Donna Richardson Joyner is what most people would refer to as a fitness guru. But she prefers a term a kid called her a few months back: “a cheerleader for Jesus.”

Even without the pom-poms, it’s a spot-on description of the seriously spirited 50-year-old who gained VHS fame as one of the “Buns of Steel” instructors, and eventually found that God had a greater plan for her toning talents.

Her mom, who would watch Joyner’s workouts with the sound off while playing gospel, had urged her for years to make a fitness video with Christian music. Joyner was uneasy about the idea until she led a “workout in worship” at a church in St. Louis, with the organ playing and the choir standing behind her.

“You know how runners get a runner’s high? We got a spiritual high,” says Joyner, who went back to her hotel, cried and settled on a new life’s mission.

It started with her first “Sweating in the Spirit” DVD, featuring her moves and musical performances by gospel artists Kirk Franklin, Yolanda Adams and Shirley Murdock. She later launched “Body Gospel” through Beach Body (the same company that hawks “P90X” and “Insanity”). In addition to workout DVDs – such as “Core Revelation,” which targets the abs and thighs – the package includes resistance bands and nutrition tips.

And now Joyner has written a book, with a little help from the Good Book. In “Witness to Fitness: Pumped Up! Powered Up! All Things are Possible!,” she provides a 28-day program that offers more than just what to eat and how to exercise.

“There’s scripture to keep you motivated and a song to keep you invigorated,” Joyner says, sounding a lot like the rhyming “Donnamite Sound Bites” sprinkled through the text. (“You need faith for this journey because life can be tough. But, honey, you’ve got God, who is more than enough!”)

Every day also brings a testimonial from or about someone who has struggled with health challenges, financial hardships or another obstacle on the way to a better life. Reading these stories, Joyner explains, reminds you that you’re not on this journey alone. “Other people are climbing the same mountains,” she says.

That includes Joyner, who has taken on the role of a caregiver, first for her father-in-law and now for her dad. She says that although the experience has made her stronger, dealing with their dementia over the past six years has felt like a lot to bear. So on days when it’s hard to get out of bed, Joyner thinks about a woman named Joyce. When they met, Joyce was 38 and living in a nursing home because her 500-pound frame made daily tasks nearly impossible.

Now, 100 pounds lighter, Joyce is on her way to walking. That progress is an inspiration to Joyner, as well as a form of motivation. She says she can’t just lie there knowing that she has the power to do so much more when other people don’t.

Joyner also understands literal mountains, having recently hiked Mount Kilimanjaro to celebrate reaching a half-century. Preparing for that climb took a few months, but that’s nothing compared with the work that Joyner is putting in to reach her loftier goal of improving lives, particularly those of other blacks.

“Every time I came home, I was going to a funeral. I was witnessing too much of my family, my community and my church suffering, and suffering from preventable illness,” Joyner says.

She jokes that she wants to put on a robe, so she can pretend to be a judge, slamming a gavel and declaring that excuses for eating artery-clogging foods or not exercising are “not approved!” But watching Joyner talk, it’s easy to imagine her in the robes – and role – of a pastor.

“I say I teach. People tell me, ‘Donna, you preach,’ ” Joyner says.

With the book, Joyner got an assist from her pastor, T.D. Jakes, who wrote the foreword. Joyner is one of the 30,000 members of his Dallas church, the Potter’s House, where he strives to make physical health a priority for himself and his congregants.

That’s a relatively new stance for churches, says Joyner, who found at the beginning of her crusade that places of worship were reluctant to address weight problems. Now, folks are embracing the idea that there’s no better place to take care of your personal temple.

At church, people feel a connection to God and to a fellowship that can provide invaluable support.

“People often think, ‘I’m in this alone.’ They go to gym and see all those beautiful bodies,” Joyner says. “But at church, you’re going to see yourself. There’s accountability and comfort like a family.”

It’s why Joyner believes churches and other places of worship are critical partners in fighting obesity in America.

She’s on the front lines of that war as the longest-serving member of the President’s Council for Fitness, Sports and Nutrition. (She started during the George W. Bush administration and was asked to stay on under President Obama.)

As soon as first lady Michelle Obama introduced Let’s Move, Joyner volunteered to push the program’s faith-based initiatives, and much of her constant travel is with kids at churches, introducing them to the joys of movement and encouraging them to bring these lessons to their parents.

Just as Joyner always asks people to try something different to get them moving, she is embarking on a new exercise program herself. When it comes to activity, there isn’t much Joyner hasn’t tried. Growing up, her family visited a roller rink in Rockville, Md., every weekend, and she was a star athlete in high school. These days, she likes bike-riding, hiking, Pilates, weight training, swimming and golf.