Bent Leg Raises
"Lie on the floor with your legs straight out, your hands under your buttocks, and your chin on your chest...then pull your knees all the way into your chest area." (Arnold: The Education of a Bodybuilder p. 168)
Modifications:
To increase the intensity, you can increase the weight by wearing ankle weights.
Modifications:
To increase the intensity, you can increase the weight by wearing ankle weights.