"Core Definition" - Part 2 - What are Core Muscles?

In the previous post, I discussed how the term "Core" was used with little or no meaning to it. Many believe that the core entails the rectus abdominis (6 pack muscle), or the transverse abdominis (the suck in your gut muscle), however, there is so much more to the "Core" than simply one or two muscle groups.   To better understand what the "Core" is, lets look at many of the muscles that are involved (in no particular order):

1. Internal and External Obliques

-These muscles aid in the rotation of the torso, but also extremely important in stabilizing the lumbar spine during movement

2. Multifidus and Quadratus Lumborum
-These muscle is found flanking the lumbar spine and helps to buttress forces during movement

3. Transverse abdominis
-Though this muscle is encouraged to be activated by drawing the belly button towards the spine but has been found to be a more effective stabilizer if the belly button is "puffed out" as if you were coughing

4. Rectus Abdominis
-This muscle is often trained as a flexor of the abdomen.  The problem with this is that when you put your lumbar spine in flexion, it puts you at risk for disc bulging and herniations.  A better understanding of the structure and function of the rectus abdominis can be discussed in a future post

 5. Iliacus and Psoas (hip flexors)
-The psoas portion of the hip flexor muscles actually attaches to the anterior part of the lumbar spine.  Because of its attachment, it can affect stability or stiffness of the lumbar spine.  It is a misconception that "tight" hip flexors can actually pull the lumbar spine forward and give you "sway back"

6. Erector Spinae muscle group
-This muscle can do extension of the lumbar spine, but more importantly works to stabilize the lumbar spine in compression by squeezing the lumbar spine together during movement

6. Latissimus Dorsi
-Many people do not think of the lats as a true core muscle, but it does have attachments to the lumbar spine and is an important link between the torso and the upper body

7. Glutes Maximus/Medius/Minimus
-Again, many people do not think of these as true core muscles, but it is an important link between the lumbar spine and the lower body

As you can see, there are a great deal of muscles that can be defined as part of the "Core" muscles.  It is important that these muscles work in concert with each other to both produce movement and to maintain stability of the lumbar spine.  I will look into good, bad and ugly training techniques for Core in a future post.