The adult playground was inspired by NBC’s American Ninja Warrior. Photo courtesy of Iron Sports.

We had already decided that Sam Sann’s 17,000-square-foot, indoor, wood-and-steel, somewhat amateur-looking obstacle course, handmade by a Cambodian refugee and stuck in an uninspiring Willowbrook strip mall, was the most Houston thing we had ever seen. That was before we realized the obstacle course was actually an extension of a hair salon.

“I still cut hair,” says Sann, wending past ladders, ropes, pulleys, hanging rings, and walls stippled with grips, past a dozen people of varying ages who had come to practice their ninja skills under Sann’s tutelage, to a small salon—“Shear Concepts”—in a room adjacent to the course. “I cut hair all day!”

Sam Sann landed in the Third Ward in 1980. He was 13 years old, and in those 13 years he had survived the Khmer Rouge-led genocide, which took the lives of his mother and five of his six siblings. He had also spent years in a labor camp, eating snakes, rats, and crickets for sustenance. When the Red Cross relocated him, his father, and sister to Houston, he found work a long way from the Cambodian rice fields, at the Shipley Do-Nuts on South Post Oak. “It was a dead-end job,” says Sann, who was quickly on the lookout for something better. Walking through the Galleria one day, watching an energetic hairdresser entertaining a pleased client, he simply decided that styling hair was something at which he would excel. He bought some space in a strip mall with savings and a credit card and went to cosmetology school with $5000 borrowed from the owner of the Shipley’s. A year later, he was running his own salon.

Given this backstory, it’s only mildly surprising that Sann’s response to a knee injury—and the attendant concern that he would lose body muscle during the healing process—was to erect an adult playground in a strip mall. This course of action was inspired by NBC’s American Ninja Warrior, a show that pits contestants against a series of obstacles most of them lack the coordination and upper body strength to overcome. Sann insists that none of the obstacles he built were hard for him to conquer, although building the course, which he has never really stopped doing since he erected the steel frame five years ago, has been replete with hazards of its own. Nine months ago he electrocuted himself with a live wire; the current passed through his body and out the palm of his hand, leaving a severe exit wound. He did not stop cutting hair, and when his palm healed, the base of his thumb had fused to the center of his palm, leaving his hand in perpetual readiness for a pair of scissors.

In May, Sann took a break from hairdressing to try out for American Ninja Warrior in Denver. At 46 he was among the oldest contestants, but at 133 pounds was also among the lightest, and he flew through the course with ease and grace. On the “grip hang,” a perversely difficult take on monkey bars, it was as if Sann’s bodyweight buoyed rather than challenged him, and he hung one-handed where most of the competitors could not manage with two. When he dropped from the hang, he sprained his ankle, an injury that did not prevent him from scaling a 14-foot wall. Having advanced from the qualifying round, he attempted a second, more difficult course in the finals, still injured. He grimaced, limped, and eventually fell, though not before making it over another 14-foot wall. The professionally hyperbolic announcers called it “one of the most courageous performances in the history of Ninja Warrior,” and for perhaps the first time in the show’s five seasons, their excitement seemed justified.

We’ve come to Willowbrook to take a thrice-weekly class Sann teaches in the ninja warrior skillset—a slightly chaotic, cheerfully led series of physical challenges, such as traversing a wall punctuated with holes (think Erector set) by gripping two removable pegs, shimmying along a horizontal rope, and swinging along hanging rings, Jungle Book–style. When the student ninjas aren’t moaning, they’re laughing, or asking “what are we supposed to be doing?” because Sann’s good-natured, soft-spoken instruction lacks the drill sergeant clarity of your average CrossFit session. For a while, we just hang from a ledge using only our fingertips, which is exactly as painful as it sounds. The instructees range in age from 20- to 50-something, a third of them women. Whereas we had suspected a bunch of motivated oil-and-gas types in search of a grueling workout, they turn out to be motivated oil-and-gas types who have already competed in or plan to try out for Ninja Warrior. One of them, an engineer named Nika Muckelroy, was the first woman in the show’s history to complete five obstacles, an accomplishment she says she owes to Sann.

At 8:30 on a Thursday night we’re all in a straight line hanging from separate ropes, swinging gently, as Sann tells us to hold on. The class was supposed to end 15 minutes ago, but no one wants to leave. Two students, both summer interns at Exxon, laugh as their hands slip, and the room falls quiet. “I didn’t have much of a childhood,” Sann says. “I didn’t have time to play. This is my childhood. I am fulfilling my childhood dreams.”