Nine-year-old Braden Derouin is on the autism spectrum and has anxiety, sensory processing disorder and low muscle tone.

When his mom, Kimberly Derouin, took him about a year ago to a workshop through Autism Climbs, he was scared and stopped after going up just a few steps on a climbing wall.

They kept trying, and his climbing steadily improved. Sunday, he happily scaled the walls during a workshop at Boulder’s ABC Kids Climbing.

“They don’t care if it takes him 45 minutes to get to the top, they’ll stick with him,” Derouin said. “When they succeed, they cheer your kiddo like he’s the only one here. We come to as many of these as we can.”

Almost 30 families signed up to attend Autism Climb’s free Sunday workshop, where volunteer certified guides and wall instructors taught basic skills like buckling a harness, tying into rope and belaying.

Yisha Wagner, of Broomfield, and Katherine Weadley, of Lyons, started the non-profit Autism Climbs about a year ago. They said they came up with the idea after experiencing the benefits of climbing with their own children on the autism spectrum.

“Climbing is a lot of fun,” Wagner said. “It has a lot of therapeutic benefits. It’s a mental challenge as well as strength building.”

Climbing allows them to be part of a team, but with more manageable social interactions and without the pressure to do well of team sports, she said.

“You’re going at your own speed,” she said. “The world’s best climbers can climb the same wall as complete beginners.”

Weadley said climbing can help children with autism with everything from gross motor skills and body planning to communication and learning that actions have consequences.

“Climbing is a one-stop shop for kids on the spectrum,” she said. “It’s all wrapped up into one cool activity. It’s something the family can do together. It’s something they can do with their friends.”

Along with hosting several events at ABC Kids Climbing, the non-profit has held events at a park in Lyons and Broomfield’s recreation center. Events so far have been free to families thanks to donated space and local climbers volunteering their time as instructors.

Now, they said, there’s so much interest that they’re applying for grants and fundraising with a goal of offering regular classes, summer camps and guided outdoor experiences.

At Sunday’s workshop, kids could choose from a variety of climbing walls, climbing with ropes or without. They also could zipline, balance on a slackline, go down a slide and tumble on mats.

Some raced to the top of the walls, some made slow and careful climbs and some didn’t get further than trying on a harness and climbing shoes — but all attempts were met with encouragement and cheers.

Nina Axelrod brought her 9-year-old, who takes climbing classes at ABC Kids, and his 11-year-old brother, who’s on the autism spectrum.

“Most activities for typical kids, he will opt out of,” she said of her 11-year-old. “This is a low pressure way for him to try climbing. He can play with his brother. It’s great.”

Aga Ramirez brought her 5-year-old son, Alex, for his first climbing experience. He quickly got the hang of scrambling up the walls, but most loved belaying down.

She said she wanted him to try climbing because he can be physically awkward and often needs more time to learn new skills, making team sports difficult.

“He loves to play,” she said. “Climbing is something he can do.”

Amy Bounds: 303-473-1341, boundsa@dailycamera.com or twitter.com/boundsa