Janet Jackson (center) performs onstage during the opening night of her Metamorphosis — The Las Vegas Residency at Park Theater at Park MGM on May 17 in Las Vegas.

LAS VEGAS — As a wall of digital screens flashes the initials of one of the most consistent pop superstars of the last three decades, a crowd of 5,200 Janet Jackson fans waits for the metamorphosis to begin.

Flanked across a stage inside of the Park MGM Theater, 14 backup dancers – ranging in age, size, gender and race — fall into formation as Jackson begins the first notes of her new track, “Empty.” They begin to deliver the precise, coordinated steps, high shoulder movement and head shakes that Jackson has been bringing to arenas since her first Rhythm Nation World Tour in 1990.

“I look at her as an athlete. I have got to make sure that she is fit to do the show.”— Paulette Sybliss, Janet Jackson’s personal trainer

But this one is different. This brief residency in Vegas — celebrating the 30th anniversary of her game-changing album, Rhythm Nation 1814 — began in May and will finish up in the next 10 days. Titled Metamorphosis, it takes place in the most intimate space she’s ever appeared in as a solo act. Over the course of 100 minutes, Jackson — at 53 — will run through a setlist of 37 hits from the entirety of her career.

And she does it without missing a beat.

Not one, single, solitary beat.

We’ve known Janet Jackson the Pop Superstar almost as long as we’ve known ourselves. But now we’re meeting Janet Jackson, the high-functioning athlete.

“I am from a sprinter’s background, so I train her at that level, and it’s intense,” said 49-year-old Paulette Sybliss, Jackson’s personal trainer who is a former amateur sprinter and long jumper who ran in primary and secondary school in London. “It is 45 minutes of intensity, doing some drills that I know from my athletics background. She — as a 53-year-old woman — will take on many who are half her age, and put them to shame, to be quite honest with you. She does that a lot of the times in sessions with the dancers. I look at them, and they look at me, and I am like, ‘Yeah …’ ”

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On April 6, 2016, Jackson announced to her fans via video that she was unexpectedly ending her Unbreakable tour, because she and her then-husband, business tycoon Wissam Al Mana, wanted to start a family. The two had secretly married in 2012, didn’t confirm it until 2013 and at 49, Jackson wanted to become a first-time mom. (The couple divorced in 2017.)

My training sessions with @JanetJackson were designed to get her looking incredibly hot, and incredibly fit for 56 shows. #MissionAccomplished pic.twitter.com/qbgyd679zj — Paulette Sybliss (@paulettesybliss) December 3, 2017

She promised she’d hit the stage again as soon as she could, telling fans in a video she posted on Twitter: “My husband and I are planning our family, so I’m going to have to delay the tour. Please, if you could try and understand that it’s important that I do this now. I have to rest up, doctor’s orders. But I have not forgotten about you. I will continue the tour as soon as I possibly can.”

Jackson’s high-impact touring shows have come like clockwork for decades — Rhythm Nation World Tour 1990; 1993-1995’s Janet World Tour; 1998-1999’s The Velvet Rope Tour; 2001-2002’s All For You Tour; 2008’s Rock Witchu Tour, 2011’s Number Ones, Up Close and Personal World Tour; 2015-2016’s Unbreakable World Tour and her most recent State of the World Tour, 2017-2019. Emphasis on the high impact. Once she shifts into the first 8-count of a complicated choreography, it doesn’t end until the show’s conclusion.

Her ability to endure that schedule — especially now — is due to intense weight training, said Sybliss.

“Predominantly, all of her sessions are based around some kind of weight training, as well as interval training. Sprinters do a lot of interval training, where you’re working really hard for maybe 30-45 seconds. When I mean hard, I mean your heart rate is at the highest, and then she will maybe take a rest at that period of time,” said Sybliss, who claims that at 13 she was once clocked as the fastest girl in London. “If you ever see sprinters’ training sessions, that’s how they train. It’s full-on intensity, you take a bit of a recovery. And then you go again.”

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Sybliss said she uses Jamaican sprinter Merlene Ottey, who ran at a world-class level into her 50s — as an inspiration for Jackson’s training. She first began working with Jackson when Jackson’s son Eissa was 6 weeks old. They’d work out four times a week for 45 minutes to an hour. Back in 2017, the goal was to trim the pounds Jackson gained from pregnancy — she eventually dropped 70 pounds — and to build lean muscle for her forthcoming State of the World Tour.

“Once she had the baby, we were doing a solid five times a week, because time was not on our side. With her hectic schedule now, it may be three to four times, sometimes five times a week. I never take her into an hour. She doesn’t need it,” Sybliss said. She stops to chuckle before adding: “She probably wants me to finish after 30 minutes, it’s so intense.”

Jackson doesn’t take her first significant pause until she’s 16 songs in, after she’s been going at it for about an hour. This is when she tells the crowd she wants to slow it down before going into her slow ballad, “Come Back To Me,” from the Rhythm Nation 1814 album. She chases that with three more soft ballads. As she works through the final notes of “China Love,” from her 2001 All For You album, she looks out at the audience and breaks into a smile. Satisfied with the eruption of cheers, Jackson then looks over her shoulders at everyone backing her up, nods her head and jumps into an uptempo track from 1997’s The Velvet Rope, “Together Again,” a house-music tune that pays homage to a friend she lost to AIDS.

“I am from a sprinter’s background, so I train her at that level, and it’s intense.” — Sybliss on Jackson

Jumping alongside her dancers — much like she did in the summer of 1998 as she performed “Together Again” at NBA arenas across North America — Jackson’s stamina is impressive for a performer of any age. But for one who in her fifth decade? It’s mind-blowing.

What we’re seeing on stage is a better version of Jackson, even better Sybliss thinks, than what she saw as a fan in her 20s, dancing to “Control” and “Nasty.” Those same movements that Jackson performed next to Tina Landon, the former Laker Girl who choreographed the tours in 1993 and 1998, sometimes look even better now than they did when she debuted them.

“She is probably a lot fitter now,” Sybliss said. “Sometimes [I] have to pull her back from maybe doing too much. As we get older, we get injuries, but it’s not necessarily getting the injury, sometimes it takes longer to recover from the injuries as we get older.

“For women as well, as we get close to our 50s, and then there are changes that are coming on as well. It’s accommodating things like that, and saying that we may need to tail back on something like this, or push harder in this section of the show. At the end of the day, she is doing a lot of shows, so we don’t want her to get burnt out during the first few shows. If Janet’s ill, there’s no show. My job is not just to train her, it’s to make sure she’s recovering, she’s getting the right fluids, the right liquids during the show, and also post-show as well.”

Throughout the entire show, Sybliss has Jackson drinking water with electrolytes. “If you see Janet during a show, it’s so intense. We don’t just lose water, we lose salt as well. I need to make sure that during the show, that she’s getting hydrated and getting electrolytes, because the worst thing that can happen is that she cramps on stage.”

After the show, it’s all about muscle recovery. “I look at her as an athlete. I have got to make sure that she is fit to do the show. She might want to train with me the day after the show, I will say, ‘Well, you know, it’s a rest day tomorrow.’ ”

“Sometimes [I] have to pull her back from maybe doing too much. As we get older, we get injuries, but it’s not necessarily getting the injury, sometimes it takes longer to recover from the injuries as we get older.”

“She’s competitive,” Sybliss said. “She likes to push herself, and she knows that I will be able to push her. If it’s a new session, as challenging as it may be, I can see in her face the determination … ‘Well, OK, I’m going to show you I can do this.’”

Near the end of the show, Jackson tells the audience she first performed at an MGM casino in Vegas as a 7-year-old with her brother Michael and her sisters.

The show appears to end with the title track of Rhythm Nation 1814 — the album she’s celebrating the 30th anniversary of. But Jackson still has three more songs left in her: “Morning,” “Doesn’t Really Matter” and “Made For Now.” On that digital screen, she’s draped in a gold material, and you can hear her son Eissa off-screen.

“Now she’s a mother and she’s still working, and she’s in Vegas. She’s touring around the world,” Sybliss said. “It really is incredible.”