by Holly Ridgeway

Created on: November 04, 2009

Still trying to get that six-pack? For rock hard abs, try these 5 exercises in a circuit. No need to count reps - just do each one to muscle failure (until you can't do another rep or hold the position with good form). Rest no more than 10 seconds between each exercise. When you're done with the 5, rest for 90 seconds, and then do a second circuit of 5. Do 2 circuits 3 times per week, but change up the order of the exercises each time.

Remember that core exercises are often more effective at a slow tempo, so don't rush the reps. Also, know that a six-pack does not show up overnight, and it will not show up at all if you don't eat right!

1.Oblique Twist: Sit on a mat with your feet on the floor and your knees at 90 degree angles. Take a medicine ball in your hands. Lift your feet several inches off of the mat while at the same time leaning back to balance yourself. Twist your torso from side to side, touching the medicine ball to the ground each time.

2. V-Up: Lie flat on your back with your arms extended. Tense your abs and your glutes. Curl your torso as if you were trying to get your ribs to meet your hips, while at the same time bringing your legs upwards. Keep your legs as straight as possible and your elbows close to your ears. Lower and repeat.

3. Bicycle: Lie on your back. Put your hands behind your head and bring your feet off of the mat until your knees make 90 degree angles. Twist your torso by bringing your left elbow towards your right knee, and then your right elbow towards your left knee, and repeat. The greater the angle of your knees (or the higher up you pedal), the harder it will be.

4. Double crunch: Lie flat on your back with your legs extended. Cross your arms across your chest. Lift your feet a few inches off of the floor. Curl your torso forward and upwards while bringing your knees to your chest. Lower and repeat.

5. Plank: Get in a push up position, then lower your body so that you are supporting yourself on your elbows at 90 degree angles. Make sure that your ankles, hips, and shoulders are in alignment. Hold until you can no longer keep good form. Put your feet on a Bosu ball or a step to make this exercise harder.

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