Is There Really A Core?

The phrase “engage your core" seeps into nearly every yoga class these days. But does it actually mean anything? Turns out there is not only no agreement but some strong disagreement on a word that has become a Tower of Babel for movement professionals.

“There is no muscle in Grey’s Anatomy called the core,” says Gil Hedley, a well-respected teacher of anatomy. "The fact that it is not an anatomical term is not a bad thing, just a fact." After 23 years of leading students through cadaver dissections, he lets individuals decide what the core is, depending on their backgrounds. When asked, he points out landmarks, like the psoas and erector spinae. Students are often surprised when they think they've got a handle on what comprises the core "and then see all the other stuff around it — organs, tissues, maybe 18 pounds of viscera.”

“You don’t have a body part called a core,” agrees karate shihan Michelle Gay, a fifth-degree black belt and Somatic Educator and Laban Movement Analyst. “In karate, we might say you are moving from the hara or pelvis. But ‘core’ is often jargon we teach our students. Is it the abs? Is it the psoas? I like to think of the core as being in every body part, in all the intrinsic muscles closest to the skeleton.”

Still others use the word to refer to conscious motivation. For a yoga practitioner, engaging the core often means activating the bhandas. For those with a Pilates or fitness background, it generally means engaging a group of powerhouse muscles, including the transverse abdominis (TA), the gluteals and the pelvic floor.

With its compressive qualities and connection to lumbar fascia, the transverse abdominis earned a prominent reputation in the 1980s and ‘90s as a spine stabilizer and stomach flattener. Located under the obliques and rectus abdominis (the six-pack muscles), the TA was thought to be essential for back care: a weak TA forecasted trouble for the low back.