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REACTION TIME IN TAEKWONDO

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The purpose of the study was to find out if taekwondo players competing on an international level have faster reactions than recreational taekwondo players or sports students. We measured three different time intervals. The time measurements started with the flashing of a light diode and ended respectively with the first visible movement of the hip, the shoulder or the foot. Differences were found depending on the skill level, age and gender with the taekwondo players competing on an international level showing significant faster reactions.
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XXV ISBS Symposium 2007, Ouro Preto – Brazil 293
REACTION TIME IN TAEKWONDO
Manfred Vieten #, Markus Scholz #, Hashem Kilani , Markus Kohloeffel *
#University of Konstanz, Konstanz, Germany
University of Jordan, Amman, Jordan
*German Taekwondo Union, Friedrichshafen, Germany
The purpose of the study was to find out if taekwondo players competing on an
international level have faster reactions than recreational taekwondo players or sports
students. We measured three different time intervals. The time measurements started
with the flashing of a light diode and ended respectively with the first visible movement of
the hip, the shoulder or the foot. Differences were found depending on the skill level, age
and gender with the taekwondo players competing on an international level showing
significant faster reactions.
KEY WORDS: biomechanics, taekwondo, reaction time, response time
INTRODUCTION
The Korean martial art Taekwondo is an official Olympic sport since the 2000 Sydney
Olympics. Taekwondo is a full contact combat art where the majority of successful
techniques are powerful kicks, which are delivered towards the opponent’s frontal upper
trunk or head. Scoring occurs when those blows are delivered accurately and forcefully.
During the last years the type of successful techniques condensed toward direct strait kicks,
which can be applied within a shorter time interval compared with more complicated kicks.
Therefore, it seems success greatly depends on the execution time of a technique. Beside
speed, reaction time and the response to the opponent’s actions appear to be one of the key
elements for victory. Naturally, coaches and practitioners need to know if a short reaction
time is indispensable for high performing athletes. There are two types of reaction time. The
“complex” reaction time arises in combat situations. Here an athlete “reads” the situation and
anticipates the further progression to take advantage of the situation. The “simple” reaction
time is the physiological response toward a neutral sense stimulus. Here (Zaciorskij, 1972) a
receptor excitation (e.g. of the eye) initiates a signal which is transmitted via the central
nervous system to the motor cortex. Its response triggers a signal that stimulates the
muscles and initiates the mechanical activity. With this study we investigated, if high
performing taekwondo players on the international level have significantly shorter “simple”
reaction times than taekwondo players on regional level or sport students.
METHOD
99 subjects participated in this study and were divided into 7 groups (Table 1) according to
age, gender and skill level. All national team members are athletes of the German
taekwondo squad competing on international tournaments. The other taekwondo players are
active on a regional level. The sport students had taken a first semester of taekwondo.
Table 1 Number of participants within the 7 groups
Group Abbreviation No of subjects
Females below 18 years F<18 9
Females below 18 years, national team members FS<18 13
Females 18 years and older, national team members FS18 20
Males below 18 years M<18 14
Males 18 years and older M18 15
Males 18 years and older, national team members MS18 19
Male sport students 18 years and older Sp 11
All participants were tested after a warm up during one of their training sessions. Within an
area of 5 by 5 meters we assigned a training mitt as the target (Figure 1). Two stacks of red
XXV ISBS Symposium 2007, Ouro Preto – Brazil 294
light emitting diodes were place beside the training mitt but not in the reach of a kick. The
athlete was positioned in front of the vaulting buck in attack position. Reflective markers were
placed on the shoulder, hip, and at the kicking foot (ankle). The subjects were asked to start
kicking at the onset of the red diode lights. Ten trials of each subject were filmed. and the
actual number of valid trials varied between 8 and 12. We used one digital camera to tape
the whole movement and the light diodes.
Figure 1 Sketch of the experimental setup from a bird's eye view
The taping was stored in MPEG2 format and later converted to AVI. The 50 half frames per
second were analyzed using the APAS trimming module. The evaluation was done by one of
us (MS) to avoid effects caused by personal judging differences. We calculated the mean
reaction time of each participant. This was the input for the calculation of the group means,
standard deviation, and standard error.
RESULTS
Our group selection shows homogeneity within six of the seven groups (see Figure 2 for
results on the standard deviation).
SD-Shoulder
SD-Hip
SD-Ankle
F-18 FS-18 FS+18 M-18 M+18 MS+18 Sp
Standard Deviation [s]
0.09
0.08
0.07
0.06
0.05
0.04
0.03
0.02
0.01
0
Figure 2 Standard deviation of reaction times for the different groups
The deviations of the groups are comparable with each other with the exception of the males
of 18 years or older. This group showed also the widest age rage as well as the highest
variability in trainings intensity. Table 2 shows the mean, the standard deviation, and the
standard error of each group’s reaction time for the shoulder, the hip and the ankle
movement.
XXV ISBS Symposium 2007, Ouro Preto – Brazil 295
Table 2 Mean, standard deviation, and standard error of the reaction times
Shoulder Hip Ankle
Subject Mean SD SE Mean SD SE Mean SD SE
F < 18 0.23 0.03 0.009 0.22 0.02 0.008 0.36 0.03 0.010
FS < 18 0.21 0.03 0.007 0.22 0.02 0.006 0.37 0.05 0.014
FS 18 0.20 0.02 0.003 0.21 0.01 0.003 0.35 0.03 0.006
M < 18 0.23 0.04 0.011 0.26 0.09 0.025 0.37 0.05 0.014
M 18 0.23 0.03 0.007 0.22 0.02 0.005 0.36 0.04 0.010
MS 18 0.20 0.02 0.005 0.20 0.02 0.004 0.31 0.05 0.011
Sp 0.23 0.02 0.006 0.24 0.02 0.007 0.38 0.03 0.009
There is a substantial difference between the reaction time of the ankle movement and the
time for shoulder and hip movement within each group. Between the reaction time for the hip
and the shoulder we find no statistically significant difference. However, there exist
differences in reaction time between different groups (Figure 3). We found significant
differences of the reaction time (see Figure 3 and Tables 3 – 5) between the different
groups. For the hip reaction time the adult male national team members are fastest, second
are the adult female national squad followed by the female national team members below 18
years of age. The slowest reaction time we found in the male taekwondo players below 18
years, second the male sport students, followed by the recreational male taekwondo players
above 18 years of age and females below 18 years.
M-Shoulder
SE-Shoulder
SD-Shoulder
M-Hi p
SE-Hip
SD-Hip
M-A n kl e
SE-Ankle
SD-Ankle
F-18 FS-18 FS+18 M-18 M+18 MS+18 Sp
Reaction Time [s]
0.42
0.4
0.38
0.36
0.34
0.32
0.3
0.28
0.26
0.24
0.22
0.2
0.18
0.16
Figure 3 Mean, standard error and standard deviation of shoulder, hip, and ankle reaction
times
For the shoulder respectively the foot reaction time negligible changes in the above order
occur. In any case the adult male national team members are the fastest followed by the
adult female national team members. The significance levels of the differences between the
groups as given in the Tables 3 – 5 are to be understood in the following way: Cursive writing
indicates the group denoted in the upper line is faster. Otherwise the group indicated in the
first column has shorter reaction time.
Table 3 Significance level of group differences for shoulder reaction times
Subject F < 18 FS < 18 FS 18 M < 18 M 18 MS 18 Sp
F < 18 1 0.1304 0.0204 0.8230 0.9800 0.0061 0.9984
FS < 18 0.1304 1 0.3202 0.1090 0.0878 0.2376 0.0762
FS 18 0.0204 0.3202 1 0.0161 0.0033 0.7285 0.0003
M < 18 0.8230 0.1090 0.0161 1 0.7757 0.0133 0.7849
M 18 0.9800 0.0878 0.0033 0.7757 1 0.0020 0.9745
MS 18 0.0061 0.2376 0.7285 0.0133 0.0020 1 0.0015
Sp 0.9984 0.0762 0.0003 0.7849 0.9745 0.0015 1
XXV ISBS Symposium 2007, Ouro Preto – Brazil 296
Table 4 Significance level of group differences for hip reaction times
Subject F < 18 FS < 18 FS 18 M < 18 M 18 MS 18 Sp
F < 18 1 0.7590 0.0963 0.2154 0.8852 0.0020 0.0978
FS < 18 0.7590 1 0.0791 0.1744 0.8207 0.0016 0.0291
FS 18 0.0963 0.0791 1 0.0759 0.0093 0.0203 0.0008
M < 18 0.2154 0.1744 0.0759 1 0.1907 0.0354 0.5560
M 18 0.8852 0.8207 0.0093 0.1907 1 0.0002 0.0273
MS 18 0.0020 0.0016 0.0203 0.0354 0.0002 1 1.51E-6
Sp 0.0978 0.0291 0.0008 0.5560 0.0273 1.51E-6 1
Table 5 Significance level of group differences for foot reaction times
Subject F < 18 FS < 18 FS 18 M < 18 M 18 MS 18 Sp
F < 18 1 0.5970 0.3217 0.6987 0.8452 0.0078 0.1599
FS < 18 0.5970 1 0.1793 0.8810 0.4576 0.0021 0.5948
FS 18 0.3217 0.1793 1 0.2175 0.4349 0.0048 0.0078
M < 18 0.6987 0.8810 0.2175 1 0.5533 0.0024 0.4749
M 18 0.8452 0.4576 0.4349 0.5533 1 0.0053 0.1112
MS 18 0.0078 0.0021 0.0048 0.0024 0.0053 1 0.0001
Sp 0.1599 0.5948 0.0078 0.4749 0.1112 0.0001 1
The most significant differences we find in the hip reaction time between the groups.
DISCUSSION
We found a significant difference in the reaction time between the members of the national
taekwondo teams and the other groups namely those practicing taekwondo for recreational
reasons and the sport students. Fontani et al. (2006) reported similar findings for karate
players whose sport demands similar skills as taekwondo. Our findings make clear success
in taekwondo is correlated with a distinctly shorter-than-average reaction time. The higher
significance between the participants’ hip reaction time and those of the other body
segments seems to indicate its specific importance. There are two strong arguments for this.
First, taekwondo players recognize an opponent’s reaction from his or her movement of the
upper body (shoulders and chest). A hip movement is harder to detect. By holding back the
upper body movement as long as possible gives an additional timing advantage. Second, an
attack in taekwondo is most probable a kick not a punch. So, the hip move must be initiated
first. The advantage of moving mainly the hip and not the complete trunk results in a
substantially reduced movement of the center of gravity. This saves energy, and because
just a part of the body mass has to be accelerated these masses can move faster.
CONCLUSION
Fast reactions are essential for success in taekwondo competitions. During an attack it is
advisable to move as little mass as possible to accelerate those segments involved in the
movement as quick and as effective as possible. Therefore, the movement should be
initiated by the hip. We showed the importance of a short reaction time but how much of it is
predisposition and how much can be archived by training? To answer this question we
propose a long-time study on beginning taekwondo students to see how they develop during
their career. If preposition is an important factor in fast reactions, measuring it at an early
stage of an athlete’s career could even be used for evaluating their potential.
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