A perfectly toned tummy is reason enough to add more core moves to your workout routine. Additionally, a strong mid-section is the essential foundation you need in order to stabilize the spine and help prevent future injury. Crunches alone won't get the job done. You need moves that will flex as well as stabilize the core. The stronger your core is, the stronger you’ll be in everything else you do.

Try these five moves to shrink and sculpt your waistline.

Walk the plank

The plank is the best example of an isometric exercise, where your muscles are contracting but you're not moving the torso at all. In this position, you are working all of the muscles surrounding the core, including your rectus and transverse abdominals, internal and external obliques, and lower back. But we’re adding a challenge. Start with a traditional plank, with your legs glued together and your wrists right underneath your shoulders. By "walking" the plank, you simply come down to your forearms and then back up to your hands. Do 30 seconds on one side and then switch the direction of which arm comes down first for another 30.

Modification for beginners: Same movement but come down to a modified plank position on your knees.

RELATED: 10 New Ways to Do a Plank

Plank jacks

Another way to switch up your regular plank is with a plank jack, where you move your feet like a regular jumping jack. This one targets the lower half of the torso, whereas the first exercise might work the upper half more. In a traditional plank position on the hands and feet, jump your feet away from each other and then jump them back to starting position. Try to keep your upper body from moving and aim for 20 reps.

Modification for beginners: Start in a plank. Move one leg at a time away from the center of your body, without moving the upper body. Do 20 on each side.

RELATED: 24 Fat-Burning Ab Exercises (No Crunches!)

Slippery plank

A third modified plank exercise is the slippery plank. Start in a push-up position with a towel (or other item which will allow you to slide your feet freely) placed under the ball of each foot, legs together. Bring your right knee in towards the right elbow, squeezing your abs. Then, re-straighten your right leg and perform the same movement with your left leg. Finally, draw both knees into your chest at the same time and then slide your legs back out to full plank. That’s one rep. Do 3 sets of 15 reps.

Modification for beginners: Perform the same movements from a modified plank position, resting your weight on your forearms instead of your hands.

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Teaser ‘toe touches’

Start lying face up, legs extended out and arms overhead. At the same time, lift both arms and legs up together and reach for your toes, balancing on your tailbone for a moment before returning your arms and legs down to their original position. (Use a mat if you have hard floors.) Do 3 sets of 15 reps.

Modification for beginners: Start with the legs at a 45-degree angle, extending the arms up overhead. Keep the legs where they are as you bring the upper body up to reach for the toes and then return the upper body down, maintaining the 45-degree angle with the legs.

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Corkscrew

Lie flat on your back on a mat with your arms held firmly at your sides. Squeeze your legs together tightly and bring them straight up so your toes point toward the ceiling. Inhale as you lift your legs overhead until you’re balancing in the middle of your shoulder blades. Exhale with control as you roll back down your spine, leaning your body slightly to the right. When your right glute touches the mat, circle your legs around to the left until you’ve made a full circle. Then scoop your abs in as you lift your legs and hips back up off the floor and reverse the movement, this time circling your legs to the right. Try and complete 5 each direction.

Modification for beginners: Make the circles, but without lifting your back off the mat. Once you feel strong enough, then you can try the advanced version.

To work more specific muscle groups, check out 5 Moves To Perk Up A Flat Butt.

Jennifer Cohen is a leading fitness authority, TV personality, entrepreneur and best-selling author of the new book, Strong is the New Skinny. With her signature, straight-talking approach to wellness, Jennifer was the featured trainer on The CW’s Shedding for the Wedding, mentoring the contestants’ to lose hundreds of pounds before their big day, and she appears regularly on NBC’s Today Show, Extra, The Doctors and Good Morning America. Connect with Jennifer on Facebook, Twitter, G+ and on Pinterest.