What the eff is my core?

PS — Why should I care?

For every person out there who knows, I would bet there’s at least one person (maybe more) who really wanted to ask, so here goes–

This Yoga Journal article goes into more detail than I will, but basically, your core includes the muscles surrounding your center of gravity, which for most people is just below the navel. Because of its location, the core muscles are involved in moving and balancing the body, supporting other organs and structures in the torso, and even breathing. As a basic primer on core health, I want to stress 3 points:

  1. Your core is more than just your abs.
  2. Fat and muscle are two independent layers.
  3. A toned core includes both strength and suppleness.

Like I discussed yesterday, there’s a big societal focus on the appearance of the abdominal muscles. So it’s probably no surprise that when a lot of people talk about the “core,” they really mean “abs” and consequently may end up neglecting other core muscles. I need to give credit to yogi Leslie Howard for this bit of enlightenment, but it may help to picture your core as a box:

A line drawing of a rectangular prism.

Pretend this is your core.

If you remember your basic geometry (or are learning it for the first time), a box has 6 sides: front, back, left, right, top, and bottom. Similarly, your core has 6 groups of muscles:

  1. The front of your core includes your rectus abdominus and your transverse abdominals — what we typically think of as the “abs.”
  2. The back of the core includes the latissimus dorsi, the erector spinae, and the other muscles of the lumbar spine.
  3. The left side of your core includes the left internal and external oblique abdominal muscles.
  4. The right side includes — surprise, surprise — the right internal and external obliques.
  5. The top of the core is the diaphragm.
  6. And the bottom includes all the muscles of the pelvic floor.

So it sort of looks like this:

Line drawing of rectangular prism, labeled with above listed muscle groups.

Pretend this is your core on pretty colors.

Even though my Paint skills are less than fantabulous, I hope this pretty clearly illustrates why abs-only (or even abs-dominant) regimens don’t fully work the entire core.

The next point might be one that relates back to my own body image issues, namely, that core fat and core muscle are two separate topics. Not that there’s never any correlation, but basically — Abdominal fat is part of the abdominal skin layer, and abdominal skin is more or less designed to help store fat. How much relative fat the body stores there can certainly be related to caloric intake and expenditure, but it can also be related to factors such as metabolic and endocrine conditions (e.g, hypothyroidism or polycystic ovarian syndrome) or to genetic predisposition. Either way, the presence or absence of fat around the midsection is not an indicator of the presence or absence of core strength.

Moreover, core strength is not the only determinant of core health. Many of the core’s functions involve movement — movement of skeletal muscles, yes, but also movement of food through the digestive system and movement of air in and out of the body. While strength is necessary for that movement, it’s only one facet of movement. Core suppleness and flexibility is also important. If you go back to thinking about the core as a box, it’s also easy to imagine it as 3 pairs of opposites:

  1. When the front abdominals are contracting (calling on strength), the back muscles are stretching (calling on suppleness), and vice versa.
  2. When the left obliques contract (calling on strength), the right obliques stretch (calling on suppleness), and vice versa.
  3. When the diaphragm contracts (calling on strength), the pelvic floor stretches (calling on suppleness), and vice versa.

(Because the body can move in multiple planes at once, these dichotomies aren’t always completely accurate. They are, however, reasonably useful general guides.) Ultimately, to most effectively engage the strength of one part of the core, you need to have flexibility in the complementary section. This is why both strength building and stretching are essential parts of core muscle tone.


I'm here. I like stuff. Some other stuff, I like less.

Posted in core, non-asana
One comment on “What the eff is my core?
  1. […] Work Out in Your Sleep! Continuing our series on core awesomeness, if you think about your core as a box, the diaphragm is the lid on that box. It’s a large […]

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