Physiological mechanisms of ensuring the accuracy of strikes in sports karate

The physiological mechanisms to ensure the accuracy of tsuki are studied in athletes involved in sports karate at different stages of sports perfection. 48 athletes, men aged 18 to 27, specializing in sport karate were examined. Formation of sportsmanship in karate manifests mainly in improving the coordination and efficiency of muscle contractions. Primarily coordinated movements in the sagittal plane is formed (it is already expressed in the average group). The formation of coordination in the frontal plane is complete at highest sportsmanship levels. Simultaneously there is a marked increase in the amplitude of the bioelectrical activity of the shoulder muscles. In the group of athletes of the highest qualification the bioelectrical activity of the rectus muscles of the shoulder is synchronous and has higher amplitude and frequency of oscillations with a shorter duration of activity. Changes in the CNS reactions are in the shortening of the latent period of the visual evoked potential. At the stage of sports improvement the latent period of early negative components (near-field potential) is shorter. With higher sportsmanship there is a shorter latent period of late positive components reflecting the functional state of the stem structures and the cerebral cortex. All of the above physiological changes in the body of athletes are accompanied with restructuring of the vegetative regulation of activities. Moreover, the restructuring of the system is not linear; at different stages of training it involves various mechanisms. With the growth of sportsmanship, first, there is an increase in the degree of muscle hyperemia (regular for average-level athletes), and then - blood delivery acceleration (in the high-level group). Beginners have a low level of adaptation strain, excessive vegetative reactivity and low fatigue. Such a pattern, in general, is typical for a healthy untrained person. Average-level karatekas develop stress and vascular system hyper-reactivity. They show high levels of fatigue and longer recovery period. All this indicates that the "adaptation price'' at this stage is the highest, and these athletes are at risk. Apparently, the formation of motor skills at this stage is ahead of the development of the autonomic system support. Average athletes need urgent attention of coaches and sports doctors - violations of training and overload can easily result in over-stress and adaptation breakdown. Further improvement of sports qualification is associated with decreased stress, eutonic reaction to stress and reduced recovery period. All the above allows us to consider the formation of skill in sports karate as a single functional system with the decisive role belonging to coordination abilities and muscle contraction organization. It is the agreement of the two systems that starts skill formation. Further improvement is accompanied with their better cooperation, with optimization of the higher parts of the nervous system resulting in a shorter latent period of the late positive components of the visual evoked potential. Formation of this motor stereotype is connected with the development of its vegetative-vascular system support. However, during sports perfection the level of the autonomic system strain is weakly correlated with motor loads, which leads to excessive stress of regulatory mechanisms and hemodynamic imbalance. At the stage of high sportsmanship the relationship of motor and autonomic mechanisms is finally formed.

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