REACTION SPEED AND COORDINATION IMPROVES THE PUNCH OF GYAKU ZUKI CHUDAN	
Dani Nur Riyadi, Johansyah Lubis and Taufik Rihatno 	
Universitas Negeri Jakarta, Rawamanguan Muka Street, Jakarta, Indonesia  
{daninurriyadigundarya@yahoo.com, johansyahlubis@unj.ac.id, taufikrihatno@unj.ac.id}	
Keywords:	reaction speed, coordination, gyaku zuki chudan
Abstract:	This study aims to determine the effect of reaction speed, eye-hand coordination towards the gyaku zuki chudan on Bandung Karate Club Athlete in Bekasi City. The research method is a descriptive associative, and the analysis technique is path analysis. The sampling technique used is a total sampling with a sample amount of  16 people. The instruments used are a test of gyaku zuki chudan, reaction speed measurement using Catch the ruler test, eye-hand coordination measurement using throw-catch the ball, The amount of value obtained by gyaku zuki chudan technique is to do a straight punch parallel to the chest or angle of the 90° with as soon as possible for 10 seconds. Samples tested 2 times, performed in a closed room, the results obtained in the execution of the test is hitting in the size of the number of punch. The conclusions are: (1) reaction speed directly affects on the gyaku zuki chudan, and (2) eye-hand coordination directly affects on the gyaku zuki chudan.

INTRODUCTION
Karate is a good example of a competitive sport with high levels of temporal and spatial constraints which require fast reactions. In sparring (‘‘kumite’’) and matches of karate, two athletes face each other within a 2-m distance, making offensive attacks against each other (Shuji Mori YO, 2002).
The gyaku zuki chudan technique  punch is a basic punch that must be mastered by an athlete since the first athlete or practicing karateka (Hofmann, Witte, & Emmermacher, 2008). 
The inability in the punch technique skills of gyaku zuki chudan will affect all other forms of punch or punch variations. The Gyaku-zuki, also known as the reverse punch, is a technique commonly used in karate kumite, a form of competitive fighting (Suwarganda, Razali, Wilson, Flyger, & Ponniyah, 2009).
The gyaku zuki chudan technique is more varied and very efficient in obtaining value, this is recognized by national karate athletes, they feel more confident using the gyaku zuki chudan technique than other techniques especially when they have not gotten a score or are in a series state. "70% of all karate techniques use a lot of punch as a powerful weapon, therefore a karateka must have a 
really good blow to be able to get a number or point if in a fight or kumite" (Purba, 2016:  48).
Documenting data released by the Karate Championship Committee in 2017 National Level PB FORKI, averaging 81.94% using the punch of gyaku zuki chudan (Muhamad & Haqiyah, 2019)

Table 1: Contributions Techniques Karate 2017 Match Results (Semi Finals and Final)
In performing thetechnique gyaku zuki chudan, reaction speed is needed (Suwarganda et al., 2009) and eye-hand coordination (Witte, Emmermacher, & Lessau, 2008)
Speed is clasically defined as the shortest time required for an object to move along a fixed distance, wich is the same as velocity, but without specifying the direction (Miller, 2012).
For example, a karateka in gyaku zuki chudan does all the above movements, when doing a blow he makes a reaction and does a non reactive acyclic motion when the arm slides towards the target, then when it is released and approaches the target he performs a combination of Reactive Asiklis and fast motion  to produce fast and directional blows. So in terms of the use of energy systems using anaerobic energy systems (ATP-PC and Glycolysis) which only have a duration of 10 seconds - <60 seconds or <1 minute. It is speculated that anaerobic metabolism is the predominant source of energy in Kumite karate (Beneke, Beyer, Jachner, Erasmus, & Hütler, 2004).
Coordination is divided into two types, namely general coordination and special coordination (Bompa, 2012). General coordination is the ability of the entire body to adjust and adjust movements simultaneously when performing a motion (Norma et al., 2014). That is, that every movement carried out involves all or most of the muscles, nervous system, and joints. For this reason, in this general coordination, there is a need for regularity of movement from other members of the body, so that the movements carried out can be harmonious and effective so that they can master the motion skills learned. General coordination is an important element in motor performance and shows the level of ability a person. Therefore general coordination is also the basis for developing special coordination
Eye-hand  coordination  is  a  complex  psychomotor  skill  with  an  essential  role  in  adaptation,  which  involves  synergistic  action  of  sensory  functions  (exteroceptive  and  interoceptive)  and  motor  function,  resulting in providing informational and energy parameters of the movement (Grigore, Mitrache, Predoiu, & Ro, 2012).
In identifying the factors that can influence and increase the speed of the gyaku zuki chudan punch based on relevant studies. Based on the results of the study, a person's thought process in coordinating sensory systems and motor systems can be assessed by reaction time. At hand reaction, good hand and visual coordination will provide a fast hand motion response. The time of hand reaction can determine success in a match, so that hand reaction time is an important component in sports (Syafitri, Supatmo, & Indraswari, 2017) Good reaction time is very important in karate, because it allows to identifying earlier opponent body movements or attacks that allowing taking decisive action or evading will be taken if necessary (Syaquro & Badruzaman, 2018).
This is the background of the authors to conduct further research on the effect of reaction speed and eye-hand coordination on the punch of gyaku zuki chudan.
method
The method used in this study was a descriptive associative  method with measurement techniques and tests. The analysis technique used was path analysis. The sample used is a Bandung Karate Club Athlete in Bekasi City amount 16 people.
The instruments used in this research : (1) Catch the ruler test to reaction speed (Widiastuti, 2015), (2) Eye-hand coordination  measured with throw-catch the ball (Ismaryati, 2011). The amount of value obtained by gyaku zuki chudan technique is to do a straight punch parallel to the chest or angle of the 90° with as soon as possible for 10 seconds. Samples tested 2 times, performed in a closed room, the results obtained in the execution of the test is hitting in the size of the number of punch (Muhamad & Haqiyah, 2019).
result and discussion
Descriptive statistics calculation (Muhamad, Memet; Aridhotul, 2015) results can be seen in the table below:

Table 2: Descriptive Statistics Calculation 
Based on the above table, the results of the calculation of descriptive statistics of 16 research samples, including: reaction speed has a minimum value of  1, the maximum value of 2, the mean of 1.49, and the standard deviation of 0.199. Hand-eye coordination has a minimum value of 11, a maximum value of 19, a mean of 13.625, and a standard deviation of 2.09364. Gyaku zuki Chudan has a minimum value of  51, a maximum value of 77, a mean of  64, and a standard deviation of 7.6626.
Table 3: Result Summary of Normality Test

Based on the above table, known asymp value. Sig. (2-tailed) research variables. Reaction speed of 0.200, eye-hand coordination of  0.176, and gyaku zuki chudan of 0.200. All Asymp values. Sig. (2-tailed) greater than 0.05. So it can be concluded that the overall data is normally distributed.
After conducting the required tests for analysis normality test then the researcher did the hypothesis testing by using path analysis. For the data processing of path analysis, the researcher used SPSS version 23 (Kadir, 2015), which the summary of test results is presented as follows:

Table 4: Result Summary of Path Analysis

Using the backward method, the path coefficients shown by the Standardized Coefficients (beta) column are obtained. From table coefficient, obtained value ρy1 = -0424; t-cal = -1.923, p-value = 0,039 < 0,05 or H0 is rejected, which means the reaction speed (X1) a positive direct effect on gyaku tzuki chudan (Y). Value of ρy2 = 0.502; t-cal = 2.272, p-value = 0.041 < 0,05 or H0 is rejected, which means there is a positive direct effect between eye-hand coordination (X2) to gyaku zuki chudan (Y).
Gyaku zuki chudan is more varied and very efficient in value acquisition. Athlete with a good intermuscular coordination the faster movements executed (Witte et al., 2008) However, in order to realize a powerful karate technique, it is very important to have an optimall inter- and intramuscular coordination (Witte, Emmermacher, Hofmann, Schwab, & Witte, 2005)
In performing the technique of gyaku zuki chudan, reaction speed is needed (Suwarganda et al., 2009) and eye-hand coordination (Witte et al., 2008) so that the movement is efficient, obtains a score (ippon) and cannot be anticipated by opponents. The form of speed training carried out, in this case, is the speed in reacting to the stimulus that comes, moving directly to a certain place quickly, the accuracy of time and position in moving the body, moving very quickly, the occurrence of movement in a short time and answer or understand something quickly. 
The faster and stronger the movement is done, the greater the power produced. The acceleration variation is related to time in the mechanical strength of the gyaku zuki chudan (Ionete, Mereuta, Mereuta, Tudoran, & Ganea, 2011).

Conclusions

Based on the results of data processing and analysis, the conclusions of this study are as follows: (1) reaction speed directly affects on the gyaku zuki chudan, and (2) eye-hand coordination directly affects on the gyaku zuki chudan.
Some suggestions to be given with respect to the results of this study are for lecturers, coaches, trainers, and physical education teachers, the results of this study can be used as a reference and information in the search for talented karate athletes on the match category based on the level of good physical fitness, especially reaction speed and coordination.
Acknowledgements
This research was supported by Lembaga Pengelola Dana Pendidikan (LPDP)  and Post Graduate Program, Universitas Negeri Jakarta who provided insight and expertise that greatly assisted the research. 
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