The first time Christine Saba climbed off her surfboard at the Canton Club fitness center her legs felt like jelly — as if she'd spent the day at the ocean.

But Saba was on no vacation. She had just spent the past hour simulating — or trying to, at least — the moves of the bikini- clad who ride the waves of the Hawaiian shores and other popular surfing areas.

"You get off and it's hard to get your balance," said 23-year-old Saba, who had just taken a Surfset Fitness class. "You feel very wobbly."

That is exactly what the inventors of one of the newest fitness trends want people to feel. During Surfset, riders do squats, planks, lunges and other exercise moves on a surfboard that uses bands and rubber balls to emulate the unsteady waters of the ocean. At points in the class, participants lie on the board and move their arms as if they're paddling through a wave.

The effect is a workout that puts more emphasis on the core and makes every muscle work harder than they would if the moves were done on the still floor.

"If you do a squat on the board it is like doing a squat and a sit-up because your core is always activated," said Nick Karwoski, a Surfset spokesman. "When you squat down, the board is going to be moving, so the core has to stabilize to stay steady. You're using so many more muscles than you would on stable ground."

The class can be fast-paced, with participants jumping from their stomachs to a squat position and then to standing in a matter of seconds — as if preparing to ride a wave.

It might take a couple of classes just to get used to being on the board, and some people might fall off the first couple of tries, said Jacki Dalsimer, Canton Club fitness director.

"Your going to feel it in your whole body," Dalsimer said. "There's no getting around it."

Surfset was founded by three friends, including a professional hockey player who surfed during the offseason and found it was one of the best workouts he had done. He began looking at how to bring surfing indoors after retiring from hockey and becoming bored with his new desk job.

The company got a boost when it appeared on "Shark Tank," the ABC reality show where entrepreneurs try to persuade investors to put money into their company. Dallas Mavericks owner Mark Cuban agreed to invest in Surfset.

The class is in 64 gyms across the country and there are plans to continue expanding, including in Maryland.

Danielle Nisson, a Baltimore schoolteacher, saw Surfset on "Shark Tank," so she was excited when she glimpsed the truck parked outside of her gym. She takes the class regularly and said it is challenging no matter how many times she does it. She sometimes finds herself doing variations of the positions when they become too difficult.

"I love that it is something different, and it's not too easy," she said.

andrea.walker@baltsun.com

twitter.com/ankwalker

If you go

Class times: Tuesday at 7:30 a.m.; Wednesday at 6:30 p.m.; Thursday at 11 a.m.; Thursday at 7:30 a.m.

Where: Canton Club, 2780-D Lighthouse Point East, Baltimore

Cost: $120 for four classes for members; for nonmembers, $120 for four classes then price rises to $180.

Information: cantonclub24.com