Instructions
Lie with your back on the floor and place your legs out straight with your ankles resting on the top of a swiss ball. Place your hands to your sides. Lift and squeeze your buttocks up to raise your hips up until your body is in a straight line.
Lift one leg off the ball and bring it out to the side. Keeping your leg straight, draw circles with your foot for the required number of reps. You can also change direction. Place your leg back on to the swiss ball and repeat on the other side.
Tips
To make this exercise harder, draw larger circles.