Core Values instructor Adriane Morgan assists student Sean Reineke with proper form on the parallette bars.

Peek into a Core Values class at Equinox and you won’t see anyone sweating profusely. There’s no jumping. No weights. But it’s one of the most intense offerings at the gym, warns instructor Adriane Morgan, because students need to be in total control of their bodies.

What It Is: Before you can strengthen your core, you have to find it. That’s harder than it sounds — but easier once you assume “hollow body” position. “It feels like you’ve been punched,” Morgan says. “Push in with your sternum and tuck your pelvis.”

The goal is to hold this posture for the duration of the class, while rolling on the floor, hoisting balls into the air and balancing on parallette bars (mini versions of the parallel bars used in men’s gymnastics). Sound like circus tricks? Bingo, says Morgan, who says this method is how acrobats learn to tap into those deep muscles.

Moves: The warm-up is designed to get you comfortable with this odd posture. You’ll start on all fours, tucking your pelvis. Then you’ll sit on your knees, tucking. Then comes a hip bridge, with more tucking. “Think about using your abdomen, not your tush,” Morgan offered at a recent class, before things really got rolling.

Students are expected to teeter-totter every which way — including lying on one side of the body while rocking front to back — to build up endurance for pelvic positioning.

Complete an intense wrist warm-up, pushups and other conditioning, and it’s time for the three circuit stations: wall, ball, bars.

Exercises change each week, but the principles stay the same. At the wall, it’s plank variations, such as walking your hands out in front of you. With a medicine ball, students practice balance, sometimes by holding it above their heads, standing on one leg and leaning back. The parallete bars are for learning how to lift your body off the floor with just your arms.

Workout: Everyone is pushing themselves to their limits. “You have to focus on body awareness,” says Sean Reineke, 52, who’s now able to hold himself on the paralletes in a pike position. “If you don’t tie it all together, you can’t do it.”

Just attempting that feat is exhausting — and that’s all that’s expected. “If you can’t do a lot, just try to understand the concepts,” Morgan says.

Eventually, you’ll be hard-core, too.

Class Details: Core Values is offered at 10:45 a.m. Wednesdays and 4 p.m. Saturdays at Equinox’s Bethesda location (4905 Elm St.). It’s at 8:30 a.m. Tuesdays and 12:15 p.m. Sundays in Tysons Corner (8065 Leesburg Pike). For details, go to