Stomach or Abdomen?

"Suck your stomach in!" goes a common instruction in yoga class. This cue is present in a lot of different lineages and styles, and goes to the heart of an important conversation in the yoga world: What are we teaching? 

Let's explore the meaning of this instruction, beginning with the elements involved. Namely, the "stomach" and "sucking in."

What is the stomach?
It is an organ in our digestive tract. It is high in the abdomen, just below the ribs and diaphragm. It is the first place our food goes after we chew and swallow it. 

How do we suck the stomach in?
We don't. We can't. The stomach itself has muscles that help us in digesting and passing food through our system. But they are involuntary muscles that we can't consciously control. This instruction, "Suck the stomach in," refers to the stomach in a much more general and imprecise way, where "stomach" actually means "abdomen."

What is the abdomen?
"Abdomen" refers to the area between your ribs and your pelvis. Technically it is bordered by the diaphragm on top and ends at the pelvis on bottom. The stomach (an organ), liver, other organs, glands and the intestines are all located in your abdomen. The abdomen is also commonly referred to as the "belly," though there are some who are uncomfortable with that term. 

Most importantly for this conversation, the abdomen has four muscles that we can control consciously, pictured on the right. Not surprisingly, these are called the "abdominal muscles." (If you Google stomach muscles, it will redirect you automatically to abdominal muscles.)

The muscle that pulls the abdomen in is called the transverse abdominis. It wraps around the belly like a corset, helping us breathe and stabilizing the spine when needed. If you are wondering what if feels like, exhale your breath forcefully and feel the sides of your abdomen. They will be tight and contracted. This is your transverse abdominis​. ​​

What are we actually teaching?
That brings us back to the instruction, "Suck your stomach in." If we take the instruction at its word, it is impossible. The stomach's position cannot be changed consciously nor can its muscles be contracted consciously.

The only way that this instruction makes sense is if we interpret "stomach" to mean "abdomen" and proceed to contract an abdominal muscle that "sucks in."

Also, if our students take us at our word (which I hope they do), they are learning that the stomach is something that can be "sucked in," which it is not. This is worrying, essentially teaching an inaccurate and incorrect concept to unknowing students. 

​The easiest of fixes
This instruction can be modified ever so slightly to become an effective cue. "Pull your abdomen in" or "pull your belly in" are both anatomically sound and they accomplish the desired result: contraction of the transverse abdominis​. They remove the danger of propagating false information to our students and encourage them to learn the correct way.