Smooth Criminal and the Physics of the 45-Degree Lean

Smooth Criminal was written by Michael Jackson and appeared on Bad (1987). The lyric tells the story of an attack on a woman named Annie, and the repeated line 'Annie, are you OK?' is widely said to have been inspired by the phrase used in CPR training with the Resusci Anne mannequin.

The best-known version of the song on screen is the long segment in the 1988 film Moonwalker, set in a 1930s-style nightclub. Jackson wears a white suit, blue shirt, white fedora and white shoes, and leads a group of dancers through a routine choreographed with Vincent Paterson and Jeffrey Daniel. The single, released in late 1988, reached number seven on the Hot 100 and was a bigger hit in several European countries.

In the lean, Jackson and his dancers tilt forward from the ankles to about 45 degrees with their bodies straight and their heels on the floor, hold the position, and then return upright. For an ordinary person, trying to do this would mean falling over: the body's centre of gravity moves forward past the feet, and the calf muscles and Achilles tendons cannot hold the weight at that angle.

A 2018 paper by neurosurgeons in India, published in the Journal of Neurosurgery: Spine, discussed the move. The authors noted that even trained dancers can typically lean only around 25 to 30 degrees forward, and they used the lean to discuss spinal injuries in dancers attempting extreme moves. It is a rare example of a pop performance being used as a case study in a medical journal.

In the Moonwalker film, the lean was achieved with support cables attached to the dancers' costumes, hidden by the lighting and camera angles. That works for film but not for a live stadium show, where cables are visible and slow to attach.

For the stage, Jackson worked with his costume designers Michael Bush and Dennis Tompkins on a mechanical solution. Each shoe had a V-shaped slot cut into the heel. At the right moment, a peg rose from the stage floor, the dancer slid the heel onto it, and the peg held the shoe down while the body leaned forward. The patent, US 5,255,452, titled 'Method and means for creating anti-gravity illusion', was filed in 1992 and granted in October 1993. Jackson, Bush and Tompkins are listed as inventors.

The lean became a highlight of later tours, including the Dangerous World Tour. Even with the shoes, the move takes strength and control: the peg holds the heel down, but the dancer's legs, core and back have to keep the body straight. There are reports of the move going wrong at least once when a peg failed to engage properly, a reminder that the illusion always carried some risk.

What makes the lean effective is not just the angle. It is the timing: the dancers freeze in normal positions, lean in unison, pause long enough for the audience to register what they are seeing, and then rise again as if nothing has happened.

The lean sums up the Bad era: a street-sharp image built on careful engineering. It is also a good example of how Jackson thought about performance. He was not satisfied with a visual trick that only worked on film; he wanted it to work in front of tens of thousands of people every night, so he found a way to make it happen and patented it.