This is a great workout for your abdominal muscles. The level of difficulty of this exercise is fairly high, so be sure to lower the number of repetitions to 8 if you need to, and gradually work your way up to 10.

Get on your knees (on a mat, if you’d prefer), keeping them shoulder-width apart. Do not rest your butt on your feet. Keep your upper body straight so that your calves and the rest of your body (torso aligned with thighs) form a 90-degree angle. Contract your ab muscles and lean backwards, keeping your back straight. Lean only as far as you can so as to not injure yourself. Return to the initial position.

Do 2 sets of 12 reps.