i may be wrong but i think you actually meant that Fa Li should not be done slow/half/speed in your original post
this of course is definitely no.
To Fa Li the Bolang Jin movement of Tailbone Dantian and Spine must be learned, but they can't be learned unless done at full speed, once learned you can do the movement slow.
It's kind of like skateboarding where you learn to jump (called an ollie) with speed. You don't have to be moving, you can learn it while staying in one place but everything (both legs waist upper body arms) all have to learn to move in harmony in one quick motion, or else it won't work. Same with Bolang Jin/ Zhedie.
But note that it's your
own full speed, which is likely to be relatively slow when compared to other experienced people, but faster and faster Fa Li and striking comes with repetitive practice, so don't seek speed, seek accuracy and efficiency of movement.
Speed is also increased in Isometric Standing practice where one is lengthening the muscles and tendons that are holding the speed back within the practitioners own body.
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