The plank is a simple, yet extremely effective exercise that not only targets your abs, but strengthens your entire core. If you want to take your workout to the next level, try these two challenging variations.

Advanced Side Plank Lift:

1. Begin by getting in the starting position of a pushup, on your hands and feet.

2. Rotate your body to stack one foot on top of the other and balance on one hand, making sure that your wrist is aligned underneath your shoulder. Work to hold your body in a straight line.

3. From this neutral position, contract your abs and lift your hips toward the ceiling as high as possible, then lower the hips back to neutral. Repeat 5 times, then start over to balance on the other hand.

4. For an easier starting position, balance with your forearm on the floor, instead of on one hand.

“Army Crawl” Plank:

1. Begin again in a pushup position, then bend at the elbows to rest your weight on your forearms. Form a straight line from your head to your feet.

2. Keep your abdominals contracted to prevent your lower back from sagging toward the floor.

3. Slowly lift one foot slightly off the floor; draw your knee away from center and pull it toward your elbow.

4. As you pull your knee in, squeeze your abs on that side, between your ribs and hip.

5. Repeat on the other side, and continue by alternating knees.

Faith Dey is an ACE-certified personal trainer and health coach, specializing in women’s wellness and nutrition. She has helped certify fitness professionals across the U.S. and is a former co-host of ESPN’s Crunch Fitness.

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