Professor, Dr.Biol. Yu.V. Koryagina
Postgraduate L.G. Roguleva
Ph.D. T.P. Zamchiy
Siberian state university of physical culture and sport, Omsk

Keywords: neurohumoral regulation system, psychofunctional state, physioeffect.

Introduction. The urgent goal of sports science and practice is searching for new, effective techniques and methods to optimize the functional state of the body and rehabilitation of athletes. The system of neurohumoral regulation is the basic system, that limits physical working capacity under strenuous muscular activity, and therefore the methods that directly affect it are of particular interest. Transcranial stimulation is one of such methods. The method of transcranial electrical stimulation (TES) is the most approved and widely used all over the world [2, 1, 4]. Transcranial electrical stimulation selectively activates the brain structures that produce endorphin, serotonin and other neurotransmitters, using a pulsed electrical stimulation applied through the head skin electrodes. The safety and effectiveness of TES has already been proven [5]. This method is actively used in various fields of medicine, but when it comes to its use in sport only the first steps are being made in this aspect and it still requires a thorough scientific basis.

The purpose of the work was to identify the impact of transcranial electrical stimulation on the psychofunctional state of athletes involved in martial arts and weightlifting.

Materials and methods. 34 highly skilled athletes, representatives of strength sports at the age of 18 to 24, who had signed the consent form, were involved in the study of the immediate effects of TES. In order to exclude contraindications to the use of TES (latent epileptic activity in the brain), an electroencephalogram (EEG) was preliminarily recorded using the Neuron-Spectrum 3 device (Neurosoft). The effects of TES on the functional state of the athletes and their recovery processes were evaluated based on heart rate variability (HRV) and psychophysiological indicators (simple and complex sensorimotor reaction time, choice reaction time). To study the effect of TES within a competitive activity the athletes were examined a week before the competition (background), after weighing prior to the competition, the experimental group (EG) was examined immediately after the competition and after the TES - and the control group (CG) - 20 minutes after the competition. The study of the TES course effects included 23 highly skilled athletes - representatives of strength sports and martial arts, 18 to 25 years of age. Regional blood flow was studied using the rheographic complex "Rheo-spectrum" (Neurosoft). Psychophysiological testing was conducted using the hardware-software complex "Sports physiologist" [3]. The TES course consisted of 10 daily procedures. A TES session (duration 20 minutes, bipolar pulse current, maximum value of 3 mA) was carried out using the TRANSAIR-5 apparatus.

Results and discussion. The effect of single TES session on the psychophysiological state of athletes at rest. The study of the effect of one TES session during training activities has shown that a decrease in heart rate from 70.8 to 65.6 bpm and in PSI (physiological strain index) from 145.8 to 45.6 cond. units after a TES session in the EG, which indicates an increase in the efficiency of the cardiovascular system. There hasn’t been detected any significant differences between the groups when studying psychophysiological indices, indicating the insignificant impact on them by a TES session at rest.

Effect of single TES session on immediate recovery processes after the competitions. The study has shown a pronounced tension of the regulatory mechanisms and the circulatory system in the athletes after the competitions: HR (EG - 111,4 ± 3,6 bpm, CG - 108,7 ± 4,3 - bpm), PSI (EG – 690,5±143,8 cond. units., CG – 1079,2±437,9 cond. units.) and mode amplitude (AMo) (EG – 61,3±4,3 %, CG – 69,1±7,1%) and SDNN reduction (EG – 21,5±3,2 ms, CG – 21,9±3,2 ms). After the TES session an improvement of a number of HRV parameters was noted in the EG related to the pre- and post-competition values: HR, R-Rav, R-Rmin, R-Rmax (р<0,005), PSI (р<0,05), Mo (р<0,01). SDNN indices, variation coefficient and AMo have been markedly improved in the EG (relative to the pre-competition ones). Significant changes were identified by the PSI values and the variation coefficient 20 minutes after the competitions in the CG and after the TES in the EG (р<0,05). After the TES the ratio of the spectrum components in the EG was as follows: (LF>HF>VLF) 47: 41: 12, and in the CG - 20 minutes after the competition - 52: 36: 12, which indicates an increased sympathetic tone in athletes of the CG compared to the EG athletes. This suggests that the use of a TES session after the competitions promotes more rapid recovery of the cardiovascular system and the autonomic regulation. After the competition in both groups the simple sensorimotor reaction time has increased, which indicates a decrease in the functional state of the central nervous system. The time of simple sensorimotor reaction to light and sound in the EG has been improved after the TES session (р<0,05). Changes in psychophysiological indicators were insignificant in the CG 20 minutes after the competitions.

The effect of the TES course (10 sessions) on the psychofunctional condition of the athletes.

Analysis of the EEG-rhythm dynamics has revealed statistically significant changes in the indices after the TES course registered in the left hemisphere (Table 1). A reduction of the amplitude of the beta-rhythm in all sites of the left hemisphere was associated with a significant reduction in choice reaction time.

Table 1. Dynamics of brain neurons bioelectrical activity

Note. Amax – maximal amplitude; Amed – medium amplitude; Bl – beta low-frequency rhythm; Bh – beta high-frequency rhythm; T – theta rhythm.

In addition, a decrease in the theta rythm amplitude was noted in the occipital leads. This can be interpreted as a sign of economization of the brain work when performing work that requires attention and visual-motor coordination.

It has been established in the study that prior to the course of transcranial electrical stimulation tone and elasticity of the leg arteries and the intensity of arterial blood flow (total variance – 30%) were the most significant factors of hemodynamics of distal parts of the lower extremities. The 2^nd and 3^rd factors were left limb blood flow and pulse wave propagation time (20% and 8% of total variance respectively). After the course of transcranial electrical stimulation, the microvasculature vessel characteristics came to the fore (12% of total variance), followed by the second factor of intensity of arterial blood flow of both feet. Then the 3^rd factor remained unchanged. Therefore, the nature of the changes indicates the primary influence of the course of transcranial electrical stimulation on the microvasculature vessels of distal parts of the lower limbs.

Analysis of the structure of cerebral hemodynamics before the TES course has revealed that the most significant factor is the tone of the arteries (23% of total variance). The next most important factor is one of the volumetric blood supply and volumetric blood flow rate (20% of total variance). The third factor is venous outflow (12% of total variance). After the course of transcranial electrical stimulation volume blood filling and blood flow speed were the most significant factors. (17% of total variance). The second factor was tone of medium and small caliber arteries (15% of total variance), followed by tone of great arteries (14% of total variance). The nature of changes in cerebral hemodynamics indicates the influence of the course of transcranial electrical stimulation primarily on the medium and small cerebral vessels, which leads to an improvement in arterial blood supply and venous return.

The nature of changes of cerebral hemodynamics indicates the effect of the TES course predominantly on the medium and small vessels of the brain, which leads to improvement of arterial blood supply and facilitation of venous return.

Conclusion. Therefore the immediate effect of a single TES session at rest is seen in the increase of the cardiovascular system efficiency. When used after a competitive load TES promotes acceleration of processes of immediate recovery of the autonomic and central nervous systems in athletes. The course application of TES optimizes the regional blood flow of the brain and of the distal parts of the lower extremities as well as the work of the brain when performing hand-eye coordination tasks.

TES is a promising physiomethod for optimizing the functional state of athletes in the process of adaptation to training and competition loads. TES is recommended as a course (10 sessions of 30 minutes) and as a single application/session (1 session of 20 min) to accelerate the process of immediate recovery after the competition and training loads.

References

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Corresponding author: aikin-va@yandex.ru