It's easy to hibernate during the winter. The days are long and cold, and the gym never seems as inviting as the comfort of your couch. Because of this, it's easy to put on extra insulation from November to February.

It's time to emerge from your cave. Spring has sprung and summer is less than 100 days away. If you want to cut the belly flab and get your beach body back, try the core-crusher circuit, devised by eight-pack-yielding Andy Speer, C.S.C.S., co-founder of Soho Strength Lab, in New York City, and creator of the Iron Body Workout. (Don't believe Speer has a legit eight-pack? Check out the photo above and the instructional images below. That's him and his abs.)

Here's how it works: After your regular workout, do the following exercises in order without resting between moves. You'll perform each exercise for 30 seconds. Once you've completed all three moves, rest for 30 seconds. That's one round. Repeat two more times. "These stability exercises hit your lower abs, upper abs, and obliques, strengthening and chiseling your middle in one go," says Speer. 

1. Plank Walkup 

Start in a plank position, with your elbows bent and your forearms on the floor. Place your left hand on the floor, then your right hand, and extend both arms until you are in the top position of a pushup. Pause, then reverse the movement and return to your elbows. On your next rep, initiate the move with your right hand. Repeat for 30 seconds.

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2. Side Plank With Rotation

Lie on your left side with your legs straight, and prop up your upper body on your left forearm. Raise your hips so your body forms a straight line from ankles to shoulders. Raise your right arm so it's perpendicular to the floor. Reach under and behind your torso with your right hand, and then lift your arm back up to the starting position. Make sure you rotate from your upper back, and not from  your lower back. Repeat for 30 seconds before switching sides.

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3. Plank With Leg Lift 

Start in a plank position. Your body should form a straight line from your head to your ankles. Keeping your core tight and your back straight, squeeze your glutes and lift your left leg a few inches off the floor. Pause, and then lower back down. Perform the same motion with your right leg. Repeat for 30 seconds.

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Test yourself with Speer's plank trio to start your road to a six-pack. And for more ab-revealing circuits, check out the complete Iron Body Workout.