This simple exercise has lots of toning perks! Try it to work your hamstrings, glutes and calves.

Fit ball hamstring roll-ins - IMAGE - Women's Health and Fitness magazine

How to

1. On the floor, lie on your back with your feet on top of the ball.

2. Position the ball so that when your legs are extended, your ankles are on top of the ball. This will be your starting position.

3. Raise your hips off the ground, keeping your weight on the shoulder blades and your feet.

4. Flex the knees, pulling the ball as close to you as you can, contracting the hamstrings.

5. After a brief pause, return to the starting position.

NEXT: browse more a-list butt exercises, or try Swiss ball roll-outs to work your core and arms.

Words and workout by Melissa Le Man, images by Noel Daganta