Sit on a bench with the legs stretched out in front of you slightly below parallel and your arms holding on to the sides of the bench. Your torso should be leaning backwards around a 45-degree angle from the bench. This will be your starting position.
Bring the knees in toward you as you move your torso closer to them at the same time. Breathe out as you perform this movement.
After a second pause, go back to the starting position as you inhale.
Repeat for the recommended amount of repetitions.
Variations: You can also perform this exercise on a mat on the floor just by placing your arms to the sides. In this case, the legs will be stretched and elevated slightly over the floor. Also, as you become more advanced you can hold a dumbbell in between your feet or attach a pulley to them for added resistance. However, you have to be very careful when adding weight to this exercise as if you add too much too quickly you could get a hernia.