I have studied Taekwondo Chung Do Kwan for about 13 years. We usually generate power by twisting the hips into the technique. I recently began studying at an ITF school where the sine wave is also incorporated as part of generating power and is supposed to be a natural motion of the body. I think the ITF's theory of the sign wave is a little over exaggerated when compared to natural movement. From a traditional point of view does the sine wave add power or does it slow the body down and leave you more vulnerable to a counter attack?xx
I started Taekwondo in the 1960’s, studying from an ROK (Republic of Korea) Marine. The sine wave was never mentioned and I never saw it used. In fact, we were taught that, while moving, the belt knot should move in the direction of the movement but should not move up or down.
I purchased the first edition of General Choi Hong Hi’s book on Taekwondo in 1970 and it does not mention the sine wave. In face, none of the early books by Taekwondo masters, such as Richard Chun, Joon Ree, etc., ever mentioned a sine wave movement. Apparently Choi and his instructors came up with the sine wave, heel drop, and knee snap concepts on their own.
The World Taekwondo Federation does not use the sine wave and many, if not most, of the other Taekwondo associations around the world do not use it. The sine wave is not a natural movement, it adds unnecessary movements to any technique, and as such, it follows that it must slow a technique, and it does not add any effective power to a technique. Runners don’t bob up and down and we don’t bob up and down when we walk. Animals don’t bob either. For example, when a cat or dog is moving, its spine stays in straight, level line.
In Taekwondo America schools, we teach students to punch and kick with speed and power using smooth techniques that flow with the natural movements of the body. When we see an opportunity to punch, the first movement is the fist moving toward the target, then the hips snap that side of the body into the punch, and the rear leg pushes against the floor to add maximum power to the punch. There is no extraneous up or down movement.
Some people, in an effort to be different, come up with all kinds of strange ideas, and, if their students follow the odd ideas without question, then the ideas get pasted on through the generations.
The sine wave theory appears to be just smoke and mirrors with no scientific or physiological basis. When evaluating any odd concept of attaining power, I find it best to look to the professionals who fight for a living, such as boxers or UFC fighters, or to street fighters who fight to stay alive. If the concept really worked, they would certainly use it.
If you train in a specific style, you have to do things their way; at least during class or when performing patterns. But when you spar, you don’t have to use the useless methods. The problem is that, when you train in a useless method, over time, it permeates your sparring and you suffer because of it.
Keep up your skepticism. Fools are seldom skeptics and skeptics are seldom fooled.