What Exactly Do Core Muscles Do?


By: Nikki Clayton, PT, DPT, ATC

Anyone who’s ever been in a gym or worked out has heard of the term “core muscles”.  We’ve always been told that it is important to “strengthen our core” or don’t forget to “work the core”.  But what exactly are the core muscles, and why are they so important?

The term “core muscles” is a rather general term that refers to the group of muscles around your belly and low back area.  It may be debated which specific muscles are included in that group, but there are a few that make up the crux of them and which we’ll discuss.

What are core muscles? Find out here.Image of a woman doing a plank exercise

Which muscles make up your “core muscles”?

The quick answer is:

  • Abdominals (lower and upper) – These are the most superficial muscles (literally and figuratively speaking) that make up the “six-pack abs” that we all wish we had. 
  • Obliques (internal and external) – These muscles lie on top of each other and form an X-type pattern along the sides of our belly and wrapping around towards the back.  They are mainly responsible for the twisting and rotating of our trunk. Like our abdominals, they are also located superficially.
  • Transverse Abdominus– These muscles are located a little deeper in the body and runs perpendicular (transverse) to our abdominals. These are our main back supporters and make up the true “girdle” of our bodies. These are the muscles physical therapists try to target when rehabilitating back injuries.
  • Multifidus – These muscles run deep in our back along our lumbar spine traveling upward towards our mid-spine. They help stabilize our spine before movement of the arms/legs occur.
  • Erector Spinae - These muscles also run along our spine but are much larger than the multifidus and are the main muscles responsible for extending our spine.

What exactly do core muscles do and why are they important?

  • Together, these muscles act as the body’s main stabilizers. They are the bridge that connects the lower body with the upper body. 
  • They are also considered the body’s natural “girdle” and so keep the lumbar spine in good stable alignment. When these muscles become weak, your lumbar spine begins to “collapse” on itself so to speak, which can create increased pressure on the intervertebral discs. This can also create excess strain on the lumbar spine. 
  • This makes you vulnerable to the dreaded “herniated or ruptured disc” that we’ve all heard about and have probably known someone who’s suffered it. It’s not fun. Every good workout program begins with emphasis on the core muscles, focusing on engaging the deep core muscles and working your way out to the more superficial ones as you progress. 

Related Articles: What is my Core?

One more tip, always make sure you practice good form, start light, and progress slowly. To schedule with a JOI Physical Therapist, please call 904-858-7045 or click below. 




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