Whether on the defensive side or striking side, it is important to have a proper method formation of power followed by the technique’s three phases. The basic formation of power is understood as such:
Power is rooted by the feet, developed by the legs, directed by the hips.
A technique’s three phases are basically: the driving phase, the speed phase, and the impact/kime phase.
The mechanics of the techniques in CMAC Goju Budo are sometimes called forms of kime, or as O’ Sensei termed them, “body dynamics or the methods of formation of power.” There are several different mechanical methods to develop power, such as rotational momentum performed in an expansion of the hips, as with a zenkutsu dachi gedan barai or contraction of the hips as with a zenkutsu dachi gyaku zuki. There is also forward momentum of the whole body as with zenkutsu dachi oi zuki and pendulum motion of the hips as in mae geri kekomi. Lastly there is vibrational and explosive contraction of the abdominal region as in kokutsu dachi shuto. Shifting, rising and dropping motions are also methods of formation of power within Karate Do, but are rarely used in the goju kaishu kata.
Taken from Yakusoku 1
by Williams & Kenny