For the past 18 months, Daniel Harder has been keeping fit in his Harlem apartment with Zoom workouts, using an ironing board as a ballet barre and trying not to kick over the furniture. He has also performed with a modern-dance troupe that streamed shows online. But none of that matches what he has put himself through for The Big Moment: his return to Broadway, dancing and singing in “The Lion King.” (The show reopens Tuesday.)

“Some days my legs are like rubber bands,” Harder says, reflecting on the recent stretch of herculean rehearsals, up to 10 hours a day, six days a week. “You’re like, ‘Okay, I just want to be able to stand up and get through the choreography.’ ”

And then he wants an ice bucket, in which to soak his aching feet.

It’s going a bit better now that Harder has regained the confidence to strut magnificently across the stage on stilts in his giraffe costume, as a zoocentric Ziegfeld Follies whirls to life with zebras prancing, gazelles soaring and Pride Rock rising out of the floor. It has taken weeks of mental, physical and emotional discipline to get here.

This is the exhausting, exhilarating reality that Broadway dancers are finding themselves in as they get ready for the spotlight. The iconic, dance-driven shows — including “The Lion King,” “Chicago” and “Hamilton’’ — are critical to Broadway’s comeback, and they reopen this week, with more to follow in the months to come. But while dancers are the heart of the industry’s song-and-dance tradition, these athletes of the stage have been uniquely vulnerable to the passage of time, the isolation and the diminished opportunities to train during the shutdown.

So even as they’re grateful for the chance to dance again for live audiences on New York’s legendary stages, they’re also stressed from ramped-up rehearsal schedules and the pressure to get back in shape pronto, so they can spin their partners overhead or tango effortlessly in high heels.

And although all the coronavirus-related precautions are appreciated — proof of vaccination, routine testing, masking, sanitizing, air filtering — some of them only add to the apprehensions of this moment.

Julius Anthony Rubio, a dancer in “Moulin Rouge!,” says that while none of the cast will be performing in masks when the show opens Sept. 24, they want to be respectful of the backstage crew and stagehands. So masks off onstage, masks on backstage — maybe. The logistics are tricky.

“Do we put our masks on when we’re offstage, before we go back on?” Rubio asks. He points out that masking up after, say, sharing a choreographed embrace with a dance partner in one of the show’s steamy cabaret numbers hardly seems meaningful. “We were literally just breathing each other’s air onstage.”

Such questions are not abstract, of course. The virus hangs over the whole enterprise. Just after Labor Day, a member of the “Moulin Rouge!” cast tested positive. That performer’s 10-day quarantine touched off a spree of cast changes. Everyone was uneasy.

“For the rest of the day,” says Rubio, “nobody took off their mask.”

Fear of the virus — what it can do to lung capacity, what it can do to an immunocompromised performer — is real. So is the lingering shadow of the past 18 months of unemployment and confinement. Every dancer interviewed for this story said that when the Broadway closures were announced in March 2020 as a temporary measure only, they reacted with relief, at first: Finally, in a taxing life of eight shows a week, a chance to rest.

But the long haul was another matter. The lessons learned range from existential (Who am I without the spotlight?) to practical (I’m so much more than just the spotlight!).

“The shutdown crushed me,” Rubio says. “You only have so much time to live this kind of life. And I felt I had no skills to offer the world. How am I going to pay rent? Everything I excelled at didn’t exist.”

He grew so depressed that he couldn’t get out of bed. His partner, a food stylist, began working from home, and after the photo shoots, Rubio found himself eating platters of burgers, three-tier carrot cakes and anything else left over.

“I ate and slept,” he says. “The two things that, as a dancer, you never do much of.”

Now Rubio is saving up to complete a business degree, because the pandemic taught him to hustle up a Plan B. “Just because I’m in a show doesn’t mean I’m set. We all thought that, and look what happened,” he says.

The shutdown was traumatic in a different way for Allysa Shorte, a dancer in “Tina — The Tina Turner Musical.” At first, she was happy for the chance to completely heal the ankle she’d sprained falling down the stairs from her dressing room one night. Later, unsettled by ambulances taking away neighbors stricken by the virus, she left New York for California, to stay with her parents and siblings. It was a tumultuous time: She was there for the birth of her nephew and the death of her father (from an illness unrelated to covid-19). She can look back now and see the silver lining of being present for her father.

“I wanted this time with him,” Shorte says, “and the universe gave it to me. If I’d been in the show I might not have made it back there in time.”

Before the pandemic, she was deeply invested in “Tina,” having idolized the singer as a child. But there’s more than admiration fueling her preparations for “Tina’s” reopening on Oct. 8. Her father had seen her dance in the show before it closed. Returning to the stage after losing him gives it a greater meaning.

“It holds an even more special place in my heart than it did before,” she says.

With everything they’ve gone through in the past year and a half, including the racial reckoning, dancers say they’re now flexing an inner strength they hadn’t dared to demonstrate before. They feel empowered to speak up for themselves.

“We’d been so conditioned as dancers to just do the work, fight through the pain,” says Shorte. “And now, physically and mentally, I’m coming back into it with the mind-set of taking care of myself. . . . I am very comfortable standing up for myself and for what I need to feel safe, to feel good. And it definitely feels like a collective feeling as well. And very different from the typical culture in entertainment. Caring for the people behind the story, you know?”

Shorte, who has danced on Broadway since 2013, is a swing in “Tina,” meaning she’s able to perform multiple roles, filling in at a moment’s notice for a missing cast member — though it was relatively uncommon, pre-pandemic, for performers to call in sick. That has changed.

“We have more swings now so people don’t feel like they can’t call out,” Shorte says. “People have people to back them up. [The producers] are trying hard to do things like that to make us feel safe. In the past, that’s not typically a focus when putting a show together.”

Harder, who grew up in Bowie, Md., and attended Suitland High School’s Center for the Visual and Performing Arts, noticed a similar spirit of accommodation in “The Lion King,” where memory was a hidden casualty of the long hiatus. At the first few rehearsals, “I didn’t remember a lot of the show,” Harder says. “I had to play catch-up.”

He was a relatively new hire before the shutdown, joining in November 2019 after a 10-year career with Alvin Ailey American Dance Theater. Three months later, Broadway went dark, so at this point Harder has spent more time out of “The Lion King” than in it. He’d also learned a whole new repertoire in recent months, as a guest artist with Ronald K. Brown/Evidence. (He’ll perform with the troupe at the Kennedy Center Eisenhower Theater, Oct. 21-23.) But Harder wasn’t alone in needing a few cues.

“All of us, even those in the show 10 or 15 years, were in that same space of ‘Where do I go?’ ” he says. “Am I on the 10 or the one note? Am I a bass baritone here? What’s that step, again?”

This is a strange sensation for dancers, who depend on their ability to recall and execute in minute detail the steps and counts of years’ worth of performances. But then again, when has this profession experienced a prolonged global layoff? The creative team’s response, Harder says, was wonderfully humane.

“Those first couple of rehearsals, the director and dance supervisors developed a pace that was conducive to the room,” he says. “Not just trying to churn out the product, but being honest and saying, ‘Okay, this is how we’re going to rehearse to figure it out again.’ That kind of peaceful pacing allowed us to find our way back in very smoothly.”

It’s all intensified by what they’ve been through, and the possibility that it could happen again. That the delta variant of the virus will close everything down, or some new variant, or some new illness.

For now, though, that unbeatable showbiz rush is just around the corner, that magic they can almost taste.

“When you hear that audience roar,” says Rubio, “the energy can be the most addicting feeling in the world.”