The Physics in Tai Chi Chuan

From the very beginning in my training I can remember words of my Sifu that still echo in my mind, "you canít disobey laws of physics, the body can only effectively do one thing at a time". Sifu Roman Czerniawsky mentions physics and body mechanics a number of times when teaching the principles of Tai Chi Chuan. It was through Sifuís teachings from drawing parallels to the principles of Tai Chi Chun and the Laws of Physics I started my own investigations, using my Tai Chi Chuan and knowledge Iíve gathered in physics. In 1991, I graduated from the University of Wollongong and successfully completed a Bachelor of Science, double majoring in physics. My physics background did help in some ways, but as my Tai Chi Chuan grew so did my understandings of physics. Putting laws, principles into practice, as Tai Chi Chuan does, really tested on a practical level a lot of what I have been theorizing and learning from Sifu Roman.

How can physics, a western science, be related to Tai Chi Chuan? The answer lies in the understanding that the body is a living machine. All machines must obey the laws of physics; otherwise it will break down and wonít function.

In this article I hope to raise awareness of how closely related the physics laws are to the classics and principles of Tai Chi Chuan, and how this awareness may help in our training. I have used some mathematical equations in my explanations to add to the meaning of the law or principle.

Lets start with Sir Isaac Newton and his laws of motion, which he developed from the theories of other great scientists before him, such as Galileo Galilee.

Newtonís Three Laws of Motion are as follows.

  1. A body at rest, will stay at rest or if in motion will continue in uniform motion in a straight line, unless acted upon by an external force.
  2. The acceleration produced in a mass by the addition of a given force is directly proportional to the force and inversely proportional to the mass.
  3. When a force is exerted onto a body, the body will exert an equal and opposite force. Or put simply, "To every action there is an equal an opposite reaction".

After reading what may seem to be simple statements, they contain like the classics in Tai Chi Chuan, great meaning when put into application.

I would now like to share an example of the use of the first law in martial practice. I will analyse a quote commonly used by Sifu.

"The body can only effectively
 do one thing at a time".

If somebody throws a punch to your head, once a person throws out that punch, they have committed the 1st law. A body, opponentís arm, will continue to move in a straight line motion, going right for my head, unless I meet it with an external force. The only way to stop this punch is with an external force or the opponent stopping it with a counter force within his body. If they want to try another punch they must use a force to re adjust and then they can send out another punch. While the opponent is doing this readjusting, a skilled Tai Chi Chuan player listens, seizes the opportunity and neutralizes the opponent. Another way of stating this is that you seize the opportunity while the opponent is in a state of emptiness. This is the moment when the opponent is doing the readjusting of movement or balance.

Question. What happens if the opponent throws out a kick and a punch at the same time at you, is the quote wrong then?

Answer. No, the word "effectively", should not be over looked in the quote above. The punch and kickís energy have been divided and if the person is concentrating on landing them at the same, they will have little impact on a personís body.

Now lets compare one of the classics with the laws of physics.

  • You need only four ounces of force to move a thousand pound force.

I will illustrate this by using right - angled triangles, a little mathematics, and show quantitatively how small the force is, that is, needed to deflect the punch from its original point of origin.

The attackerís, body and punch, which are directed to defenderís head, travel a distance of 95cm. The defender then joins with this force and directs it 2 cm at arms length, which is enough to deflect it away from the defenders head.

Note: - speed of punch = 23.6 m/s (approximately 85km/h) over a distance of 95cm.

Mass of punch = 70kg.

The speed was worked out using light gates, data logging equipment, and computer analysis. I threw a punch, cutting the light beam at the first gate; this started an internal timer within the data logger. Then when my fist cut the light beam at the second gate the data logger stops timing and records the results. It calculates time of travel and takes in account of the distance and then works out speed of my punch. I weigh about 90 kg so I estimated the weight behind my punch from weight transfer from one bubbling well to the other. I estimated around 70 kg.

The 2nd Law is just a description how an object with mass (m) when it accelerates (a), (starts and then finishes or changes its speed), exerts a force (F). A mathematical formula can be established: -

F = ma

Force = mass multiplied by acceleration

The forces in a punch and deflection were calculated, by considering total moving mass and the acceleration (calculated electronically by the data logger).

From the example above of an attacker punching to a defenderís head a deflecting angle of approximately1.2 degrees was calculated. The initial force was calculated at

20519 N and the deflecting force were calculated at 430 N.

The classicís say that an initial force of 1000 pounds can be taken off with 4 ounces. This converted into kilograms is as follows;

1000 lbs = 408 kg

4 ounces = 0.122 kg

Iíve converted the force calculations of the initial punch and deflection into kilogram amounts, by dividing with the force due to gravity (9.8m/s/s) then stated them below;

20519 N = 2094 kg

430 N = 44 Kg

Now lets compare the two by Ratio

Tai Chi Chuan Classics

Physics Calculation

Initial Force to deflection force

Initial Force to deflection force

408kg to 0.122kg

2094 to 44kg

3344kg to 1 kg

48 kg to 1kg

From the results above we can see that the physics calculation does give a significant reduction in the amount of force required to deflect a punch, as it takes a 1kg force to deflect a 48 kg force. But comparatively it doesnít come anywhere near the statement from the classics of a 1kg force deflecting a 3344 kg force. Why such a large discrepancy?

Well one major factor that is not considered into this is Chi. I have purely analyse the event from a totally mechanical external point of view. The human body is a highly sophisticated chemical and electrical bio Ėmechanical machine. It would be very hard to accurately assess factors and beyond my capabilities. If anybody has seen any articles or know of any research please feel free to contact me.

I do find it interesting that moving the body on an external level in the manner above you can gain some mechanical advantage.

From training with certain people who understand how to adhere to correct internal body alignments I have witness some remarkable martial feats. Considering their age and the size of the students they were effortlessly moving around showed clearly they were not using hard muscle force. So I feel our advantage as Tai Chi Chuan practitioners is not only correct body movement but also the use of correct internal body alignments to facilitate the flow of chi.

I think this raises an important issue in terms of the health aspects. Anyone can gain short term health benefits from waving their arms in the air and moving in a few months. But the long term health benefits will not show themselves if students are on the right path of chi development. Tai Chi Chuan is an Art that requires diligent study in its many areas and itís very important when you begin your practice to be aware of structure, external and internal alignments. Because without correct movement and balance how can you be balanced on a physical and mental level.

The last law I wish to analyse and share my insights with you all is Newtonís third law, and anatomic nerve system.

Generally, if we feel a force, most people react against that force with equal or with more force out of revenge or fear. Sifu once told me about the people that Tai Chi Chuan practitioners cannot defeat and that is, "men of iron, men of stone, men of wood". As these types of men, donít have this anatomic nerve system.

Lets analyse the action of Newtonís 3rd law and the anatomic nerve system. One of the classic examples that I have witnessed and used myself is that which was shown to me by Sifu, when explaining how to interrupt a personís movement and balance. I should explain before I begin, that as a general rule Tai Chi Chuan practitioners donít initiate the first movement, as a skill Tai Chi Chuan player will take advantage of the situation. This is just a teaching tool, used for demonstration purposes. First, you hold a students arm as in lift hands and if you want to make them go backwards you give a gentle pull forward. studentís anatomic nerve system sends a message to the brain telling it that the body is moving forward. The student then moves to counteract this and will resist pulling his/her arm backwards. This is where you are listening to all this movement the student is doing and then as the student resists, pulling his arm back you seize the moment and push his arm back through his center and the student will move backwards. For added fun you can even tell the student you are going to make him go backwards and there will be little he/she can do about it.

Using Newtonís 3rd law we can examine the motion from physics point of view. First you supply a force by pulling the student ever so gentle forward, he/she resists and uses an opposite force, usually far greater from being to reactive in movement, and then as a Tai Chi Chuan player we take advantage of this movement. If you give a gentle push backward the student will react and move his/her arm forward and you can pull the student down. I am sure you are now thinking of other examples where this type of strategy can be put into place; donít think as after a while this will all come naturally to you.

Even though I am analyzing movements I am doing them from a scientific point of view in explaining the Physics in Tai Chi Chuan. Remember thinking, over analyzing can result in not seizing the moment. Relax, train diligently, and seek out the correct alignments so your chi will flow uninhibited and after a while things will become second nature and your body will be aware and just move.

Take Care
Yours Sincerely Darren Cox Sifu
Australian Tai Chi Chuan Li Chi Hsiang School of Health and Self Defence.

Tao moves in cycles;
Tao functions through softness,
All is born of something;
Something is born of nothing.

Tao Te Ching


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