The Intense Ab Workout You'll Barely Make It Through

Paired bundles of muscles and tendons that hook into the spine, the erector spinae runs along the sides of the spinal column and hooks into the back of your pelvis to protect and strengthen your entire back.

The Intense Ab Workout Move: Diamond Back

"People forget that to have amazing abs, you need to have a strong back," says Shaun T. "This move is deceiving. It doesn't look nearly as challenging as it is."

A. Lie facedown on the floor. Squeeze glutes so that legs lift slightly off of the floor. Raise chest and extend arms out in front, off of the floor to start.

B. Keeping chest lifted, draw one elbow toward back.

C. Extend that arm, then repeat on the other side. That's 1 rep.

Do 10 reps, alternating sides.

When most women say "abs," they're talking about the rectus abdominis. It's a long, paired muscle that, thanks to connective tissue, gives abs their six-pack look. Plus, it works to help your torso bend forward, which is pretty important if you want to get out of bed or bend down to pick up anything. Ever.

The Intense Ab Workout Move: Scissor Clap

"This intense ab workout move provides a great burn, but it's fun to do at the same time," says Shaun T. "Every time I hear that clap, I know I am staying in it!"

A. Lie face-up on the floor, shoulder blades raised off the floor and legs extended.

B. Keeping legs straight, lift the right leg so that legs form an L shape, lifting torso to clap hands behind the right leg.

C. Lean torso back slightly and lower the right leg, then immediately lift the left leg and sit up to repeat on the other side. That's 1 rep.

Do 10 reps.

Among the largest and outermost muscles in your core, the external obliques run on each of your sides. They help your body bend from side to side and your spine rotate. Since they're so large, they can do a number for your physique. (Related: These Are the Ultimate Abs Workout Moves, According to Trainers)

The Intense Ab Workout Move: Low Plank Oblique Knee Lift

If you thought side planks were hard, get ready.

A. Start in side plank, balancing on one forearm with shoulder directly above elbow. Hold the other hand at chest height.

B. Raise top knee toward chest until it taps hand, then lower it back down, maintaining a side plank throughout.

Do 10 reps. Switch sides; repeat.

Running underneath and perpendicular to the external obliques, the internal obliques work with the external obliques to help you bend and rotate. They work with the diaphragm to help you exhale during exercise—which is key to helping you work out harder, longer. (Find out the *real* difference between muscular strength and muscular endurance.)

The Intense Ab Workout Move: Ab Sprint

A. Lie face-up on the floor, legs extended. Lift legs just off the floor, sit torso up to a 45-degree angle, and pull one knee in toward chest to start. Allow opposite elbow to swing forward as if running.

B. Switch legs and arms without dropping feet to the floor. That's 1 rep.

Do 10 reps, alternating sides.

Your innermost abdominal muscle, the transverse abdominis, runs along the front and side of your abdomen and pulls it in like a corset. It's also the powerhouse of your entire core, fueling athletic performance—whether you're running, swimming, lifting, or cycling. (See: Why It's Important to Have Core Strength)

The Intense Ab Workout Move: Drum V

"There's something about pounding your fists against your stomach that's so primal and makes you dig deeper in every sense of the word," says Shaun T.

A. Sit on the floor, legs extended. Lean back slightly to balance on glutes and lift legs up until the entire body forms a V.

B. Take fists and bang them (not too hard!) against abs while maintaining the V shape.

Repeat for 30 seconds.

A group of muscles in the pelvis and upper thighs, the hip flexors are those "lower abs" you always have trouble hitting. More important than looks, though, they're critical to core strength and athletic performance. And since they're responsible for driving your knees up to your chest and keeping your pelvis aligned with your thighs, any weaknesses can put you at risk for running injury.

The Intense Ab Workout Move: Pike Up

"I love this move because it's like doing work on the ball, just without the ball," says Shaun T. "It's so good for the lower abs, which I know can be a tough spot."

A. Start in high plank position.

B. Keeping legs together and straight, hop feet in toward chest, piking butt toward the ceiling to form an inverted V shape.

C. Pause, then hop feet back out to the plank position. Repeat.

A thin, long, muscle that runs from the base of your spine up to the middle of your back, the multifidus provides stability and support to the spinal column. It helps each vertebra work its best and stay injury-free.

The Intense Ab Workout Move: Alternating Plank Balance

"This move is so hard and never stops challenging me," says Shaun T. "My goal is to limit how much I wobble and then I know I am really working that core."

A. Start in high plank.

B. Extend right arm in front and left leg behind at the same time. Pause, keeping hips square to the ground.

C. Slowly lower hand and foot toward the floor. Repeat on the other side. That's one rep.

Do 10 reps.