15 Exercises For Flat Abs

#15 The Plank

There is no ab exercise as widely known as the plank position. This position will help engage your core, while adding arm and leg movements will help burn belly flab and flatten your stomach.

#14 Butterfly Sit-ups

This variation of your everyday sit-up requires you to press your feet together, bringing your legs into butterfly position. Engaging both your upper and lower abdominals, inhale and curl up to a sitting position. Exhale as you return to starting position. Start with 25 reps and work your way up to a higher number.

#13 Twisted Sit-ups

A dance class favorite, these altered sit-ups incorporate your entire abdominal region, including your obliques.

#12 Knee Tuck

Shape.com likes this exercise for it's ability to target your "pooch" area. Start on your back with your knees bent, arms stretched overhead with palms facing the ceiling. Raise hips up and open knees, bringing them into your underarms. Exhale and return to starting position. Do 20 reps.

#11 Knee Curl

This exercise goes a step beyond your usual plank, and can also be done with hands on blocks and your feet on the ground. While in plank position, inhale and draw one knee into your chest, creating the feeling of pulling your bellybutton back into your spine. Exhale and return to plank position and repeat with other knee. Start with 10 reps.

#10 Good Ol' Side Plank

Your obliques need a workout too, and side planks are the perfect staple--and most basic exercise--for melting away muffin top and trimming your sides down.

#9 Side Plank With A Twist

This extra boost to the side plank requires a little more balance: While balancing on your right arm, extend your left arm straight into the air for balance. While balancing on your left foot, draw right knee up to a 90-degree angle, and trace circles in the air with that knee. Repeat on other side.

#8 Lumberjacks

Don't have room to lie on your back? No problem; Women's Health Magazine has plenty of standing ab exercises that you can perform. And the lumberjack is one of your best bets. Up the difficulty by using a medicine ball or barbell.

#7 "Weighted Bicycle"

Shape.com promotes this move for its San Diego State University-backed research proving its effectiveness on flattening abs. While lying your back, bicycle your legs and arms slowly and simultaneously, coordinating your right arm with your left leg, (and visa-versa.)

#6 "Pass The Block"

Fitnessmagazine.com uses a brick, but you can use a medicine ball or weight. Pulling bellybutton into the floor, bring feet to and hands together and pass off weighted object. Start out with 10 reps and gradually work up to 25.

#5 Touch The Sky

A lower ab workout that also engages your glutes and thighs. Lie on your back with you legs straight up in the air, hands lying parallel to your hips. Drawing your bellybutton into the floor, inhale lift your feet STRAIGHT UP into the air. Exhale and bring hips back to the ground for one rep.

#4 The Scoot

Named the "Magic Carpet Ride" by fitness.com this exercise will hit your lower abs like no other. Starting in plank position, inhale and engage your lower abs to pull knees into your chest; exhale and release. Start with 10 reps and work up to 25. (Tip: Perform this exercise on hardwood or linoleum floor with your feet on a towel.) Can also be performed with an exercise ball for extra difficulty.

#3 Semi-Downward Dog

A variation of The Scoot, this exercise requires you to start in a downard dog yoga pose. Engaging your lower abs, inhale and pull your feet into your hands. Exhale and slide feet back into downward dog position. Start with 10 reps and gradually work your way up to 25.

#2 "X-Abs"

Shape.com promotes this exercise because it targets EVERY ab muscle you have. Lie on your back with arms and legs extended so your body creates an 'X' shape. Inhaling and drawing your bellybutton to the ground, lift legs and hips up and over your head while bringing your upper body and arms up past them. Repeat 20 times.

#1 Stand Up Straight!

We know we know, your busy schedule doesn't always allow you to try all these gut-blasting workouts. But that doesn't mean that you can't still work towards a flatter stomach while you're at work or on your commute! Sitting up straight, walking upright and breathing deeply are all great ways to help flatten your abs.