Wednesday, March 28, 2012

Proper Body Positioning for Abdominal Training

The hip flexor muscles such as the psoas, along with the abdominals, both act to pull your trunk towards your legs. However, the psoas can operate in a much greater range of motion than the abs. The psoas are activated to the highest degree when your feet are supported and/or your legs are extended straight. Also, the psoas take over the majority of the work when your upper body comes off the floor by more than approximately 30° in crunching or sit-up movements.
It has become fashionable in recent years for trainers to recommend that people try to “isolate” their abs and minimize any hip flexor activity. Although these professionals have good intentions with this recommendation, I don’t believe it’s a good idea to try to eliminate any kind of hip flexor activity. A balanced approach will be much better. The recommendation to minimize hip flexor activity during ab training stems from the thought that excessive psoas activation during attempts at ab training creates compressive forces on the discs of the lumbar spine. The psoas attach to the lower spinal vertebrae. When the psoas are activated to a high degree, they pull on the lower spine, creating compressive forces on the discs. If your abs are very strong, the abs will keep the back from arching and prevent damage from occurring. However, even those with strong abs may not be able to keep the back from arching once the abs have fatigued. Once the back arches during heavy psoas activity, the vertebrae around the psoas attachment can grind together, potentially resulting in disc degeneration over time.
Now with all of that said, I believe that a balanced approach is best, and that you must focus on building both strong hip flexors and strong abdominals. Strong hip flexors are necessary to improve on movements such as sprinting or any other movements involving hip flexion.
As long as you perform the exercises in this manual with the correct body positioning, you will develop very strong abdominals to protect your back, and you will also develop sufficient hip flexor strength. I do believe that there are certain exercises which are both ineffective and can potentially put undue stress on the lower back. Some of these exercises that I recommend you avoid are straight legged sit-ups, sit-ups with the feet supported, hanging leg raises with an arched back, floor leg raises with straight legs and an arched back, and machine crunches.
Proper body positioning is essential to maximal development of the abs while protecting your back from injury. One of the most important aspects to understand in order to best develop the abs, is to maintain a proper posterior pelvic tilt during ab training. To explain this concept, think of yourself lying on the floor while arching your back. In this position, the top of your pelvis is tilted forward, otherwise known as an anterior pelvic tilt. Now if you rotate the top of your pelvis down towards the floor such that you have removed the arch in your back, you are now in a posterior pelvic tilt. This is the optimal position in which to train your abs when doing floor exercises (although it may not be appropriate for an individual with lower back disc disease).
Now consider an ab exercise in a hanging position, such as the hanging leg raise or hanging knee up. Most people complete these exercises with a slightly arched back position utilizing mostly the hip flexors with minor assistance from the abs to complete this movement. In order to complete a hanging leg or knee raise in a safer and more effective way for developing both the abdominals and the hip flexors, you must have your back in a rounded position as you literally curl your pelvis up closer to your upper body. This aspect makes these exercises much more challenging and puts a much higher demand on your abs. Most people cannot complete a properly performed hanging leg raise until they have adequately strengthened their abdominals and are in very good physical condition.

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