Differences in the preparatory phase of mawashi geri jodan in karate

Differences in the preparatory phase of mawashi geri jodan in karate Pecoraioli F., Merni F. Faculty of Exercise and Sport Science, University of Bologna, Italy Introduction In martial arts there are several ways to perform the turning kick [2]. Following the martial arts or different learning models many types of kicks take shape. Many authors were focused on the rising phase of the kick [4,5] but never on the preparatory phase that is the phase before the take-off of the striking foot. At the moment there are two models of mawashi geri, one comes from the traditional karate [3] (OLD), and the other newer [1] (NEW), who agrees to the change of the rules of W.K.F. (World Karate Federation) happened in 2000. In this study we are focus on the preparatory phase of the mawashi geri jodan of karate in two clubs who use different training of the kick. The purpose of this study is to analyse the preparatory phase of mawashi geri jodan to find out the implication of two learning models OLD and NEW relatively to the posture and preparatory actions. Method Six skilled females practicing karate from two different clubs: OLD and NEW each composed by three subjects. OLD: (mean level; black belt 2nd dan; age 25±6 yrs; height 167±7 cm; weight 54,7±7,2 Kg) and NEW: (mean level black belt 2nd dan; age 20±5,2 yrs; height 170±3,5 cm; weight 53,3±2,9 Kg) were the groups of this study. A Vicon system 460 IR with 6 cameras at sample frequency of 200 Hz was used. 37 reflective markers have been set on the skin of the subjects following the “PlugInGait-total body model”. The participants performed many repetitions of mawashi geri jodan at maximum rapidity with their dominant leg against a ball suspended in front of them placed at ear height. Five trials for each subject have been processed, and base on execution time the best and the worse have been rejected (the intraclass correlation range is 0,799 – 0,987). The start event (STR) of the preparatory phase was set with the centre of mass shift (COM), while the take-off event (TKF) of kicking foot with the trajectories of foot markers. Time between STR and TKF is the length of the preparatory phase. Flexion-extension and abduction-adduction hip angles, and flexion-extension knee angles in STR and TKF events have been collected. In the same way the kicking foot axis relatively to the striking direction has been evaluated. By means of the Mann Whitney-U test (Spss-package) the differences between the two groups were verified. Results. The two groups (OLD, NEW) showed significant differences (p< 0,05) for main variables. The angles differences that are not put in table didn’t show significant differences. Discussion For each type of kicks the body is set in difference manner already before the take-off of the kicking foot. Differences in the preparatory phase could be due to the different learning model used in the two clubs. Trainer should pay attention to starting posture both during the teaching session and in case of technique conversion. In fact before change the rise phase of the kick the teacher should change previously the preparatory phase. References [1].Aschieri P. (2000). Karate – il combattimento. Sperling & Kupfer Editori s.p.a. Milano. [2].Pecoraioli F., Merni F. (2007). Different executions of turning kick in martial arts. 10th Sport Kinetics Conference, Belgrade - Serbia. [3].Sacripanti A. (1996). Biomeccanica degli sport di combattimento. Filpjk vol. n° 6. [4].Sorensen H. at all (1996). Dynamics of the martial arts high front kick. J. Sports Sci. 14. 483-495. [5].Witte K., Emmermacher P., Soren B., Potemberg J. (2007). Movement structures of round kicks in karate. XXII ISBS Symposium. Ouro Preto- Brazil