Note: This post talks both about the anterior abdominal muscles and about societal messages about that section of the body. Off-site links especially may be prone to anti-fat and/or weight loss talk.
Coming back to core conditioning.
Many of us are conditioned to think about our rectus abdominus muscle as our entire core:
In reality, the rectus abdominus is the more superficial of two layers of muscles that make up the front of the core, running vertically from the pubic bone up to the ribs. Aesthetically, for people who have a “6 pack abs,” this is the muscle that creates that look**. Functionally, its main job is to flex the spine, moving the chest toward the pelvis (as in a traditional sit up) or the pelvis toward the chest (as in a reverse crunch). The rectus abdominus also helps compress the abdomen, which makes activities like exhaling air or pooping… poop… easier.
** Interestingly, it may not be healthy, safe, or possible for every person to have a “6-pack,” no matter how fit that individual is. Some experts estimate that women with this appearance need to have a body fat composition of 15-18%, men 7-10%. According to the American Council on Exercise, even the body fat percentages for “athletes” and “fitness” can be notably higher than that. While I’d speculate that, just based on individual variation, there are folks who can show “washboard abs” with a body fat percentage near the upper end of the “athlete” guidelines, I’d also speculate that for others, having that same appearance would require them to dip into their essential body fat.
Most people hear a lot about this muscle, whether they want to or not. There’s a lot of info out there about working — clarification: strengthening — the rectus abdominus, even if the muscle’s name is not explicitly mentioned. A majority of exercises labeled generally as “ab” exercises target the rectus abdominis.
But even looking only at the front of that “core box,” there’s a whole other muscle there:
The transversus abdominis, or transverse abs, is a muscle layered deep into the front of the core, running horizontally from rib to rib and hip to hip. Aesthetically, the transverse abs do play a role in drawing in the abdominal cavity and the waistline; however, even that bit of aesthetics gets downplayed compared to the more superficial abdominal muscles. Functionally, the transversus abdominis’s main job is to stabilize the low back and pelvis during movement. (It also aids with the same breathing/poop/expelling matter from the body stuff above.) This stabilization is pretty key to safe and efficient trunk and limb movement, whether we’re talking an asana practice, another fitness routine, or just daily life.
Basically, the transverse abs can help stabilize your body to make your vinyasas easier, to help you run more efficiently, to keep you safer through the jostling movements of riding the city bus. But this muscle is never, ever going to give you 6-pack abs (even if you have the genetics for them); it’s simply not what the transverse abdominals are designed to do.
Yet when searching for visuals to accompany this post, I waded through a LOT of material that conflated the more superficial stomach muscles (primarily rectus abdominis but also external obliques) and the entire core. It bears repeating — a LOT. Not only this, but they also tend to assume that a toned core equals slim/chiseled/strong/washboard/blasted abs. Not that the rectus abdominis isn’t important, and not that strengthening it isn’t a good thing. But they’re focusing on one or a few surface muscles and on one type of muscle movement.
It’s a little like writing a book report after reading only the first chapter: Even if your analysis of that one chapter is spot on and brilliant, it’s probably not enough.
So while we will still talk about the rectus abdominis and transversus abdominis next time, we will not be talking about strengthening them just yet. There’s another part of muscle “tone” that — probably for safety — comes first.