Vertical (Sine) Wave and Horizontal Wave

[Sanko]

When we look at the sine wave motion in its typically down-up-down
form, we can identify it as a vertical sine wave. With vertical I mean
that the wave oscillates on the Y-axis, moving up and down. This
motion is usually used in order to drop body weight onto the technique
and works excellent for techniques with a slight or strong downward
angle like a middle section punch and a knife hand downward strike.
This sine wave motion can also be used in an upward direction; for
example, when one does a forearm rising block you move from a relaxed
position to an upward position. The final drop of the typical down-up-
down motion is omitted as it will act contrary to the direction of the
upward technique. The (vertical) sine wave motion is therefore
employed for techniques where the force of the technique moves either
up or down.


The sine wave can also occur horizontally; in other words, the wave
oscillates on the X-axis. Usually when we talk about this type of sine
wave, we refer to hip rotation or hip twist. Typically the hip is
pulled back slightly and then jerked in the direction that the
blocking or attacking tool needs to travel. Hip rotation is often part
of a whip-like action where the different parts of the body are
uncoiled to create kinetic chaining. Techniques that benefit from a
horizontal wave typically move horizontally, for instance a back fist
strike or a knife-hand side strike.


Do we combine (vertical) sine wave motion with hip rotation? Yes and
no. It depends on the technique. A technique like a wedging block that
uses two forearms moving horizontally in opposite directions do not
use hip rotation because it is impossible to rotate your hips both
left and right to accommodate both arms. For a wedging block we only
use vertical sine wave motion. The forearm rising block is also a good
example where the main force of the technique goes up; for this
technique a horizontal wave, in other words hip rotation, is
downplayed.


There are techniques where the main angle of the technique goes
forward and downward and can therefore benefit from both the forward
hip rotation as well as body dropping through the sine wave motion. A
clear example would be a diagonal downward elbow strike (as seen the
pattern Juche) or even just a forward stepping middle front punch. The
middle front punch reaches its target in a slight downward angle.
Another example is the low forearm block, which moves both downward
and to the side.


Actually, the simple rotation of the fist during punching is in fact
the combination of a vertical and horizontal sine wave. The rotation
plus forward motion creates a spiral or helix, which can be described
mathematically as the combination of a vertical and horizontal sine
wave. These types of combined vertical and horizontal wave forms can
often be seen in ITF Taekwon-Do by the trained eye.


The important thing is to understand the direction of the forces
created by these waves and also the force directions required by the
various techniques you are using. Certain techniques benefit more from
a vertical sine wave, in other words the typical sine wave motion,
while other techniques benefit more a horizontal sine wave, in other
words from hip rotation. Using or putting emphasis on the wrong wave
form should be avoided as it may nullify the power of your technique.
Also, different parts of the wave benefits different techniques. One
should not drop your body weight at the end of a rising block, nor
should you raise your body at the end of a low block. Similarly the
hip should rotate towards the target, not away from it.


Learning how to use the different wave forms is crucial in mastering
ITF Taekwon-Do.