Rha
"but soft mud dramatically reduces the force of friction and it is this force that is being used to create the 'pull' and the 'push' on the dance floor."
Of course friction is reduced in soft mud - that's why i'm using it in the experiment. The foot will move in soft mud, and as one who has run in soft mud countless times, it's clear that it slips forward every time - proving that there is no force back towards the body but, if anything away from it.
Dave - if you really want to excel, don't try to do something that you don't do naturally when you're walking or running - it will make your dancing un-natural. And certainly never 'slap' your foot down. When the heel lands and the knee absorbs the forward momentum, the foot could easily slap down, but you must control this to make your dancing soft and smooth.
We're all learning