How MJ Defied Gravity: The Secret to 'Smooth Criminal'

June 27, 2009— -- He was Michael Jackson. He could do anything.

So when fans saw him do the impossible on the dance floor, they never thought he had help.

But when the King of Pop and his dancers leaned at a gravity-defying 45 degrees in live performances of the 1987 hit "Smooth Criminal," it was a secret gimmick -- not super-human talent -- that made it all possible.

A patent filed with the U.S. Patent and Trademark Office in June 1992 lays it all out.

Naming Jackson, Michael L. Bush and Dennis Tompkins as the inventors, the patent describes 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."

That's a complicated way of saying the dancers' shoes had heels with slots that can hitch onto pegs that protruded from the stage at predetermined times. The pegs retracted back into the stage after the move was executed so as not to impede the performers.

"Music entertainers and dancers are constantly searching for new and interesting elements which can be incorporated into their musical and dance performances," the patent reads. "Interesting stage design, lighting, fog generators, laser light shows and large video screens all enhance the appealability of live and recorded performances."

"Many popular music and dance entertainers expend great effort in enhancing and choreographing their performances and dancing," the patent document says.

The tech blog BoingBoing pointed out the patent Thursday. To see a full pdf of the patent, click here. To watch a YouTube clip of a live performance of the song, click here.