These American Ninja Warrior Juniors television stars are about strength, agility, flexibility - and community.

Thirteen-year-old Cal Plohoros of Chester Springs has always been a climber.

“From when he was 3 or 4, if he saw a chain-link fence, he would climb it,” recalled his mom, Ivette Tolentino, “He climbed all the molding in the house.”

Fourteen-year-old Avery Glantz of Lafayette Hill scampered heights from an early age, too, but she rock-climbed. She also spent a decade in gymnastics, where she stood out for her remarkable upper-body strength.

Last week, both teens were in Los Angeles to film Season Two of American Ninja Warrior Junior (ANWJ), the kids’ spin-off of the TV show American Ninja Warrior, which itself is a spin-off of the Japanese TV show, Sasuke. The new season will be shown early next year on the Universal Kids Network.

ANWJ features kids facing off two by two on twin obstacle courses. The competitors run, jump, scramble, lache — a two-handed swing-jump from object to object — and otherwise launch themselves over and under objects in a less-than-one-minute parkour race. Last year, Plohoros, a.k.a. “Ninja Cal,” appeared on the show’s first season and finished in fifth place

Glantz and Plohoros spent two days in Los Angeles in the company of 140 other ninjas, aged 9 to 14, culled from a pool of 10,000 applicants. If Season Two was anything like Season One, they likely had what Plohoros would describe as an “insane” time.

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But that was last week. Glantz is back in summer camp now. Plohoros is home. Although their contracts with Universal Kids prohibit them from talking about what went down in California until after the shows run, they can say how they got there and what the fast-growing sport of ninja is all about.

Turns out, it’s not about just strength, agility and flexibility. It’s also about creating and supporting a community.

Plohoros trains at home in gyms built for him in his dad’s basement and his mom’s garage. Three or more days a week, both teens train at iCore Fitness, a ninja gym in West Chester.

Mark Falcone opened iCore in 2015. A runner, skateboarder, and surfer, “I never fit into sports teams growing up,” he said. “Anything extreme was my jam.” After college, he worked construction and got into ninja. He built obstacles in his backyard and looked for a gym suited to his new passion. When he couldn’t find one, he founded one.

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The obstacles in iCore mirror those on the show. There’s even a 14-foot-6-inch warped wall that Plohoros and Glantz have both scaled.

Falcone said his gym got off to a slow start but is now approaching capacity, thanks to a clientele of mostly “kids that don’t fit into regular sports.”

That description fits Plohoros. “I used to do basketball and soccer, and I was really uncoordinated,” he said. “I’m super bad at ball sports.”

At ninja, however, “Cal is the best at his age that I’ve ever seen in our facility,” said Falcone.

Glantz fits a slightly different bill. She excelled at gymnastics, but when the time came to commit to a sport, she chose ninja. She’s now often the first to arrive and the last to leave iCore, according to Falcone, who is grateful to have her there. “Her bubbly personality brings life to the gym,” he said.

Glantz chose ninja for the camaraderie. “It’s a lot less competitive and more about teamwork," she said. "Even though it’s an individual sport, people really, really help each other out.”

That’s how Plohoros and Glantz met at iCore. He showed her the ropes — or, at least, the double salmon ladder. She took it from there.

“Ninja-ing is by far the most supportive sport I’ve ever seen,” said Cal’s dad, Tony Plohoros. “Everyone supports each other.” For proof, one need to look no further than Cal and Avery’s Instagram pages, chock full of videos of them cheering on — and being cheered on by — other kids — including each other. Kid and adult ninjas keep in touch by giving advice and support via social media, group texts and “FaceTime on the regular,” said Cal.

Having raised daughters who played volleyball and basketball and having attended their nephews’ ice hockey games, Cal’s parents are impressed by what Tolentino called “the spirit of ninja.”

“You rarely ever see a ninja throw their hands up. You never hear smack talk,” she said.

“No angry sideline parents. No yelling at refs,” added Tony Plohoros.

Matt Cahoon, executive producer of ANWJ, has televised major athletic competitions, including the Olympics, his entire career.

He said, “In no other sport that I’ve ever been a part of, have I ever seen every single athlete root for each other, for the competitors to want their competition to win in every way. They’re all about positivity and inclusivity. It’s hard for people outside [ninja] to understand how much of a family it is.”

“It’s such a different world,” agreed Tolentino, “It’s how ninja started and how it’s always been.” During the filming of ANWJ, pro ninja coaches and the competitors’ family and friends run along the course, encouraging the kids. She said, “Win or lose, afterward, you hug the other parents.”

The kids have definitely picked up on the ninja spirit.

Tolentino said her proudest moment of her son’s ninja career wasn’t when he took third in a National Ninja League competition, or even in the races he won on the show. It was right after he lost.

“He was a mess. He was devastated. But he held it together. He congratulated Caleb [his opponent] immediately. They hugged, and then Cal came down and had his interview with Laurie [Hernandez, the Olympic gold medal gymnast and an ANWJ host]. His interview was basically nothing but praise for his opponent,” said Tolentino.

“Back at the hotel, he fell apart. But right after the race, he was able to hold it together, to be gracious, because that’s what the community taught him. In ninja, you talk about only your strengths and your opponent’s strengths. Cal wouldn’t want to be anything but a great ambassador to the sport.”