Lift Your Way to Sliced Abs with Hanging Leg Raises

By Stephen E. Alway, Ph.D.

Every guy wants to reveal a solid six-pack when his shirt comes off, but not everyone wants to work to get one. The upper abdominal rows are activated by most abdominal exercises, but the lower sections of the abdominal wall are more difficult to isolate. However, straight leg raises from a chinning bar are among the best exercises that will shorten and optimize contractions of the lower abdomen and hip flexors. They will also work the sides and most of the anterior abdominal wall very intensely.

Muscles Used

The rectus abdominis muscle of the anterior abdominal wall is split by a thin, tendon-like called the linea alba.¹ Typically there are three or sometimes four rows of horizontally placed tendons making the “blocks” on the abdominal wall. The fibers of the rectus abdominis are short, and they extend from one horizontal tendinous insertion to the next. This muscle has a taper to it, so it is three times as wide at the top (superiorly) as it is at the bottom (inferiorly). When the rectus abdominis is tensed, the short fibers bulge between the tendinous grooves, and this gives your abs the “six-pack” look. If both right and left halves of this muscle contract, the thighs are flexed forward, which is the movement in the hanging leg raise exercise (assuming the pelvis is free to move).

The iliopsoas muscle of the lower and posterior part of the abdomen is a made of the psoas major and the iliacus muscles.¹ The psoas major is a long, thick muscle that is located beside the thoracic and lumbar vertebral column. The iliacus muscle is a large triangular muscle that sits over the inner surfaces of the iliac bones of the hip. The fibers of the iliacus and psoas major attach to a single tendon that connects to the femur bone of the thigh. The posas major and iliacus function as a single muscle (hence the name “iliopsoas” muscle). The iliopsoas is the most powerful flexor of the thigh at the hip joint and it is therefore very active during hanging leg raises.²

Two lateral abdominal muscles are activated by hanging leg raises.³ The external oblique runs from the lower ribs towards the center of your abdomen to form a flat, fan-shaped muscle. It attaches to the iliac bones of the pelvis and hip structure and also the linea alba.¹ The internal oblique muscle sits just deep to the external oblique muscle.⁴ It extends from the lower back and the iliac bone of the hip to the lowest three or four ribs. When both left and right sides of the external oblique and internal oblique muscles work together, they flex the trunk and move the feet towards the head.

Exercise: Hanging Leg Raises

1. A straight chinning bar works great for this exercise. You will hang from the bar during the exercise. If you have poor grip strength, you can use arm straps that attach to the chin bar to eliminate this problem.

2. Begin with your legs hanging straight down from your waist, to the floor. Keep your knees locked (almost completely straight) and slowly raise your legs (hip flexion). Do not swing, but use a controlled pulling of your hip flexors to raise your legs.

3. Raise your feet as high towards your head as possible, taking care not to bend your knees. Your hip angle (i.e., the angle between your abdomen and thighs) should be 90 degrees or less, at the top. Try to curl your pelvis forward to activate the rest of the abdominal wall.

4. Hold your legs in the highest position possible for 3 seconds, then slowly lower them to the beginning position. Ensure that you do not swing your legs past a position that would be vertical to your upper body. This could cause excessive extension of the lower back. In addition, swinging your legs backwards will stretch the fibers of the abdominal wall, but the goal is to shorten not lengthen the fibers. The swinging action is harder to control if you are hanging from a chinning bar as opposed to a leg raise station with a padded back to minimize your body movements.

5. Exhale during the upward movement and inhale as the legs descend. Although holding your breath will make the exercise easier, because this increases your intra-abdominal pressure (and arc of the rectus abdominis), this also stretches the abdominal fibers and does not allow the muscle fibers to fully shorten.

Hanging leg raises activate the lower regions of the rectus abdominis, although the iliopsoas muscle is still very much active in this exercise. In the hanging leg raise, the spine is unloaded and not stressed. This makes the hanging leg raise a much better exercise than lying leg raises, which create huge torques through the lumbar disks. To add some variety to the exercise, while also contracting both the internal and external oblique muscles you can twist the legs to the right on the first repetition as you raise your thighs, then twist the legs to the left on the next repetition. Do not twist quickly or this will generate unwanted torques across the lumbar vertebrae. As an added benefit, strong abdominals improve back stability.⁵

There is no exercise that will solely recruit the lower fibers of the abdomen without also activating other abdominal fibers and muscles. But no matter what exercise you choose, it is important to recognize that no exercise will perfectly carve deep ridges across your abdomen if it is buried in fat. The best strategy is to engage in aerobic training to utilize the fat calories as an energy source and use hanging leg raises to tighten and strengthen your lower abdomen. With a few months of hanging leg raises under your belt, coupled with intelligent dieting and aerobics, the metamorphosis under your shirt will reveal six-pack lower abs that are tight, strong and sliced.

References

1. Moore KL, and Daley AF.:Clinically Oriented Anatomy. Lippincott Williams & Williams, Baltimore, 4th Edition pp. 1999. 178-187.
2. Hu H, Meijer OG, van Dieen JH: Is the psoas a hip flexor in the active straight leg raise? Eur Spine J 2011; 20: 759-765.
3. Teyhen DS, Williamson JN, Carlson NH et al: Ultrasound characteristics of the deep abdominal muscles during the active straight leg raise test. Arch Phys Med Rehabil 2009;90: 761-767.
4. Feldwieser FM, Sheeran L, Meana-Esteban A et al: Electromyographic analysis of trunk-muscle activity during stable, unstable and unilateral bridging exercises in healthy individuals. Eur Spine J 21 Suppl 2012; 2: 171-186.
5. Stokes IA, Gardner-Morse MG and Henry SM: Abdominal muscle activation increases lumbar spinal stability: analysis of contributions of different muscle groups. Clin Biomech (Bristol, Avon ) 2011;26: 797-803.

Illustrations by William P. Hamilton, CMI