A lot of techniques in Hapkido have clear derivations from other arts. A lot of our kicks come from either TKD or from a parent art of TKD, while a lot of the hand-techniques seem to be derived from Daito-ryu. The implementation tends to vary a bit from the parent arts and even between schools, but the fundamentals of the techniques look quite similar.
I am, however, curious about the backspinning heel kick. Note the differences between that technique and what we call a backspinning hook kick, which a lot of taekwondo schools refer to as a heel kick (in the heel kick the leg doesn't bend while striking).
Some TKD schools do practice a heel kick like it shows up in HKD, but according to my instructor they borrowed these techniques from HKD rather than the other way around. I do not know if this is true, but I haven't seen it much outside of HKD and since I've been working on the details of this kick recently I figured I'd ask here.
So my question is two part:
- What other arts practice a backspinning heel kick, as distinct from a hook kick?
- Does anyone know the origin–likely or just potential–of this kick in HKD?