'Simone is a very, very rare bird': Experts discuss the science behind Simone Biles' gymnastic prowess

With eight Olympic medals and 30 World Championship medals under her belt — and potentially more to come soon — U.S. gymnast Simone Biles is considered one of the greatest gymnasts of all time. 

So what's the science behind her success? 

There's a certain "X factor" that Gina Pongetti, a former gymnast and physical therapist who is treating athletes at the 2024 Paris Olympics, calls "Simone being Simone." Beyond that, the answer lies in Biles' dedicated training of her neuromuscular system — everything from the ribbon of tissue that traverses the frontal lobe in the brain and controls movement to the sensory receptors that provide feedback to the muscles themselves. 

"To be an elite athlete is one level," Pongetti told Live Science. "To step up to Simone's level involves an absolute keen understanding of her body and the input signals that come to it." 

Biles stands out from other gymnasts both in terms of how she senses her body in space and how she hones her muscle memory, "as well as [her] having one of the most phenomenal bases of strength and conditioning that I've ever seen in an athlete," Pongetti added.

Related: Will Olympic athletes ever stop breaking records?

Proprioception to perfection 

Biles started gymnastics at 6 years old. A youthful start is common among elite gymnasts; growing brains are adept at taking in information, said Dr. David Neuman, a fellow of the American Academy of Orthopedic Surgery and clinical director NY Sportscare in Manhattan. And that early practice, he told Live Science, often provides a basis for later adeptness.