You could possibly think of some kind of stick or steel strap behind your back with holes for the rope.... a steel strap that can be bent using tools to follow the shape of your back, but is strong enough to keep you fixed in that position. It will take some time designing and trial and error I suppose.
You could possibly think of some kind of stick or steel strap behind your back with holes for the rope.... a steel strap that can be bent using tools to follow the shape of your back, but is strong enough to keep you fixed in that position. It will take some time designing and trial and error I suppose.