Vienkartinių dinaminių ir izometrinių pratybų poveikis keturgalvio šlaunies raumens susitraukimo ir atsipalaidavimo savybėms

The aim of the testing was to measure the changes of leg muscle voluntary and involuntary contraction features and muscle resitance to fatigue during one time isometric and dynamic workout. Research was performed with healthy adult men who did not have any sport activities for two years prior to the testing day or those who exercised no more than twice a week for 1—1.5 hours. The frequency of electrostimulators’ impulses and the contraction power of thigh quadriceps was registered with IBM personal computer (CPU i486-33MHz, RAM 8M) using “Stimula Lab” program devised by E. Povilonis in 1994. The measurements were made only of contraction fi rce stimulated with the frequency of 1, 10, 20 and 50 kHz, and the maximum voluntary strength. A simplyfi ed “Wingate“ test of anaerobic power was used to perform a dynamic speed test. It was made by using a Monark 834E veloergometer which allows to measure work power and frequency of pedaling during the time of the test with 5 minute intervals. During one time dynamic workout 12 sets with intervals of 5 minutes were accomplished. Time duration of one set was 5 seconds. The participants had to keep maximum pedaling speed for 5 seconds. The mechanical resistance of veloergometer differed for each individual and equaled to 7.5% of body mass. During the process of isometric workout, the participants were asked to achieve maximum voluntary power for 5 times during 5 seconds and to relax the muscle completely. 5 minute break followed this workout and a total number of 12 sets were repeated for 5 times. In the middle of the workout, when the 6th set was completed, the force exerted by electro-stimulation and maximum voluntary strength were registered in addition. For both cases, the data were registered right after the test was completed, then 5 minutes, 30 minutes and 1 hour later. According to the results, after dynamic and isometric testing with the frequency of P 1, P 20, P 50 Hz, the contraction and rest time of muscle did not change statistically signifi cantly (p > 0.05). For both cases, fatigue of low frequences appeared. Results show that the most remarkable feature changes of thigh quadriceps contraction and rest time can be seen after involuntary force developement workout (12 × 5 seconds, dynamic muscle contraction). The mentioned tension raises a higher fatigue of isometric muscle contraction than the tension exerted by isometric regime.