There are two elements that you need to incorporate into your abs routine if you want a tight midsection in little time: instability and weight. We've paired an unstable surface with a medicine ball to create an amazing exercise that will carve your entire core.
If you're a beginner, master the move on the floor first before moving on the ball.
Stability Ball Crunch with Medicine Ball
To Do: Three sets of 15 reps.
Target Muscles: rectus abdominis
Set Up: Position yourself faceup on a stability ball, so that your back is supported and your legs form a 90-degree angle with your feet flat on the floor. Holding a six- to eight-pound medicine ball in your hands, extend your arms overhead, keeping them straight and lined up with your ears throughout the exercise.
Action: Contract your abdominals to lift your shoulders and upper back from the ball [B]. Hold for one count, then slowly return to the starting position. Repeat immediately.
Tip: If you have shoulder problems, leave the medicine ball out of the mix and simply extend your arms overhead.