Investigation of “Quickness” in Taekwondo roundhouse kick

Abstract

The purpose of this study was to clarify the quickness of the Taekwondo roundhouse kick in the preparatory phase. Quickness includes objective points (shorter kicking time and higher kicking speed) and a subjective point (impression). We focused on the rhythmic hop in the stepping-motion phase prior to the start of kicking in order to investigate “quickness” including the three points above. The rhythmic hop frequencies of forty-eight Taekwondo practitioners were measured and eighteen male Taekwondo practitioners participated in a further motion-analysis experiment. The experiment trial consisted of roundhouse kicks delivered to a target using the preferred leg. The target height was the same as the subject’s torso. The 3D coordinates of reflective markers on the body segments and the target were captured by a motion capture system. The following results were obtained. i) There was no significant difference between physical characteristics and rhythmic hop frequencies, ii) The subjective point was able to be evaluated by the index of similarity obtained in the rhythmic hop in preparatory phase, iii) A tendency was exhibited that subjects who kicked with a higher kicking speed had a lower subjective point index. In conclusion, it was found that there was the possibility of a trade-off relation between the subjective point and the objective points. Coaches should pay more attention to considering which “quickness” is suitable for each situation or practitioner.