A hanging leg raise is a dynamic exercise that simultaneously strengthens several muscle groups. Although the primary target of the hanging leg raise is the rectus abdominis, other muscle groups located in the hip and thigh are performing most of the work. When performed properly, the muscles of the back serve only to stabilize the body during a hanging leg raise. Muscles Involved In order to raise the legs during a hanging leg raise, there is an increase in intra-abdominal pressure created by the obliques, functioning to support the vertebral column. The obliques are classified as a waist muscle, usually encompassed by the broad term "abdominal muscles." The oblique muscles span the lower half of your torso, running from the soft tissue on your back, attaching to the lower seven ribs and inserting on your pelvic bones and abdominal soft tissue. Additional muscles involved in hanging leg raises include the hip flexors and leg extensors. How to Perform a Hanging Leg Raise To perform a hanging leg raise, stand below a horizontal bar. Grasp the bar and lift your feet from the ground; you may need to slightly bend your knees to prevent your feet from touching the ground, depending on the height of the bar. Next, raise your legs by flexing your hips and knees until the hips are fully flexed. Continue raising your knees toward your shoulders by flexing your waist. Slowly return to your starting position with your waist, hips and knees extended downward. Modifications The intensity of a hanging leg raise can be increased or decreased by applying various modifications. To decrease the intensity, perform the hanging leg raise movement lying on your back on a flat surface or incline. Conversely, to increase the intensity of this exercise, attach a weight to your feet or ankles. The amount of weight added depends on your ability. To determine how much weight you should add, perform five to 10 leg raises with increasing weight until you reach a challenging level without compromising form. Additional modifications include performing this exercise on a vertical leg raise apparatus with or without added weight. Safety Tips Before beginning any exercise program, consult your doctor. To prevent injury, do not swing your hips or lower body in order to raise your legs. If you are unable to perform a hanging leg raise, try an easier modification. When in doubt, have a fitness instructor demonstrate this exercise and evaluate your form.