The comparison of the dynamics of selected leg strokes in taekwondo WTF

The aim of the study was to compare a dynamics of selected leg strokes in taekwondo WTF (Word Taekwondo Federation). Investigations were carried out in the group of 5 competitors with mastery class of taekwondo WTF. Indicators which described two maximal trials of each limb of the body for the side-kick (yop-chagi) and spinning back kick (dwit-chagi) were analyzed. The athletes executed strokes against vertically mounted force plate equipped with an appropriate absorption layer which minimized the risk of injuries. The signal of force was sampled with the frequency of 800 Hz. Signals were filtered by Bessel’s filter at a limit frequency of 75 Hz. The following indicators were analyzed: maximal and average values of stroke force, impulse of stroke, time of gaining maximal force, average velocity of increasing stroke force. The results show that taekwondo athletes recorded similar values of the strokes investigated. The differences in maximal stroke force were 6 % and in average stroke force – 3 % and they were also related to athlete’s weight. The results confirm athlete’s ability to use the total body mass to increase the stroke force. No significant relations were found between time of gaining maximal force and the value of stroke force. This proves that the technique of stroke, different size and kind of striking surfaces influence the value of stroke force. Key words: biomechanics, taekwondo WTF, force of stroke, impulse of stroke 1