Arabella Jariel also climbs outdoors, as she did during a recent trip to Kentucky. (Jennie Jariel)

How does Arabella Jariel climb?

“I’ll show you,” says the 12-year-old from Herndon, Va. “It’ll be easier to understand.” She slips one leg and then the other into the loops of a harness, and knots a rope around her waist in a figure eight. Suddenly, the 90-pound dynamo hits the wall in her hard plastic shoes, and heads for the top. Within 90 seconds, Arabella is 40 feet up in the air at Earth Treks Climbing Center in Rockville.

The impressive demonstration explains how Arabella placed fourth in her age category (12-13) at the Sport Climbing Series Youth National Championships last year. Her coach, Taylor Reed, who’s holding the other end of her rope, says he expects Arabella to turn in another rock star performance on Saturday. That’s when the climbing gym will host the regional competition that’s the first step in qualifying for this year’s nationals.

Athletes ages 9 to 18 from around the area are expected to show up for the event, which is open to spectators (see box). Competitors are put in an isolation room to warm up, and one by one, they’re brought out to attempt a climb. When they finish — or fall — they’re done. And then the process repeats for a total of four climbs.

Arabella should be a standout, says Reed, who expects her to graduate to international matchups next year. She’s been climbing since she was 7, when her dad introduced her to the sport. A year later, she joined the Earth Treks competitive team.

Her goal is always the same: “You’re competing against yourself to see how well you can do. You try and do the best you can.” And while she’s at it, she can make friends.

Good thing Arabella appreciates the sport’s social side because her practice schedule requires hitting the gym with her teammates four times a week. Workouts test endurance and build power, says Reed, who often orders up a “4×4” — four climbs in a row, four times for a total of 16 trips up the wall. That’s in addition to core training, pushups and other conditioning exercises. (One sample move: holding an L with their arms on a pullup bar.)

The climbs can be tough — and even scary, Arabella says. But that’s what makes the sport fun: “It’s telling yourself you can do something.”

Sounds like she has pretty great perspective, even from the ground. Harriet Edleson (For Express)

Details: It’s free to watch the Sport Climbing Series Regional Championships between 10 a.m. and 3 p.m. Saturday at Earth Treks (725 Rockville Pike, Rockville;