This text has been faithfully reproduced from the original teachings of that time period, do with it as you may and change it to suit your particular needs, but first research the principles outlined below, before you do that,. these principles are based on sound knowledge of body mechanics to achieve the desired "Shock on Impact"

It goes against The Non Telegraphic Idea, but, as mentioned before, this is a training method for Maximum Shock on Impact.

The 13 Scientific Elements in the Reverse Punch

1) Relaxation / Concentration

2) Double Hip

3) Traction / Grip

4) Reaction / Recoil

5) Zero Tension

6) Changing Weight

7) Balance

8) Gravity

9) Angles

10) Locking Joints

11) Breathing

12) Snap

13) Impact / Tension / Reaction

I shall discus these elements of the punch separately and and give the reference if the notes are mine or those of Hanshi "Chojiro Tani"

Preface by Chojiro Tani

Before you read this text I would like you to consider a few of the basic theories listed below

REACTION-----RELAXATION-----ACCELERATION-----IMPACT

This is a logical or dynamic expression of karate movement, The following is a technical body movement

DOUBLE HIP-----BANKING OF THE FORCE IN THE SHOULDER-----SNAP-----IMPACT

DOUBLE HIP MOVEMENT means, grip the floor with the front foot and twist the hip back (Do both together and this is the first twist) then twist the hip forward. The DOUBLE HIP MOVEMENT is a REACTION to get a larger rotation in the body.

BANKING OF THE FORCE IN THE SHOULDER, is to enable you to RELAX before you punch

SNAP is to ACCELERATE your fist prior to IMPACT,

The elements which give the impact and the related diagrams are important to observe when practising to increase your speed, If you apply these theories to your training, the time it takes to improve will be decreased, naturally you will have to put a lot of effort into your practice but the most important factor is to realise the feeling of power. Your punches will be faster and stronger if you follow these theories correctly

Another part of the progression in Karate is the mental attitude, recently many Karate films have been shown everywhere in the world of goodies beating baddies; - it looks exciting but only to people of this standard, Karate beginners must deny resorting to force right from the very beginning before they lower themselves to this standard.

Exercises in Karate are ment to progress your physical and mental condition with EFFORT and this EFFORT is the element which will make you strong physically and mentally

EFFORT---------- for yourself.

8th. DAN HANSHI CHOJIRO TANI

( TRANSLATOR ) TAMIO TSUJI

DIFFERENCE IN IMPACT

You may wonder why we say that a person who has a strong impact has correct coordination of the impact elements and a person who has a weak impact has not got the correct impact elements, naturally there are exceptions, but in accordance with the previously explained theories, the person who has weak impact has muscles moving against the correctly moving muscles . The person whose movement is stiff is using his strength well before his impact, he is omitting the relaxing factor of the double hip movement, The arm punching or the leg kicking is not what results in a strong impact, every karate movement must start with the body to get the right body line and stance, "THE REALISATION THAT BODY ROTATION COMES FIRST, is the key point to obtain strong blow.

INCORRECT BODY LINE ( which will be explained later ) slow HIKITE (pulling back of the opposite arm ) and incorrect movements of arms and legs must be overcome before a perfect blow can be achieved.

Once you have learned all the important elements, striking at the punch bag will enable you to see if your blow is correct and strong, If, it is not, then carefully retrace all your movements and try to correct your faults.

The ideal impact will cause the an opponent to feel the force GO THROUGH HIS BODY, not not spread in all directions on his body, This type of impact brings his body down and forward in the event that you really punch his body or his feet will come up in the air if the blow strikes his face.

Commonly when we talk about a punch we refer to it saying " light punch or a heavy punch", neither of them is ideal, a light punch maybe fast but would not give enough impact, a heavy punch maybe strong but generally is not fast enough.

Probably you already know that you don't use your strength to punch, you use only natural body movement, Anybody can approach the ideal impact if you can understand the correct body movement.

SPEED

When we compare the impacts of an arrow and a bullet, we know that the bullet's impact is stronger because of its increased speed, simply, speed is force.

This section is about speed, for the aim of the majority of sports and Martial Arts practice is to get this speed----Maximum Speed.

Please swing your arm naturally a few times and then use the double hip movement to help you swing it, Repeat this motion a few times and it will give you the idea that your arm swings forward automatically and faster when you use the double hip movement, ( REACTION ) this motion will also give you another important factor in the faster punch, and this is the relaxation factor evident in the double hip movement

Most karate movement is to get speed, there are so many theories in Karate and they are all to get this speed, how to accelerate your fist or feet is the most important theory in Karate and these will be explained later, you must remember the rule about acceleration "ACCELERATION IS PROPORTIONAL TO THE GIVEN FORCE AND IS INVERSELY PROPORTIONAL TO IT'S MASS"

Recoil action and snapping actions give acceleration, How to use these actions is the first thing you have to learn.

ZERO ( Tension)

To make this explanation easier we have used the word "Zero" for describing ones body in a relaxed condition, and "Tension" to describe the tensed position

RELATIONSHIP BETWEEN ZERO AND TENSION.----------Snap your hands a few times as if you were shaking water from your hands or flick a towel, between the forward and return movements of the above examples, you can feel or see the tension momentarily,

We can deduce from these examples the following rule, ZERO-------TENSION-------ZERO. It is easy to get ZERO if you use a snapping or whipping action.

Next, please stand straight in the parallel stance and push off the floor with your left leg, Did you find that your right leg became relaxed? This will apply to most of the stances.

The ideal is to "Zero" you arms or legs before the actual movement as this will result in maximum speed without unnecessary tension

The double hip movement involves the above explanation and is essential to obtain maximum power.

RECOIL

Before twisting your hip forward, you must twist it backward, we call this movement RECOIL , There are many similar everyday movements which use this same action, for example hammering in nails, batting a ball, most sportsmen and physical workers use reaction or recoil.

People use recoil to make acting parts of their bodies relax

A relaxed body makes the action stronger and this strength comes from speed, without recoil you can never obtain maximum speed.

THE RELATED ELEMENTS OF RECOIL FOLLOW-----

RECOIL----ZERO----SPEED.

For further examples we have picked out the recoil actions being used in sports

"Up and Down" movements ---Basketball, Leaving the blocks in Swimming or Sprinting, High Jumps, Shot Put.

"Left to Right" movements Tennis, Baseball, Batting, Golf.

"Back and Forward" movements Volleyball, Soccer, ( when a player throws the ball in to the field )

Most Karate movements are based on hip action and this takes the form of the double hip movement explained previously, Your use of recoil will decide your technique.

TWISTING OF THE HIP

To rotate smoothly is is essential to have an axis, A spinning top and a wheel both have an axis, An axis is necessary to obtain fast rotation.

Please stand straight and twist your hip a few times and then repeat it a few times in a long stance, Which stance was the easier to twist your hip? It is easier to twist your body standing in a shorter stance.

Most sports use the double twist but not most forms of Karate or Martial Arts Training excepting Shokokai, Shokokai Karate hardly ever uses the single hip movement because of the reasons we explained previously

The above shows you how to shift your weight

b and c must be performed together

GRIP

You might find it difficult to understand the meaning we assign to "GRIP", The meaning is to shift the weight onto one leg, "Grip" is important as the you can then move your body LIKE A TOP, This GRIP will make your hip movement exact and smooth and this is the basic of all Shukokai techniques

If your grip is not firm enough your weight will be evenly distributed instead of shifting to one leg, and therefore twisting your body will not be smooth enough to obtain maximum power.

GRIP is the FIRST movement in the double hip movement, This GRIP comes with the double hip movement.

SHOCK

When a nail is hammered into a piece of timber, or a pencil is struck from the edge of a table or desk, it will depend on the strength of the striking force as to how far it will go, The harder the hit the more they will move.

If somebody hits your elbow from behind while you fist is resting on your hip, your arm will jump forward, There is a way to obtain that sort of strike without somebody hitting your arm

It is very important to FEEL the shock, You won't be able to make your arm relaxed when you punch unless you can feel the SHOCK, The stronger the SHOCK you receive the greater the impact you can deliver,

The double hip Movement is simply to get the stronger shock into you shoulder, To understand this NATURAL TENSION is the easiest way to approach the fast punch because this accelerates your fist much faster.

HOW TO GET SHOCK

THERE ARE THREE WAYS TO GET SHOCK

2) Pushing the body forward and pulling the arm back at the same time

3) Pushing the body forward without moving the arm forward,

These exercises will let your body understand "SHOCK" which means simply "Banking Force In The Shoulder", These shock methods have to be used separately depending on which technique is required.

GRIP----DOUBLE TWIST----SHOCK----IMPACT.

When you are performing this double twist you will FEEL the SHOCK in your RELAXED shoulder before you begin to twist your hip, The strength of this SHOCK will determine your impact in technique.

SNAPPING

If you use the snap of your wrist just before you actually strike, your technique will gain tremendous strength, especially the knife hand strike and the vertical punch, the reason for this added strength is the extra acceleration just before impact, this type of SNAP is also called SHOCK and applies to every movement.

Formula; FORCE = ACCELERATION X MASS

The snapping action becomes faster and stronger in a RELAXED body, legs or arms.

The DOUBLE HIP Movement is a type of SNAP action, in other words this is a SNAP OF THE WHOLE BODY, Therefore your body will be like a whip untill the time of impact.

EXAMPLE------- Back Fist Strike

Double hip movement-----First Snap

Elbow----- ---------------Second Snap

Wrist--------------------- Third Snap

The above example shows clearly that your body must be relaxed to perform the technique.

BODY LINE

It is advisable to watch your body line in a mirror and to try to keep your posture correct, the correct form for free sparring will give you an easier stance to move and perform the techniques.

A) Leaning the body forward will not give a smooth hip technique and therefore a fast technique cannot be performed from this stance.

B) bending the back leg is good for some techniques for example jumping in reverse punch, but it makes it difficult to move your body forward fast.

C) The stance Sensei Kimura has adopted above in the photo will give you fast transference of recoil to the whole body and it becomes easier to move in fast

You should not forget to keep your balance as this transfers the recoil to your entire body

PULLING OPPOSITE ARM

When you punch with your right fist you should naturally pull your left fist back to you hip, We call this movement HIKITE, it appears to be a subsidiary action when you punch but this is not correct, HIKITE is MORE important than your punching arm movement.

Please put your right fist on the wall and then pull back your left arm back hard, You will find that your right fist will push harder against the wall

There is another way to help you understand , Push your left fist hard on the subject ( Punching Pad ) yoiu are going to punch, push it harder and then suddenly right punch that subject, You will be able to punch very hard because you have pulled your left arm back fast in a RECOIL action off that subject.

The above tests explain to you that there is a relationship between both arm movements, FASTER HIKITE gives you a faster punch and slow Hikite gives you a slower punch.

Please remember, The Impact of the punch, Block, sometimes even the kick will depend on the Strength of Hikite

THE BODY MOVEMENT FOR HIKITE AND PUNCH ARE INTER-RELATED

DROP THE BODY

We have explained to you the relationship of the arms, and this relationship similarly applies to your stances

If someone pushes your head down as illustrated, your body goes down but the force comes back upward

This movement is required to get a stronger impact at the time when you finish your punch

We mentioned before that in your stance your legs help each other, and at this point you should understand that if your front foot is strong then your back leg will also be strong. There is no instance where only your back leg or your front leg is strong, When your front leg is tensed then automatically your back leg will be tensed.

The force in your feet is also inter-related, There are two ways to get body drop

A) showing body drop slanting with the feet moving forward B) showing the body drop perpendicularly

If we compare the two body movements, A) appears stronger and will give the bigger impact

It will be difficult for a person used to doing A) type of drop but with practice you will find the B) type of drop is stronger. A) type of drop can be adapted for some technique but remember B) type is stronger.

It is easy to give an answer to the question "Why do we need body drop"? We have already explained how to get the strongest impact, and maximum acceleration but you don't know yet how to use your weight effectively

A person whose weight is 100 kg. ( 220 Lbs) can punch harder than a person who weighs 40 kg. (88 Lbs) because he can absorb more recoil from the punched sebject, You can't change your weight but you can use it effectively by dropping your centre of gravity

THE HEIGHT OF THE CENTRE OF GRAVITY HAS TO CHANGE DEPENDING ON THE TECHNIQUES.

A higher centre of gravity gives you freer footwork which means you can get easier body movements, A lower centre of gravity gives you more solid position but it is hard to move your body fast, Therefore it is necessary to change your stances from high to low or low to high depending on whether you are going to attack or block.

TRUNKS AND BRANCHES

Most Karate and martial Arts organisations and their instructors start to teach new students how to punch with their fist and how to kick with their feet but we are completely the opposite, We teach how to move the body first and then the fists and feet. It is a logical sequence and you will understand this if you have read the aforementioned theories

The illustrations below show how to move you arm forward without trying

2) Moving your body ( Double hip movement ) until your arm comes up into the punching position

3) keeping the arm on your hip, practice to move your arm forward without any tension by just using your body.

There are two ways to do it, you might have found these already. One is to twist your hip backward and then twist it forward ( Double hip movement ). Another is to move your hip forward diagonally and then twist it forward ( another way of doing the double hip movement )

Both ways have the same theories which depend on reaction to get shock ( banking force in the shoulder ). This is the basis of the punch.

Please remember :- your body moves first, and then your arms follow your body automatically.

To ensure clarity we will repeat this important hip movement again.

A) Is twisting the body forward first and then twisting it forward again, this is more of an attacking movement than a defensive one.

B) Is twisting the body backwards first and then twisting it forward. This will be a defensive movement rather than an attacking movement.

The above two body movements are the foundation of the basic movements

Sometimes you will notice that somebody's movement looks very relaxed but somebody else's movement looks very tense. This relates to their double hip movement. The person who uses the double hip movement looks smooth and relaxed and his blow is strong. The opposite will apply with a single hip movement and the blow will not be strong, This will not apply in every case because everybody has a different build and it will depend on their constitution.

" AFTER HAVING LEARNT HOW IMPORTANT RECOIL IS, PLEASE MAKE SURE YOU USE IT IN EVERY MOVEMENT"

Steve Powell with Hanshi "Chojiro Tani 8th. Dan 1972

Hanshi Tani affectionately used to call Me "Nunchaku Sensei"

A brief summing up in laymen terms

1) RELAXATION, Relaxation is a necessity for the fast contraction of the triceps muscle and for the twisting of the body, as any tension will cause the antagonistic muscle to pull against the forward movement

2) DOUBLE HIP movement is a necessity for the attainment of Grip and Recoil.

3) TRACTION OR GRIP is a necessity for fast forward body motion and for the transference of weight to the target area. for example, we have all seen a fast car stuck in the mud in the movies with the wheels spinning all that power in the car and no TRACTION to use the power, Try pushing a car when your feet are on ice, without the grip it's impossible to force the car forward, no GRIP no forward pressure

4) REACTION OR RECOIL, The recoil will not be there unless you are totally relaxed, the stronger the recoil the stronger the punch will accelerate to the target area, compare the recoil of a pellet gun to that of a magnum. or the drawing back of a bowstring to the distance the arrow goes, byt remember it must be a recoil not merely a drawing back of the arm.

5) ZERO, Means No tension in the arm or body right up to the impact point and then the tension is "Natural Tension" brought about by the "Locking of the joints" and is there only for an instant.

6) CHANGING WEIGHT Is essential for transferring "The whole of the body weight" to the target area. and the weight must be transferred to the forward leg to allow the freedom of the right side to rotate to the target area, back to the car analogy, Try pushing a car with your arms alone, you must bring in the use of your major muscle groups like the hips and back, that is what is being transferred to the target area with recoil.

7) BALANCE. You should not forget to keep your balance as this transfers the recoil to your entire body

8) GRAVITY. When punching down to the solar plexus or spleen area drop the weight to the target area, the assistance of gravity will help you to gain more body weight behind the punch, Example lift a 120 Lbs. weight try to throw it at a target above your head, now throw it to a target on the ground, the second one has more impact because Gravity is doing the work for you.

9) ANGLES. The correct angle of the joints on impact are necessary because they help transfer the shock and impact to the target area

The relationship angle from the shoulders to the arm is 90% and relationship from the floor to the ankle should be 45%, the hips and shoulder has also turned through a 90% angle on their way to the target area, more about this will be discussed in class along with The Interaction of Forces and the Parallelogram of forces, and Kinetic Energy.

10) LOCKING JOINTS, Locking the joints is essential for the transmission of shock from the floor to the fist---. and also for allowing the total body weight to be transmitted the target area, if you just use the triceps to penetrate that's all you will have, but if the locking of the joints is coordinated with the body rotation then the total body rotation will be through the target area with shock impact.

11) BREATHING, Breathing out helps in the contraction of the muscles to produce more explosive power, for example, when a weight lifter groans during the lift, Try lifting a heavy weight and breathing in at the same time.

12) SNAP, Everything is snapped on at the impact time, not just the fist, but the whole of the body is locked at that instant and snapped into the locked joint position

13) IMPACT / TENSION / REACTION. At the impact time the punch should carry enough Kinetic Energy that the shock should travel right through the body and not spread out in all directions, F=M x V2, For example a small crater is seen on the surface of a meteor impact but two miles below the surface all the rocks are broken from the Kinetic Energy, I have personally seen Sensei Shigaru Kimura make 6 pupils stand tightly together in a row the front person holding the pad, and on impact the sixth person at the back of the row flew back because of the transmission of shock "through" the target area, TENSION is the natural tension brought on by the joint locking action, and the REACTION is the shock travelling from the Fist to the Floor and Back up again, that is why the joints have to be locked at the impact time.

STEVE POWELL, 31-3-2002

KICKS

There are many different kinds of kicks in Karate but we will explain mainly the Front kick in this text

A football player kicks similar to a Karate player but their kick is stronger than ours when we both try to kick a football, we will never be able to kick as far, for naturally they practice to kick a ball from the ground and their body movement are more scientific than a karate kick.

After realising the above, we must try to improve our kick to the body ( higher than ground level ). When a football player kicks they pull their hip back once or push one side of their hip forward and then twist the other side forward, This is exactly the same as the double hip movement that we have been explaining. Most kickers are only using a single hip twist while others are using the snap at the knee joint. If you use only the single hip movement there is a limit to your impact and this is not strong.

You can increase your impact tremendously by using the double hip movement.

Continous movement 2 and 3 with kick off from your back foot will give AUTOMATIC LIFTING the knee up movement, The people who can lift their knee up fast are the people who can kick fast.

The leg is much longer and bigger than the arm but it is difficult to move it as fast. It has the advantage of being able to reach further distance.

Kicking is not just a feint to get a better chance to punch but it is a strong individual technique.

Body movement is also the first move in a kick and if you extend your kicking side hip your range will extend about 20cm ( 8 inches )

KICK SHOCK

To make this explanation easier we will call the movement where we kick off the floor "Kick Shock". This method is used not just when we kick but also when you slide or step in. It creates a bigger recoil from the floor therefore your leg moves faster.

Kick Shock isn't separated from hip movement for there is a relationship between them. The first hip movement ( twisting of the body forward or twisting the body back before the second hip movement ) gives you grip and makes the grip Kick Shock.

IMPACT ANGLE

Punches, Kicks, Strikes, and Blocks have a Speed and Direction, we call it VECTOR

"A" Punching Arm, "A1" Effective Force, "A2" Non Effective Force, "T" Target

Basic trigonometry proves that punching 90 degrees against the target gives full effective force into the target

C= b cos o

Cos = o degrees = 1

C = b x 1

C = b

This simple theory applies to all Karate techniques. Following are a few examples which you would normally practice.

Front kick

The force comes from your body and knee snap, But if you don't lift your foot high enough, the kicking angle will be wide.

Kick the target after lifting your foot will have a less angle than the first illustration, but this way of kicking will still not be good enough to give a strong impact because you are only using the length of your leg

You can make the angle narrower by using your hip, In the above illustration it shows a strong impact from extra angle "D" and a narrow angle -0

Lifting the knee up higher than the target in a short distance gives a narrow kicking angle and it will be sufficiently strong, it can be used for a front foot front kick for a counter attack.

Slide or Step for Body Movements and Kick Shock

Normally when you are moving in to an opponent, you would move your front foot first and then bring your back foot up but you can move faster with kick shock

It is difficult to move in when your opponent is watching your moves in free sparring. Kick Shock makes your movement fast enough to gain sufficient distance to deliver you punch

Double hip movement and and kick shock are also inter-related. After repeating it many times you will understand the first twist gives you kick shock, Kick Shock results from the recoil movement

1) Front kick------Use grip then Kick Shock

2) Slide or Step------use kick shock to move your body forward

3) Kick Shock and Punch are at the same time

Strength of Various Stances

Now we'll explain the strength of different stances, Before we mention this, please remember the height of the centre of gravity, It makes all the difference evn with the same stance

Front Stance A

Front Stance B

Back Stance

Cat Stance

X------Resultant Force front leg

X'------ Resultant force back leg

Y------- Total resultant force

A------Driving force

B------Balance ( Vertical Force )

The above illustrations are showing recoil which you get from the floor,

Front Stance A has the most recoil going forward, which means this stance is the easiest to step in forward with your back foot and hold the most recoil from the punched subject.

Front Stance B is not as easy as Front Stance A to step forward

Back Stance has a recoil in the back leg which goes forward, This is a stance that makes it easy to slide forward.

Cat Stance is not suitable for free sparring as a Kamae position, although it is very easy to move back or for the front foot kick,

These Stances are the basic positions, it is not necessary to stand like these for your purposes. Kamae ( Get Ready ) freely to be able to change to the stance which is most suitable for your technique

It is important to have a SPECIALISED TECHNIQUE, Please study these different stances carefully to make your body movement stronger and faster

Body, Hands and Legs

We have sais don't punch with your fist, don't block with your arm and don't kick with the foot, The fist, arm and foot are what actualy hit the opponents body but they need some force to motivate them. Body movement is what is required

The boughs, branches and leaves of a tree start to move when you shake the trunk, White belts are moving branches but not the black belts.

The combinations of techniques are not so difficult, Recoil and double hip movement make them easier and stronger

Grip

when you push down hard on the floor with your foot and toes, You feel as though you are holding the floor hard. We call this action GRIP ( shifting the weight from one foot to the other we call CHANGING WEIGHT )

The related feelings of the impact elements.

IMPACT----SNAP----SHOCK----FIRST TWIST----GRIP

Reverse these

GRIP----SECOND TWIST----BANKING THE FORCE----SNAP----IMPACT

The action on the way to a strong impact is GRIP, and it affects the strength on the impact,

Following are the reasons you need GRIP.

1) To create an axis to make you hip movement smoother and stronger

2) To make one side of your body relaxed--------------If you want to punch with your right arm then your right shoulder must be relaxed, By putting the weight on your left foot it makes it possible

3) Grip Is the first twist of the double hip movement

GRIP----FIRST TWIST----DOUBLE TWIST

To hold the weight the axis must be strong and this tension is gained by gripping the floor hard

ZERO----TENSION----ZERO,

Grip and shock happen in a split second. they are also Z - T - Z

Everything lasts only for an instant, therefore your body must be relaxed before any action.

Reverse Punch

1) First movement is to get grip which means you twist your body to put your weight on your front foot.

2) Second hip movement is to get natural tension in the shoulder ( tame ), your fist come slightly behind your body.

3) Pull your opposite arm back fast and punch at the same time

FIRST TWIST SECOND TWIST

Grip----Propel the belly forward--------Banking force in the shoulder----Punch------Tense the body

Drop the body

Lunge Punch

This is the strongest punch you can deliver because your body can travel a long distance o get to the target, but this is a most difficult opunch to perform because of this reason

How to move the body close to your opponent is the most difficult and most important part of the Lunge Punch

FIRST TWIST SECOND TWIST

Grip--------Propel the body forward------------------banking force in the shoulder----Punch----Tense the body

The front foot moves in many directions when you perform the Lunge Punch but theories for the lunge punch discribed above are the same.

The reason why you movwe your front foot is to control or adjust the distance between you and your oppopnent, but if you are able to perform the punch without moving the front foot, it is much faster.

Front Fist Punch

Two types of front fist punches can be practised,

No. 1) Twisting your hip so the front fist comes back to the side of the body with the first hip movement and the second hip movement gives you shoulder "Shock"

FIRST TWIST SECOND TWIST

Grip,,,,--------Propel the body forward-----------------Banking force in the shoulder----Punch------Tense the body

This type of fist punch is very useful when you use the reverse arm for blocking your opponents blow or when you attack without blocking

No.2) This punch is used only to the face because of the theories which We'll explain below.

FIRST TWIST SECOND TWIST

Grip----Banking force in the shoulder----Punch-------------------------Pulling the fist back

If you look at the above relationship carefully, you'll find that you are punching from just a single hip movement, This is against the theories which we have been explaining. There are always exceptions in any field.

Twist your body like the first twist of the reverse punch and try to get TAME ( Banking the force in the shoulder ) without moving your front fist position. Punch to the head and pull your fist back to the side of of your body immediately, Your hip must come back square when your arm is straightened. Distance of this punch is very short therefore you need terrific acceleration to make this punch strong

V2-V1 A---Acceleration

A= ----------- T---Time between V2 and V1

T V1---First Speed

V2---Second Speed

According to the above formula, shorter delivery time of the fist (T) gives more acceleration with faster finishing speed (V2)

"Acceleration is proportional to the given force and is inversely proportional to its mass"

can't increase the mass of your fist but you can take unnecessary tension form your arm to move it smoothly, "Given Force" in the above rule is a "Banking Force" in the shoulder ( Shock ).