EXECUTION
- Jump or step up on a low stool to grasp a high bar so that the body can hang freely without the feet touching the floor. Also use a small footstool to stand on when adjusting straps to support your grip.
- Assume a full hanging position with a slight arch in the lower back, ie, with a neutral or a slightly exaggerated arched position in the lumbar spine.
- When you are ready, inhale and hold your breath as you bend the legs and raise the knees as high as possible.
- To be fully effective the knees should come up above the thigh level position. Hold the up position for approximately one-two seconds to ensure maximum shortening and tension of the abdominals.
- Exhale and relax slightly as you return the legs to the initial position. Then pause momentarily and repeat.
- When the bent leg version becomes easy, do the exercise with straight legs. Be sure to start from a stationary position and to lift the legs up as strongly as possible with the hip flexor and abdominal muscles.
- Work up to being able to touch the bar with the feet with straight legs.
Training Tips
- To get the greatest abdominal muscle involvement it is important that you raise the legs as high as possible. The reason for this is that the first part of the movement is controlled by the hip flexors while the abdominals are isometrically contracted. The abdominals do not begin to shorten until the thighs reach approximately the 30-45 degree angle from the vertical. In essence, the higher the knees go, the greater the rotation of the pelvis and the greater the involvement of the abdominal muscles, especially in the straight leg variant.
- Do not swing the body when executing this exercise. Be sure the body is perfectly still when you begin raising the legs.
- When first attemtping this exercise, begin with the bent knee variant which is half as difficult as the straight leg variant. When you raise the bent legs well above the thigh level position the exercise becomes more difficult and effective.
- Although involvement of the hip flexors has been negatively criticized by many “experts” this involvement should not be feared. The abdominal and hip flexor muscles have a close working relationship and are always involved together. You cannot eliminate one or the other contraction in movements of the legs or pelvic girdle.
- When hanging from the hands you receive a beneficial stretch of the entire spine. It helps to elongate you by getting more space between the vertebrae.
- Because the legs are a long lever and the training shoes are typically fairly heavy, additional resistance is not needed. The long leg lever with the weighted feet increase the difficulty of the exercise greatly. Thus to increase difficulty, keep extending the legs rather than trying to add weight to feet. When you can do straight leg raises with the feet touching the bar on each repetition then you should add more weight.
- The tighter your hamstring muscles the sooner the abdominal muscles come into play to rotate the pelvis. If your hip flexors are strong and you have good hamstring flexibility you can probably raise the legs somewhat higher before the abdominals come into play. This is how your physical abilities affect execution of the exercise.
Major Muscles Involved
The major muscles involved in raising the legs (hip flexion) are the psoas and iliacus, collectively known as the iliopsoas, the rectus femoris and the pectineus. The psoas lies deep in the abdomen and cannot be seen or easily palpated. The same holds true for the iliacus which lies to the side of the psoas on the inner surface of the ilium, the side bone of the hip. The rectus femoris is a long muscle that runs straight down the front of the thigh and is one of the major muscles of the quadriceps femoris muscle group. The pectineus is a short thick muscle located close to the groin and is covered somewhat by the sartorius and rectus femoris muscles. The major abdominal muscles involved are the rectus abdominis and the internal and external obliques. The rectus abdominis is a long slender muscle that extends vertically from the pubic bone to the sternum. The internal and external obliques cover the front sides of the abdomen from the rectus abdominis to the latissimus dorsi. The fibers of the internal and external oblique run at 90 degrees to one another in the upper portion of the abdomen. Muscle Joint Actions The hip joint muscles come into play initially to perform hip joint flexion in which the legs are in raised while the pelvis is held in place by isometric contraction of the abdominals. As hip flexion reaches it maximum range of motion (approximately 30-45 degrees from the vertical position) the hips and pelvic girdle maintain their position via isometric contraction of the hip flexors. The abdominal muscles, initially the lower portion, come into play to rotate the pelvis backward to allow the legs to continue to rise up. The leg-hip joint angle remains the same as the pelvis is rotated backward (the top of the pelvis moves backward). The higher the legs are raised the greater is the involvement of the upper portion of the abdominals. At this time there is total shortening of the abdominal muscles.
Sports Uses
In bodybuilding, strengthening the hip flexor muscles is important for maintaining balance with the hip joint extensor muscle development and, to a certain extent, the muscles of the lower back. Since an increase in muscle size is not easily seen with hip flexors, they play a relatively minor role in posing. The abdominal development, however, is very important especially when done through a full range of motion. In this case, especially in the straight leg variant, you get involvement of both the lower and upper portions to ensure maximum muscle shortening. This produces the greatest tension, and, as a result, the greatest amount of definition. In sports, hip and spinal flexion (backward rotation of the pelvis) are extremely important for raising the legs high in front of the body. This occurs in kicking through a full range of motion, in running when driving the thigh forward in the push off, when executing cutting actions, and when taking a long step to reach a ball or other object. Leg raises are also important in sports such as football, soccer, gymnastics, karate, rhythmic gymnastics, pole vaulting, hurdling and others. Development of the muscles involved is also important for prevention of injury to the lower back since these muscles help to stabilize the pelvis which in turn plays an important role in maintaining proper alignment of the spine.