Sine Wave Motions

Sine wave motion is a movement unique to original Tae Kwon Do to create maximum force in every moment according to the theory of power. In almost every moment this sine wave is utilized. Sine wave is natural and simple, and often I heard an instructor say: "Simple and natural = beautiful".

During class and in seminars Tae Kwon Do practitioners are being taught to use "sine wave" in their techniques.

What we actually do by performing this sine wave in Tae Kwon Do techniques is moving the center of our body mass by means of a motion, which would look like a sinus wave if we would draw it.

There are some key benefits to using sine wave that are linked to the training secrets of Tae Kwon Do. Moving our center of mass in the motion of a sine wave require us to keep our arms and legs bent while the body is in motion. To keep the arms and legs bent during motion we need to be relaxed. Relaxing the body adds speed to a technique because we are not all tensed up with one part of the body working against another. Small increases in speed produce a large increase in the power of a technique.

Secondly, when employing a sine wave we have to use the knee spring properly. That is to say bending the knee is what moves our body up and down as we move forward. Using the knee spring while our body is in motion allows our center of mass to travel along a curve, which by definition is another form of acceleration, which then helps us accelerate into a target.

Finally, when using sine wave we are dropping our body downwards at the end of the technique with helps us use gravity to our advantage and keep our acceleration building until the point of impact.

To correctly apply the sine wave to Tae Kwon Do we need to modify the wave shape before we can achieve maximum power. In other words the sine wave is not a uniform curve as shown in the previous figure. The sine wave is modified so that the body drops as it passes the half way point of the technique, and rises to the maximum height at about the ¾ point and then drops rapidly at the end. The rapid drop at the end of the technique helps accelerate our mass into the target using gravity to our advantage

How much of a sine wave should there be in a Tae Kwon Do technique? The displacement that the center of mass moves from the zero line to get to the bottom and top of the sine wave this is called the amplitude. Using too much sine wave defeats a technique because all the body’s energy and motion would be dedicated to moving along the sine wave rather than accelerating into the target -- (Harry Burke)

Basics of Sine Wave

The basics of sine wave are down up down, in other words there is always a downward motion first, followed by an upward motion, and ending in a downward motion. There is however variations on sine wave, which are related to the motion, combination and speed of the techniques used.

In traditional Tae Kwon Do, the fundamental exercises and the tuls there are five different motions:

• Normal motion
• Continuous motion
• Fast motion
• Connecting motion
• Slow motion

Normal motion (1-1-1)
In saju jirugi, saju makgi and Chon-Ji tul the Tae Kwon Do student learns the normal speed of following movements. This is the first "motion": normal motion. Movements are performed in normal speed, with a complete sine wave in one breath.

Continuous motion (2-2-1)
In Dan-Gun the Tae Kwon Do student learns the second motion: continuous motion. Two movements are consecutively performed, with two sine wave during one breath.

Fast motion (2-2-2)
Do-San teaches the student another motion: fast motion. Two movements are performed consecutively in fast speed, with two sine wave and two breaths.

Connecting motion (2-1-1)
In Yul-Gok there is another new motion: connecting motion. Two movements are performed in one sine wave and one breath.

Slow motion (1-1-2)
Joong-gun completes the fifth and final motion: slow motion. In slow motion the movement is performed slowly, but according to the theory of power there has to be a slight acceleration at the end of the movement. There is one (slow) movement, one sine wave, in one breath. Slow motion techniques are meant to learn the student body control and balance.

These five motions influence the sine wave, of which there are three variations:

• Full sine wave
• 2/3 sine wave
• 1/3 sine wave

Only in normal motion, continuous motion and slow motion there is a full sine wave (down-up-down).

In fast motion there is 2/3 sine wave, as there is only an upward and downward movement. An example is found in do-san tul: the two punches following the apcha busugi. (Movements 15 & 16 and 19 & 20)

In connecting motion there is 1/3 sine wave, as there is only a downward movement. An example is found in yul-gok tul: the punch which follows the second hooking block (movements 16 & 17 and 19 & 20)