Students cycle through ab exercises, strength moves and cardio bursts as they complete a circuit at Capitol Hill Fitness.

Capitol Hill Fitness promotes a balance of powers. Or, rather, balance and power. Throw in strength and you have a full-body workout that’s worth electing to do.

What It Is: When Dia Michels hired a personal trainer, she figured the empty space next to her publishing company on Barracks Row would make a good spot to meet. The location worked out so well that she realized it could become an actual gym — and one she’d have no excuse to avoid.

“We were already training here. This could work,” says Michels, who partnered with her trainer, Breelaun Marchai, to transform the room into a boutique fitness facility that opened June 15. The small size isn’t really suited for a free-for-all, so the facility is set up for classes only. Each session is taught as a circuit, with between eight and 14 exercises. Folks stay at a station for 30 to 90 seconds before rotating to the next move, and cycle through two or three times before it’s all over.

Moves: The workouts come from his list of 873 favorite low-impact exercises, says Marchai, who starts each class by quickly demonstrating what’s on tap for that day’s routine. Last Wednesday, he began by grabbing one handle on the dual-adjustable pulley, sinking into a lunge and yanking downward. Next up was taking a step on top of several risers and lifting a knee. Then came “just a regular plank,” which turned out to involve resting his feet on a Bosu and alternating lifting arms in front of him. After working his way through side plank, kettlebell raises, bicep curls, rowing machine sprints and other stations, he was ready to let the students take his place.

“I’m already sweating and my heart rate is elevated,” Marchai said. “Good luck.”

His job involves more than just watching the clock. He swoops around the room correcting form, throwing out nutritional tips and reminding people who’ve forgotten what they’re supposed to do. (There are signs with photos posted at each station, but sometimes another live demo is necessary.) All of that leads up to the signature move that ends each circuit: the high-five. Better get that — and a sip of water — fast, because Marchai doesn’t wait long before diving into the next round.

Trainer Breelaun Marchai, right, shows students how to perform exercises and offers pointers on technique.

Workout: “Except for my ears, I think we worked everything,” Elizabeth Burns, 21, declared after taking her first Capitol Hill Fitness class. So which exercise did she think was the toughest? “Are you asking which one I cheated on? It’s hard to cheat because Breelaun is watching,” added Burns, who predicted her tummy would ache the next day after all those ab moves.

The intensity reminded Sean Farley, 19, of his high school football training: “My whole body is shaking.” And former cross-country runner Heather Kitt, 20, appreciated that the circuit-style setup tested her endurance.

For motivation throughout the workout, clients don’t have to rely solely on encouraging advice from Marchai. They can also look at the TV, which loops clips of animals, sporting events and Marchai’s reality show, currently in production. (“I find people on the street and force them to work out,” he says.)

Crowd: Because Marchai’s goal is to challenge but not overwhelm, he’s quick with modifications to make sure people can keep up.

“Everyone is doing something different, which is why I can have a student who’s 83 and another who’s 10,” says Marchai, who likes to have a mix of abilities in the room. He has experience training sports teams, as well as handling medical rehabilitation clients and prepping models for photo shoots.

The result is a routine that feels customized despite the group setting, Farley adds: “I like the fact that he’s watching over you. It’s your own workout, and he’s almost a personal trainer.”

Details: Capitol Hill Fitness (725 Eighth St. SE, 877-657-0004, offers 45- and 30-minute circuits, as well as 20-minute abs classes. Attendance costs $15, $10 and $5, respectively, and students have the option to buy multiple class packs at a discount. Through Labor Day, all classes on Tuesdays and Sundays are “Name Your Own Price.” There are two changing rooms and two bathrooms on site, but no shower.