Michael Jackson's gravity-defying 45-degree forward tilt was a combination of a stage trick and the pop legend's physical ability, scientists say.
The "mind-boggling" dance move, first seen in the 1987 Smooth Criminal video, was a clever illusion invented by the pop star.
Fans were amazed to see him repeat the feat live - and were completely fooled.
A team of three neurosurgeons wrote in the Journal of Neurosurgery: Spine: "Several MJ fans, including the authors, have tried to copy this move and failed, often injuring themselves in their endeavours."
A patent registered under Jackson's name reveals how the trick was achieved.
The pop legend designed a special shoe with a triangular slot in the heel which hooked onto a metallic peg that emerged from the stage floor at just the right moment.
This allowed Jackson to lean forward at a seemingly impossible angle without collapsing in an undignified heap.
The scientists were led by long-time Jackson fan Nishant Yagnick, from the Postgraduate Institute of Medical Education and Research in Chandigarh, India.
In their journal article they explain how most trained dancers with strong core strength can achieve no more than 25 to 30 degrees of forward tilt.
During the move, strain is shifted from the erector spinae muscles that support the spinal column to the Achilles tendon.
The researchers wrote: "This allows for a very limited degree of forward bending from the ankle joints, while keeping a stiff straight posture - unless you are Michael Jackson.
"MJ pulled off a gravity-defying 45-degree move that seems unearthly to any witness."
The authors stressed that despite the illusion, Jackson's physical abilities were nonetheless impressive.
They wrote: "Even with specially designed footwear and the support of the hitch member, the move is incredibly hard to pull off, requiring athletic core strength from strengthened spinal muscles and lower-limb anti-gravity muscles.
"Trick or not, new forms of dancing inspired by MJ have begun to challenge our understanding of the modes and mechanisms of spinal injury.
"Ever since MJ entertained us with his fabulous moves, throughout the world dancers have tried to jump higher, stretch farther, and turn faster than ever before."
© PAA 2018
Image: In this Feb. 24, 1988, file photo Michael Jackson leans, points, sings, dances and struts during the opening performance of his 13-city U.S. tour in Kansas City. (AP Photo/Cliff Schiappa, File)