problems of development of endurance, note, that MOC of the strongest athletes of the world has hardly changed since the 30s and their sports results are determined by the level of AT, which reaches 90-95% of MOC. It has been established [20, 21], that AT correlates with the result in endurance running, and the degree of the correlation increases with the length of distance.

Thus, in the competition the strongest athletes of the world struggle not with fatigue (not with lactate), but aim to increase the speed of movements, etc. This can be achieved only by using in the training process systems of movements of such a level of organization, after which the energy supply of working muscles in a competitive activity occurs practically at the level of MOC. In this case the athlete is focused only on the process of sports contest, as the most economical energy supply takes place, all metabolic processes are carried out with high efficiency at the level of muscles themselves and the critical level of blood lactate, which primarily fatigue CNS, is not accumulated [14].

The main factors that increase the ability of muscles to utilize oxygen from the blood are as follows [9]:

- Increase in the number and structure of mitochondria;

- Increase of the activity of oxidizing enzymes, in particular cytochrome oxidase etc.;

- Increase of the diffusion surface area of working muscles due to increased capillary density;

- Increase of the number of muscle fibers in a muscle, as well as involvement in the active state of a large number of neuromotor units;

- Increase of the number of energy substrates and myoglobin.

The slowly contracting type 1 muscle fibers are rich with the last one and also contain more oxidative enzymes and mitochondria. Therefore, the contingent of individuals with the largest number of slow MU is to be qualified to cyclic sports where it takes long time to maintain high physical working capacity of the body, especially at the level of motor system,.

Based on the above, and considering that "... there is no abstract truth, truth is always specific" [11], endurance is to be interpreted as athlete's body ability to supply energy for the competitive muscle work mode adequate to motor task and preventing early fatigue.

If we interpret muscle contraction force and speed as athlete's ability to overcome external resistance or oppose it by muscle efforts, based on the specific motor task, then endurance will provide energy to the solution of this task or series of tasks in the form of a certain ability of the body, which we eventually develop via appropriate modes of functioning of NMA.

Conclusion. Muscle contraction force and speed, being developed in the dialectic unity with energy supply systems stipulate for building up of athletes’ motor potential, they realize via competitive systems of movement in the form of progressively increasing speed abilities (Diagram 1). The growth of the muscle contraction force and speed in any sport will ultimately bring to increased speed of movement, athlete’s movement in general or its parts, apparatus take-off speed and airspeed enhancing etc. Thus, it is easy to see that the longer, for example, the distance to be cleared by an athlete in running swimming, cycling, etc. is, the more significant the role of systems of energy supply is, performing the oxygen transport function and the more significant the capacity of the intramuscular energy potential is that determines the amount of oxygen utilization by working muscles. Conversely, the shorter the distance is, the quicker athlete's competitive movements, dislocations are, the more significant the power of the phosphocreatine and glycolytic mechanisms of energy supply is.

Thus, speed of movement as an integral criterion of athlete’s training will be determined by the level of development of his special strength fitness, with its specifics of development and improvement in accordance with the sport, as shown in all monographs by Y.V. Verkhoshansky, who studied and analyzed the long-term process of formation of sports skills in the context of dialectics.

The practice itself demands dialectic and materialist development of the most adequate definitions of physical qualities in their correlation and as derivatives from the entitative body functional systems. Their eclectic interpretation and further eclectic insight will inevitably bring the practitioner to metaphysical conclusions and big, and sometimes fatal, methodological mistakes.

"... Human concepts are not stationary, but are always in motion, intercrossing, proceed one from another, without it they do not reflect the real life. The analysis of the concepts, their studies... always require studying concepts in motion, their relationships and mutual transitions ... "[10].

Diagram. The interaction of athlete’s body systems and physical qualities.

References

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Author’s contacts: fvi1945@mail.ru, 89036904297.