Ch'ang H'on, with sine wave. However, I disagree with the above explanation, although I know where it came from and how it came about. When Gen. Choi was still alive and teaching seminars, he tried to get people to move in a natural motion. At several seminars (including both those I was at and some I only heard about), Gen. Choi was trying to get people to not move straight-legged, and kept telling people to bend their knees, emphasizing the concept of "down-up-down". The junior BBs stood there nodding and not changing anything, while the seniors kept dropping lower and lower as they moved... thus, exaggerated sine wave as the excessive motion described above was born, with people who were trying to follow the directions of a frustrated instructor with a heavy accent and difficulty conveying his desires verbally.
Done correctly, sine wave is a very natural motion, and much less emphasized than it is in some places. When you move, naturally, your head will move up and down slightly; watch yourself walk in a mirror, or tape yourself, or watch other walk naturally - then compare it to someone walking completely straight-legged, and you'll see what I mean. The "down" portion at the beginning is the natural slight drop your body makes as you bend your knees when stepping; the "up" portion is the natural rise your body makes as you step; the second "down" portion is the natural drop your body makes as you land in stance. Look at the attached picture and see if it helps (it might not; computer drawing is not my strong point).
As far as using your body weight goes - that was an explanation added to the above as an attempt to justify the weight drop that came from the previously described situation. Gravity is not sufficient to add power - and trying to time things so that it will slows your techniques considerably.
) styles, basically.
