by
Erik Oosterwal
Tae Kwon Do, like other martial arts, applies the priciples of physics to
allow the human body to accomplish incredible feats. We will discuss how
the principles of physics relate to the various blocks, kicks, and strikes
used in Tae Kwon Do. Along with the discussion of physics, we must also examine
what movements can be done by an average human body without causing damage
to the person performaing the move, while still getting strength and speed
from physics.
This book is intended for anyone who has had some professional training in
a martial art and is familiar in the proper techniques of blocking, kicking,
and striking. This book will not try to instruct how to perform these techniques,
but will give pointers to increase the force of the techniques by using the
principles of physics, and using the mechanical motions of the body as they
are intended.
The first chapter of the book introduces the basic principles of physics
that will be used to describe how to increase the effectiveness of your
techniques.
The second chapter describes how your muscles and skeleton work together
to produce various motions, and the limits of those motions.
The remaining chapters each describe one block, kick or strike, and give
pointers to increase their effectiveness by using the information provided
in the first two chapters.
The apendices provide reference information to show how you can safely measure
the force of your techniques, the amount of force required to break boards
and concrete tiles, and methods for increasing flexibility, reflexes, and
aim.
While the book only talks about Tae Kwon Do, due to the author's familiarity
with that art, the principles are equally suitable for Karate, Judo, Jujutsu,
Aikido, Hapkido, Boxing, Kick Boxing, Kung Fu, Bando, and Wrestling as well
as the hundreds of other styles and substyles of combat techniques. To
gain maximum effect in your own style, use the pointers provided in the first
two chapters and apply them to your specific fighting style.
The most important thing you need to know about physics with regards to Tae Kwon Do is this simple formula:
What it means is that the amount of force you get is equal to the mass of
whatever you're punching or kicking with multiplied by the acceleration of
that hand or foot. My teacher, Master Tomasi, used to say, "Power equals
weight times speed." That's not technically the same thing, but close
enough for what we're talking about and it makes it a bit easier to picture.
The power of your punch or kick depends on the weight behind your hand
or foot and how fast you can get them moving.
To understand what I'm talking about, picture using a hammer to pound in
a nail. If you use a very small hammer, you either have to hit the
nail a whole bunch of times or you need to swing it really hard. A
small hammer has a small mass, so in order to get the nail into the board,
you have to swing it very fast. If you use a heavy hammer, even small
taps seem to drive the nail into the board. The heavy hammer has a
lot more mass, so to get the same amount of force you had with the small
hammer, you don't have to swing it as hard.
To relate this back to Tae Kwon Do, picture your hand or foot as being the
hammer; to increase your force you either have to increase the mass of your
hand or foot, or you have to increase the speed of your punch or kick. To
increase the mass of your hand or foot, the only thing you can do is wear
heavier shoes, or put something in your hand. For a martial arts
competition this would not be allowed, but for real world defense, wearing
heavy boots or picking up a rock or book would definately increase the force
of your punch, kick or block by increasing mass.
Acceleration is the tricky part of the equation. Strictly speaking,
acceleration is how much your velocity changes over some length of time and
is figured out using this equation:
This means that your acceleration will be your ending velocity minus your
starting velocity divided by the time between them. For instance, as
you're driving down the highway you happen to look down at the speedometer
and see that you're driving 55 mph. Exactly one second later you check
your speed again and see that you're still driving 55 mph. According to our
formula, that means that our acceleration is (55 mph - 55 mph) / 1 second,
or 0 miles / hour / second. A constant velocity always means that you
have 0 acceleration. When you're stopped at a traffic light in your
car and the light changes from red to green, you step on the gas pedal and
your car starts to move. If you have a fast car and you step hard on
the gas pedal, your velocity changes quickly and you feel the car seat pushing
into your back. In the first second, you may go from 0 mph to 5 mph
which means that you accellerated for 1 second at an average acceleration
of 5 miles / hour / second.
The reason that sometimes seems confusing is because in real life you know
that you can swing a hammer at a constant speed and do a lot of damage to
a nail and board. If our formulas are correct, then a constant speed
would mean 0 acceleration, which would in turn mean that there's 0 force,
and that just doesn't seem right. The trick is to realize that there
is a change in speed. If you're swinging a 5 pound hammer at
1 mph just before you hit the nail, and the nail stops the hammer over a
period of 0.1 seconds as it sinks into the board, then your change in velocity
is (0 mph - 1 mph), and your acceleration is (0 mph - 1 mph) / 0.1 seconds,
or -10 miles / hour / second. The force that the nail and board absorb
is 50 lb miles / hour / second, or more specifically 22.35 Newtons.
The bottom line is that you don't have to increase the speed of your punch during the whole punch, you just have to get it going as fast as you can before your arm is completely extended.
Copyright Erik Oosterwal - 1996 - 2004
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