You don't have to spin your body. You can do the
- side kick instead of turning back kick.
- hook kick instead of turning hook kick.
This way, you don't have to worry about your opponent from moving in when your body is spinning while standing on 1 leg.
I have come into the habit to have a special technique focus for myself on each heavy bag session [when I am alone with the heavy bag - no instructor around] it's much better than spreading the time of doing just a little bit of everything. Last time I focused on improving the SPEED in my ushiro mawashi geri. I then practiced the hook kick separately first, and one conclusion is that at least for me the plain hook kick is WEAK. I'd say it's only use against a tought conditioned opponent is to the head, or as a distraction.
When I add the spin, I get significantly power power, and it definitly has potential against ribs or the buttock nerve kicks. My hunch is that MOST of the energy comes from the spin, only a small part is from the hook.
So far I have mainly practiced the wheel kick version, as it is gives slightly more energy, but is significantly slower. I notice that it is often spotted in sparring. I managed now to improv the more proper spinning hook by thinking that I twist the upperbody first, insted of thinking that I rev up by leg as a bat. I had trouble with that in the past, but now I am finally improving. I noticed that while I often trained the power wheel kick in the heavy bag, I spontaneously used the faster spinning hook in fighting every now and then and surprised both myself and the opponent (that are used to my slower wheels kicks), and i often got good hits with it. And I couldn't figure out why I had trouble with it on the bad, but that it comes without thinking in flow of kumite but during my last heavybag session I got a new insight., and now see the difference
it was so englightning when I found the natural motion on the body that makes this happen by itself, instead of forcing it. And i look forward to testing this more in kumite.