Dr.Hab., Professor A.V. Samsonova¹
Dr.Hab., Professor G.N. Ponomarev²
PhD, Professor L.L. Tsipin¹
PhD, Professor O.A. Bogdanov^2
1Lesgaft National State University of Physical Education, Sport and Health, Moscow
²Herzen State Pedagogical University of Russia, St. Petersburg

Keywords: muscle strength building mechanisms, strength training, selection of exercises.

Introduction. Success in strength and speed-strength sports requires a sufficient level of development of strength qualities and excellent technique of exercise performance. Trainers and scientists are in constant search for up-to-date means and methods of strength training.
Objective of the study was to describe modern views on two aspects of strength trainings: skeletal muscle activity mechanisms during strength training, and special strength exercise selection methods.
Results and discussion. There is a great number of variables determining the strength training result (amount of weight, duration of rest breaks, specifics of competitive exercises, etc.). One of the aspects of the use of strength exercises concerns the skeletal muscle activity mechanisms influenced by heavy weights (more than 70% of the maximum). It has been proved that the use of heavy weights during strength exercises leads to hypoxia of muscle fibers (MF), which makes them accumulate lactate and, consequently, results in the fiber damage [6]. Reoxygenation of the muscle after hypoxia and its mechanical tension lead to the MF damage too [6, 9, 10]. This provokes the release of calcium ions, which activate enzymes that break down proteins. It has been proved that a single strength training can lead to damage of more than 80% of the MF [10]. The MF sarcolemma damage provokes the satellite cell division [5], increases the number of nuclei, which enhances protein production in the MF. The MF sarcolemma damage also leads to the penetration of leukocytes into the muscle, which causes its inflammation [6], as well as delayed development of pain, which reaches its maximum 24-72 hours after strength training. During this period, it is undesirable to subject the skeletal muscle to increased strength loads due to the inflammation processes in it. During the recovery period, protein production in the MF increases, which, in turn, leads to an increase of strength and hypertrophy of the skeletal muscles. Therefore, the more damaged the muscle fibers, the greater the effect of strength training, the greater the strength and volume of the skeletal muscles.
There are a few assumptions in this context needed to be checked by an experiment. First of all, after intensive strength training, close-up aerobic trainings with fast walking or jogging are not recom-mended as they speed up the lactic acid removal from the MF and may diminish their damage; secondly, anti-oxidizing agents are not recommended either, since they restrain the MF damage too. Thirdly, the immunity sags reported in athletes after high-intensity strength trainings may be due to the myogenic leu-kocytosis associated with the inflammation process in the skeletal muscles.
Another aspect of the use of special strength exercises concerns their selection. So far, several principles have been established, on the basis of which such exercises are selected. The most widely used principles are those of synergized effects - according to V.М. Dyachkov [3] and dynamic matching – ac-cording to Y.V. Verkhoshanskiy [2]. I.M. Kozlov proposed the principle of progressive movement bio-mechanics [4]. Foreign experts consider the principle of specific effects [11, 12]. Common to all of these principles is the condition of correspondence of competitive and special exercises in various indicators and development during special exercises of efforts, greater or equal to those developing during competitive exercises.
At the same time, the existing principles ignore the fundamental differences of specific sport dis-ciplines, associated primarily with the movement biomechanics. Taking into account the exercise classifi-cation [7] and the ideas of founder of Russian biomechanics N.A. Bernstein of the levels of movement composition [1], we believe that special strength exercises should be selected with competitive routine stereotypes and compositions being taken into account. It is these parameters that determine what to strive for when comparing competitive and special exercises. Consequently, a new principle was proposed – the differentiated biomechanics matching principle [8]. It implies the following: in sport disciplines with highly stereotyped movements, it is the relevant sensor patterns of competitive routines and special train-ing exercises that should be harmonized; in sport disciplines with less stereotyped movements – it is the relevant kinematic and dynamic patterns that should be harmonized; in sport disciplines with situational irregular movement – it is the identity of the core muscle groups involved in competitive routines and special training exercises that should be preserved.
Conclusion. The modern concept of the use of strength exercises in athletic training proves the prospects of the training methodology, first, based on the knowledge of the processes occurring in the skeletal muscles during and after the strength loads and, secondly, taking into account the fundamental differences in sport specific disciplines when selecting exercises.

The study was initiated pursuant to the Ministry of Sports of Russia Order №1247 of December 25, 2015, on Lesgaft National State University of Physical Education, Sport and Health, St. Petersburg, being awarded a state contract for the "Improvement of the effectiveness of special strength exercises in training of skilled athletes of cyclic sports and martial arts based on the biomechanical analysis of the stereotypes and compositions of motor actions during competitive exercises" studies.

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Corresponding author: g-ponomarev@inbox.ru

Abstract
The study considers the following two aspects of strength trainings: skeletal muscle strength building concept; and strength exercise combination concept. Many study reports have found that the muscle strength growth is associated with minor damages and inflammation processes. There are a few assump-tions in this context needed to be checked by an experiment including: close-up aerobic trainings with fast walking or jogging are not recommended after intensive strength trainings; and anti-oxidizing agents are not recommended too. The immunity sags reported in athletes after high-intensity strength trainings may be due to the myogenic leukocytosis associated with the inflammation process in the muscles. The second recommendation on how the strength building exercises should be combined implies that they should be close to the competitive routines. In addition to the common principles of synergized effects, dynamic matching, progressive movement biomechanics and specific effects – we believe that the exercises should be composed with competitive routine stereotypes and compositions being taken into account based on the differentiated biomechanics matching principle. Depending on the specific sport discipline, the latter principle implies the relevant sensor, kinematic and dynamic patterns of competitive routines and special training exercises being harmonized to secure the focus on the core muscle groups in the trainings.