Standing just over 5 feet tall, Jennifer Tavernier faced her opponent with steely-eyed determination. She knew it would take strength, strategy and, above all, guts to defeat her nemesis: a 14-foot concave climbing wall.

The Hopkins mom took a deep breath and charged. She made it more than halfway up before sliding back down.

Again, she ran at the wall. Again, the wall won.

At last, she managed to grasp the ledge, pull her herself up and clamber over the top.

It was all in a day's work for the obstacle-running phenomenon, who is expected to make her first appearance at 7 p.m. Tuesday on Esquire Network's "Team Ninja Warrior," a spinoff of the popular "American Ninja Warrior" TV show.

For Tavernier, 33, who goes by Minneninja on the show, getting in "ninja shape" has been a dream come true. "I eat up fitness," she said.

"Everybody has something in life that lights them up and makes them come alive. For me, it's being active — and pushing my body hard and seeing what my body can do. I've never been in this kind of shape before."

Tavernier personifies the explosion in popularity of obstacle course workouts. As the fan base for shows such as "American Ninja Warrior" has grown, so has interest in obstacle training. Ninja warrior-style gyms are popping up throughout the Twin Cities area.

Ninjas United opened last year in Buffalo, Minn., and is slated to open another gym in Edina this spring. Conquer Ninja Warrior in Eden Prairie offers classes for adults and kids and has become a popular spot for kids' birthday parties.

Kevin Hogan, owner of Ninjas United, said the fast-rising popularity makes sense. "I think it's a return to our roots as kids playing on playgrounds," he said.

And just what is a ninja? "Basically, it's if a gymnast, rock climber and parkour runner had a kid," he said.

Just her and the guys

Hogan has competed on "American Ninja Warrior" in the past, going by the nickname the Taxinator, a nod to his day job as a tax accountant.

To create his gym, he transformed an old warehouse into an obstacle runner's paradise, with cage nets and thick ropes dangling from the ceiling. The gym also features replicas of the show's most iconic obstacles, including the salmon ladder (vertical structure with a movable rung that is a pullup bar), the warped wall (a concave quarter-pipe scaling wall) and the rumbling dice (a box frame made of two steel squares and four bars that must be rolled by a hanging ninja across two parallel bars).

He said his gym attracts aspiring contestants from all over the metro area and even from neighboring states. On Thursday nights, it attracts Tavernier and a group of uberfit gym buddies.

"They are people who are pretty dedicated to the sport and are trying to make it on the show," Hogan said. The Thursday night crew numbers 10, including just two women.

"Often it's just me and the guys," Tavernier joked. By day, they are teachers, bartenders, commercial painters. She's a personal trainer. But by night, they are all warriors.

Between obstacle runs, they take breaks to file down bulging calluses on their palms — which they proudly display like hard-fought battle scars.

It takes considerable strength to get through many of the obstacles, which involve hanging from your fingers. But balance and mental toughness also help.

"It's a lot of overcoming fears," Tavernier said. "You fall on something once and it doesn't feel good, and you don't want to do it again."

The salmon ladder used to vex her.

"I had such a mental block," she said. "I had fallen on it quite a few times. I had a hard time figuring out how to move my body in the right way in order to get it to go up."

Born to run obstacles

A native of White Bear Lake, Tavernier grew up playing soccer and tennis. She continued playing tennis at Bethel University. After graduating, she became a teacher, got married and started having children and sort of let fitness go.

She was living in Boston when she found a stroller fitness company — fitness classes for moms with babies. "I got into that," she said. "It was a lifesaver for me."

She became a fitness instructor and a personal trainer and started her own stroller fitness company.

A few years later, Tavernier moved back to Minnesota and started taking high-intensity fitness classes including CrossFit. The classes were tough, she said, and included a combination of weightlifting and intense cardio such as running stairs, squats and running hills.

Then one day, one of her friends sent her a video clip of an "American Ninja Warrior" episode in which Kacy Catanzaro became the first woman to make it to the final round of competition. She became an overnight sensation, and the hashtag #mightykacy trended for days.

Watching the clip of Catanzaro's performance, Tavernier was inspired. "I thought, 'Wow, that looks so fun. I think I can do that!' " she said.

She discovered the newly opened Ninjas United gym and began seriously training for the show.

"I just decided that I was going to make it my goal to train really hard," she said. "I wanted to be the first mom to make it up the warped wall. No moms have ever made it up the wall. I started training regularly and traveling to different competitions around the state."

She tried out for "American Ninja Warrior" but didn't make it. However, she did qualify to be a tester, running through the obstacle course before the competitors performed to make sure the difficulty level was correct. Last year, a veteran ninja on the show noticed her performance and invited her to join his three-person team, competing on a new spinoff show, "Team Ninja Warrior." She taped the program last fall in Los Angeles.

Although she's done with "Team Ninja Warrior," she's still fierce about obstacle course training. She has added rock climbing and weightlifting to her routine to develop "explosiveness" in her legs.

But there's one thing she can't change: her height, which makes some of the obstacles harder.

"The balance obstacles scare me a little bit," she said. "Often it's pretty far you have to end up jumping. So some guys can just reach with their legs, but I don't have that option."

These days, the soon-to-be-divorced Tavernier often brings her two daughters to the gym, where they run around and tear it up on the kid-sized obstacles.

She won't reveal how she fared on the show, but she said she hopes her example will teach her daughters — and girls everywhere — to chase their dreams, no matter what obstacles they may encounter.

"I think there is a lot of empowerment in finding ways to be strong and having a healthy body. And just finding something that you're passionate about," she said.

She added, "I know I'm inspiring people."