PhD, Associate Professor V.N. Shlyakhtov
Velikie Luki State Academy of Physical Culture and Sport, Velikie Luki

Keywords: electric stimulation, electromagnetic stimulation, H-reflex, M-response, physical qualities, competitive performance.

Background. The traditional movement coordination and physical qualities excellence components of modern sports training systems are complemented by a variety of stimulation methods including the biomechanical muscle stimulation; muscles and peripheral nerves electric stimulation; spinal cord and muscles electromagnetic stimulation etc. It should be emphasized that these stimulator methods are applied only as complementary, although the relevant study reports have verified the following: benefits of the biomechanical muscle stimulation method for the athletes’ flexibility [5]; benefits of the muscle electric stimulation for the strength and speed-strength trainings [4]; benefits of the muscle electromagnetic stimulation for the strength and speed-strength trainings [1, 6]; and benefits of the key muscle group electromagnetic stimulation for the movement controls and performance excellence trainings [7]. These studies were designed to analyze the specific stimulation mechanisms and their benefits, although we should note that the sport science is still in need of comparative analysis of specific applications, pros and cons of the stimulator systems for the neuromuscular apparatus.

Objective of the study was to analyze benefits of the electromagnetic and electric stimulation methods for the human motor system control and functionality.

Methods and structure of the study. We sampled for the study 48 subjects aged 18-27 years. The first stage of the experiment was designed to profile the electromagnetic / electric-stimulation-induced variations of the moment of forces, H-reflexes and M-responses in peroneal nerve, with the electromagnetic / electric stimulation signal strength and frequency growths. The second stage was designed to profile the above variations in the 10-day calf muscle electromagnetic stimulation in the foot flexing trainings. And in the third stage we tested variations in the run stride coordination pattern in a 10-second maximum-speed treadmill (HP Cosmos Venus) test with a permanent electric stimulation of the lumbar spinal cord segment. Details of the electromagnetic / electric stimulation stimulation methods and test procedures may be found our prior study reports [2].

Results and discussion. The tests found the moment of force growth at the maximal-intensity electric stimulation being 185.5% higher than that in case of the electromagnetic stimulation, with the top moment of forces achieved at 25Hz frequency rate (4 times higher than in case of the electromagnetic stimulation). The electromagnetic stimulation -related peak in the moment of forces was associated with a higher growth of the H-reflex amplitude than in case of electric stimulation. It may be concluded, therefore, that the muscle electromagnetic stimulation secures a higher motor functionality growth and higher muscle contraction amplitudes than the electric stimulation.

The electromagnetic stimulation and electric stimulation methods are different in their nature since the electric stimulation impulse affects the body tissues via the surface/ needle/ implanted electrodes [3], whilst the electromagnetic stimulation induces an electric field deep in the body tissues to create potential differences and the resultant impulses. The magnetic field will excite the nervous and muscle tissue only when there is an induced electric field in place to act as a mediator [9]. In practical terms, the electric stimulation method is more user friendly for the standard training environments since the modern electric stimulation equipment is portable and autonomous, whilst the electromagnetic stimulation systems may be used for the motor functionality improvements and tests only in laboratories.

We analyzed the benefits and limitations of the both stimulation methods and their application options for the training process improvement purposes to lay a basis for further experiments. The 10-days electromagnetic stimulation of the subject muscle contractions was found beneficial as verified by the electric stimulation post- versus pre-experimental moment of force growth by 52.3%; and the EG versus RG growth by 24.1%. The electromagnetic stimulation was found to spur up the H-reflexes and, consequently, increase in the reflexive excitability of spinal cord. The spinal cord electric stimulation in the treadmill training was tested to significantly boost the electromyographic activity of the the hip flexors by 35.3% (p<0.05), and decrease the anterior tibial muscle activity by 10.7% (p<0.05); with the angular velocity of the femur increased in the swing phase and the knee joint angle decreased in the swing leg movement.

The stimulated variations in the muscle group and central nervous system functionalities are unlikely to seriously affect the movement coordination patterns in the competitive routines/ motor skills, although the motor skills coordination patterns formed by the long systematic trainings need to be adjusted to the stimulation-improved muscle functionality. The stimulation methods applied in the experiment were found to activate the spinal cord controlled neural networks responsible for the movement control and coordination qualities [8]; and we believe that these effects should not be detrimental for the movement coordination patterns in the competitive routines/ motor skills.

Conclusion. The study data and analyses showed that the spinal cord and muscle electromagnetic and electric stimulation methods are beneficial for the motor system functionality, with the electric stimulation tools being particularly user-friendly for practical application in the modern training systems.

References

1. Gorodnichev R.M., Petrov D.A., Fomin R.N., Fomina D.K. Magnetic stimulation in sports. Study guide. Velikie Luki, 2007. 95 p.
2. Gorodnichev R.M., Shlyakhtov V.N. Physiology of Strength. M.: Sport publ., 2016. 232 p.
3. Komantsev V.N., Zabolotnykh V.A. Methodological foundations of clinical electroneuromyography. St. Petersburg, 2001. 350 p.
4. Kots Ya.M., Khvilon V.A. Electrostimulation to train muscle strength by. Message II. Teoriya i praktika fiz. kultury. 1971. no 4. pp.  66-72.
5. Nazarov V.T. Biomechanical stimulation. Reveal and hope. Minsk: Polymya publ., 1986. 95  p.
6. Popov G.I., Malkhasyan E.A., Markaryan V.S. Specificity of magnetic stimulation depending on sports specialization. Human physiology. 2015. v. 41. no. 3. pp. 90-97.
7. Ratov I.P., Popov G.I., Loginov A.A., Shmonin B.V. Biomechanical technologies for training athletes. M.: Fizkultura i sport publ., 2007. 120 p.
8. Shcherbakova N.A., Moshonkina T.R., Savokhin A.A., Selionov V.A., Gorodnichev R.M., Gerasimenko Yu.P. Non-invasive method to control individual spinal locomotor networks. Human physiology. 2016. v. 42. no. 1. pp. 73-81.
9. Barker А.Т., Jalinous R.А., Freeston I.L. Non-invasive magnetic stimulation of human motor corteх. Lancet. 1985. V. l. pp.1106-1107.

Abstract

In addition to educational tools, a range of stimulation methods are used for physical fitness and coordination improvement purposes including: biomechanical muscle stimulation; electrical stimulation of muscles and peripheral nerves; and the electromagnetic stimulation of the spinal cord and muscles, with all these methods applied to complement the training systems. Objective of the study was to rate benefits of electrical/ electromagnetic stimulation for human motor system. Sampled for the study were the 18-27 years old individuals (n= 48). The experiment was intended to rate the moment of force gradient, the H-reflex and the M-responses under growing power and frequency of electromagnetic and electrical impulses on the peroneal nerve; and profile variations of the above rates in the 10-day electromagnetic stimulation of the calf muscle in foot flexing exercises; plus variations of the running stride coordination structure in the 10-second top-speed treadmill practice with the continuous electrical stimulation of the lumbar spinal cord. The moment of force gradient for the top-intensity electrical stimulation was tested to exceeded by 185.5% the rate induced by the electromagnetic exposure. The highest moment of force was achieved at 25 Hz. The above 10-day electromagnetic stimulation was tested to increase the maximum moment of force in the EG by 52.3% versus the pre-experimental rate in RG that grew by 24.1%. The electrical stimulation of the spinal cord in the treadmill exercise was tested to boost the electromyographic activity of the hip flexors by 35.3%, whilst the anterior tibial muscle activity, on the contrary, was tested to drop by 10.7%. The study data contribute to the knowledge of the electrical stimulation and electromagnetic stimulation effects on the spinal cord and muscular performance.