PhD, Associate Professor V.S. Sychev¹
PhD, Associate Professor S.S. Davydova¹
PhD, Professor V.A. Kashkarov^1
1Lipetsk State Pedagogical P. Semenov-Tyan-Shansky University, Lipetsk

Keywords: functional asymmetry, determination of dominant asymmetry profile, sensorimotor asymmetries in sport, changes and selection.

Introduction. High sports results come from a combination of physical, technical and tactical training, and mental conditioning. Various functional characteristics of the athlete’s body are to be considered in order to accomplish the goals in question. In many instances, if not to say always, various types of functional asymmetry determine the realization of man’s motor abilities [7, 9].

According to numerous studies, the asymmetry indicators, those of motor asymmetry in particular, change in the process of athletic training, during adaptation, and under the influence of long-term practical experience. At the same time, it is noted that athletes are generally characterized by certain changes in the motor profile. Tennis players more often appear to be left-handers or ambidexters, wrestlers - ambidexters [8]. Asymmetry indicators may change with respect to the goals, needs and irrespective of the initial type of lateralization. Motor lateralization can change in stressful situations, under fatigue. [9] argues that motor asymmetries in a particular sport depend on the symmetry or asymmetry of technical actions.

Objective of the study was to theoretically substantiate the athletes’ functional state in relation to asymmetry.

Results and discussion. It is generally accepted that manual asymmetry is the most thoroughly studied, while asymmetries in the leg muscle function and sensory systems are understudied. Even so, manual asymmetry causes lots of contradictions and ambiguities.

One of the current questions is: who should be considered left-handed, and who - right-handed. Handedness is more often determined by means of the test [2], which determines the percentage of right-handedness (RH%), and it can vary from -100% (those using their left hand only) to +100% (those using their right hand only). Typically, RH% ​​in the population (like other psycho-physiological and psychological indicators) is characterized by a variance that could be described as a normal distribution curve with some deviations associated with the influence of environmental factors, primarily, different teaching methods.

The evaluation of the mean values of handedness softens the peculiarities of different parts of variation. This is one of the circumstances leading to the arbitrary selection of the handedness criteria, which, apparently, affects both the manual asymmetry values and their dynamics. For instance, according to some literature sources, the number of left-handed people in the populations varies from 1% to 10% [8], but in some populations their number reaches 20-19%.

Some researchers emphasize the difference between the number of left-handed men and women, reduction of manual asymmetry with age, others insist the numbers are not different and, on the contrary, the share of left-handed people increases with age [13].

The same circumstances change the big picture of display of handedness in a particular sport, especially since sports activities can be more or less successful due to various circumstances and mechanisms. For example, reduction of manual motor asymmetry under the influence of symmetrical movements (swimming, walking, certain types of wrestling, etc.) may be due to the peculiarities of the training process, its influence on the nature of movements, though may indicate the effect of selection in a particular sport. Of prime importance is a combination of factors "training process – selection" that should be manifested in small groups.

Changes in manual asymmetry during the training process apparently do not affect all athletes. For instance, some left-handed people are characterized by a high level of neuroticism, which complicates their psychological adaptation to unfavourable sports environments. This is superimposed on the peculiarities of the training process carried out by a particular trainer, and personal characteristics of an athlete. Plastic properties of the nervous system play an important role here. Our studies found a decrease in the share of extremely right-handed people among elite swimmers. But similar changes were observed in the group of athletes – 4^th-year male students versus freshmen. The girls did not have such changes.

It is known that up to 80% of finalists of the major judo tournaments are ambidexters, but 20% are right-handers, despite the same or comparable conditions of the training process.

Conservatism of a part of right-handers is also confirmed in our studies involving elite wrestlers. Yet, it is not clear to what degree the plastic properties of the brain can be used and how strong the readjusted natural mechanisms, that underlie motor skills, will be. According to some observations, in critical situations the brain of retrained people starts using natural, genetically determined mechanisms, as registered with retrained pilots. The indirect confirmation of this is the right hemisphere activated when adapting to extreme natural or climatic environments [7]. As for athletes, studies on the manifestation of retraining in different situations and its impact on sports results are still lacking.

Nevertheless, certain observations show that the "alteration" of the lateral dominance in left-handers (apparently, a part of them) reduces the quality of a number of important mechanisms and adversely affects the effectiveness of motion control [4]. In addition, there are data indicating that the right hand of right-handers performs usual actions more effectively, while their left hand is better at complex actions performed under time pressure. The latent period of visual- and auditory motor responses decreases with increasing right hand and eye lateralization. The right hand and ear lateralization helps estimate time better [3]. It is not clear whether the restructuring of lateralization affects these characteristics. It is also unknown to what extent the eye and ear asymmetry profiles are conservative - plastic.

The low level of technical fitness in combat athletes correlates with a greater degree of asymmetry in motor actions [5]. But the role of the functional asymmetry profile, the impact of the training process on these features, as well as other factors, have not been determined thus far. Perhaps, they lead to contradictory athletic training records. Thus, [1] indicates the dominance of the right asymmetry profile in football players. [10] insists on the mixed type of functional asymmetry. Our research confirms the observations of [10]. Recent studies have shown that there may be groups of boxers with a dominant right asymmetry profile [6]. Despite the specifics of the training process, the handedness distribution curves for football players and wrestlers may be similar.

It is also possible that the motor asymmetry profile selection is made based on other parameters that can correlate with asymmetry. Left-handed tennis players are probably better at solving visual-spatial and visual-motor tasks, and besides, they can be more uncomfortable rivals. As a result, according to [12] the percentage of left-handed tennis players is 2-5 times as high as that of left-handed elite athletes.

The psychological and psycho-physiological personality characteristics are determined based on the profile of functional asymmetry (FA) in the motor and sensory systems, since consideration of one manual motor asymmetry only is often not enough [11]. But the rest of the functional asymmetry components have been insufficiently studied. Even if the manual motor asymmetry indices cannot correlate with each other, it is not surprising that some features of the body locomotion in space are even more specific. For example, postural asymmetry is associated with manual motor asymmetry [8], which can be important in wrestling and team sports.

An increase in the right field of vision is associated with a higher rate of simple motor reaction to stimuli. This phenomenon is especially pronounced when it is the right hand that dominates. Its importance in different sports is insufficiently studied. [1] notes that 85% of athletes are right eye dominant, while in karate 28% are left eye dominant, and in football - 30% have no dominant eye. The figures obtained in football players testify to much the same data, according to which 24% are left eye dominant.

In many sports, asymmetry is a factor that limits sports working capacity [9]. It can be superimposed onto fatigue that leads, in particular, to an increase in asymmetries in skiers and swimmers [9], which gives a different view of the problem of fatigue mechanisms, their significance for different components.

Conclusion. The issue of functional asymmetry has moved to a new level, which requires a deeper and more comprehensive study of the problem, determination of the baseline parameter values, the dynamics of functional asymmetry in ontogenesis, its changes during sports activities driven by the specific features of organization of the mechanisms.

References.

1. Berdichevskaya E.M. Profil mezhpolusharnoy asimmetrii i dvigatelnye kachestva [Profile of interhemispheric asymmetry and motor qualities]. Teoriya i praktika fiz. kultury, 1999, no. 9, pp. 43-46.
2. Bragina N.N., Dobrokhotova T.A. Funktsionalnye asimmetrii cheloveka [Functional asymmetry]. Moscow: Meditsina publ., 1988, 288 p.
3. Bushov Y.V., Nesmelova N.N. Individualnye osobennosti vospriyatiya chelovekom dlitelnosti intervalov vremeni [Individual characteristics of man’s perception of time interval duration]. 1994, vol. 20, no. 3, pp. 30-35.
4. Gutnik B.N. Funktsionalnaya asimmetriya i vozmozhnye fiziologicheskie mekhanizmy ee aktivnogo otrazheniya v manualnoy deyatelnosti rastuschego organizma. Avtoref. diss. dokt. biol. nauk. [Functional asymmetry and possible physiological mechanisms of its active use in manual activity of a growing organism. Doct. diss. abstract (Biol.)]. Moscow, 1990, 45 p.
5. Ermakov P N. Asimmetriya dvigatelnykh reaktsiy verkhnikh i nizhnikh konechnostey u cheloveka [Asymmetry of motor reactions of upper and lower extremities in humans]. Fiziologiya cheloveka [Human Physiology], 1986, vol. 12, no. 3, pp. 507-508.
6. Efimova I.V., Simonov V.N., Budyka E.V. Profil lateralnoy organizatsii motornykh i sensornykh funktsiy studentov, zanimayuschikhsya boksom [Profile of lateral organization of motor and sensory functions of students practicing boxing]. Asymmetry, 2012, vol. 6, no. 4, pp.18-24.
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9. Solodkov A.S., Sologub E.B. Fiziologiya cheloveka [Human physiology]. Moscow: Sport, 2015, 620 p.
10. Khomskaya E.D., Efimova I.V., Budyka E.V. Neyropsikhologiya individualnykh razlichiy [Neuropsychology of individual differences]. Moscow: RPA publ., 1997, 270 p.
11. Chermit K.D. Dialektika simmetrii i asimmetrii v teorii sportivnoy trenirovki [Dialectics of symmetry and asymmetry in sports training theory]. Teoriya i praktika fiz. kultury, 1994. no. 8, pp. 29-32.
12. Holtzen D.W. Handed and professional tennis. Int. J. Neurosic, no. 1-4, pp. 101-119.
13. Stoyanov Z., Nicolova P., Stavrev D., Trendafilova S. Hendedness proportions in Bulgaria: II sex and age differences. Asymmetry, 2014, vol. 8, no. 1, pp. 5-12.

Corresponding author: fizkult@teoriya.ru

Abstract 

High sports achievements require all components of the athletes’ body functional fitness to be taken into account. Functional asymmetry of the brain is one of the most important determinants of human capabilities in motor task solution. There is a considerable body of evidence to suggest the role of various asymmetries in sports activities, their peculiar dynamics in the training process. However, a number of key issues of motor and sensory asymmetries remain unclear so far, and their resolution requires further research and discussion.

One such issue is to provide a precise definition of the leading motor skills and sensory mechanisms. The existing methods have given mixed results. In different sports, different profiles of sensorimotor asymmetry are being discovered, but it is still not clear to what extent various peculiarities are the result of a purposeful process and to what extent they are a consequence of selection of appropriate indicators. Some characteristics of the functional asymmetry can be quite stable, being driven by a specific genotype, they are unaffected by the training process and can become an obstacle to achievement of high sports results.