Simone Biles talked about how her mentality towards gymnastics changed before pulling out of the team event

• Simone Biles withdrew from the women's gymnastics team event, citing mental concerns.
• Hours before, Biles said she gets nervous doing her skills, fearing something going wrong.
• Biles said on Tuesday that she felt anxious about the tremendous expectations placed on her.

Simone Biles withdrew from the women's gymnastics team event, citing mental health concerns.

Biles first left the floor with a trainer before it was announced that she had pulled out of the event.

Afterward, Biles said she was mentally "not there," and that she had been anxious and stressed throughout the week.

In an interview with NBC that aired Monday night, hours before the gymnastics team event, Biles said that, at age 24, she had begun to get nervous about her skills.

"I'm a little bit more scared of my skills now," Biles said. "Because whenever I was younger, I was pretty fearless. But now I'm just like, 'Okay, I'm getting older. This could go wrong, this could go wrong, that could do this.' And so, that kind of scares me a little bit."

Biles' brief appearance in the team event raised questions about whether she had been injured. She bailed on her vault attempt, scoring just a 13.766.

After the team event, in which the U.S. won silver, Biles told reporters that she doesn't "trust" herself as much as she used to.

"I just don't trust myself as much as I used to," Biles said. "And I don't know if it's age - I'm a little bit more nervous when I do gymnastics. I feel like I'm also not having as much fun, and I know that."

In the interview with NBC, Biles also said years of gymnastics had started to take a toll on her body.

"Just getting up every day and going back to the gym, it's just like, something always hurts. You always have aches and pains."

Biles' recent run of events hasn't been her strongest. On Day 2 of the Olympic trials in June, she fell on the balance beam and finished second to teammate Sunisa Lee.

In Olympic qualifications, Biles stepped out of bounds during her floor routine, finishing in second place. She still finished first in the all-around, however, to make the final.

In the lead-up to the Tokyo Olympics, Biles had made it clear she felt the pressure of being considered the greatest gymnast of all time, one expected to do things no one else has done.

On Monday, Biles had posted an Instagram, writing that she felt like she had "the weight of the world on my shoulders."

She told reporters on Tuesday that she had been in her own head about trying to meet expectations.

"It does suck when you do feel the weight of the world, and you feel like there are no outlets for the amount of training that we do," Biles said. "We were totally prepared, but it just sucks when you're fighting with your own head. Like, you want to do it for yourself, but you're still too worried about what everybody else is going to say on the internet and stuff sometimes. So I just had to stay off of it for the past couple days."