The 6 best exercises for six-pack abs

. Pullup

Why it works your abs: People typically think of the pullup as an exercise for your biceps and back, and it is. But when done correctly—no flailing legs, no kipping, no hip hinges—pullups also require a formidable amount of core strength. As you pull yourself up to the bar, your abs need to work hard to keep your body still.

How to do it: Grasp a pullup bar with a grip that's slightly wider than shoulder width. Pull your shoulder blades down and back, bend your legs behind you, cross your feet, squeeze your butt, and brace your abs (this ensures your core gets worked). This is the start position. Pull yourself up until your collarbone reaches the bar, driving your elbows down toward your hips. Return to the start position. If unable to pull yourself up, loop an exercise band over the bar and around your knees, and use that force to help you

Sets: 3 Reps: To failure Rest: 2 min. between sets

2. Medicine Ball Slam

Why it works your abs: This one's a double-whammy. Picking up a weighted ball requires your posterior chain to fire, like in a deadlift or a clean. When you slam the ball downward, make sure you fire your core hard while hinging at your hips, which will ensure your entire abs muscle has to fire. Don't just drop it from above your head.

How to do it: Grab a fairly light-weight medicine ball and hold it up above your head. Keeping your torso totally upright with good posture, throw the medicine ball directly downward at the ground as hard as you can. Just be careful: Some bounce back!

Sets: 3 Reps: 20 Rest: 1 min. between 2 set

. Ab Wheel Rollout

Why it works: This one's a classic, and rightfully so. Contrary to what you might expect, your abs don't actually move all that much in an ab wheel—it's more of an isometric exercise—but they do have to work extraordinarily hard to keep your torso from collapsing onto the floor. A few sets of these and your abs will be screaming for mercy.

How to do it: Kneel on the floor with your knees directly under your hips and your hands directly under your shoulders holding the handles of an ab wheel. Slowly push your hips forward and roll the ab wheel out, keeping your back flat and allowing your arms to extend in front of your body. As soon as it feels like you can’t roll anymore without the risk of falling, push your palms toward the floor, simultaneously squeezing your abs and pushing your hips back toward the start position until you reach it.

Sets: 4 Reps: To failure Rest: 90 sec. between sets

4. Pallof Press

Why it works so well: The Pallof is relatively exotic. You don't see many guys doing it, at least not in the gyms we've been in. But trust us: Few moves combine rotational effort and straight-ahead effort like the challenging Pallof press, which require your abs to prevent your torso from turning as you increase the torque by moving your hands forward. Bonus: It's also a great way to improve your shoulder strength.

How to do it: Attach a D-handle to a cable cross machine and adjust the pulley to chest height (a resistance band around a pole works, too). Stand about two feet away from the machine and pull the handle to your chest. If your right shoulder is closest to the machine, your right hand should hold the handle and your left should be more of a guide. While bracing your core, push the handle straight out, so the handle stays directly in front of your chest. Slowly return the handle to your chest.

Sets: 4 Reps: 10 on each side Rest: 1 min. between sets

5. Barbell Landmine

Why it works: This fundamental movement works your entire body, as pretty much every muscle you have has to stabilize your torso as you press the weight up and away from you. Your abs will have to do a lot of work to sustain the tension of the weight.

How to do it: Wedge one end of a barbell in the corner of two walls (use a towel so you don't scuff the paint), or use a landmine attachment if your gym has one. Lift the barbell up by the other end and hold it on your chest. Next, press the barbell directly out from your chest with both hands, fingers laced. Keeping your arms straight, rotate from your shoulders to one side, then to the other. Return to the start position.

Sets: 3 Reps: 10 on each side Rest: 2 min. between sets

6. The Pendulum

Why it works: Also known as a "lying windshield wiper," this supremely challenging ab exercise forces your entire core and torso to hold steady as you shift your legs from side to side. It also hits the obliques.

How to do it: Lie on the floor flat on your back and raise your legs until you have a 90-degree bend at the hips. Keeping your legs straight, lower them to the right, allowing them to come almost all the way to the floor. Return the legs to the upright position and then lower them to the left. Repeat in this fashion until all prescribed reps are performed.

Sets: 4 Reps: 10 to each side Rest: 1 min. between sets