| Abstract [eng] |
Concerning the muscular contraction, as a rule it is analysed when applying single stimuli or stimuli sequences of a certain frequency. Physiologically, muscles are activated by impulses coming from motor neurones. Recently, it has been observed that motoneurones generate sequences of potentials of irregular frequency impact. Therefore, a question is raised whether contraction characteristics differ when a muscle is activated by sequence of regular frequency and realistic potential impact frequency. We investigated if muscle fibre contraction parameters differ when stimulating with sequences of stimuli of regular and irregular frequencies. Stimulating with 80 ms duration 5 irregular frequency electrical stimulus sequence, the maximum force of contraction of the muscle fibers was higher than the regular frequency stimulation of the same duration sequence of five stimuli. Regularity of stimulus sequence does not influence maximum of the muscle fiber contraction force if duration of sequence is shorter than 40 ms or longer than 160 ms. The maximal force of the muscle fiber contraction decreased when the duration of regular and irregular stimuli sequence increased from 40 ms to 160 ms. |
