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.
“You don’t have a body part called a core,” agrees karate shihanMichelle 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.
But it isn't quite that simple. "This assumption is a dramatic leap of faith,” writes Eval Lederman in "The Myth of Core Stability," an article in the Journal of Bodywork & Movement Therapies. According Eyal Lederman, a whole fitness and wellness industry exploded around the concept of “pulling in.”
Lederman made several conclusions in his scholarly review, including this: “There may be potential danger of damaging the spine with continuous tensing of the trunk muscles during daily and sports activities.”
Lederman and others call for a closer examination of the role of specific core muscles. Even if clients engage them in a crunch or sitting on a rubber ball, they may not be able to transfer those skills into a healthy posture while sitting or running. “We can’t learn to play the piano by practicing the banjo,” Lederman wrote.
“The abdominal muscles are certainly useful, but they are not the source of all support for our spine,” agrees Amy Matthews, a respected movement therapist and yoga teacher at The Breathing Project.
Coauthor of the best-selling Yoga Anatomy, Matthews doesn’t believe strength comes from any one area of the body. As a result, she rarely uses the “core” vernacular in her classes. “There's a strong case for organizing movement from the periphery to the center, rather than the idea of starting from the center,” she says. “This is based on a developmental idea that once we've learned to do movements from our own volition, rather than reflexively, it's most efficient to start at the most distal points, hands and feet, because we can calibrate the amount of effort required to do the task, and we do not have to work any harder than necessary.”
Women who’ve had C-sections know what it means to lose core strength by any definition. Yoga teacher Margarita Manwelyan, whose second child was born via an emergency C-section, believes that rejuvenating the core after such an invasive procedure helps re-integrate body and spirit. She describes core function as the coordination of abdominals and the pelvic floor with the whole body. When instructing new moms, she asks them to “bring the front of the body to the back of the body” or to “feel the ground while against it” in tadasana.
While the core is key to overall balance and range, it’s not the whole enchilada, according to Matthews. “I'd propose that functional strength — the ability for the body to respond to the demands/requests placed on it — comes not from individual muscles but from the effective communication and coordination of all the tissues of my body,” she says. “Muscles, connective tissue, nerves, bones, blood and everything. Not just in the torso.”
When your teacher tells you to engage your core, go ahead and try, knowing that it means something different for each of us.