A Core Workout for Flat Abs in 4 Simple Moves

Whittle your waist with this 20-minute routine based on Kira Stokes’s super-hot Core Cuts class at the Reebok Sports Club/NY. These standing ab moves require lots of balance and stability, giving your core muscles an extra challenge.

Do this workout 3 times a week (plus 40 minutes of intense cardio 4 times a week)—and you can lose 2 inches off your midsection in just four weeks. Do all the moves once, then repeat the entire circuit 2 more times.

A.

Stand with feet slightly wider than hip-width apart, with your weight on your right leg and a 3- to 5-pound dumbbell in your left hand. Stretch your left hand up and overhead to the right so you feel a stretch in your left side waist (aka your oblique).

B. Crunch your torso to the left, bringing your left knee up and left elbow down toward each other as if trying to crack a nut between your ribs. Return to previous position. Do 12–15 reps, then switch sides and repeat.

Trainer tip: For maximum core challenge, tap the ball of your foot on the floor after each rep instead of putting your whole foot down.

A.

Stand with feet wider than hip-width apart and knees slightly bent. Hold a 3- to 5-pound dumbbell between both hands, and extend your arms toward the ceiling.

B. With head between arms, bend to the left as far as possible, keeping hips and shoulders square. At the last moment, rotate toward floor, then rotate back to forward-facing position and return to arms overhead. Repeat on other side, moving smoothly (like a pendulum). Do 10 reps per side.

A.

Stand with feet together, holding a 3- to 5-pound dumbbell with both hands. Extend arms and slowly tilt forward at the waist, lifting left leg so it and your upper body are parallel to the floor and your arms are by your ears.

B. Bend elbows to bring the weight in toward your chest. At the same time, bring left knee in toward your chest so elbows and knee meet at the midline. Return to previous position. Do 12–15 reps, then switch sides and repeat.

A.

Stand with feet shoulder-width apart, holding a 3- to 5-pound dumbbell between both hands. With your shoulders and hips square and knees pointing forward, lower into a squat and bring the weight down by your right hip.

B. Push from your heels up and out of squat position, sweeping the weight diagonally across your body until it’s above your left shoulder. Do 15 reps; switch sides and repeat.

Trainer tip: Need help maintaining proper form? Hold a yoga block or ball between your legs.