CLASSIFICATION OF JUDO THROWING TECHNIQUES ACCORDING TO THEIR IMPORTANCE IN JUDO MATCH

Abstract

Analysis of judo throwing techniques, as the most important attacking structures in a judo match, can help experts to improve training process. The aim of this paper was to analyse and classify throwing techniques from the aspect of their importance in judo matches. For this purpose eight judo experts assessed the importance of throwing techniques in seven official senior weight categories for men. Sample of entities consisted of 40 throwing techniques and the sample of variables consisted of seven weight categories. Cluster analysis was used for the classification of throwing techniques. The Euclidean distance method and Ward's method of cluster mergers was used. The differences between the established groups were tested by discriminant analysis. Unlike in some other classifications, a smaller number of groups was formed. According to the criterion of importance two main groups of throws were identified (group A and B). Group B contains the most important and the most applicable throws in current judo matches, whereas group A contains less important throwing techniques. Group A has been divided into two significantly different subgroups and group B into three significantly different subgroups. The proposed classification clearly distinguishes throwing techniques according to their performance importance and provides a clearer insight into the technical structure of judo sport. The results of this research can be useful to judo experts for the selection of the most rational methods of the technical and tactical preparation and for the establishment of new and modern approaches to judo training.

Full text

CLASSIFICATION OF JUDO THROWING TECHNIQUES
ACCORDING TO THEIR IMPORTANCE IN JUDO MATCH
Ivan Segedi and Hrvoje Sertić
Faculty of Kinesiology, University of Zagreb, Croatia
Corresponding author: Ivan Segedi, Ph.D.
Faculty of Kinesiology, University of Zagreb, Croatia
ivan.segedi@kif.hr

ABSTRACT
Analysis of judo throwing techniques, as the most important attacking structures in a judo
match, can help experts to improve training process. The aim of this paper was to analyse
and classify throwing techniques from the aspect of their importance in judo match. For this
purpose eight judo experts assessed the importance of throwing techniques in seven official
senior weight categories for men. Sample of entities consisted of 40 throwing techniques
and the sample of variables consisted of seven weight categories. Cluster analysis was used
for the classification of throwing techniques. The Euclidean distance method and Ward's
method of cluster mergers was used. Differences between the established groups were
tested by discriminant analysis. Unlike in some other classifications, a smaller number of
groups was formed. According to the criterion of importance two main groups of throws
were identified (group A and B). Group B contains the most important and the most
applicable throws in current judo matches whereas group A contains less important
throwing techniques. Group A has been divided into two statistically significant different
subgroups and group B into three statistically significant different subgroups. The proposed
classification clearly distinguishes throwing techniques according to their performance
importance and provides a clearer insight into the technical structure of judo sport. The
results of this research can be useful to judo experts for the selection of the most rational
methods of the technical and tactical preparation and in the establishment of new and
modern approaches to judo training.
Key words: weight categories, cluster analysis, applicability of throwing techniques, judo
training

Introduction
Classification into groups, as a scientific method, solves the problems of systematization of
elements of a certain area and represents an important theoretical basis for the study in any
scientific discipline. Classification helps recognition of the similar in the different and the
different in the similar. The most common reasons for classifying entities in groups are as
follows: visibility of data, data compression, and determination of the typology (Furjan
Mandic, 2000).
In judo sport there are several relevant classifications of throwing techniques. The main
criteria for the classification, in most of them, are biomechanical parameters (Koizumi,
1960; Gleeson, 1967; Geesink, 1977; Sacripanti 1989; Kano, 1994). Although
biomechanical parameters are useful for better understanding of different types of throws,
they are less important from the tactical aspect of judo training. Since the tactical
preparation is an important part of judo training, it is crucial to know the most important
facts related to performance or situational effectiveness in a match. Judokas are divided by
weight categories, and various studies have demonstrated that there is a difference in the
frequency of use of certain throwing techniques between different weight category
(Franchnini & Sterkowicz, 2000; Boguszewski & Boguszewska, 2006; Marek, Laskowski,
Tabakov & Smaruj, 2013). Therefore, one can conclude that body weight of judokas is a
very important performance factor in a judo match and one of the crucial elements of
tactical preparation in judo.
Techniques of throws are the most important attack elements in judo and analysis from the
standpoint of their importance in different weight categories seems to be a logical step in
further analysis of throws. The main goal of this paper was to perform a comprehensive
classification of all throwing techniques usable in a judo match according to the criterion of
their importance to different weight categories.

Methods
Subject sample
Forty throwing techniques recognized by the official rules of the International Judo
Federation (IJF) represented the subject sample. All other throws that exist in judo but are
not allowed in official judo match were not a part of this research.
Variables
The sample of variables consisted of seven official weight categories for men: up to 60 kg,
up to 66 kg, up to 73 kg, category up to 81 kg, up to 90 kg, up to 100 kg and over 100 kg
of body weight.
Procedures
A measurement instrument, questionnaire, was designed according to which eight judo
experts assessed importance of throwing techniques to the defined variables. Team of eight
international judo experts was recruited specially for this research (one from Brazil, Italy
and Poland, three from Japan and two from Croatia). Every expert had to satisfy two out of
three criterions: to be a lecturer of the teaching judo at a higher education institution
somewhere in the world; to be a coach or a member of coaching team of elite judo
competitors – members of a national team; was previously elite judo competitor and a
member of a national team. The experts were previously introduced to the methodology of
the research and they assessed importance of throwing techniques to a particular weight
category with grades from 1 to 5, in a way that 1 ment a very little importance of a
technique to each variable, while the grade 5 ment a very great importance of particular
technique to each variable. Importance was defined as the applicability, application rate and
performance effectiveness of a throwing technique.
Statistical analysis

Based on the scores of their importance to performance within a particular weight category,
throwing techniques were classified into homogeneous groups using cluster analysis. The
Euclidean distance method and Ward's method of cluster mergers was used. The differences
between the obtainedgroups were tested by discriminant analysis.
Results
Figure 1. Diagram of dividing throwing techniques into clusters
Figure 1 shows that at the Euclidean distance of twelve units two groups of throwing
techniques can be identified: group A and B.
Group A contains twenty-two throwing techniques, and group B eighteen throwing
techniques.
Table 1. Discriminant analysis of groups A and B
The difference between the defined groups was statistically significant at the significance
level of .01 (Table 1).
A more detailed analysis of the structure of isolated groups reveals the presence of several
sub-groups at the Euclidean distance of seven units.
Group A is divided into two sub-groups (Table 2), and group B into three subgroups of
throwing techniques (Table 3).
Table 2. Group A
Table 3. Group B

The statistically significant difference between the sub-groups of throws identified by
cluster analysis was determined by discriminant analysis (Table 4 and Table 5).
Table 4. Discriminant analysis of subgroups A1 and A2
Table 5. Discriminant analysis of subgroups B1, B2 and B3
Discussion and conclusions
Unlike in some other classifications, according to the criterion of performance importance
of certain throwing techniques to various weight categories a smaller number of groups was
formed. The throwing techniques classified into a certain group are similar as regards their
application, thus such a distribution is logical and interpretable from the aspect of
performance in a judo match.
Group B mainly contains the most used (the highest importance) techniques of throws
(Marek, Smaruj & Tyszkowski 2011; Marek, Laskowski, Tabakov & Smaruj, 2013), while
group A contains less used throws.
Within group B, sub-group B2 comprises throws that are commonly used by judokas of
light and medium weight categories. According to execution structure, the throws are
performed in a way to affect the opponent’s centre of gravity by a judokas’ rapid descend
below its level. These throwing techniques require a high level of speed, this motor ability
characterizes judokas in these weight categories (Almansba, et al., 2008). If one analyses
judo matches of judokas in these weight categories, it can be seen that intensity of a bout
and frequency of throwing techniques application are very high (Boguszewski &
Boguszewska, 2006; Sterkowicz, Lech & Almansba, 2007). These techniques of throws are
characterized by judokas’ capability of quick "entering" into a throw, but also with a quick
"exit" or escape out from throwing if he/she has estimated that the application of the final
phase of the throw (kake) will not be possible.
Throws in sub-group B1 are commonly used in heavier weight categories. Due to their
anthropological characteristics, judokas in higher weight categories rely on their strength
and body mass and not on speed, as is the case in the lower weight categories. More

suitable throws for them are those that can be performed without a deep descend below the
opponent’s centre of gravity, and those in which the body does not do a large range of
motion.
Sub-group B3 contains throws that are equally important in all analysed weight categories
(Franchnini & Sterkowicz, 2000). Also, from the aspect of judo training, the throws from
group B must be a basis in training process in order to enable judokas to be more effective
matches.
Group A comprises throwing techniques that are used less frequently in judo matches and
that are, according to their importance and applicability, “secondary” in modern judo.
Throws from sub-group A2 fulfill this criterion in particular. These throws are hardly ever
used in a modern judo match and can be found in “Judo Nage no Kata” (a form that
includes throwing techniques that are performed by a pre-defined order). In the sub-group
A1 are throws occasionally used in a judo match, but they do not belong to the group of the
most important throws. It is interesting to note that most of the throws from this subgroup
were presented in the first classification of throwing techniques in 1885 (three years after
first mention of judo). It can be assumed that these throws had a greater importance and a
more frequent application in the ancient judo and that they lost their importance due to the
development of judo sport and judo match.
A large number of throwing techniques exist in judo, therefore it is not realistic to expect
that every judoka will equally master all throws. However, every throw has at least a
minimum applicability and relevance to performance in a match and that enables judokas to
select throwing techniques according to their own individual characteristics. Judokas,
according to their anthropological characteristics, will modify basic throwing techniques
and will use them in a specific way, thus creating their own "special techniques" (tokui
waza) and their own fighting style. Relationship of judokas motor abilities and
morphological characteristics affects the selection and use of throwing techniques in a judo
match (Franchini, Takito, & Bertuzzi 2005; Jagiello, Kalina, & Korobrelnikow, 2007). For
that reason the classification of judo throwing techniques according to the criterion of
importance to performance of judokas of a different weight categories in a match is
important and can help to improve technical and tactical aspects of training process. The

results of this research can serve experts in selecting the most rational content of the
technical and tactical preparation and in the establishment of new, modern teaching
procedures and approaches to judo training. Thus, the results of this study can be used for
rational planning, programming and organization of judo training and that is a practical
contribution of this paper.
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T r e e D i a g r a m f o r 4 0 C a s e s
W a r d ` s m e t h o d
E u c l i d e a n d i s t a n c e s
0 5 1 0 1 5 2 0 2 5 3 0 3 5
L i n k a g e D i s t a n c e
C _ 3 5
C _ 3 4
C _ 3 2
C _ 2 5
C _ 2 4
C _ 2 3
C _ 2 2
C _ 3 0
C _ 2 9
C _ 3 8
C _ 2 7
C _ 4 0
C _ 1 0
C _ 3 3
C _ 3 7
C _ 3 1
C _ 2 6
C _ 9
C _ 1 5
C _ 1 1
C _ 2 1
C _ 7
C _ 3 9
C _ 2 0
C _ 3 6
C _ 1 9
C _ 1 3
C _ 4
C _ 1 8
C _ 1 6
C _ 1 7
C _ 1 2
C _ 3
C _ 8
C _ 2
C _ 2 8
C _ 6
C _ 1 4
C _ 5
C _ 1
A 1
B
A
B 3
B 2
B 1
A 2
Figure 1. Diagram of throwing techniques divided into clusters

Table 1. Discriminant analysis of groups A and B
Eigenvalue Canonicl - R Wilks'
Lambda Chi-Sqr. df p-value
2.374870 .838864 .296308 41.96431 7 .000001

Table 2. Group of throws divided into cluster A
SUB-GROUP A1 SUB-GROUP A2
C1 ASHI GURUMA C17 YAMA ARASHI C7 OBI OTOSHI
C5 HIZA GURUMA C16 UKI WAZA C21 YOKO WAKARE
C14 UKI GOSHI C18 YOKO GAKE C11 SUMI OTOSHI
C6 KOSHI GURUMA C4 HIKIKOMI GAESHI C15 UKI OTOSHI
C28 O GOSHI C13 TSURIKOMI GOSHI
C2 HANE GOSHI C19 YOKO GURUMA
C8 O GURUMA C36 NIDAN KOSOTO GAKE
C3 HARAI TSURIKOMI ASHI C20 YOKO OTOSHI
C12 TAWARA GAESHI C39 OKURI ASHI HARAI

Table 3. Group of throws divided into cluster B
SUB-GROUP B1 SUB-GROUP B2 SUB-GROUP B3
C9 SOTO MAKIKOMI C22 TOMOE NAGE C32 OUCHI GARI
C26 SASAE TSURIKOMI ASHI C23 SODE TSURIKOMI GOSHI C34 UCHIMATA
C31 HARAI GOSHI C24 MOROTE SEOINAGE C35 KOUCHI GARI
C37 TANI OTOSHI C25 IPPON SEOINAGE
C33 OSOTO GARI
C10 SUMI GAESHI
C40 DEASHI HARAI
C27 TSURI GOSHI
C38 KOSOTO GARI
C29 URANAGE
C30 TAI OTOSHI

Table 4. Discriminant analysis of subgroups A1 and A2
Eigenvalue Canonicl - R Wilks'
Lambda Chi-Sqr. df p-value
3.025602 .866943 .248410 22,97913 7 .001719

Table 5. Discriminant analysis of subgroups B1, B2 and B3
Discriminan
t function
Eigen
value
Canonicl -
R
Wilks'
Lambda Chi-Sqr. Df p-value
03.831364 .890516 .049792 35,99874 14 .001044
13.156886 .871456 .240565 17,09719 6 .008933