Abs & Core Workout :-

This abs and core workout involves a variety of exercises designed to strengthen the rectus abdominis, oblique’s, the transverse abdominis and the erector spinae.  This is a great overall workout for intermediate exercisers who've been strength training for at least 4 to 8 weeks.  

    

Precautions
See your doctor before trying this workout if you have any injuries, illnesses or other conditions. 

Equipment needed
An exercise ball and a mat.

How To Do

• Begin with a 5- to- 10-minute warm-up of light cardio (walking in place, etc.).
• Perform 2 sets of 16 reps of each exercise with 20 to 30 seconds of rest between sets unless otherwise noted.
• Perform this workout 2 to 3 times a week with at least one day of rest between workouts
• For best weight loss results, combine this workout with regular cardio, strength training and a healthy, low-calorie diet.

Ball Crunches

Lie on the ball with hands behind the head.  Contract the abs and lift the shoulders off the ball, crunching them toward the hips without rolling on the ball.  Lower and repeat for 2 sets of 16 reps.

Reverse Crunches

   

Lie on your back with knees bent in to the chest.  Contract the abs to lift the hips off the floor.  Lower and repeat for two sets of 16 reps.  Try not to swing the legs or use momentum to lift the hips.

Long-Arm Crunch

Lie on a mat and extend the arms straight out behind the head.  Contract the abs and lift the shoulder blades off the floor.  For more neck support, place one hand behind the head while keeping the other arm extended.  Lower and repeat for two sets of 16 reps.

Bicycle

Lie on the floor with hands supporting the head and bring the knees to the chest.  Lift the shoulders off the floor and straighten the left leg while rotating the upper body to bring the left elbow toward the right knee. Switch sides, bringing the right elbow toward the left knee, and repeat for two sets of 16 reps.

Plank

Rest on your forearms and toes (put the knees down for an easier modification) and keep the hips down and back flat.  Hold for 20 to 60 seconds.

Knee Tucks

Position the ball under shins/ankles, with hands on the floor, and roll the ball in, bending the knees toward the chest as you squeeze the abs.  Try not to push back with your arms, but instead, keep all the movement in the knees.  Return to start and repeat for two sets of 16 reps.

 Back Extensions

Lie face down with hands either behind the back or lightly cradling the head. Lift upper body off the ground a few inches, keeping the head and neck in alignment. For a challenge, lift feet off the ground keeping legs straight (knees don't have to be together).  Lower and repeat for two sets of 16 reps.

P S : Article courtesy About.com