The Lower Abdominal Exercises: Are they helpful?

So you go to the gym and everyone is doing all of these crazy abdominal exercises.  Different versions of side bending, crunching, leg lifting, hanging twists, all in the attempt to "shred" different parts of their abs (to be perfectly honest, they are "shredding" their low back...and not in a good way.)

I was in discussion with a few people trying to understand where this epidemic of abdominal exercises.  Are there really any abdominal exercises that can help sculpt the "lower abdominals?" 

If you were to ask me if there was a way to "stress" the lower abdominals to a greater extent, I would not fully disagree with you.  However, if you believe you are "isolating" the lower abdominals, I would vehemently disagree with you.

The entire abdominal group (transverse abdominis, internal and external oblique, and the rectus abdominis) are innervated by the thoracoabdominal nerve (anterior branches from T6-12.)  To simplify, the abdominals are all controlled (collectively) by ONE NERVE source.  So if the abdominals were to turn on, the ENTIRE abdominal group would turn on.

With the abdominals being "wired" together to all turn on at the same time, shouldn't we be using this to our advantage and training the ENTIRE abdominal musculature functionally?  By functional training of the abdominals I mean using the abdominals to BRACE.  So why not do pushes, pulls, lifts, carries and drags.  Why not practice stuff you do for your sport or stuff you do for work.  Pick boxes up off the ground, carry a heavy bag, do a bunch of push ups or squats.  These are all good abdominal exercises! 

 
If you still believe that you can isolate the lower abs, I would like you to show me a "Long head of the biceps" exercise that isolates the long head of the biceps.  If you can prove to me you can isolate the long head of the biceps, I'll may believe that you can isolate lower abs (but not likely!)

The Shock Absorbers of the Spine

We have learned in traditional anatomy classes that the discs are the shock absorbers of the spine.  This is logical seeing as we know the discs are somewhat built like a jelly donut with a "squishy" jelly center.  It also makes sense as we think of the bones in the body as hard, rigid structures.  As vertebrae are bone, we would assume that they would be rigid also.


So in isolation, the disc may appear "squishy," however, we tend to forget that the discs are sandwiched between vertebrae.  What we don't often think about is how the vertebrae is constructed.  Vertebrae are composed mainly of spongy bone.  That's right, SPONGY bone!  Though the outside of the vertebrae is more rigid, the inside of the vertebrae looks like a dense sponge.  It is this property of the vertebrae that allows it to be the shock absorber of the spine. 


The structure of the disc is more fluid (or jelly like).  Fluids tend to be more difficult to compress so as our spine compresses, our vertebrae "bulge" in upon itself as the jelly pushes against the vertebrae.

Still don't believe me?  Think about it this way:  Imagine you were to eat a massive hamburger.  Think about the buns of the hamburger as the vertebrae and the patty as the disc.  The first thing you would do would be to "compress" the hamburger.  What just underwent the greatest amount of deformity (most compression?)  The "spongy" bun of course!  This is a bit over-simplified as the vertebrae aren't quiet as squishy as a hamburger bun, but it does illustrate the point.



So as your spine undergoes compression when you are running, jumping, sitting or sneezing, it is the vertebrae themselves that are the shock absorbers of the spine.