Olympic all-around champion Simone Biles said the gymnast she most wants to beat in Tokyo is herself and that she is excited about trying things in the sport that were once "unimaginable".
The 24-year-old has won a record 25 world championship medals, 19 of which are gold, and has won every all-around competition she has contested since 2013.
She won four gold medals, and a bronze, at the Rio Games and is fully expected to add to that tally this year.
"I'm trying to be better than I was at the last meet, so I'm trying to beat myself," Biles told NBC television.
"And so now I'm doing things that were unimaginable to the sport, and even for myself, and it's honestly crazy but I'm really excited because I feel like I've pushed my limits."
Earlier this year Biles became the first woman to land a Yurchenko double-pike vault in competition.
Biles, who over the weekend confessed to being bored as she moved from her hotel room to practices under strict coronavirus protocols, on Monday posted a triumphant photo showing her and a teammate in front of a wall at the athletes village in Tokyo.
USA Gymnastics said in a statement on Monday that an alternate on the star-studded women's gymnastics team had tested positive for COVID-19 in an Olympic training camp in Japan while another alternate was placed into isolation because of contact tracing.
It was later revealed in an email to The Associated Press by Al Fong, the personal coach for both Kara Eaker and Leanne Wong, that they are the two athletes.
Fong said Eaker, 18, who tested positive, was vaccinated against COVID-19 two months ago.
Four alternates travelled to Japan with the six-woman US delegation of Biles, Jordan Chiles, Grace McCallum, Sunisa Lee, MyKayla Skinner and Jade Carey.
Alternates have been rooming with other alternates since arriving in Japan, with the competitive team rooming with fellow competitors.
All Olympic athletes and coaches have been moved to their own rooms since the positive test, with the Olympic athletes also moving to a new hotel, as was originally planned.
The Tokyo gymnastics competition gets underway on July 24 with the men's qualification round, and the women's competition starts a day later.
Australian Associated Press