TOKYO – The name is almost cute – the “twisties” – offering little sense of the confidence-shattering danger it can bring for a gymnast.

But what they are and what they mean has become relevant globally and known outside the sport after Simone Biles pulled out of the Olympic team and all-around competitions here because of mental health concerns.

Biles came to Tokyo with expectations of winning five gold medals, but the prospect of her going home with any is very much in doubt. Biles balked at a vault during the team final, bailing on her Amanar mid-air. One of the most difficult vaults that women do, Biles dropped out of the air a rotation short and barely landed on her feet.

“It's not worth getting hurt over something so silly, even though it's so big. It's the Olympic Games,” Biles said. “But at the end of the day, it's like we want to walk out of here, not be dragged out here on the stretcher or anything. So I’ve got to do what's best for me.”

What are the “twisties?”

Gymnasts hone a sense of air awareness over years, and by the time they reach elite-level gymnastics, they have the muscle memory to complete a skill that matches what they are seeing during it. But when someone gets the twisties, they disconnect.

“The rhythm is off, and your brain will like stutter step for half a second, and that's enough to throw off the whole skill,” 2016 Olympic gold medalist Laurie Hernandez told Olympics.com.

A judge who spoke with GymCastic co-host Kensley Behel compared it to a baseball player with the yips or a golfer shanking the ball.

“Having the ‘twisties’ means that her inner gyroscope which gives her the cat-like ability to land on her feet isn’t working quite right,” Behel tweeted. “When a golf player experiences the shanks, their ball goes flying off out of control in wonky directions. In Simone’s case, her body is the equivalent of the ball. If she can’t determine which way is up while flipping and twisting in the air, it can have catastrophic results.”

What’s the harm?

Quite simply, the “twisties” could lead to catastrophic outcomes.

Take Biles’ vault in the team final here. An Amanar requires her to do 2½ twists in the air. In podium training, she did two Yurchenko double pikes. The vault requires her to do a roundoff onto the takeoff board and a back handspring onto the table before doing a double somersault with her body in a piked position.

If Biles did that vault and lost where she was in the air – like with the “twisties” – she could easily land on her head or neck.

“In our sport, we essentially dive into a pool w/ no water,” 1996 gold medalist Dominique Moceanu tweeted. “When you lose your ability to find the ground—which appears to be part of @Simone_Biles decision—-the consequences can be catastrophic. She made the right decision for the team & herself.

What are the lasting effects?

Aside from the physically disorienting part of the “twisties,” they can break an athlete’s confidence. Skills they could once do easily are now difficult. Their inability to do them snowballs as they question their ability in the sport.

Biles said that she was having breakdowns in 2019.

“I forgot how to twist and flip,” she told Olympics.com in early 2020. “It wasn’t great.”

How can gymnasts get over them?

Perhaps the easiest way is to recalibrate in a safe environment. In their home gyms or training camps, gymnasts learn new skills into a foam pit or using a harness. It gives them a chance to learn the skill without risking injury on a hard surface.

Those tools can help reset from having the “twisties,” but they are not standard in training or competition venues at an Olympics.

This article originally appeared on USA TODAY: Simone Biles: How twisties are impacting gymnastics at Tokyo Olympics