Lying Leg Curls are a great and simple exercise that will work your hamstrings and transverse abdominals.  They can be performed with a 55 or 65cm exercise ball.

Start Position

Lying on your back with your arms at your sides, place your extended legs on top of you exercise ball.  Slowly lift your hips off the ground so you create a bridge between your ankles on the ball and your shoulders.

With your abdominals pulled in tight slowly pull your knees into your chest so that the ball rolls towards your bottom.

Leg Curl Start Position

Curled Position

Keeping your knees and ankles tight together, slowly push your legs back out to the start position.

Try to keep the abdominal muscles tight to stop the ball rolling from side to side.

Leg Curl