Correct body positioning
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).
So how long should your ab training take?
One of the reasons that many people who spend a half an hour during each workout doing hundreds of crunches fail to ever develop six pack abs is that after a certain point, regularold crunches just don’t provide much resistance to develop your abs.
In addition, all of the time wasted doing crunches or other minimally resistive ab exercises (i.e. working a very small muscle group) could have been better utilized by working larger muscle groups which burn more calories.
By focusing the majority of your time in the gym on bigger compound movements like
squats, deadlifts, lunges, and upper body multi-joint presses and pulls, your body is forcedto work harder and burn more calories during and after the workout. Don’t get me wrong, crunches can have their place in a routine, especially for beginners, and advanced versions of crunches can even be challenging enough for well-trained athletes.
So how long should your ab training take? Well, the good news is that you don’t have to
spend a half hour or more every day training abs. You can complete an intense ab training session in about 5-10 minutes during your workouts, either at the end or in the beginning of your workout, or on a separate day.
We would recommend doing your ab training at the end of your workouts to assure that you don’t pre-exhaust the abs when you might need their stabilization to protect your back during some of the bigger compound exercises that might make up your workout.