The dumbbell weight should be challenging but not ... Using your core—not your arms—hinge at the hips and crunch down to slam the ball to the ground, as you lower into a squat position.

Hold a 5-pound medicine ball (or dumbbell ... and bring your arms overhead. Do 15 reps. Crunches, teasers, planks, and body-weight squats are some of the best exercises for stronger abs.

The crunch is a classic ab exercise. It’s also pretty straightforward: Lie on your back with your knees bent and feet flat on the floor, contract your abdominals, and lift your shoulders, neck, and ...

If you need proof of concept, just look at the guy. You might take you a week or two to get into the habit of knocking out ...