Fomin R, Sergeev V, Nesterik K, Kosminin V. Effect of intense muscular activity on motor potentials under magnetic stimulation of brain and spinal cord. J. Hum. Sport Exerc. Vol. 5, No. 3, pp. 348-357, 2010. In this work, the parameters of motor evoked potentials of upper and lower extremity muscles were evaluated, under magnetic stimulation of cerebral cortex motor areas, spinal segments, and nerve tibialis in athletes adapted to work of various duration and intensity (sprinters, stayers) and having various qualifications. It was established that the maximum amplitude of the motor evoked potentials of muscle gastrocnemius med. and muscle soleus under transcranial magnetic stimulation of the brain is higher in the stayer group than in sprinters. High qualification ski racers, in comparison with lower qualification ski racers, have lower excitation thresholds and a higher maximum amplitude of the motor evoked potentials of muscles carpi radialis, biceps brahii, gastrocnemius med., and soleus. No statistically significant differences in the central motor conduction time and the latent period of motor evoked potentials have been revealed between the compared groups of persons being tested.