Lie on your left side and see to that you maintain a neutral spine .
Get your left arm across your chest i.e. in front of your torso close to your right hip and put your right hand behind your head.
Initiate the movement both at the torso and your legs, bringing your head towards your hips.
Return to the start position and repeat.
If you find this exercise difficult , you can start by only lifting your legs.
Your Fitness Club.