Amy Purdy had one condition before agreeing to dance a five-minute solo in the Opening Ceremony of the Paralympics in Rio. Her top priority: Making sure she could move like a Brazilian.

The Paralympian snowboarder nearly won season 18 of "Dancing With the Stars" in 2014. (She came in second.) A sensational performer with the sensuous abandon of a pro, she danced rings around her competition on her prosthetic legs. But the springy running blades she'll be dancing on in Rio on Sept. 7 are altogether different from the stiffer, less responsive legs she sported in the dance competition. The titanium and carbon-fiber blades will put a high-tech twist on Purdy's samba-inspired performance at Maracana Stadium. (The ceremony will be televised from 7-10 p.m. on NBC.)

"They're made to propel you forward, but you can't really stop that whole time, 'cause they store energy," Purdy says from Rio, where she's spent the past month rehearsing. "But once I mastered it, I found myself with more movement in my blades."

So she knew the running blades would work fine. And they're also just plain cool. But Purdy wasn't sure the rest of her would fit the aesthetic she was going for. She wanted to make sure she could whip her hips like a Carnival dancer. Before she said yes to the dance, Purdy worked on those circling actions at her home in Colorado, with the show's choreographer.

Attitude is key, she discovered. "It's very sexy, but not at all in a raunchy way. The type of samba I'm doing is all about confidence and charm. You allow yourself to feel very feminine and charming, in how you hold yourself, with your shoulders back and your chest high, but your arms are really relaxed.

"And at same time your hips are doing figure eights, and your feet are doing something different. But if you allow yourself to feel this relaxed attitude, your body moves the way it's supposed to."

Satisfied with her swiveling, Purdy arrived in Rio. The ceremony's organizers were amazed with the result, she says with a laugh. "It was like, nobody believed that they were gonna hire an American and she'd move like a Brazilian!"

A five-minute solo would tax any dancer—not to mention performing under the pressure of a live spectacle in a soccer stadium for a global TV audience, as well as infinite online exposure. In her dance, Purdy will pair up with a KUKA robotic arm at one point, and she'll also take a quick break to switch out her running blades for a different set of prosthetics.

Still, in all her years as a competitor after losing her legs to meningitis at age 19, Purdy, 36, has never held the spotlight in a physical activity for this long. On "Dancing With the Stars," most of her routines were only 90 seconds long, and she had a dance partner. Even in snowboarding, the sport in which she won a bronze medal at the 2014 Paralympics in Sochi, her runs were closer to a minute long.

"I guess I'm always up for a challenge," she says with another laugh, betraying her Olympian core. Purdy will start getting ready for snowboarding season after leaving Rio, gaining back the weight she's lost with her rehearsal schedule. The past month hasn't been all work–she and her husband celebrated their first anniversary in Rio, and they've grown fond of nightly caipirinhas, the Brazilian national cocktail. But mostly, Purdy has been immersed in her dance.

"What's most difficult for me is, I'm not a trained dancer," Purdy acknowledges with a mix of perfectionism and humility. "Dancers know how to move their arms and their hands. But I don't know the first thing about how to move my arms and hands gracefully."

Purdy doesn't give herself enough credit; her grace was beautifully apparent in "DWTS," especially because she was such a joyous dancer. Joy in moving, and her exuberance about life in general, is what she'll carry into the performance in Rio, she says: "I've always made the choice to do everything to my fullest potential."

That philosophy is perfectly in step with the theme of the Paralympics, and the Opening Ceremony.

"It's the relationship of the human spirit with technology," Purdy says. "That's really what the Paralympics is about, these amazing athletes and this technology that's allowing them to reach their full potential."