Stability moves like the plank are a great way to strengthen a weak core and prevent lower back pain. But if you want to kick things up a notch, then start dancing. When you perform the breakdancer, you'll quickly move your feet from side to side and across your body. However, you must maintain the same rigid, straight torso that you would when performing a plank.
Muscles exert higher EMG tension when they are contracting eccentrically (lowering the resistance) versus raising it; but the problem with most exercises is that the amount of weight you can lower is limited by how much you can lift positively (concentric work). This exercise compensates for the problem by changing the leverage during the lowering (eccentric) phase of the exercise.

While staying hydrated is important no matter your fitness goals, you absolutely have to drink up if you want to see the abs you’ve been working so hard to sculpt. Your body is two thirds water, and you want to make sure it stays that way, Delbridge says. Keeping your water levels up prevents water retention and helps your body rid itself of toxins and excess salt to reduce boat. And if you’re puffy, your abs aren’t going to look as chiseled as they could. When you hit the urinals, your pee should be pretty much clear.

Why it made the list: Decline-bench crunches amp up the challenge by increasing the range of motion over standard crunches, and you can dial up (or down) the degree of difficulty by adjusting the angle of the bench. Adding a medicine ball or weight plate against your chest adds a further level of customizable resistance. This also allows you to manipulate where you want to fail: low, medium, or high reps.

How to: Lie faceup on floor with arms and legs in the air, knees bent 90 degrees. Maintaining contact between low back and floor, brace core, then slowly and simultaneously lower right leg until heel nearly touches floor and left arm until hand nearly touches floor overhead. Pause, then return to start and repeat on the opposite side. That’s one rep. Do 15 reps.

Before you launch into the advanced ab workout, you will want to ease into it with some basic core exercises to warm up the abdominal muscles. The Plank is a great way to begin. The plank provides a simple and effective core warm-up because engages all the muscles of the core from your toes up to your head. Holding the plank requires the activation of all the major ab muscles as well as many stabilizer muscles that are often ignored.
To do it: Stand with your feet hip-width apart and pressed firmly into the floor and hold a medicine ball (or other similar weighted object). Brace your abs in tight (as if preparing for someone to punch your stomach) and use your lower body to start the movement by bending your knees, sitting back into your hips, and reaching the ball down across the outside of your left leg. Stand up, swinging your arms across your body and up to the right while pressing your hips forward. Do 10-12 reps going from left hip to right shoulder, and then repeat on the other side.