Biomechanical Classificationof
Judo Throwing Techniques (Nage
Waza)
A. Sacripanti
Italian Wrestling. Weigh~liftingand Judo Fcdcration. (F.1 L.P.J.). Romc. Italy
I) HISTORICAL SURVEY
The classification of standard Judo throwing techniques (Nage Waza)
was born from the following didactic requirement - To group thc
standard techniques under logica1 criteria for an easier understanding and
useful systematic study.
The two problems of Classification and Teaching arrangement were
tackled and solved by dr. Kano (founder of Judo) and his assistants in a
scientific way, according to the knowledge of their time.
The first classification of Nage Waza (1882) was carried out by a real
proto-biomechanical method.
As a matter of fact, the standard techniques were classified by parts of
Tori's (the attacker) body which work as greater contact-point for energy
transfer in throwing.
From that we have the ~KodokanClassification~:Te waza = shoulder,
arm and hand techniques; Koshi waza = hip techniques; Ashi waza = Icg
techniques; Sutemi waza = body-abandoning techniques or sacrifice
techniques (Tab. 1).
This admirable classification is simple, intelligible and almost perfect.
That is the reason of its long success even if it has some shades in itself; in
fact it is unusual to see hands, hips or legs of Tori working alone in
throwing.
Besides the Kodokan classification uses a different way to classify the
body-abandoning techniques, which are classified by the body side
touching the mat: Ma sutemi waza and Yoko sutemi waza, bodyabandoning
techniques on his own back and on his own side.
In his golden book My study of J u d o ~G. Koizumi classified the
standard judo techniques by Uke's (the defender) body motion.
This study, perforrned as systematical analysis of Nage Waza, permits
to group the standard techniques in three sets, according to the basis of
the technical principles.
Namely the ((Koizumi Classification~:Kuruma waza = wheel techni-
ques.
Throws which are effected in such a way. that Uke's body is curled and
turned as a wheel.
Tenbin waza = Scale techniques. Throws which are effected by
tripping or propping Uke's body, as a scale while it is held as a pole.
Tsumazukase waza = Tripping techniques. Throws which are effected
by tripping Uke's foot or leg, preventing it from rnoving to regain or
maintain stability.
In reccnt years A. Geesink and G . R. Gleeson have synthetized other
kinds of classification.
The formcr Duch champion, in his work, emphasizes the dynamic role
played by biodynamical chains, while the latter, English senior coach.
surely the subtlest student of western judo ones, in his historical book
~(Judofor the West, makes a very clever classification based on his
enormous theoretical and empirical knowledge.
This classification collects the throwing techniques under two groups;
First-Class o f xturning~UkeS body around an obstacle (hip, leg, etc.) Second-Class
o f xstriking~ Uke's legs.
This historical survey through various classifications introduces the
attempt to rationalize the matters in a scientific way, looking for the basic
physical principles of Nage Waza.
TABLE l
FIRST KODOKAN CLASSIFICATION (1885)
T E WAZA KOSHI WAZA ASHI WAZA
Uki waza Uki goshi Okuri ashi harai
Seoi nage Harai goshi Sasae tsurikorni ashi
Kata gururna Tsuri korni goshi Uchi rnata
Tai otoshi Koshi gururna Hiza gururna
Obi otoshi O goshi O soto gari
Seoi otoshi Ushiro goshi De ashi harai
Uki otoshi Hane goshi Ko uchi gari
Tsuri goshi Ko soto gari
Utsuri goshi Harai tsurikorni ashi
O uchi gari
Yarna arashi
O soto gururna
O soto otoshi
MA SUTEMI WAZA YOKO SUTEMI WAZA
Tornoe nage Yoko gake Uchi rnakikorni
Ura nage Yoko gururna Tani otoshi
Sumi kaeshi Yoko otoshi
Hikkikorni gaeshi Daki wakare
Tsuri otoshi Yoko wakare
Tawara gaeshi Soto rnakikorni
LI) BIOMECHANICAL CLASSLFICATION
A biomechanical analysis of judo throwing techniques must be dcalt
with in the following steps: firstly by simplification and secondly by
gcneralization.
As a sirnplification principle for thc problem of classes of forces
involved, at first wc can use the differential rnethod pointed out by dr.
Kano: subdivision of the throwing rnovernent in three steps l" Tsukuri
(preparatory movernents aimed at throwing out of balance Ukc's body);
2" Kuzushi (the final unbalancing action); and 3" Kake (execution of
rnovements aimcd at throwing), and later we analyse the motion of Uke's
body eutting out secondary forces.
Then we generalize the classes of forces, putting out the inner physical
principles of standard judo throwing techniques.
This rnethod, applied to Nagc Waza. is able to group 77 throwing
techniques (40 Kodokan go-kyo and 37 others) under two dynarnic
principles.
It is correct to remark that this is one of many possible biomechanical
classifications, and we select it for its valuable simplicity and immediate-
ness.
It comes very handy to find the Genera1Principles~,first to define two
corollaries on direction offorces (Statical Analysis), and then to analyse
Uke's body flight paths (Dynamical Analysis) and their symmetries.
STATICAL ANALYSIS
Principium of resolution o f forces.
These two corollaries determine the whole directional problem of static
use of forces to execute throws.
UNBALANCES
1) Forces are effective and can be applied, on the horizontal plane, on
the whole round angle (3607.
Unified under these terms are the biomechanical problems of forces
employed for unbalancing Uke's body. (Tsukuri-Kuzushi steps).
THROWS
2) Forces are effectiveand can be applied, on the vertical plane, nearly
for the width o f a right angle (907.
Determined under these terms are the biomechanical problems of
forces employed for throwing Uke's body. (Kake step).
Rea1 limits of throwing forces can be obtained with an angle of nearly
45 degrees, up or down a horizontal line, because the resistance caused by
Uke's body structure or by force of gravity, beyond these angles, allows
throwing again but with more waste of energy.
DYNAMICAL ANALYSIS
Principium o f composition of forces
Study of flight paths and symmetries
If in the space the composition of forces obeys, at the same time, the
previous static two corollaries the solution of dynamical problem
(considering time) goes through the study of flight paths and their
symmetries.
Paths along which Uke's body moves during flight following throwing
can be collected under two simple types or their composition:
Circular paths and Helicoidal paths.
I) CIRCULAR PATH: SPHERICAL SYMMETRY
For throwing techniques in which the limbs of Uke's body follow a
circular path
the radius of circumference coincides with the distance r from the rotation
axis of inertial momentum.
These techniques have spherical symmetry and circumfcrence that is
the ~geodeticline of sphere (the shortest line between two points) is the
path of minimum work then the trajectory of least waste of energy which
extremal parts of Uke's body can cover.
11) HELICOIDAL PATH: CYLINDRICAL SYMMETRY
For throwing techniques in which Uke's body follows a helicoidal path
the bending radius of helix is proportional to distance r from the rotation
axis of inertial momentum.
These techniques have cylindrical symmetry and the helix that is the
geodetic line of right cylinder is the path of minimum work then the
trajectory of least waste of energy which Uke's body can cover.
If we think of two corollaries on direction of forces (Statical Analysis)
and study of trajectories followed by Uke's body (Dynamical Analysis) it
is possible to state the dynamical principles of biomechanical classification,
which show the inner mechanisms of throwing techniques.
A) Techniques where Tori makes use of a couple of forces for throwing
Uke.
B) Techniques where Tori makes use of physical lever for throwing Uke.
Movernents, that seemingly make different throwing techniques, in
appearence but non in biomechanical essence, can be collected in
Tsukuri-Kuzushi stages and other preparatory actions (Taisabaki, etc.).
We think this classification, grounded on clear scientific criteria, is very
suitable to give an easier understanding of physical principles linking judo
throwing techniques.
A) Techniques of couple of forces.
In the first group, we found al1 throws produced by sweeping away legs
and pulling or pushing Uke's body in the opposite direction simultaneously
.
The techniques of ~ G r o u po f couple o f forces~can be classified by
parts o f Tori's body which apply the couple o f forces on Uke's body.
Namely: two arms, arm and leg, trunk and leg, trunk and arms, two
legs. (Tab. 2).
GROUP OF COUPLE OF FOHCES
STATICAL C O N D I T I O N S D Y N A M I C A L C O N D I T I O N S
Complete unbalance angle 360° C i r c u l a r r l i g h t patti
n i g h t t h r o w i n g a n g l e 90° S p h e r i c a l s y m m e t r y
This biomechanical classification is able to show new likness not
evident in standard techniques, e.g. the asymmetry face-back of human
body explains astonishing examples of biomechanical likness: O Soto
Cari and Uchi Mata are the same techniques applying the couple of
forces on Uke's body.
,It is very intercsting to note that most throws of couple of forces (thc
ones applied by Tori standing on a leg) can be led to only one Tori's basic
aetion: rotation on coxo-femoral articulation with three degrees of
fredom.
First: rotation of trunk-leg set on coxo-femoralarticulation around a
horizontal latcral-lateral axis of rotation.
Second: rotation oftrunk-legset on coxo-femoralarticulationaround a
horizontal antero-posterior axis of rotation.
Third: rotation of trunk-legset on coxo-femoralarticulation around a
vertical axis of rotation.
This points out the fundamental role played by COXO-FEMORAL
ARTICULATION in this group, and entails that this athlete's articulation
must be provided with a great flexibility.
B) Techniques of physical lever
In the second group we found al1 throws produced by turning Uke's
body round a stopping point (hip, leg, foot, etc.).
The techniques of ((Groupofphysicallever* can be classified by length
of arm of lever, applied on Uke's body.
Namely: minimum arm (fulcrum under Uke's waist), medium arm
(fulcrum under Uke's knees), maximum arm (fulcrum under Uke's
malleola), variable arm (variable fulcrum from the waist down t6 CTke's
knees) (Tabl. 3).
Because in this group throws of ~minimumarm are energetically
unfavorable (greatest force applied), that clears why, for competition,
people like more to turn them in throws of variable arm, pulling down
fulcrum under Uke's waist more and more.
That rneans less waste of energy.
GROUP OF MOMENTUH OF FORCE
ComplcLc unbalance angle 360" iight throwing anglc 90'
Minimiim arm
Maximum applicd lorcc
Medium arm
Medium applied Corce
Maximum arm
Minimum applied lorcc
CROUP OF PIiYSICAL LEVER
o
DYNAMlCAL CONDITIONS
Flight path: minlmum end mcdlum arm lielicoidal
maximum arm Clrcular or Ilelicoldal
Symmetry : minlmum and medlum arm Cylindricel
maximum arm Spherical o r Cylindrical
360' 560'
_ _ . - ....-_- - _ - o - - - - - - - .
.. .- - - _ _ _ - -- - - _ _ _ _ - - Minimuin
arm
Maximum applicd forcc
Fulcrum of pliyslcal levcr
Medium arm
Mcdium applied force
Mnximum arm
Minirnuin applicd rorcc
Again this biomechanical classification shows, in this group, likness
examples: classica1 Ashi Guruma and Hiza Guruma are the same
techniques applying a lever of medium arm on Uke's body.
It is very interesting to note that most throws of group of lever can be
led to only one Tori's basic action, if we do not consider the severa1Tori's
legs positions:
rotation of trunk on waist around a generic variable axis of rotation.
Also the body-abandoning techniques must be classified as throws of
Group of physical levern with maximum arm, in this case thc stopping
point (fulcrum) is givcn by friction between foot and mat (tatami).
Although thcy are more favorable encrgetically spcaking, the starting
force (body weight falling down) is applicd with an angle grcatcr of 45"
(see I1 corollary of statical analysis).
That is matters nced significative, directional help by arms or legs, for
rightly throwing Uke's body.
In the light of our analysis we think thc clarification of basic physical
principles and the evidence of basic action, proving the leading role of
Tori's pelvic bclt, can be useful for a better understanding of inner
mechanisms and for looking at ncw improvements in training thcory,
whieh should prevent erroneus mcthods and possible damages in the
joints.
TABLE 2
BIOMECHANICAL CLASSIFICATION
TECHNIQUES OF COUPLE OF FORCES
Couple Applied by
ARMS ARMIS AND LEG
Kuchiki daoshi De ashi barai Ko uchi gari Yoko gake
Kibisu gaeshi Okuri ashi barai Ko soto gari Ko soto gari
Kakato gaeeshi Ko uchi barai O uchi gari O uchi gake
Te guruma O uchi barai Ko uchi gake Ko soto gake
Tsubame gaeshi Harai tsukiromi ashi
TRUNK AND ARMS TRUNK AND LEG
Morote gari O soto gari Uchi mata Harai goshi
O soto guruma Hane goshi Yama arashi
LEGS O soto otoshi Hane makikomi O uchi sutemi
O tsubushi Okurikomi uchimata
Kani basami
TABLE 3
BIOMECHANICAL CLASSIFICATION
TECHNIQUES OF PHYSICAL LEVER
Lever applied with
MINIMUM ARM (FULCRUM UNDER UKE'S WAIST)
O guruma
Kata guruma
Tama guruma
Obi otoshi
Sukui nage Tawara gaeshi
Ushiro goshi Ura nage
Utsuri goshi Ganseki otoshi
Soto makikomi Uchi makikomi
MEDIUM ARM (FULCRUM UNDER UKE'S KNEES)
Ashi guruma Hiza guruma
MAXIMUM ARM (FULCRUM UNDER UKE'S MALLEOLA)
Uki otoshi
Yoko otoshi
Sumi otoshi
Ura otoshi
Waki otoshi
Tani otoshi
Tai otoshi
Uki waza Sasae tsurikomi ashi
Dai sharin Seoi otoshi
Tomoe nage Hiza seoi
Sumi gaeshi Suwari seoi
Hikkomi gaeshi Obi seoi
Yoko guruma Suso seoi
VARIABLE ARM (VARIABLE FULCRUM FROM THE WAIST DOWN T 0
KNEES)
Tsuri komi goshi Uki goshi Kata seoi
Sasae tsurikomi goshi O goshi Seoi nage
KO tsuri komi goshi Koshi guruma Eri seoi nage
O tsurikomi goshi Kubi nage Morote seoi nage
Sode tsurikomi goshi
111) JUDO SKILLS AND THEIR TREND IN TOP COMPETITION
With the continuous evolution of competitive style, for a right training
of top athletes, we need a better understanding of judo skills and thcir
trend in top competitions.
Obviously the basic physical principles of standard judo techniques and
judo skills (competitive throwing techniqucs) are the same, but thc
dynamical conditions are quite different (fast movements, more opposition,
timing, change of speed, ctc.).
The right way to learn the connection with standard techniques, and to
understand the competitive evolution of judo skills, was signed for the
first time, by dr. Kano with the formulation of principium of ~Maximum
cffect with minimum efforb.
This principium can be translated in two useful biomechanical remarks:
1) To improve techniques to win, signifies to produce maximum economy
of movements.
2) To better techniques to win, signifies to produce rnaximum economy of
strain.
The explication of remarks is: in competition champions, consciously
or unawares, tend to find the right methods of minimizing the total
energy to win.
In two ways: either minimizing his own muscular strain with right
changes in throwing patterns (e.g. pulling down the fulcrum), or
minimizing the defensive antagonist capability with right changes in
attack directions (e.g. attack in the direction of the adversary side where
the resistive muscular capability is weaker).
These are two biomechanical rules, which give us a better understanding
of trend of judo skills in top competitions.
BIBLIOGRAPHY
Judo Kyohan - Yokoyama Sakujiro and Oshima Eisuke: traduit par Messieur Le
Prieur, Berger Leverault ED. Paris 1911.
My Study of Judo - G. Koizumi, Sterling Publishing New York 1966.
Lo Judo - A. Geesink, A. Mondadori ED. Milano 1975.
Judo for the West - G. R. Gleeson 1973.
I Principi dell'Analisi Quantitativa Biomeccanica - Kronenberg ED. Stampa
Sportiva Roma 1983.
Muscles Reflexes and Locomotion -T. Mc Mahon, Princeton University Press 1984.
Biomeccanica del Judo - A. Sacripanti, In print 1987-88.
The Kinetics of Judo - M. Ikai and Y. Matsumoto 1958.
Electromyographic Studies on the Nage Waza (throwing techniques) of Judo - M.
Ikai et al. 1963.
Studies on Judo Techniques with Respect to Distribution of Body Weight
Matsumoto, Y. et al. 1963.
Analysis of the Kuzushi in the Nage Waza - Matsumoto, Y. et al. 1978.
Kinetic Analysis of Judo Technique - Tezuka, M. et al. 1983.
Fisica e Judo - Sacripanti, A. 1986.
Lo Squilibrio Statico in Judo - Sacripanti, A. 1987.