She is known as "Sparkle," a nickname she's had for decades.

It fits.

Petite but strong, friendly but determined, enormously talented and yet pleasantly self-effacing, Sheri “Sparkle” Williams is a rare and remarkable person — at age 50, she looks back on a 40-year career with the internationally known Dayton Contemporary Dance Company.

Yes, 40 years. And still dancing.

This, in a business that is certainly not known for longevity. Like professional athletes, dancers go into the work knowing that theirs will be a limited creative lifespan; injuries and age eventually catch up with the body, drawing the curtain on careers years before middle age.

But, amazingly, not for Williams. Not yet, anyway. She dances on — and not only is she still performing with the hard-charging DCDC, she’s the group’s fitness trainer, a job in which she sets the pace and calls the workout shots for her years-younger colleagues.

Her take on a career that still shows no signs of ending?

“I guess it’s the luck of the draw,” Williams says, flashing a broad grin. “But I’m happy about it.”

Already well known in Dayton’s arts community and beyond, Williams’ story was even more widely disseminated last year when she became the subject of a short documentary made by a pair of filmmakers from nearby Yellow Springs. Steve Bognar and Julia Reichert — whose previous documentary, about the closing of the Dayton area’s last GM assembly plant, was nominated for an Academy Award — focused on Williams’ career in the 18-minute “Sparkle.” What could have been a simple tribute ended up telling the story of how her career nearly came to a crashing halt.

The film opens with footage of the Williams that all DCDC fans know so well: her tight, chiseled physique at center stage, swirling and twirling, bouncing and swaying, diving and lunging, moving through spot-lit space with a feline, graceful energy as she is surrounded by her fellow dancers.

“The first time I saw Sheri perform, it was absolutely amazing,” 12-year DCDC dancer Nabachwa Ssensalo says early in the film. “And the audience thought it was awesome. I thought it was awesome. And I thought to myself that if there are people out there who dance like this, I want to dance like that, too.”

“I watch her in amazement,” Debbie Blunden-Diggs, DCDC’s artistic director, says on camera. “When all of us were hanging up our shoes at, what, 25, 30 — whatever time when we thought, ‘I can’t do the stuff that I need to do’ — she’s still going like the Energizer bunny.”

Williams joined DCDC in 1973, when it was still run by its founder, the late Jeraldyne Blunden. In 1968, Blunden had the vision to create in a small Midwestern city a modern dance company deeply rooted in African-American culture and heritage, but which incorporated the gamut of contemporary dance styles.

A Dayton native, Williams had no plans as a girl to become a dancer. She was a runner and budding track star, with a lot of family encouragement, and thought that would be her path. She attended a dance class with a friend, enjoyed it enough to go back and realized dance was her future. Now that she’s been part of it so long, DCDC feels right, like something she was always going to belong to.

“It’s based in the African-American experience,” Williams says, “but it’s not limited to that. We bring together the best possible in dance and the most exciting performance to the broadest possible audience, working with choreographers from all over the world and from different nationalities who bring their own voice to what we do. The sky’s the limit. I like the amalgamation; we’re trained in ballet, ballet moderne and jazz, but I like being able to fuse the techniques together, so that what we do is up in the air, a contemporary fusion.”

DCDC audiences know to arrive ready to be surprised. The company performs at least twice a year in Dayton, where it’s based and trains, and travels around the globe to perform. The accolades that have been accorded its oldest dancer speak to the overall reputation of the group: Among Williams’ honors is the New York Dance and Performance Award — the “Bessie” — which is rarely given to a dancer outside the city. “It was a coup,” Williams admits, proudly.

“Sparkle” gives viewers a glimpse into the world of Williams and the other dancers, and of the grueling training and preparation that goes into what they do. Staying in top shape is of the utmost importance. “A typical day starts at 9, conditioning class with me until 10,” Williams says. “There’s a lot of complaining, yelling and having a good time.”

The film shows a tired young dancer wandering off the floor, looking forward to a dose of Advil.

“We take a 15-minute break and then start a 90-minute technique class, either ballet moderne or jazz,” Williams adds. “There’s usually about two hours of rehearsal before lunch, and two hours after. Rehearsal is learning the works and running those ballets over and over.” In other words, pretty much an entire day of working out.

In October 2011, however, Williams’ world of hard work, extreme physicality and smooth movement nearly came to an end. She was performing on stage when, while making a simple, routine turn, her hip blew out. “I got through the piece and finished being on stage at that moment,” she recalls. As soon as she got backstage, she collapsed. “It was pain like I’ve never felt in my life.”

She worked with Carol Fisher of Kettering Sports Medicine on the injury, a near dislocation for which she was supposed to be immobile for several weeks. Instead, she immediately traveled with the company to offer her support for colleagues during an important engagement in Dallas. It was while she was recovering that Bognar and Reichert posed the idea of the documentary to her.

“Sparkle” shows how Williams worked with Fisher and conveys the concern she and Blunden-Diggs had about whether she’d be able to dance again. In 2012, she came back for a triumphant performance of a signature DCDC work, captured in the film. The movie premiered to a packed house last fall at the Dayton Art Institute, after which Williams performed a new piece choreographed for the occasion.

Williams admits she worked hard, but gives real credit to Fisher. “She’s an alchemist,” she says. “And she taught me a lot.” She pressed so hard to come back because, she says, she did not want to leave the career on an injury — to go out hurt. “I didn’t want to let this defeat me,” she says. “I didn’t want to go out because I had to. I want to go out when I want to.”

And since she pulled it off, being hurt and almost out did have the effect of giving her some perspective on the remarkable nature of her career.

“It’s just what I’ve done,” she says, reflectively. “People say, how is it that you’re still doing that kind of thing, but I don’t even think about it. I take care of myself. As a trainer, I put myself on a life plan, and I’ve lived that the whole time. If I had to think about it … this is all my body knows. It doesn’t know you shouldn’t be able to do this, or you shouldn’t do that. We just need to think as we age — and at 50, you can still be doing fine.

“Granted, what I do is ridiculous, but I don’t think of age as a number. The mind is powerful.

“And I’m enjoying it.”