This Guest Post is by Mario McKenna of the Okinawa Karatedo Kitsilano Dojo in Vancouver, British Columbia, Canada. Mario is an instructor of Tou'on-ryu Karatedo and Ryukyu Kobudo. He is the English translator of Kobo Jizai Goshinjutsu Karate Kenpo (Kenwa Mabuni, 1934) and Seipai no Kenkyu Kobo Jizai Karate Kenpo (Kenwa Mabuni, 1934). His excellent article Okinawa Kata Classification: An Historical Overview appears at the Hawaii Karate Seinenkai website. Mario also has a Karate Blog.
Rotation of the koshi (torso/pelvis) is important to the generation of power in general. The whipping of the hips is another matter and has to be approached with a lot of caution. Certain techniques/kata in Goju-ryu lend themselves very well to this type of motion such as Seipai. To this list I would also add Kururunfa. However, I have seen many practitioners do these kata with no connection between the whipping motion of the hips and the resulting technique. It seems quite empty and wasteful.
Another observation that I have with this whipping motion is that it appears to be done from a stationary position, which is not always possible when fighting someone. In this case I feel non telegraphed whole body movement is superior in some instances - at least for me. This is not to say that I do not do these whipping motions, but just that I am very conservative about when and how I do them and how I impart them to my students. Just my 2 yens worth of ideas.
Heading back to the kotatsu and my cup of ocha....