Karate fist punch

ISBS Conference 2008, July 14-18, 2008, Seoul, Korea BIOMECHANICAL ANALYSIS OF FIST PUNCH GYAKU-ZUKI IN KARATE Martin Hofmann, Kerstin Witte, and Peter Emmermacher Department of Sport Science, Otto-von-Guericke-University, Magdeburg, Germany
The purpose of this study was to characterise the most used fist punch in karate, the so called Gyaku-Zuki. Having a look at current publications, most ofthem describe the Gyaku-Zuki in a verbal form or they concentrate on analyses about physical parameters. In order to understand and even improve the movement, it is necessary to describe the punch by using biomechanical parameters. Recording the performance of three different karatekas with a VICON system, this study only focuses on the basis-version of GyakuZuki. After giving the movement astructure, first results can be presented e. g. the total time of movement and maximum velocity of fist. For performing a punch all three athletes require less than 400ms and reach a maximum of fist velocity of about 8m/s. So this study will help to understand the Gyaku-Zuki and will pave the way for further analyses. KEY WORDS: karate, Gyaku-Zuki, kinematical analysis.

INTRODUCTION: Karate Kumite ischaracterised by two active athletes fighting against each other in a certain area (DKV, 2008). The purpose of this study is to analyse the most used fist punch in karate kumite, the so called Gyaku-Zuki. Although performing an attack with the leg is judged with three points, lots of attacks are made by using fist punches in kumite. The main reasons for using the fist punch Gyaku-Zuki are thatthe execution does not require much time and the movement is less complicated compared to a kick e.g. Mawashi-Geri. In order to be better than the opponent and receiving the judgement, the aim of the karateka is to reduce the total time of movement of the used technique. Regarding the situation of publications in karate, there are analyses concentrating on physical education (e. g. Lehmann &Jedliczka, 1998). Furthermore there are analyses which explore karate movements by using technical equipment and biomechanical methods e. g. Sforza et al. (2000). But a lot of the existing publications describe the Gyaku-Zuki in a verbal form, e. g. Wichmann (1985), Lind (1999) and Okazaki & Stricevic (1987) who do not consider biomechanical information. The first essential biomechanical investigationsof karate techniques were carried out by Emmermacher et al. (2005, 2007) and Witte et al. (2005, 2007). But a complex three-dimensional kinematical analysis of the Gyaku-Zuki was not reported yet. So the aim of the study is: • to get knowledge and understanding about the movement structure and the specifics of the fist punch. • to analyse the total time of movement and velocities of punching fistin order to optimise both during execution of movement. Before starting the research it is important to know that there are many different types of performing the Gyaku-Zuki. This study will only focus on one version which is presented on the first position in the following Table 1. This version is characterised by the athlete standing still in an upright position before performing the fist punchwith active hip movement. Table 1 presents also a short description of different possible versions of the Gyaku-Zuki in kumite. METHOD: Three male karatekas with different graduates participated in this study: subject I (4th Kyu), subject II (3rd Dan) and subject III (2nd Dan). Each karateka executed different versions of the fist punch Gyaku-Zuki (see Table 1), whereas each version was performedfor six times. As already mentioned, the focus of this study will be the execution of variant 1 only, because this version represents the basic one. The other versions have been performed and recorded for further analyses and comparisons between the techniques. The break between the six punches was about one or two seconds, among the different series of the Gyaku-Zuki the break was about three...