Sendo-Ryu Blog

Karate Motion Efficiency Analysis

May 19th, 2009

In this article I would like to describe the proposed title in view of the science of physics. The article will always give examples using 2 martial artists in action. When we deal with 2 martial artists for motion efficiency analysis (KMEA) we have several physical properties to deal with, such as: Force, momentum, impulse, torque, displacement, power, energy, work, mass, inertia, velocity, lever and so on.

In order to describe and categorize the KMEA, I will start with some basic definitions. One of the most important physical property is the force of a human being which is measured by the mass of the participant and multiplied by the acceleration of force (F = ma) or kg(m/sec²). The force is measured in Newton. 1 Newton (N) = 1 kgm/sec²).

Newton 2^nd law of acceleration which states that when a body is acted on by a force, its resulting a change in momentum which takes place in the direction in which the force is applied, and is proportional to the force causing it, and inversely proportional to its mass. Change in velocity means acceleration or deceleration by a force which was applied.

In this case we are talking about a new physical property which is the momentum. The momentum (p) = mass x velocity or kgm/sec where m/sec represent velocity in case of linear motion. In case of rotary motion the equation is: L = Iω or I = kgm²/sand ω = rad/sec or (θ/sec). Where the “L” represents the angular momentum, the “I” represents the moment of inertia (angular inertia) the “ω” represents the angular velocity, “m” represents meter and “rad” represents radian, “θ” represents angle of a circle. The momentum represents the amount of motion possessed by a moving body. Thus, a body’s momentum can be changed by altering either its mass or its velocity.

Another important physical property is the impulse = force x time (J = Ft). In physics we talk about the impulse of force for a given time interval and is equal to the change in momentum produced over that time interval, i.e. J = m(v_f- v_i) where m = mass, v_frepresents the final velocity and v_i represents the initial velocity.This impulse and momentum relationship derived from Newton’s second law. In sports there are two different impulse.

1. Controlled impulse refers to the muscle effort and bone leverage, as with the kicking leg. 2. Transmitted impulse occurs when, for example a karateka is about to take off for a flying side kick. The take-off leg acts against the floor, but the magnitude and direction of impulse is determined by the free arms and leg, and not through the take-off leg. The next physical property is the torque (T) or (Г) (moment of force or just moment). The torque is a force which produces a twisting or rotary motion about an axis of rotation. This force is related to the angular or rotational motion. Defining torque or moment by mathematical terms is the same; however, there is a little difference about understanding exactly the two terms.

Torque typically refers to the twisting motion, whereas moment is related to the bending or rotational action of a force. Torque (T) = Fd or Newton x meter (Nm) where, F represents the applied force multiplied by perpendicular distance (d) from the axis of rotation to the line of force action. The perpendicular distance is known as the torque arm, moment arm, or lever arm (). Fig. 1. Show different class levers.

Figure 1.

As you can see in the first class lever the fulcrum is always between the effort and the load, resistance (weight) or gravity. The fulcrum is not necessarily must be exactly in the middle of the lever. In human mechanics the effort is represented by a muscle group in contraction. The weight can be represented also by a muscle group or by the gravity.

In the second and third class lever the fulcrum is always at the one end of the lever. In the second class lever the force arm (FA) is longer than the resistance arm (RA). In the third class lever the RA arm is longer then the FA. Second class levers are used for force. Third class levers are used more for speed.

Displacement is another physical property which is a vector quantity and refers to the distance where an object moved in a given direction. It is measured as a length of a straight line between the initial and final position. In karate we speak about distance instead of displacement which is strictly related to velocity. Distance is related to the speed. The speed in karate is not related to the distance, but is related to the timing e.g., how fast somebody can kick or punch an opponent.

Let’s analyze the following physical properties which are strictly related to each other such as; Power, Energy and Work. We can hear words from instructors or even athletes such as; hit with more power or you do not have enough power etc. We seldom hear the word force, why is this? Here is the explanation. Recall that force is an agent which can alter the state of a matter by pushing, pulling, twisting, sliding etc., and this agent is the product of the mass and acceleration. Power (P) defined as “the rate at which energy is expended or work is done.

The amount of power (P) delivered by a person depends on two components; force and velocity or speed (P = Fv). In other word if you have force which you do, and you have velocity more or less then you have power. In this way when an instructor says put more power in your hit, he/she meant, put more force or speed in your action. By the way force is almost omnipresent in any physical activity.

Recall that power is related to energy and work. Here we have another formula of the power which is: P = work/time. But how can we measure the work, here is the formula of the work (U) = F x displacement (s). The energy (E) =F x distance (d). As you can see the formula of the work and energy is very much interrelated and can be used almost unconditionally depending on the problem to be solved.

Speaking about energy, we know that there are many different kind of energy such as; chemical, electrical, light, wind, thermo-nuclear, water, and physical energy The linear kinetic energy (E_KL) = 1/2mv² or kgsec²/2. The angular kinetic energy (E_KR) = ½ Iω². According to the law of thermodynamics, (conservation of energy), which states that in any system not involving nuclear reactions or velocities approaching the velocity of light, energy cannot be created or destroyed but can be lost. Yes you can lose or deplete your energy if you do not store the energy supply by the mean of meal and drink.

There are two kind of physical energy: Potential energy which is a stored energy in a body or system. The other one is the kinetic energy which is the energy of motion, which is defined as the work. So where is a motion such as a wind blow, the water fall, the karateka kick, and the chemical composition with its atoms and molecules that are in permanent motion there is a kinetic energy. In karate we deal mostly with kinetic energy. The kinetic energy comes from the potential (stored) energy.

Let’s give some examples about kinetic energy where the energy can be transformed. For example, a karateka will use chemical energy that was provided by food to hit and kick faster and to resist against tiredness during a long fight. If we do not take in consideration the friction of his feet against the floor he probably can maintain his speed during the entire bout. His energy has been converted into energy of motion (kinetic energy), but also his body just created heat energy by spending his calories. Supposedly who has a bigger mass probably has more energy using more calories to work etc.

I guess by now everybody with a little education knows about mass, inertia and lever arm. The question now is which physical property is the most important for a karateka to be efficient? How to analyze and when to put it in action to be most efficient during a sparring or a real fight. In the next pages I will give some indication purely by mechanical rules neglecting the most important factor for the victory which is the tactical preparation/actions before and during fight.

Calculations by the Newtonian (classical) mechanics.

Using any examples in biomechanics we use mostly Newton laws. Example 1: Calculate the kinetic energy (E_K) of a 70 kg mass of karateka kicks from a natural position (both legs are parallel to each other) at 4 meters per second. (An expert karateka can even kick with 10 to 14 m per seconds). The distance is not specified and the speed has been registered as an average speed. We use the equation of E_K = 1/2mv². ½ (70kg) x 4 m/s² = 560 Joules (the unit of measuring energy) or (N-m). (The kicking distance usually is about 95 cm or a little bit more than 1 meter).

Where should a good instructor concentrate when he uses biomechanical examples to give his students for the technical improvements? Recall that the beginning this article I mentioned about so many physical propertied. Here is my advice. Some physical properties are more related to each other such as momentum to impulse and work related to energy and to power. In this way the instructor can establish a very good reference method for examples. Also the karate the instructor should know which physical property has the priority over the other(s). In karate the most important physical properties are and here I name just few:

Force, mass, speed, momentum, impulse and kinetic energy. Karate is practiced mostly with linear motions such as; straight front arm punch and the front kick. Even the roundhouse kick is somehow linear. Understanding the attack as a linear execution means that the opponents try straight contacts and do not turn away from the opponent as a diversion. Also there are no large movements such in Aikido, where half of the motions are angular.

In the following I will describe 4 kind of situation in dealing with karate motions: Nr.1. Two karateka is mostly in standing position and are very close to each other (they can touch each other simply by extending their arm’s or leg’s) Chika-ma in Japanese. The word ma = distance.

Nr. 2. Two karateka are farther from each other. The attacker must take a small step in order to reach his opponent Uchi-ma. Nr. 3. Two karateka are even farther from each other To-ma in Japanese. Nr. 4. One karateka grabs the opponent’s kimono in order to off-balance his opponent during a leg(s) sweeping execution.

Let’s analyze each possibility: Nr. 1. In this case the attacker (Tori) has the advantage by using correctly the impulse momentum-relationship. In this case the tori to be successful in his attack must create a large force using a very short time which will be possible by the short distance. By the way this kind of execution is the so said kime or focus in karate.

If the karateka use a longer time the speed will be maximum and in this way the force used can be less. By the way using a very high speed the impact will be devastating. Force will has less importance, because the speed will be maximum. At the time of impact the tori should withdraw his arm immediately; in karate terms is called a Snap-Punch which will create the most devastating effect. Why is this? Because the impulse required bringing something to a ‘stop’ and then, again in effect “throw it back” is much greater than the impulse which require merely to bring something to a stop.

Let’s examine Nr. 2. Uchi-ma positions. Because the distance is larger there is a possibility to accelerate the speed. The karateka must use his mass with acceleration (F = ma).

Example Nr. 3 where the distance is even greater. Any of the opponents should use a large step in order to be at punching or kicking position. Here in this example I use the possibility when both karateka simultaneously attack each other then;

A. Punch or kick each other.

B. One is the tori and the other one is defender (Uke) which counters at the same time with the attack.

What can happen in this case in terms of biomechanics? A) Both will have probably a large momentum (mv) and one which has the larger momentum either using the mass or the velocity will hurt the other one. In this situation we cannot talk about impulse (Ft), because they have approximately the same time of reaching each other for the impact force. B) In this case the tori must have a better impulse by using a longer time for the impact. The uke must have a shorter time for a better impulse which creates a better use of his force.

The following paragraphs will describe the force and time relation related to impulse. The importance of creating as large an impulse as possible is evident in the case of a baseball pitcher. The pitcher uses the longest time over which to apply the force to the ball before releasing it. Another example in baseball is the hitter which is often encouraged to follow-through when striking a ball. We can find the same example in tennis.

High speed films of the collision between bats/rackets and ball have shown that the act of following through serves to increase the time over which collision occurs. Surprisingly this prolonged time for hitting, favors not the force of the impact between the ball and the bat rather favors the change of the velocity of the ball. These two examples are more important for acquiring distance than impact force.

In karate however is a different story. The karateka must favor force over time. Where the force is larger and the time is shorter the impact will be devastating especially when the punching arm will be withdrawn or bounced off.

The withdrawn arm or in karate term Snap-Punch is which creates more devastating effect on the opponent. To demonstrate the time and force relations who are inversely proportional the following table will demonstrate this.

Let’s say we need to inquire 100 N for the maximal effect of a blow/throw/push.

F x	t =	J
Force (N)	Time required	Acquired impulse
100 N	1 sec	100 units (max.impulse)
50 N	2 sec	100 units (max.impulse)
25 N	4 sec	100 units (max.impulse)
1 N	100 sec	100 units (max.impulse)

Now let’s analyze a little bit the kinetic energy (E_K) of both karateka: We use the equation described before in this article ½ mv². Example Ba: related to the tori which have a mass of 70 kg and a velocity of 2.5m². Then ½ (70) 2.5²= 218.75 Joules or N-m.

Example Bb: related to the uke; even he started at the same time and he is defending himself, the time for countering must be and will be shorter by focusing on his force in order to be effective. Uke’s mass 80kg, velocity is only 1.5m². Then ½ (80) 1.5² = 90 Joules or (N-m). In the uke’s case the kinetic energy remains less than in the tori’s case. The tori still loses energy because the attack was diverted by the uke.

Example Nr.4. In this example where the tori grabs the opponent’s kimono in order to sweep the leg(s) of the uke many physical properties will be used. Here I enumerate them in order of importance in my opinion: 1. Distance 2. momentum (speed) 3. strength 4. balance 5. friction 6. leverage 7. impulse 8. energy. This order of the physical properties can be different depending on the circumstances. I must specify that the speed, distance, balance and the lever are not physical properties.

Let’s describe a few words about each physical property: 1. Distance is primordial to approach the opponent’s safety space. Diverse feints and distraction must be use in order to grab the uke’s kimono. 2. Momentum must be used by giving priority to your velocity. 3. To use your strength in grabbing action to overcome a resistance of the opponent. 4. Using balance is two folded. Keeping your balance and the opponent’s balance for controlling him. Guiding the opponent in such a way to lose his balance.

5. Friction is always everywhere, when two forces act against each other and one is giving up by sliding. There are many kind of frictions, static/dynamic friction, rolling friction, sliding friction etc. In our case is the sliding friction is what happens. The tori’s leg which he uses for sweeping the uke’s leg must be very strong. 6. A karateka uses very seldom a leverage. Leverage cannot be used without contact to any other person or object. The tori has the opportunity to grab the uke’s kimono in different parts.

A. Grabbing on the collar is disadvantageous compared by grabbing on the sleeve. If you grab on the collar or on the shoulder, by pulling the opponent for losing his balance you have to deal with a large mass particularly the shoulder mass. By grabbing and pulling on the sleeve the task for off-balancing your opponent is easier, because you can maneuver easier a limb than a large body.

B. If you execute a sweeping technique without having contact on the sleeve, then the sweeping technique will be more difficult to carry out. In this case the tori must have a very good momentum and/or he must create feints which will induce the uke to lift up his front leg. By this way the tori can sweep uke’s both legs. The easiest case to sweep the front leg of the uke is when the weight proportion is more on the front leg then on the rear leg.

See the Fig. 2, a, b, c and d, shows the different kind of actions before and during foot sweeping. The impulse, has been described earlier, however again the kinetic energy will have an important role during fighting for a longer time period.

The following figures will show different levers such as First class lever and Second class lever.

Fig. 3. Represents 1^st class lever where the axis is in the middle of the two forces (FA or effort arm and RA or resistance arm). At the 1^st class lever the FA can be longer than the RA or vice versa in our case the FA is longer. Fig. 4. Represents 2^nd class lever where the axis at the one end of the lever arm. In both cases the axis is at the coxo-femoral articulation of the karateka and is represented by a double large circle (O). The FA is always longer at the 2^nd class lever.

For to better understand how this two different levers work it is important to describe some details about them: Interestingly the majority of the 1^st class lever FA and RA acting mostly towards the same direction e.g., seesaw (both FA and RA acting downward towards the ground). In our case both forces act in opposite direction just like a scale working in an unbalanced position. The effort arm (moment arm) is stronger than the RA so the FA determines a rotation of the RA in the opposite direction. The shank and the thigh should work together as the FA (moment arm).

Looking at the Fig. 3. There are two “X” signs one is on the top of the shoulder and the other one is at the elbow pit. Recall that I mentioned if you use the grabbing position at or on the elbow pit the sweeping technique will be more successful. Another problem can occur if you grab the sleeve at the level of the wrist and try to pull to off-balance your opponent, you may not succeed because your opponent’s lever arm (RA) will not act in unison with the upper part of his body. In other words he will move only his arm.

Let’s turn our attention to Fig. 4. Here the FA is the same as at the Fig. 3. The RA forces particularly the biceps femoris, semitendinosus, semimembranosus act together by opposing to be in extended position (the shank and the thigh). Also in addition the center of mass (CoM) of the thigh and the gravity act together as RA. Few more things I would like to explain here. You probably will ask, how can be established for the same kind of action two different class levers. To get the answer right to the point you should know that in mechanics the case is simple where the levers are represented by rigid bars. In human body the levers (representing the bones) are moved by muscles. Also there is controversy between biomechanists about establishing the exact lever system for each case in part.

These two lever examples are the author’s opinion. Levers are always established between two segments. In our case the 1^st class lever involves three body segments such as the shank, thigh and the upper body part. But you can see that there are only two body lever parts: The whole leg and the upper body. In Fig. 4. The case is simple. There are two body link connections. There is a lot of to say about levers.

So far you found examples about energy, leverage, displacement/distancing. In the following I am giving some examples/calculations about impulse-momentum relationship.

Example Nr. 1. A karateka kicks a stationary punching bag. A technique is a roundhouse kick to the imaginary midsection of an opponent. The question is to find out the final impulse delivered by the bag to the kicking leg.

The karateka has a 70 kg body mass and has an initial momentum (p = mv) = 11 kg x 4m/s = p = 44 kgm/sec. The kicking leg force encounters a force from the impact of the bag which is an impulse (J = Ft) = 108 N x 1.5 sec = J = 162 Nsec. Since this impulse acts in the direction of motion, it changes the kicking leg momentum from 44 kgm/sec to 206 units (44 + 162 = 206). This is an initial impulse; the final impulse is encountered upon rebounding.

The bag creates an opposite force (Newton’s 3^rd Law of Action and Reaction). This law states that in every action there is an equal and opposite reaction. However in our case of kicking a bag which is moving upon impact, the force which was delivered will not receive the equal force as in other case where the object is immovable. Taking into consideration the fact described above will result the final impulse force where the kicking leg can lose approximately 28 N. In this case the final impulse will be 162 N-sec – 28 N-sec = (J) 134 N-sec.

Example Nr. 2. A karateka hits a punching board (Makiwara in Japanese). We use his total arm length kg-force = 3.45 kg. He hits the makiwara with a speed of 5 m/s. It rebounds with a speed of 3 m/s. The contact time is 0.10 seconds. A). Determine the impulse with the makiwara. B). Determine the force of the makiwara on the punching fist.

Find the impulse. Given: m = 3.45 kg ; v_i= 5 m/s; v_f = 3 m/s; t = 0.10 s. Impulse = Momentum change = mΔv = m(v_f – v_i) = (3.45 kg) (-3 m/s – 5 m/s). Momentum (p) = - 27.6 kgm/s = Impulse = – 27.6 Ns (Ft).

The “-“ indicates that the impulse was opposite the original direction of motion. The Greek Δ sign indicates change. (Note that kgm/s is equivalent to Ns).

Find the force. Given: Ft then F = Impulse/t = (- 26.7 Ns) / ( 0.10 s) = Force = – 267 N.

In conclusion what can a karateka or instructor do to be sure that his/her karate techniques/motions are efficient? He should analyze the aforementioned examples adapted always to his karateka physical shape and somatotype.

If you have any comment, please send an email to stickyhandsjj@gmail.com. Please visit our web site: www.sendo-ryu.com. Prof. Emeric Arus, Ph.D. is the Founder and President of the Int’l. Sendo-Ryu Karatedo Federation and the USA Sticky Hands Combat Jujutsu Federation.

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Biomechanical Analysis of the Reverse Punch Technique in Karate and Boxing

November 28th, 2008

The Effectiveness of the Reverse Punch

By Prof. Emeric Arus, Ph.D., MS.

This article describes the biomechanical differences of the reverse punch executed by a karateka and by a boxer. Also try to shed light about the effectiveness of the two sports.

There are great differences of opinion between karateka and boxers over which sport has the better hitting power, which is more effective destroying an opponent. The author hypothesizes that boxers hit harder than karateka. This means, that their punching efficiency (momentum and/or force) is better than a karateka’s. The author has different assumptions about his hypothesis:

1. Boxers in general are better trained athletes;

2. Boxers are better fit and they can generate a greater force, because they have larger mass then karateka;

3. Karateka are more supple athletes with less bulky muscles that is why their force (mass x acceleration) is less effective.

Let us say for the sake of argument boxers train exclusively for arm techniques and karateka train for arm and leg techniques. This could mean the time spent on effectiveness for punching techniques is less for the karateka. It is important to differentiate between a punch with a boxing glove and one with empty hand. The impact is dispersed when somebody is hit with the boxing glove. The empty hand concentrates impact because of the smaller size of the fist.

Question: Why is there more penetrative power when somebody hits with the empty fist? Answer: The target energy is concentrated on a very small point (particularly on the two knuckles of the fist) and with the same amount of energy (which comes from the mass behind) the impact will be more devastating than in the case of hitting with a glove, where the energy of impact will dissipate. Prior to explaining the biomechanical hypothesis of the hitting efficacy of these two sports, we will describe the muscular kinematic chain specifically involved in the execution of the reverse punch.

It is important to state that in hitting, pushing and throwing executions, the first muscular region to be contracted is the pelvic girdle. From there, the accumulated muscular force travels up to the shoulder, arm and finally to the fist. The muscles of the lower extremities enter into play at the same time, starting with the body twisting/arm pushing movement. These stabilize the final pushing action of the arm.

During the early development of shot-putting, great champions such as James Fuchs in the 1950 have and later on Parry O’Brien, created different styles to achieve maximum shot put distance. They considered hip work (more than anything else) as the prime mover in shot-putting. Karate coaches put a lot of emphasis on hip rotation while teaching during the early stages.

By the same token, boxers are working more than karateka on weight training and it seems likely that weight training far exceeds benefits attributable to improvements in technique. Interestingly, weight training does not drastically develop the muscles of the hip region. But working on other parts of the body – such as the shoulder, back, and arm – seems to give an edge to those athletes (particularly boxers) who use the shoulder region muscles more. Karate and boxing coaches know that the heavier a body part, (particularly the pelvic region) the more force can be pushed into action. Additionally, the lighter the body part (particularly the arm) the faster the execution of the technique.

Let’s begin with a short description of the most important muscles involved in a reverse punch. We would like to specify that these muscles have mostly the role of adductor, rotator intern, extensor and pronator.

Here is the kinematic chain in the execution of the reverse punch:

From the thigh region down, ventral part of the thigh, the quadriceps femoris (all four parts -vastus lateralis, medialis, intermedius and rectus femoris) is the most important. Dorsal part of the thigh and lower part of the pelvic girdle there are musculus gluteus maximus (buttock), semimembranosus amp; semitendinosus, biceps femoris (long head). The calf and the foot muscles are not described in this article.

The pelvic girdle (region) links the trunk and the lower extremities. Here we find the most important muscles for reverse punch execution.

Ventral and interior muscles include the musculus iliopsoas, psoas major and iliacus). These act mostly as flexors, but the dorsal and exterior muscles act as extensor at the time of punching. The gluteus maximus is the most superficial and bulkiest muscle, and its action includes extension, rotation, adduction and abduction on the thigh. Gluteus medius and g. minimus are also extensors/rotators. Gluteus minimus is the only muscle between the gluteus family which medially rotate the hip joint and abducts the femur.

Several muscles from the lower/ventral part of the torso are also extremely important in reverse punching. They include the musculus obliquus externus abdominis, obliquus internus, and transversus abdominis. These compress the abdomen, helping to support the abdominal viscera against the pull of gravity, they contribute for the hip rotation during reverse punch. Also they cause trunk rotation and flexion.

The most important muscles of the shoulder girdle are:

Deltoideus ventral fascicule is the most important muscle of the shoulder girdle. This produces internal rotation of the arm, the dorsal fascicule produces external rotation and the middle fiber adduct the humerus. The musculus teres major is an internal rotator/adductor of the arm and synergist with latissimus dorsi amp; antagonist to the dorsal fiber of the deltoid. Musculus subscapularis is an internal rotator of the humerus. Another two muscles are important for reverse punch execution. They are latissimus dorsi and pectoralis major. Both rotate medially and adduct the humerus.

Upper arm ventral part most important muscles are:

Musculus coracobrachialis is a tiny muscle compared to biceps brachii. This muscle is deeply situated under the biceps it is a strong adductor of the humerus and acts as a forward projector of the arm. Musculus brachialis situated at the front and lower part of the biceps, also behind. Is a flexor of the forearm on the upper arm and is a tensor of the articular capsule of the elbow. It is an important muscle protecting the elbow in general.

Upper arm dorsal part most important muscles:

Musculus triceps brachii is one of the most important and strongest muscles which are an extensor of the forearm, tensor of the elbow’s articular capsule, adductor of the upper arm through caput longum insertion at the scapula beneath the glenoid fossa. The forearm muscles are not described in this article.

Biomechanical hypothesis of the reverse punch

As I mentioned earlier, the force used in any punching (pushing or throwing) begins from the hip region and progresses to the shoulder, upper arm, elbow and lower arm muscles. Finally, this force is transmitted to the punching fist. The leg muscles begin contracting at the same time as those of the hip girdle. Well known, that beginners (karateka or boxer) are unable to use correctly the hip rotation in punching as the “first muscular link.”

In case of a shot putter or discus thrower the beginner has the advantage of the time to deliver the expected force by not only rotating the hip, but also rotating the body. However, advanced karateka use the hip rotation as the first link in transmitting the force to the rest of the muscular link. Karate instructors emphasize the importance of the hip rotation.

Analyzing a right hand reverse punch (gyaku zuki in Japanese) the athlete (karateka or boxer) stands with the left foot forward in a fighting position. The posture is very similar in both sports. The reverse punch executed by the karateka: At the time of pushing forward the right fist there is a rotation of the fist from a supine position to prone position and the left hand is energetically pulled back to the left hip.

By pulling the left fist energetically to the hip, the karateka adds more rotational force to the hip and more stability too. A boxer does not rotate the hip as hard when he executes the reverse punch for two reasons:

1. The left fist is withdrawn close to the left shoulder or the boxer’s face, where it is used to protect the face and jaw;

2. The boxer tends to lean forward and uses the right shoulder more to augment the punch’s effectiveness.

Ph.1. Reverse punch executed by a karateka Ph. 2. Reverse punch executed by a karateka

Ph.3. Reverse punch executed by a karateka Ph.4. Reverse pushing punch

Photos 1. and 2. Clearly show the use of the hip by the karateka. Photo 3. Shows a real match where the left arm is open to the possibility of blocking or catching the opponent’s arm. Photo 4. Shows a reverse pushing punch where the shoulder is pushed forward for extra force delivery. This technique can be seen in Wado-ryu, Sendo-ryu styles, and perhaps other styles too. Photo 5. and 6. Clearly show the use of shoulder by boxers.

Ph. 5. Reverse punch executed by a boxer Ph. 6. Reverse punch executed by a boxer

Now I’d like to go into greater detail about the effectiveness of the reverse punches used in karate and boxing. I stated earlier that boxers are more effective even though they don’t use their hip region musculature in an effective way. You might ask, “Why is it so difficult to rotate the hip as the first part of the kinematic punching chain?” The answer is simple: hip region musculature is the heaviest in the human body and a lighter body part is easier to move than a heavier part!

By the way the hip is considered the heaviest part of the human body by most instructors and kinesiologists, but in our case the shoulder region includes a tiny part of the upper region of the chest, which is the correct way establishing the shoulder region.

Additionally, the trunk can be divided theoretically into three parts. The lower part is the pelvic or hip girdle. The middle comprises the abdomen and the upper region comprises the chest and shoulders. As the hip starts to rotate, so almost instantaneously does the rest of the trunk; this continuing to the shoulder. Muscles are contracted less efficiently at hip level than at the shoulder level because the shoulder muscles (deltoideus, trapezius and pectoralis) are broad and have greater force production than the relatively smaller hip muscles which are found on the inner surface of the pelvis. These muscles laterally rotate the hip joint.

Gluteus maximus, medius and minimus are larger muscles and they are found on the outer surface of the pelvis. They abduct and medially rotate the hip joint which is exactly important in reverse punch action. Gluteus maximus is an exception which laterally rotates the hip. In the transmission of the punching force the serratus anterior has an assisting role.

Biomechanical considerations

Hip and shoulder rotation involve an eccentric force which produces translation and rotation. Its effect known as “torque,” where torque ( G ) or ( T ) = Force x distance. We express it more correctly in mechanics where the torque is measured in Newton’s ( N ) x meters T = (N-m).
The magnitude of the hip torque is smaller at the beginning of the rotation time, then in case of a shoulder, where the torque is greater.
If the spine is considered as the axis of rotation, then the perpendicular distance from the axis to the line of action of the force (the lever arm) is shorter for the hip than for the shoulder. Here the available force is less because the short lever arm. Also, the longer the lever arm, the higher the speed. This is why the boxer develops higher velocity and ultimately, more momentum (see explanation later on). Because we speak about rotary motion we have to make a differentiation between the rotary and linear motion by describing inertia.

The tendency of a body to remain in its state of rest or motion until acted upon by an outside force termed inertia. This is Newton’s first law of motion and is equally applied to a body which moves in a straight line or which moves in a rotary path. The big distinction between the two motion (linear and rotational) is that to move or stop an object which moves in a linear path is easier than the body which moves in a rotational path. The tendency to resist against motion or to stop/slow down (angular resistance) under rotary condition named moment of inertia.

When the rotating mass is multiplied by the square of its distance from the axis of rotation we speak about moment of inertia (I) I = kg x m² or transfer of momentum. The torque ( G ) also represented by moment of inertia (I) times angular acceleration (a). G = I · a. Torque may be increased by increasing the magnitude of force or by increasing the length of the lever (moment arm).

If the mass of an object is concentrated close to the axis of rotation, the object is easier to turn because the radius for each particle is less, as is the moment of inertia. Conversely if the mass is concentrated farther away from the axis (in the case of the shoulder), inertia becomes greater and the rotating body will require more force to start or stop it.

When the rotational force (torque) from the shoulder is transformed into rectilinear (straight) force then the impact force will be equaled by the stopping force coming in the opposite direction (Newton’s III law). This force comes from the attacker’s body, which reflects back the same magnitude of force to that delivered to it. The kinetic energy of impact is absorbed into potential energy and some of this will be dissipated as heat. The defender’s body will react by absorbing the energy of the attack damaging itself.

It should be kept in mind that a rotating body is more difficult to stop than a body moving in a straight line. A rotating body has more penetrating force than one with no rotation (e.g., a bullet is rotating around its axis). So now you are beginning to see the pros and cons emphasizing the shoulder more than the hip rotation for developing better penetrating force.

Now I would like to describe and clarify the hip and shoulder torque actions. Mass, weight, force and gravity are closely related. Mass represents the quantity of matter that comprises an object. Mass is measured in kilograms. The mass represents the measure of a body’s inertia, i.e., its resistance to acceleration. Weight is the product of the mass of an object and the acceleration due to gravity (which is approximately 9.80 m/sec²). Force defines a pulling or pushing action that causes a change in the state of motion of an object or a mass. In mechanics F = m x a, where F – represents force, m – represents mass and a – represents acceleration. Force is measured in Newton’s (N) and in this case, 1 Newton = 1kg 1m/sec². A body of 70 kg mass has 686 N force (70 kg x 9.80), but how can we measure the force by Newton’s of the individual body segments. The answer to this is not simple.

I will use an approximate description based upon anthropometric calculations of different body segments made by different authors. According to V.M. Zatsiorsky, PhD., Professor at Pennsylvania State University describes mass segments of body parts from 100 physically fit young men, where the hip region contributed approximately 12% and the shoulders approximately 16% of the total 100% body mass. Analyzing this data indicates that the shoulder region is larger and also is heavier. We are interested about the mass of the shoulder region, the mass of the total length of the arm (from shoulder to end of the hand) and the mass of the hip region.

The mass of one arm (only one arm) is approximately 4.94% of body mass so we can calculate the arm force of a 70 kg body mass as 4.94 x 9.8 = 48.41 N. The mass of the hip region for the same body mass is 11.18%, so hip force is 11.18 x 9.8 = 109.65 N. The mass of the shoulder region in a similar weight person accounts for 15.96% of the mass, so the force it generates is 15.96 x 9.8 = 165.40 N. According to these calculations it is obvious that the shoulder can deliver more force than the hip.

Additionally, the shoulder is directly connected to the arm so discharge of the shoulder force is immediately transmitted to the arm. The hip region transmitting force is somehow lost because the torso muscles which transmit the necessary force are not directly connected to the shoulder. So overall, shoulder action delivers approximately 10% more force than the hip by adding also the total arm mass.

However, a big question is remains: how can we calculate the acceleration and impact force of the arm itself? This cannot be calculated without using highly specialized apparatuses capable of measuring impact force and/or acceleration.

You need to know something about levers because this will help you understand some of the principles being talked about here. Levers in human anatomy basically comprised of bones. Levers are not only rigid bars – they represent the perpendicular distance from the axis of rotation (fulcrum) to the line of action of a force.

However levers in mechanics are described as long arms (or objects) connected to a rotational axis at one end and the line of action where the force is activated, at the other end. Lever arm is named also moment arm or force arm. In daily activity using a lever the work is done much easier. There are three types of levers known as class 1, class 2, and class 3.

While it is difficult to decide in some cases, we can say that the majority of human levers fall into classes 1 and 3. Look at the shoulder, for example. Here the vertebral column is the fulcrum and the head of humerus (with its connection to the scapula) makes up a class 2. The fulcrum is at one end of the lever; the load is in the middle (the shoulder muscles) and the effort is considered to be the articulation of the humerus which the athlete uses for pushing punching.

However there may be a problem here because the vertebral column has no connection with any bone to the shoulder and certainly not to the humerus. The humerus is connected to the scapula laterally in the glenoid cavity and the clavicle on the dorsal par of the body through the acromion of the scapula. In general terms the muscular connection to clavicle and scapula represent the lever arm. In our case the vertebral column could not represent the axis because the clavicle is attached to the sternum (sterno-clavicular joint). However the sternum is close to the vertebral column so the sterno-clavicular joint and vertebral column together can work as one during reverse punch. The lever arm as a rigid entity in this case can be described is the clavicle.

The above described explanation to establish the leverage in human body is fairly difficult. In mechanics the case is simple where no sophisticated connections are found such as in the human body.

See the length of the lever arm advantage in case of hip and shoulder (Fig.1)

The hip does approximately 45 degree turning while the shoulder can do approximately 90 degrees turning. The diagram is viewed from the top of the head.

It may help to better understand the forces (muscles and bones) acting at the shoulder girdle in terms of the moment of inertia which has been described earlier. When speak about moment of inertia in terms of body mass, we could be referring to total mass amount or only just a particular portion

article of the mass of the body/object in question and how this mass is distributed relative to the axis of rotation. If the mass is concentrated close to the axis, it is much easier to alter the angular motion of a body than if that same mass is farther form the axis. The moment of inertia of a body can be determined in a variety of ways.

One of these methods is the segmentation method where human segments are compared to geometrical shapes. E.g., the head is spherical, the upper arm is cylindrical, the forearm is conical etc. In this case we can find different publications where authors enumerate body segments and their moments of inertia. The author will use such an example for the following body segments and their moment of inertia (kg-m²). We need the following segments and their moment of inertia:

Total arm length (upper arm, forearm and hand) = 0.0294 kg-m²

Upper level of the trunk (both shoulders) = 0.441 “

Lower level of the trunk (hip girdle) = 0.399 “

This clearly shows the advantage of the shoulder over hip region. Now we need briefly to mention impulse and momentum. Impulse is described as the relation between the force and time (F x t). A better impulse will be produced by a greater magnitude of force or a longer time application of the existing force. When sufficient force is applied to a mass, an acceleration will occur, because the change in time of velocity. F = m x a, from this equation rearranging the following yields that F = m (?_f- ?_i) where the ?_f = final velocity and the ?_i = initial velocity and t = time.

A karateka or boxer needs an impulse to initiate a punch. This impulse is mostly a nervous impulse generating force from muscular contraction. Then the impulse becomes momentum and later on when there is a contact then there is an impulse again.

Momentum expresses the relationship between mass and velocity, Momentum = m x ?. Analyzing the importance of the impulse result that the impulse of a force (F_t) is equal to the change of momentum (m?_f- m?_i) that it produces. This way the impulse-momentum relationship is basic to an understanding of many sports techniques including our article. The importance of creating as large an impulse as possible is evident in the case of a baseball pitcher. The pitcher uses the longest time over which to apply the force to the ball before releasing it.

Another example in baseball is the hitter which is often encouraged to follow-through when striking a ball. High speed films of the collision between bats/rackets and balls have shown that the act of following through serves to increase the time over which collision occurs. Surprisingly this prolonged time for hitting, favors not the force of impact between the ball and the bat but favors the change velocity of the ball. So this example is more important for acquiring distance than impact force.

In karate however is a different story. The karateka must favor force over the time. Where the force is larger and the time is shorter the impact will be devastating especially wen the punching arm will be withdrawn or bounced off. The withdrawn arm or in karate terms Snap-Punch is which will creates more devastating effect on the opponent. To demonstrate the time and force relations which are inversely proportional here is a table which demonstrates this.

Let’s say we need to inquire 100 N for the max. effect of a blow push.

F x t = J

Force (N) Time required Acquired impulse

100 N 1 sec 100 units (max. impulse)50 N 2 sec 100 units (max. impulse)25 N 4 sec 100 units (max. impulse)
1 N 100 sec 100 units (max. impulse)

We don’t need to prove that a ping-pong bat doesn’t hit the tennis ball as hard or as far as does a tennis racquet, the ball will have a shorter landing distance. Knowing this, we can understand that the hip has a shorter distance by turning and delivering the force (let’s compare as a ping-pong racket) versus the shoulder (compare as a tennis racket) so the impulse and momentum will be larger. See Figure 1. Shows the hip and the shoulder relationship.

That summarizes, then the pros and cons of hip versus the shoulder power and I believe I have shown that the shoulder is probably more effective than the hip. Even so, I still believe that reverse punch begins with hip action acting in unison with the rest of the torso and shoulder muscles. If you want to compare the contact force output generated by a boxer and a karateka by means of force testing apparatus, then both should be barehanded or both should wear a light boxing glove. Make your data more encompassing by using different methods and different force/impact detection apparatus.

Prof. Emeric Arus is the President/Founder of the International Sendo-Ryu Karatedo Federation For contact: 27-18 Newtown Ave., Astoria, NY 11102/USA or visit www.sendo-ryu.com and drarus@earthlink.net or stickyhandsjj@gmail.com

Prof. Arus is the author of the book of “Sendo-Ryu Karatedo, The Way of Initiative” and a new DVD “Sendo-Ryu Karatedo and Sticky Hands Combat Jujutsu.

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Introduction to USA Sticky Hands Combat Jujutsu

January 25th, 2007

By Professor, Dr. Emeric Arus – Kinesiologist – Copyrighted by Prof. Emeric Arus

Theory and Philosophy

The system of STICKY HANDS JUJUTSU is one of the youngest Jujutsu styles in the world today. The style was established on April.9, 2000. The founder of this style is the Kaicho (President) Professor, Dr. Emeric Arus – 10^th Dan Karate, 6^th Dan Jujutsu and 4^th Dan Judo, Budo master.

Sticky Hands Jujutsu is based on scientific research conducted into other martial arts such as; Judo, Aikido, Aikijujutsu, free style wrestling, Karate, and of course Jujutsu.

The basic principle of the style is founded upon the possibility of attacking/grabbing the opponent’s hand, particularly the pinkie & the ring fingers together, and maneuvering in such a way as to create violent pain in the fingers and wrist joints ultimately immobilizing the opponent.

Techniques with large movements: O Kote Gaeshi, Kaiten Nage, Shiho Nage etc. from Aikido and Uchi Mata, O Soto Gari, Harai Goshi, Hane Goshi, Seoi Nage etc. from Judo; although not completely excluded, are not primarily utilized in this style.

The defender (Uke) in this style can use Aikijujutsu techniques on the ground (Ne Waza) such as: Ikkyo, Nikyo, Sankyo and Yonkyo instead of Judo or wrestling ground techniques. Pressure points (Kyusho) techniques and blows are used in this style against vital points and areas in order to loosen the opponent’s grip, and then to attack his grip to reach the pinkie and ring fingers.

The methodology of teaching/learning is different from other Jujutsu styles. For instance this style emphasizes correct and efficient punching, and kicking techniques from Karate. This is contrary to general teaching methodology of Jujutsu, where the emphasis is placed more on the grappling, while almost completely neglecting striking and kicking techniques.

Another difference of the methodology of teaching from other Jujutsu styles is the grappling method of the opponent’s grip and/or pinkie and ring finger. The student of STICKY HANDS JUJUTSU style spend a lot of time on the so said “fingers play method,” which teaches the student how to change one Kyusho technique to another one.

Basic principles in defense/attack in this style:

1) Balance/stability – The participant must take a constant care to maintain good balance whether in motion or in stable position. The center of gravity and base of support for your body must be kept under control.

2) Continuous motion – In order to successfully control your opponent, you must maintain a continuous motion from the beginning of your action to the completion of the technique.

3) Contact/firmness – When applying techniques on one’s opponent, your contact must be firm.

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4) Fluidity – During your contact, if it is necessary to change the technique, you must find the way to go from one technique to another with fluid uninterrupted motion.

5) Speed/mobility – If you are mobile, then you have fluidity and if you have fluidity, the speed that you posses will be economical.

6) Atemi/Kyusho — Before applying any technique use a blow directed at vital areas/points or use pressure against vital points.

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7) Leverage/fulcrum – It is vital to know when you press on the fulcrum (joint), and when you must lift up the lever or vice versa. You must create the smallest base to create pain in your opponent.

Control/sliding – When you control your opponent with a particular technique, your fingers must slide down or up on your opponent’s arm until final immobilization.

9) Additional base – Create another base to inflict pain and to control the first position.

The weakness of human body

Human vital areas

Head & neck

Eye balls – nose – ears – temples – lips – mandible bone – top of head – neck (back, front, side)

Trunk

Heart – clavicle bones – solar plexus – kidneys – liver – ribs – groin area — spine

Arms & legs

Elbows – knees

Striking or kicking these vital areas can cause temporary loss of consciousness, severe pain or even death

Human vital points

Head

1) Hit with the middle finger at middle phalange joint (Nakadaka Ippon Ken) between the 2 eyebrows.

2) Press hard under the ears with the middle finger on the condylar process of mandible (head of mandible) where the great auricular nerve (anterior branch) lies.

3) Press or hit on the temple with the thumb bent (Oyayubi Ippon Ken) or ridge hand (Haito).

4) Press or hit with the joint of the proximal and middle phalanx (Nakadaka Ippon Ken), or with four finger knuckle fist (Hiraken) on the upper part of the mouth between the upper lip and nose.

5) Pull apart the opponent mouth with your fingers

Neck & shoulders

1) Press on the head of the humerus bone frontal part (tubeculum minus humeri = lesser tubercle) and/or lateral part of the humerus bone (tuberculum majus humeri = greater tubercle).

2) Press on the sternocleidomastoid muscle on the lower third (closed to clavicular portion) not on the sternal portion, closed to clavicle bone where the internal jugular vein, common external carotid artery and the Vagus nerve (X) are.

3) Press or pinch on trapezius muscle between the shoulder and the neck exactly in the middle part of the trapezius and above the scapula, where the Accessory nerve (XI) and supraclavicular nerve will be activated.

4) Press vertical directly down near the sternocleidomastoid muscle and clavicle bone (greater supraclavicular fossa).

Arms & hands

1) Hit or press energetically on the biceps muscle (middle part).

2) Hit or press hard with four finger knuckle fist (Hiraken) on the triceps brachial ligament.

3) Press on the frontal proximal part (laterally) of the radius bone on the brachioradialis muscle (approximately 1 ½ inches from the radius head).

4) Press on the distal part of the radius bone (activating the radial nerve) approximately 2 inches from the (radial styloid process) wrist.

5) Press between the first two metacarpal bone insertion, close to the second metacarpal bone.

6) Press on the thenar eminence (ball of the thumb).

7) Press hard or hit on the back of the palm. Hit with Hiraken.

Pelvis, thigh, legs & feet

1) Press on either side of the pubic bone on the inguinal ligament, which covers the ilioinguinalis nerve and inguinal lymph nodes.

2) Pinch or kick on the biceps femoris (long head muscle).

3) Kick or press hard on the quadriceps muscle (at vastus medialis, closed to sartorius muscle). Approximately 1/3 part from the knee on the inside part of the thigh.

4) Pinch, press or kick on the medial part and/or the dorsal part of the gastrocnemius muscle (middle region) of the leg.

5) Press or stomp on any of the metatarsal bones and/or the joint of the proximal phalanx.

There are many more vital points on the human body, however here the founder of this style described mostly those which are the most effective to use in combat.

Hitting or pressing sharply on these vital points, will cause the opponent to lose control of his grip, because of the violent pain. The opponent will be temporarily incapacitated. Continuing to apply pressure to these vital points will cause the opponent to abandon his hold or pin.

Note: In order to understand and to find the correct spots of these vital points the practitioner should consult/read a good anatomy book or to be guided by a highly expert Jujutsu instructor.

The author’s intention in capitalizing the first letter of each word in Japanese is to place emphasis on the words, contrary to grammatical rules.

See below for the human anatomy sketch

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How to Conserve Energy in Martial Arts

November 16th, 2006

By Prof. Dr. Emeric Arus/Founder of the Int’l. Sendo-Ryu Karatedo Federation

Copyrighted by Prof. Emeric Arus

Energy is the capacity for doing work. Energy takes many different forms such as: Solar, mechanical, electrical, chemical, nuclear, heat, and sound energy. Mechanical energy has two different manifestations: 1) Potential energy which is the capacity of a body to do work by virtue of its position relative to a reference, measured in Joule, and 2) Kinetic energy which is the energy due to its motion/action. Kinetic energy also has two forms of manifestation: Linear kinetic energy (LKE) and angular/rotational kinetic energy (RKE).

Both linear and angular kinetic energy are dependent upon the interaction of mass and velocity. If we take the mass and velocity in each case as a constant attribute, the angular kinetic energy is much stronger than the linear kinetic energy. This is because in rotational motion any mass tends also to accelerate due to centrifugal (pseudo) force; and during the time of liberation of the body mass with the technique, e.g. spinning back kick, the energy liberated will be much stronger than in the case of linear kinetic energy. In this case a punch such as an uppercut, a fencing technique such as cut, or a spinning back kick will be much stronger than techniques executed linearly.

An explanation is important here why is a spinning back kick stronger than a straight front kick. During a rotation the body along with the kicking leg holds a grouped position (the kicking leg is closed to the body). Before the liberation of the kick the rotational angle which is approximately 123 degrees measured between the shoulder line and the thigh (see Figure B and C). Later on will be larger approximately 140 degrees (see Figure D). The figure graphically represents the spinning back kick.

Before the impact to the face the degrees between the leg and the thigh will be approximately 160 degrees. Because the kicking leg will be straightened out, the leg will have a longer range for attack (longer lever) and in this case will gain speed. By gaining speed will have also a better penetration power.

These two forms of mechanical energy have important biomechanical implications for the understanding and controlling of the technical executions of the various martial arts.

Let’s start with something of a simple explanation to understand energy. The following will describe different forms of activity (non activity) where the martial artist can conserve his/her energy the best: meditation, sleeping, lying on supine position. Now let’s turn our undivided attention to the practice of martial arts. To understand better which martial art will conserve your energy best (understand the kinetic energy), first we should classify martial arts according to energy expenditure.

In the author’s opinion here are the various martial arts selected in order of energy expenditure, the first denoting the most energy expenditure: Total martial art (including wrestling, kicking, striking etc.), boxing, Judo, Jujutsu, Muai Thai, Karate, Kendo, Fencing, Aikido, Tai Chi Chuan etc. Another classification is between the arts themselves. Karate, for instance has many different “styles”; some styles are recognized as “soft styles,” and others are recognized as “hard styles.”

Hard style karate demands more energy expenditure because almost every action/attack and even defense must be done with the total concentration of the athlete’s energy. The more energy that is invested in an attack the more destructive will be the effect of that impact.

Most of the attacks demand anaerobic power, where the oxygen is insufficient. In order to invest more energy into the action, the athlete loses not only mechanical, but also physiological and mental energy (where the electrical and chemical energy exchanges takes place).

The above figure explains the way of the right kicking leg to the target. Initially the attacker stay with the left foot forward and his/her shoulders are oriented diagonally (see fig. A.). The attacker will turn around to the right and makes almost a 360^o degrees. At the time of the impact his/her shoulders will change position (fig.D.)

Soft style karate uses less energy because the actions/techniques are executed more gently. The athlete is not required to perform anaerobically, and most importantly the athlete uses techniques with soft guiding movement.

Further analyzing the different techniques within a style, we observe that kicking techniques require more energy than punching techniques for two reasons: Legs are heavier than arms; legs must work harder against the force of gravity. Accordingly, the higher an athlete lifts up his/her leg the more energy is needed.

Soft style karate tends to use more body shifting, explaining that it is easier to avoid an attack than to block. There is a big misconception about this proposal. Let me explain this misconception in detail. It is true that when two body parts collide there is a dissipation of energy (explosion of energy), this is the case in hard style karate; but it is also true that when you must avoid an attack by moving away, you also lose energy by moving. Now the question is which action makes you to lose more energy? The contact time (explosion of energy) or the body movement?

The attacker always loses more energy than the defender whether there is contact or not. Theoretically the defender should lose more energy when he/she is moving than simple just blocking and holding his/her position. Moving a larger mass such as the body,

The defender will lose more energy than moving a smaller mass such as an arm. So why do many of the proponents of the soft style promulgate and maintain that body movements/shifting (Tai sabaki in Japanese) will make you to be more economical.

There is one answer to this controversial aspect of “controlling” your opponent and/or “conserving” your energy. These two words controlling and conserving are related to each other, but they have different meanings. Controlling your opponent means that you can direct/redirect his/her actions (attacks, even his/her thought) in your favor. Conserving means maintenance of your previous actions in a smooth way, and by this way your actions will be economical, and you will use less energy conserving it in your favor.

I explained some aspects about conserving the energy in your favor. Now I’d like to add a few words to clarify the aforementioned issue of conserving energy in martial arts. An excellent martial art instructor should guide his/her martial artist’s training combining hard style and soft style techniques. If the training is extremely hard for a very long period of time (months of training) with little or no rest between the training sessions, the martial artist enter in a so said overtraining or burn out state. By using an adequate training protocol the martial artist will be able to control his/her actions and in this way he/she will conserve energy.

This article is simplified for everyone’s understanding. The article did not contains the biomechanical formulas e.g., F = m · a (F = force, m = mass, a = acceleration) etc.

Any comment, please contact the Int’l. Sendo-Ryu Karatedo Federation:

www.sendo-ryu.com kaicho162@yahoo.com drarus@earthlink.net

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Tactics of Karate

September 1st, 2006