EXECUTION
- Support yourself on a standing vertical bench by pressing your forearms against the pads and griping the handles. Your back should be in contact with the vertical bench and your legs should hang freely directly under the body.
- Inhale slightly more than usual and hold your breath as you bend the legs and raise the knees until the thighs are slightly above level. Hold the position for approximately 1-2 seconds.
- Exhale and relax slightly as you return the legs to the initial position. Pause momentarily and then repeat.
- Execute the up phase with a vigorous drive of the knees upward and return slowly.
- When the bent leg version becomes easy do the exercise with straight legs.
PERFORMANCE TIPS
- To get the greatest abdominal muscle involvement it is important that you raise the knees as high as possible. The reason for this is that that the first part of the movement is controlled by the hip flexors while the abdominals are isometrically contracted. The abdominals begin to shorten when the thighs reach approximately 30-35 degrees from the vertical. The higher the knees go, the greater the rotation of the pelvis and the greater the involvement of the abdominal muscles especially in the upper portion. .
- Although involvement of the hip flexor muscles has been negatively criticized this involvement should not be feared. The abdominal and hip flexor muscles have a close working relationship and always involve together. You cannot eliminate one or the other muscle involvement or contraction in movements of the legs and pelvic girdle .
- Because the hip flexor muscles initiate the thigh raise the movement can be fairly vigorous since development of these muscles it not a main objective in this exercise. When the thighs reach approximately 35-45 degrees (depending upon your hip joint flexibility) the hip flexor muscles contract isometrically to maintain the pelvic girdle thigh relationship and then the abdominals come into play to rotate the pelvis, and as a result, continue to raise the thighs.
- Breath holding is important in a full range of motion execution. The breath holding helps to stabilize the upper body and provide a strong base on which the abdominal muscles can contract. In addition, the breath holding creates additional force to enable you to raise the thighs as high as possible to get maximum abdominal muscle involvement.
- Additional weights are usually not necessary in this exercise. The reason for this that most women experience discomfort or fatigue in the shoulder and arm muscles so that it becomes difficult to maintain the same position during execution. However, the more you do the exercise the stronger the shoulder and arm support muscles should become. To enhance your ability to maintain the upright position you should also do some modified dips so that you become accustomed to supporting your body weight.
- If execution of the exercise becomes easy, you can place some ankle weights for increased resistance when raising the thighs or do the straight leg variant, which is twice as difficult as the bent knee version.
MAJOR MUSCLES INVOLVED
The major muscles involved in raising the legs (hip flexion) are the psoas and iliavcus, collectively known as the iliopsoas, the rectus fermoris and the pectineus. The psoas lies deep in the abdomen and the iliacus is located 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 primary abdominal muscles involved are the rectus abdominis, a long slender muscle that extends vertically from the pubic bone to the sternum and the internal and external obliques, which 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. The side- angled muscle fibers are well seen when the muscles are well developed and you have little fat in this area. They greatly compliment the “rippled” appearance.
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 legs 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 thighs are raised, the greater is the hip rotation and involvement of the middle and upper portions of the abdominals. Complete shortening of the abdominal muscles occurs at this time.
Sports Uses
In bodybuilding strengthening the hip flexor muscles is important for maintaining the balance with the hip joint extensor (gluteus maximus and hamstring) muscle development and, to a certain extent, the muscles of the lower back. In this exercise you get involvement of both the lower and upper portions of the abdominals. This produces the greatest tension, and as a result, the greatest strength and definition especially of the lower portion of the abdominals. 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 is seen in dance, ballet and chorus lines, kicking, as in soccer, in running, when driving the thigh forward in the push off, and when taking a long step to reach a ball or other object as in tennis, field hockey and lacrosse. Leg raises are also important in sports such as gymnastics, especially on the bars and in free exercise, karate, rhythmic gymnastics, pole vaulting, hurdling and kickboxing. Development of the muscles involved also reduces risk of injury to the lower back since these muscles help to stabilize the pelvis, which in turn helps maintain proper alignment of the spine.