Like any good dancer, Amy Purdy has a great pair of legs. But as with any good dancer, there is far more to her talent than what she does with them.

Still, the legs grab your attention. Purdy is a double amputee, and her prosthetic limbs have carried her with deceptive ease through four weeks of competition on ABC’s “Dancing With the Stars.” She and partner Derek Hough have been scoring just below such unsurprising favorites as Olympic gold-medalist ice dancer Meryl Davis and pop singer James Maslow.

“We have Wonder Woman in this room, I’m telling you!” gushed Bruno Tonioli, one of the show’s judges, after Purdy and Hough entwined themselves in more ways than you’d think possible throughout a steamy, ingeniously choreographed cha-cha on the season’s first episode. The twisting hips and tight, fast footwork posed no problem for Purdy, a competitive snowboarder who won a bronze medal at the Sochi Paralympics.

As for her powerful chemistry with Hough: Has anyone checked the mirror ball for scorch marks?

Tonioli is right. Purdy is a natural superhero, with all the required muscle power and retro-glamour. She has abs of steel. Red-carpet looks. Sex appeal to burn, in a lithe body that’s perfect for the show’s skin-baring costumes. And those legs: Peeking out of her adorable gold-fringed cha-cha pants were gleaming metal rods leading to flesh-toned plastic feet, part Terminator, part department-store mannequin. Purdy’s bionic limbs give her a fascinating fembot-bombshell look. (She may be too modest to consider herself a bombshell, but “fembot” is a label Purdy proudly embraces in her motivational speeches and her blog, Through the Eyes of a Fembot.)

A year after losing her ankle and foot during the Boston Marathon bombing, dancer Adrianne Haslet-David performs with Christian Lightner during a TED Talk by MIT professor Hugh Herr. Herr, who lost both of his legs in a climbing accident 30 years ago, designed the custom bionic leg that allows Haslet-Davis to continue to dance. (Lauren McEwen/The Washington Post)

Purdy is without question an inspirational performer. “And what have you done with your day?” the show’s host Erin Andrews deadpanned to the camera, after Purdy described how she won her medal, flew to Los Angeles, rehearsed and danced, all in little more than a weekend. Yet what is most extraordinary about her is the sheer beauty — and artistry — of her dancing.

You expect to see skin on “Dancing With the Stars,” and glitzy get-ups and snappy footwork. But for most of the contestants, conveying feeling is the toughest part. Most never get there. Purdy and Hough shade their dancing with emotion without making it forced and schmaltzy. Looks pass between them as if they are sharing secrets. Purdy is all slow burn with her circling hips and supple spine, and she makes you feel it. Even with those mechanical limbs, she has more honest expression in her body than the other contestants have with their full complement of fleshly parts.

Maybe it’s because of her life story. She survived bacterial meningitis in 1999, at age 19, which robbed her of her legs, kidney function, the hearing in one ear and very nearly her life. She has looked into the abyss, and clawed her way back. Seven months after receiving her prosthetics, she was back on her snowboard, regaining the moment-to-moment responsiveness, core strength and sense of balance that make her a sensation on the dance floor.

When she dances, she sways her hips like a merengue queen. She isn’t the least bit self-conscious or afraid; there’s no tension in her shoulders. And you’d never know she has any hearing loss from the full-bodied way she responds to music. In Hough, an Emmy-winning choreographer and the show’s reigning champion, she has a gifted partner who makes her look good. But he has been transformed by her, as well. In his performances so far, he hasn’t raced about with the frenzied footwork that all the show’s pro dance partners rely on to pump up excitement.

Perhaps he’s wary of upsetting Purdy’s balance; perhaps her unflappable equanimity has touched him. What’s clear is that Hough has brought his physical expression in line with hers, so it is warmer, more grounded. He doesn’t mug outrageously for the judges. He is fully attentive to his partner. Hough appears more human because of the bionic woman in his arms.

‘I can live a great life’

There’s a Zen saying, “When the shoe fits, we forget the foot.” Watching Purdy dance, we forget her disability. It doesn’t even seem right to use the word disability. In fact, Purdy is helping to bury the very notion of disability.

A post-disability world is closer than we think. When soccer’s World Cup begins in Brazil in June, a paralyzed teenager will rise from a wheelchair on the field to make the ceremonial first kick. The teen will be wired into an exoskeleton, with electrodes in his brain that will make the machine respond to his desires, and move the immovable.

One day, exoskeletons could even enable a paralyzed person to dance, by neurally commanding the limbs. “A person can think, fire their own biological muscles and the exoskeleton can respond appropriately,” says Hugh Herr, head of the Biomechatronics Research Group at MIT.

“They could help us learn a new task, like dancing, or playing piano and golf,” Herr says. “They could wrap around our bodies and teach us.” Like our own personal Derek Hough.

The forthcoming film “Transcendence,” starring Johnny Depp, carries this idea further, imagining life beyond the body, with human consciousness existing in a digital realm after the body has failed. The concept is extreme — or is it? Is it the logical endpoint of efforts to transcend the body’s limitations?

Bio-mechanical engineers will tell you transcendence is here already.

Bionics is not only about making people stronger and faster, says Herr: “Our expression, our humanity can be embedded into biomechanics.”

“As technology becomes more intimate to our bodies, connected to our nerves and brains and mechanically linked to our bodies, our very nature will be expressed to those synthetics,” he says. “In fact, when the human-machine interaction is seamless, it’s not clear when biology ends and synthetics begins. It really won’t matter what we’re made of. The only thing that will matter is quality of life and expression.”

Herr has been watching “Dancing With the Stars” with interest. Purdy has come to MIT to speak with him about collaborating on a better set of limbs for snowboarding, with the limb integrated into the board, he says. Like Purdy, Herr is a double amputee and an athlete, having lost his legs to frostbite while rock climbing in 1982. He was able to climb better after his accident than before, he says, using specially designed prosthetic limbs.

And unlike flesh and bone, his legs are upgradable.

“There is no disability,” Herr says. “There is only poor design.”

Dance is a new frontier. Herr recently unveiled a bionic leg specially made for dancing. He designed it for Adrianne Haslet-Davis, a ballroom dance instructor who lost a leg in the Boston Marathon bombing a year ago. Last month, she danced for the first time since the bombing, padding softly through a brief rhumba with a partner at a TED conference in Vancouver.

Inside Haslet-Davis’s titanium-silicone-carbon dancing leg are a motor, wires, tiny computers and springs that mimic tendons. Unlike the conventional, “passive” prosthesis, this leg “can act like a gas pedal, can thrust,” says Herr.

Yet with all the advances of science, he laments that there is still a biology bias.

“We put cells and tissues on a pedestal. We think cells and tissues are godly and spiritual. And that a person who has an artificial limb — that limb is not really human. But that idea will disappear.”

This is why, in terms of blurring the boundaries between flesh and titanium, Purdy’s appearances on “Dancing With the Stars” matter even more so than her sports achievements. She’s earned a high profile on one of television’s most popular shows, for one thing. For another, the poignancy, emotion and beauty of her dancing can leave you breathless.

On Week 3, the contestants were tasked to commemorate the most memorable year of their lives. Purdy chose the year her father gave one of his kidneys to her. A family video showed her in her hospital room, dancing with her dad, twirling under his arm on her new prosthetics before she had mastered walking in them.

“If I can dance, I can walk. And if I can walk, I can snowboard. And I can live a great life,” she reasoned at the time, recounting the moment on camera.

How did she convey that on the show? Tiptoing onto the stage for her contemporary-style dance with Hough, Purdy wore a simple silver dress with an airy chiffon skirt, the hem short enough to show her muscular thighs and sleek, jet-black shins, exposed metal ankle joints and rubbery Barbie-doll feet in a permanent point. (The legs were designed for swimming, which is why the feet were pointed.) The music was Christina Perri’s “Human,” perfect with its slow buildup and huskily sung lyrics about vulnerability. Hough’s brilliantly devised choreography played with images of fall and recovery in surprising ways. But the emotional power lay in the way he and Purdy moved together, as if the dance floor were a private realm beyond reach of physics.

At one heart-catching moment, Purdy melted into his arms and he swept her around his back as if she were weightless. As if she were swimming through air.

“I am not my legs,” says Purdy.

“We are such stuff that dreams are made on,” wrote Shakespeare.

Bodies are temporary; dreams don’t have to be. It’s not science fiction: As Purdy and Hough and other resilient innovators show us, transcendence is within reach of all of us.

Dancing With the Stars

airs on Monday nights at 8 on ABC.

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