Simone Biles details her struggle with ‘the twisties.’

TOKYO — With only two days left until the gymnastics apparatus finals begin at the Tokyo Games, Simone Biles still hasn’t announced whether she will compete in them. But she said on Instagram on Friday that she was still struggling with a mental block that gymnasts call “the twisties” that in part prompted her to withdraw from the team final and the all-around.

“Literally can not tell up from down,” she wrote in an Instagram story. “It’s the craziest feeling ever. Not having an inch of control over your body.”

Biles, the four-time Olympic gold medalist, wrote that she “seriously cannot comprehend how to twist,” and noted that this disconnect between her mind and body is scary and has happened before, but only on the vault and floor exercise. “This time it’s literally on every event,” she wrote.

Since backing out of the all-around that teammate Sunisa Lee ended up winning on Thursday, Biles has left the Olympic training venue for a gym in Tokyo that has soft landings, including a foam pit. Taking it easy with training and progressing in little steps as she tries to regain her twisting skills and confidence will be key to her bouncing back to normal, coaches say.

“It’s kind of like going into a slump where you can’t hit the curveball,” said Jess Graba, Lee’s coach. “Sometimes your brain just doesn’t fire right, so it takes time to get back to normal.”

Biles might be running out of time. Her next events are the uneven bars and vault on Sunday, the floor exercise on Monday and the balance beam on Tuesday.

On Instagram, she said there was no telling how soon she could overcome the mental block so that she could regain her ability to sense her body position midair in relation to the ground. She said that she would evaluate herself “day by day, turn by turn,” but that in the past it has taken her two or more weeks to recover.

She said she would not be performing any twisting skills during her post-Olympic gymnastics tour, called the Gold Over America Tour.

Her mental block began, Biles said, on the morning after qualifying — Monday in Tokyo, one day before the team final. The problem became clear during team finals, when the U.S. team was on the vault, its first apparatus of the night, and Biles lost herself in the air, high above the competition floor. She backed out of performing 2½ twists and ended up doing 1½ twists, bounding forward on the floor after her landing.

Afterward, she consulted with her coach and team doctor before removing herself from the finals, leaving her teammates to compete on their own. They won the silver medal, and it was the first time the U.S. team hadn’t won the team event in an Olympics or a world championships since 2010.

Addressing why this phenomenon happens to gymnasts, Biles wrote in a postscript in tiny letters on Instagram that it “could be triggered by stress I hear but I’m also not sure how true that is.”