In order to accomplish his famous forward lean, Michael Jackson invented a special shoe that had a slotted heel which slid onto bolts that protruded from the floor, essentially creating a dovetail joint between the dancer and the stage.
Along with two co-inventors, he patented the shoes in 1993. The abstract reads…
A system for allowing a shoe wearer to lean forwardly beyond his center of gravity by virtue of wearing a specially designed pair of shoes which will engage with a hitch member movably projectable through a stage surface. The shoes have a specially designed heel slot which can be detachably engaged with the hitch member by simply sliding the shoe wearer’s foot forward, thereby engaging with the hitch member.
Here are a few images from the patent…
