Physiological markers of the speed of muscle contraction and relaxation of type I muscle fibers in racing skiers

Aim. The aim of this study is to define physiological markers, determining the speed of muscle contraction and relaxation of type I muscle fibers in the racing skiers of high qualification. Material and methods. We studied male racing skiers aged 21-23 with the qualification of the Candidate for Master of Sport (14 persons) and the Master of Sport (6 persons). In order to reach the aim of the study we used instrumental methods and mathematical statistics techniques. Results. We registered that the slowdown of the end of blood coagulation from the training stage to a competition one by 5.04 % (р = 0.02) against the increase in hematocrit by 19.12 % (p = 0.035) results in the increase in the speed of type I muscle contraction. At the same time, the increase in the acetylcholinesterase level (ACH) by 4.07 % (p = 0.015) indicates the increase in the speed of muscle relaxation. Conclusion. As a result of the study, we found out changes in the muscle performance of racing skiers with a high level of sport efficiency. The increase in the activity of actomyosin ATPase of type I muscle fiber in racing skiers before competitions together with the increase in the acetylcholinesterase enzyme (ACH) determine the intensification of sport performance.