Hanging knee raise: tighten your abs with this bodyweight exericse - Perfect Form

technique

* Step up on a low stool or jump to grasp a high bar so that your body hangs freely without your feet touching the floor.

* Grasp the bar with a wide, pronated (palms-away) grip. Hang with your arms fully extended and a slight arch in your lower back.

* Inhale and hold your breath as you bend your legs to a 90-degree angle or less in your knees and raise your thighs as high as possible by contracting your abdominal and hip-flexor muscles.

* For greater effectiveness, raise your knees above the thighs-level position with a momentary hold at the top.

* Exhale before lowering your legs to the initial position under control. Pause momentarily and then repeat.

* Be sure to start from a stationary position and lift your legs as strongly as possible.

* When the bent-leg version becomes easy, do the exercise with straight legs and work up to touching the bar with your feet.

performance

* When first attempting this exercise, do the bentknee variant.

* For the strongest muscle contraction through the greatest range of motion, be sure to raise your legs as high as possible, well above the thighs-level position. The higher you raise your legs, the greater the abdominal muscle involvement.

* Don't swing your body to help raise your legs. Your body should be still when you begin the exercise. Arching your lower back and then vigorously bringing your legs up is acceptable; this prestretches the muscles to ensure a stronger contraction.

* When hanging by your hands, you get a beneficial stretch of the entire spine. This can help maintain or improve your posture, especially if you have a tendency to slouch or if you have a job where you're constantly bent over, as in working on a computer.

* Because your legs form a long lever and athletic shoes are typically somewhat heavy, additional resistance isn't usually needed. The long leg lever with weighted feet greatly increases the difficulty of the exercise over the bent-knee version.

* The tighter your hamstring muscles, the sooner the abdominal muscles come into play to rotate the pelvis. If you have good hamstrings flexibility, you can probably raise your legs somewhat higher before the abs begin to shorten.

* Although involvement of the hip flexors in abdominal exercises has been criticized, it shouldn't 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 that involve both the legs and pelvic girdle.

primary muscles involved

The primary muscles involved in raising the legs (hip flexion) are the psoas and iliacus -- collectively known as the iliopsoas -- as well as the rectus femoris and pectineus. The psoas lies deep in the abdomen; the iliacus lies to the side of the psoas on the inner surface of the ilium, the side bone of the hip. The rectus femoris, a long muscle that runs straight down the front of the thigh, is one of the major muscles of the quadriceps. The pectineus is a short, thick muscle located near 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 latis-simus dorsi. The fibers of the internal and external obliques run at 90 degrees to one another in the upper portion of the abdomen. The side-angled muscle fibers can be seen when the muscles are well developed and you have little fat in this area. They can greatly complement the "six-pack" effect.

sports uses

In resistance training, strengthening the hip flexor muscles is important for maintaining balance with the hip-joint extensor (gluteus maximus and hamstrings) muscle development and, to a limited extent, the muscles of the lower back. The abdominal strengthening plays a role in spinal stability and the performance of various sports. The straight-leg variant of this exercise involves both the lower and upper portions of the abdominals, which ensures maximum muscle shortening to produce the greatest tension and, as a result, the greatest amount of strength and definition.

In sports, hip and spinal flexion (backward rotation of the pelvis) is crucial for raising the legs high in front of the body. This is seen in raising the legs in ballet, kicking in karate and soccer, 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-raise movements are vital in sports such as gymnastics, especially on the bars and in free exercise; rhythmic gymnastics; pole vaulting; hurdling; kickboxing; and others. Development of the muscles involved reduces risk of injury to the lower back since these muscles help stabilize the pelvis, which in turn helps maintain proper alignment of the spine.