In the backyard of his mother's home, Seth Caskey erected a 12-foot-tall, wooden pull-up ladder featuring ascending notches on which a metal bar can rest.
The so-called salmon ladder is the first of several obstacles that Caskey is building for his "ninja warrior" course — one not unlike others popping up in recent years in backyards and gyms nationwide.
The interest in ninja-style workouts has been fueled largely by TV shows such as "American Ninja Warrior," which pits contestants against one another in timed challenges that tax their fitness, athleticism and willpower.
Although few on-air contestants have completed the grueling course, viewers nonetheless seem to connect with the competition, said Kent Weed, executive producer of the show.
"People feel like they can do it," Weed said.
Since appearing on "American Ninja Warrior" in April, Westerville resident Michelle Warnky has seen a growing interest among central Ohioans looking to give a course a try.
"Two years ago, there weren't many gyms where they had obstacles," the 29-year-old personal trainer said. "This past year, everyone is starting to build things at home or at gyms."
In the spring, Warnky received permission from the owner of Vertical Adventures to set up 20 handmade obstacles behind the indoor rock-climbing facility on Busch Boulevard.
She has since been hosting monthly "American Ninja Warrior" contests as a way for people to test their skills and learn a new workout.
"We'll practice for an hour or two, trying different obstacles, and run a course and see how (people) do," she said.
For the masses, ninja workouts encompass climbing (ropes), leaping (from trampolines to cargo nets), beam walking and other such feats.
Trainers say that such exercises improve balance, strength, endurance and more.
Jim Steffen — owner of XT Fitness in Findlay, which three months ago began offering adult ninja classes — said such courses also build camaraderie.
"You're working in a community more so than putting your headphones on, watching a TV on a treadmill," said Steffen. "People stick with this longer, and they see better results."
Caskey has been using his salmon ladder a few times a week for strength-building at his mother's home in Galloway.
"It gets a lot of your back muscles worked out, then it starts to work out your arms, too," he said.
The standard use of the salmon ladder involves leaping to grab ahold of the metal pipe, doing a pull-up on the bar and then "jumping" the pipe up a notch on the ladder — with the notch jumping repeated several times up the ladder.
The popularity of ninja workouts has also given way to mainstream obstacle-themed races such as the Mud Ninja and the Tough Mudder.
Dublin resident Marty Parker introduced an annual Mud Ninja event last summer — which he hosts in South Salem, in Ross County, in hopes of drawing participants from the Columbus, Dayton and Cincinnati areas.
Britnee Powell of Worthington was among the 45,000 who entered the Mud Ninja race this year.
"I really think the fitness community is changing in general," said Powell, 24, a human-resources coordinator at the design firm Big Red Rooster.
"People are finally realizing that working out doesn't simply have to be lifting weights and doing cardio which is really exciting."