Simone Biles just keeps getting better headed into this weekend's U.S. Classic in Louisville. (Vadim Ghirda/AP, File)

Simone Biles already has proved she is the best gymnast in the world, winning the women’s all-around competition at the 2016 Rio Olympics and four times at world championships. As the 2020 Games approach, she’s not just ahead of all her fellow competitors; she continues to push the boundaries of the sport.

During training before this weekend’s U.S. Classic, Biles performed a triple-twisting double tuck, which no female gymnast has done in competition. She doesn’t plan to perform the skill in Saturday’s competition, according to the Olympic Channel, but Biles showed she is capable of executing it on the competitive surface. She even rebounded out of it, which usually shows a gymnast has more power than necessary.

In May, Biles sparked a surge of excitement in the gymnastics community when she tweeted a video of this skill. Gymnasts frequently experiment with difficult skills in training, but by practicing a triple double in Friday’s pre-meet training session, Biles showed she is making a realistic push to perform it in competition.

Even without the triple double this weekend, Biles is expected to upgrade her already difficult routine. She will connect the skill named for her — a double layout with a half twist — to a front layout.

The U.S. Classic will be the first major domestic competition for American gymnasts this season, followed by the U.S. championships in August and the world championships in October.

A handful of American gymnasts can do a double-twisting double tuck, but usually that’s the hardest skill in their routines. Biles, however, has recently included a double double as the final tumbling pass in her routine, the spot for skills that typically require the least amount of energy.

No gymnast in history has performed a collection of skills as difficult as Biles, who can execute them well, too. When learning a new skill, sometimes gymnasts will land short with their chests down, but Biles has more than enough power, even when flipping twice and spinning three times.

Scoring-wise, Biles is far ahead of her peers in nearly every competition. She won in Rio by nearly two full points, and won the most recent world championships by a record margin, even with two falls.

Nearly all gymnasts have worked on skills much harder than what the public sees in competitions, and those who compete at the elite level — the sport’s top tier — can be coy when it comes to sharing their experimentation in the gym. Biles’s former coach, Aimee Boorman, has tweeted about some of the ridiculous skills Biles has tried while “playing around,” including a double backflip on a floor beam and a double-twisting double tuck dismount off beam. Boorman said Biles has been able to add an additional flip to her eponymous skill since 2014, even though she is including it for the first time this weekend.

There’s a balance when it comes to adding new skills to routines, with safety as the most important consideration. And with Biles so far ahead of the competition, it might not be worthwhile to add any new ones. She already has plenty of breathing room without adding to her difficulty score. Yet Biles continues to innovate, changing the landscape of gymnastics and redefining what had been perceived as impossible.

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