(with mass kept constant) then the power is increase by a factor of nine ." The sine wave as performed today (diagram 2), is in fact counter-productive in developing speed! If we go back to diagram 1, I feel this has always been practiced to certain degrees before the sine-wave by name, was thrust into the spot light but never referred to as sine-wave. Thus, making the 'new' sine-wave seem like a different concept to original motion, which is now pushed as a different way of movement (diagram 2), so instructors are teaching something different from what they learnt or originally did, when in fact they should be teaching the same! And it is not a natural movement. Rising up as you shift forward & dropping back down is natural, as the legs straighten & bend that way, dropping, rising & dropping again is unnatural & when students try to emulate that, the results are far from good in relation to helping make patterns applicable to self defence. Another major point to note is that General Choi said that when moving forward the shoulders should be half facing, this goes in line with the natural motion of walking, where the hips sway, thus creating another natural motion, the hip twist. Try stepping the length of a walking stance (1 & ? shoulder widths), with your shoulders half facing & hips full facing, it is very uncomfortable & feels very unnatural! Why remove hip twist from natural motions, i.e. moving forward