ELECTRICAL ACTIVITY OF THE MUSCLES OF THE LOWER LIMBS OF KARATEKAS DURING THE PERFORMANCE OF A FRONT KICK

Abstract

Subject. The study was aimed at analyzing the processes of muscles activation of Kyokushin karate practicioners during the kick performance. The process of skeletal muscle activation was studied by the analysis of their electrical activity. Our study aimed at the examination of the electrical activity of the muscles of the lower extremities of karate athletes during kick performance. Methods. The study involved 3 highly qualified karatekas (I Dan), aged 18-21 years, with a training experience of 12-15 years. Surface electromyogram (sEMG) was recorded during the Mae geri performance from Zenkutsu dachi stance for the following muscles: m. gluteus maximus, m. rectus femoris, m. biceps femoris, m. semitendinosus, m. gasterocnemius (caput lateralis), m. tibialis anterior. The activity period (AP, ms), mean amplitude (MA, % from maximal), and mean frequency (MF, % from maximal) were determined by sEMG analysis. Results. It was found that the duration of AP of different muscles ranges from 0.19 to 2.02 s during a Mae geri kick performance. The shortest AP was found for the m. gluteus maximus and m. rectus femoris. The highest MA values were registered for the m. tibialis anterior sinister (55%) and m. gasterocnemius dexter (47%), MF - for the anterior tibialis muscles (41-56%), right m. gasterocnemius (caput lateralis) (52%), and the m. rectus femoris dexter (47%). In many cases, the AP, MA, and MF of the supporting leg muscles exceeded those of the symmetrical muscles of a kicking leg. For many muscles, including the m. gluteus maximus, m. rectus femoris, and m. biceps femoris, the increase in MF of sEMG during kick significantly exceeds the MA changes. Conclusions. The main features of the activation of the muscles of the kicking and supporting leg of karate practitioners during the performance of the Mae geri kick were revealed. Most probably, one of the important mechanisms of muscles activation during the kick is the increase in the firing rate of motoneurons.