Our other three abdominals are deep to the rectus abdominus. The internal and external obliques run diagonally across the abdomen and are commonly thought of as muscles that rotate the torso. The transverse abdominus is our deepest abdominal of all, and when it contracts, it has a corset-like effect of compressing the entire abdomen inward.
MY ABDOMINALS ARE MY CORE, RIGHT?
No, your abdominal muscles are actually not your core - at least, not in and of themselves. Your functional “core” is actually made up of all of the muscles which stabilize your spine as you move - also often referred to as your “core stabilizers”. Depending on whom you talk to, this can mean up to 40 different muscles - whoa, man!!
Yes, your four abdominal muscles are part of this group, but your core stabilizers also include the multi-layered muscles of your spine, your pelvic floor musculature, your back muscles, your psoas (an important muscle you’ve probably heard a lot about which deserves a whole blog post of its own!), the muscles that stabilize your shoulder blades, and your respiratory diaphragm.
When all of these muscles are functioning well, they will successfully keep your spine stable and protected as you twist, squat, climb, bend over, lift heavy objects, and generally move your way through life.
Once we understand the interconnected role that this large group of muscles plays in stabilizing our spine, it becomes clear that it’s physiologically incomplete to treat the core as simply the abdominals, or worse yet, as just the superficial rectus abdominus. In fact, because it’s common for our sense of “the core” to be so narrowly-defined, there is often too much emphasis placed on working the six-pack muscle when we do our “core strengthening” exercises, resulting in many (many!) people who have visibly-defined abdominals, but weak cores.
WHAT IS THE BENEFIT TO HAVING SIX-PACK ABS?
While six-pack or otherwise flat abs are an aesthetic that our culture finds attractive, they actually offer no physiological benefit to our body. In fact, not unlike other body aesthetics that our culture idealizes (think high heels and that all-too-common overly-arched spine), creating too much tension in your abdominal area can actually lead to musculoskeletal imbalances which can contribute to health problems with time. Learning to wean ourselves off of the over-use of the six-pack muscle is therefore an essential step toward restoring balance in our body.
DO YOU TUCK YOUR PELVIS TO “PROTECT YOUR SPINE”?
We used to think that one of the best ways to “protect the spine” was to “engage the core” by tucking (posteriorly tilting) our pelvis via contracting our rectus abdominus. Although new biomechanics info has taught us otherwise, it’s still quite common in many yoga classes and in some schools of pilates to teach students to tuck their pelves throughout their practice. And surprisingly enough, teachers often instruct a pelvic tuck without even realizing it! Because most yoga teacher training programs don’t include much anatomy education, their students often ending up memorizing cues to teach during poses without understanding the anatomical action the cue is describing. Did you know that the instructions “lift your belly”, “tailbone toward your heels” and “tailbone down” are all pelvis-tucking cues?
We now know, however, that not only does tucking our pelvis not innately protect our spine, it also does not necessarily engage our core.