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Core Strength Fiction and Facts

in Featured, Practice, YogaDork Ed


by Jenni Rawlings

When many people think about a strong core, they picture someone with “six pack abs” like this fine underwear model man right here. But our functional core is actually much more complex than this over simplified notion, and whether your abdominals are super defined and underwear model-worthy or not says nothing about how strong your core truly is.  And even if you’ve already learned about the fuller picture of our deeper core, it’s very likely that you have been practicing and/or teaching yoga with an over-reliance on the six-pack muscle without even realizing it.


The six-pack muscle (a.k.a. the rectus abdominus) is actually just the most superficial (closest to the skin) of our four abdominal muscles.  It runs vertically along the front of the abdomen and when it contracts, it pulls the rib cage and pelvis toward each other, usually resulting in a rounded spine (spinal flexion) and/or a tucked pelvis (posterior tilt).

The Rectus Abdominus. (Image used with permission from Real Bodywork, Inc.)

The Rectus Abdominus. (Image used with permission from Real Bodywork, Inc.)

Our other three abdominals are deep to the rectus abdominus.  The internal and external obliques run diagonally across the abdomen and are commonly thought of as muscles that rotate the torso.  The transverse abdominus is our deepest abdominal of all, and when it contracts, it has a corset-like effect of compressing the entire abdomen inward.


No, your abdominal muscles are actually not your core — at least, not in and of themselves.  Your functional “core” is actually made up of all of the muscles which stabilize your spine as you move — also often referred to as your “core stabilizers.” Depending on whom you talk to, this can mean up to 40 different muscles…whoa, man!!

Yes, your four abdominal muscles are part of this group, but your core stabilizers also include the multi-layered muscles of your spine, your pelvic floor musculature, your back muscles, your psoas (an important muscle you’ve probably heard a lot about which deserves a whole blog post of its own!), the muscles that stabilize your shoulder blades, and your respiratory diaphragm.

When all of these muscles are functioning well, they will successfully keep your spine stable and protected as you twist, squat, climb, bend over, lift heavy objects, and generally move your way through life.

Once we understand the interconnected role that this large group of muscles plays in stabilizing our spine, it becomes clear that it’s physiologically incomplete to treat the core as simply the abdominals, or worse yet, as just the superficial rectus abdominus. In fact, because it’s common for our sense of “the core” to be so narrowly-defined, there is often too much emphasis placed on working the six-pack muscle when we do our “core strengthening” exercises, resulting in many (many!) people who have visibly-defined abdominals, but weak cores.


While six-pack or otherwise flat abs are an aesthetic that our culture finds attractive, they actually offer no physiological benefit to our body. In fact, not unlike other body aesthetics that our culture idealizes (think high heels and that all-too-common overly-arched spine), creating too much tension in your abdominal area can actually lead to musculoskeletal imbalances which can contribute to health problems with time. Learning to wean ourselves off of the over-use of the six-pack muscle is therefore an essential step toward restoring balance in our body.


We used to think that one of the best ways to “protect the spine” was to “engage the core” by tucking (posteriorly tilting) our pelvis via contracting our rectus abdominus.  Although new biomechanics info has taught us otherwise, it’s still quite common in many yoga classes and in some schools of pilates to teach students to tuck their pelves throughout their practice. And surprisingly enough, teachers often instruct a pelvic tuck without even realizing it!  Because most yoga teacher training programs don’t include much anatomy education, their students often ending up memorizing cues to teach during poses without understanding the anatomical action the cue is describing. Did you know that the instructions “lift your belly”, “tailbone toward your heels” and “tailbone down” are all pelvis-tucking cues?

We now know, however, that not only does tucking our pelvis not innately protect our spine, it also does not necessarily engage our core.

Our natural spinal curves are like built-in shock absorbers or springs in our body.

Our natural spinal curves are like built-in shock absorbers or springs in our body.

Because our pelvis serves as the base of our spine, its orientation in space directly affects the shape the spine. If the pelvis tucks, it causes our low back, which would otherwise have a natural inward (lordotic) curve, to flatten (hypolordosis). We now understand, though, that our natural spinal curves are actually crucial to our spine’s optimal functioning. They serve to “force-dampen” the effect that gravity has on our spine, and can be thought of as our built-in shock-absorbers.  As much as possible, we want to preserve these natural curves and therefore the integrity of our structure by stabilizing our spine.

But tucking our pelvis actually does the opposite of stabilizing the spine – it mobilizes the spine by flattening the lumbar curve (spinal flexion). And because the action of tucking our pelvis comes from the contraction of only our most superficial, “six pack” abdominal muscle, our true core wasn’t asked to work at all when we tucked.


The big picture of core stabilization isn’t quite as black-and-white as this, and there are of course some instances in which we do want to work a posterior pelvic tilt. But the idea that we should “lift our belly,” “move our tailbone toward our heels,” or otherwise tuck our pelvis indiscriminately throughout our yoga practice in order to create core stability is outdated and biomechanically incorrect.

In upcoming blog posts, I’ll offer more insight into our core as well as ways to make sure we’re turning on our deeper core for true stabilization. The more we understand our body and refine how we move, the more overall mindfulness we’ll cultivate both on and off the yoga mat.  As always, if you have any questions or comments, feel free to let me know!


Jenni Rawlings loves to weave her natural interest in anatomy and biomechanics into her yoga teaching. She is grateful to so many teachers who inspire her, most notably amazing biomechanist Katy Bowman. You can find out more about Jenni at www.jennirawlings.com.

~ Article reposted with permission ~



34 comments… add one
  • Davy

    Yes. Thank you!

    I’m a yoga & Pilates teacher and students are constantly asking me for “core” exercises, and I give them posterior (back) chain work or stabilizing work mostly with a straight aligned spine or rotation. Most find it incredibly challenging to locate and work their deep core, it takes a lot of re-training to get people to understand why I’m generally teaching in a 2:1 ratio of posterior chain activation + anterior chain opening (twice as much as the reverse) to counterbalance our anterior dominant daily lives. People want their hip flexors stretched and assume they should do deep backbends, and while backbending can help I find gluteal activation seems to provide far more relief in every student I address this with.

    Additionally, I’ve personally had to work at softening my rectus abdominal muscles because I did so much “core” work with Pilates etc that I actually reinforced a pelvic anterior tilt that is common for most people in a generally sedentary lifestyle. This caused me a host of health problems, including trouble breathing, digestive problems, even anxiety from chronic tightening of the psoas that has consequences that even extend to emotional life. If you look at the strongest yogis with incredible control, you’ll notice that while supple and toned, their bellies can breathe fluidly and expansively – this is the ideal – strong but supple.

    The “weakest” cores I’ve seen in students? Male power lifters (strength, body builders) with crazy 6 pack abs. They can barely recruit their deep core muscles and are shaking within a few seconds of minimal work.

    Do less traditional “core” or work your core from proper anatomical position of the spine and pelvis, and work your back muscles the same way (watch the tendency to try to work the back from a hyper extended lumbar spine). I find 2:1 ratio appropriate for most especially if you spend a good amount of time sitting or in a limited range of motion of your joints. A biomechanist Katy Bowman says “exercise is a poor substitute for movement”. Get moving and leave the ambition behind, work in a corrective manner for better health.

    Sorry I just geeked out all over your comment section! Thanks for the great post and a topic that I think is really important! Look forward to your follow ups 🙂

    • Thanks so much for your great comments, Davy! SO agree about the importance of posterior chain strengthening – all of our chair-sitting and computer-using tends to make us very anterior chain dominant, and it doesn’t really serve us to reinforce that imbalance in our yoga/pilates/movement time. And Katy Bowman, the biomechanist you mentioned in your comment, is actually currently my main teacher! 🙂 Her teachings are really mind-blowing and you might really appreciate learning from her on a deeper level if you haven’t already. Thanks again so much for your insights here!

    • EMG

      I’m very much on-board with the idea that the obsession with abs is misguided. However, one quibble with Davy. I strongly doubt that you have ever had a powerlifter in your classes. The people you had in your classes were likely bros who spend all their time doing crunches and curls. Powerlifters are athletes who specialize in the squat, deadlift, and bench press, and as a result of these complex, compound movements (squat and deadlift), they have some phenomenal ‘core’ stability. It is not possible to lift several hundred pounds off the ground with a weak posterior chain. Also, it’s worth noting that most serious powerlifters do not have six packs, because they know that excessive leanness is the enemy of strength.
      Anyhow, as someone who has done yoga, pilates, and non-competitive powerlifting, I would recommend that yogis give compound lifts a try. They are actually much more complementary than the partisans on each side would have you believe.

      • John

        I second this. The core strength and flexibility required to be a halfway decent olympic lifter are impressive.

      • lala

        I agree EMG. I had a very frequent “strong” asana practice for many years. Due to a long term shoulder injury, I stopped my asana classes a year ago and began working with a personal trainer to rehab my shoulder. I never thought it would happen, but I really took to strength training. I do a lower body workout a few times a week that is heavy on the squats, deadlifts, lunges, and Romanian deadlifts. My core is so much stronger and my body feels so much better than when I practiced asana several times a week.

        Moving away from asana was a hard thing for me to do because I was so attached to it. Maybe I will return to studio practice someday, but, for now, most studio classes in my area do not serve me.

  • Tim Papps

    There are cute strengthening exercises called the Foundation that are incredibly excellent for strengthening the core.

  • Tim Papps

    There are core strengthening exercises called the Foundation that are incredibly excellent for strengthening the core.

  • Colleen

    thanks for your post. I am very interested in this! So it seems you may think it is misguided to advise students to lift their hip-points and engage lower abdominals in a crescent lunge– therefore lengthening the tail downward (which would be like tucking the pelvis?)? What would be a better instruction to keep the pelvis stabilized and prevent sinking into the low back in a pose like this. Thanks for your help!

    • Hi Colleen! That’s a great question, and this is where things start to get a bit more complicated… There’s a difference between simply working the muscles that tuck your pelvis and actually *having* a tucked pelvis. (Aahhh so confusing, I know!) In the case of crescent pose, most people have tension in their hip flexors which tends to pull the pelvis out of neutral and into an anterior tilt. In order to get back to neutral, most people need to work the muscles that create a posterior tilt or a tuck, but only to bring the pelvis back to neutral – not to actually posturally tuck it. So crescent pose is a shape in which cueing to lift the frontal hip points (by contracting rectus abdominus) is definitely helpful, but in this case the intention is just to get the pelvis back to neutral so the spine can stay stable – the intention isn’t to create a postural tuck.

      The bigger issue about “tucking” that I’m talking about in the post is the tendency for people to teach that we should be posturally tucking our pelvis (i.e. pubic bone out in front of frontal hip points and lumbar curve has flattened) as a strategy for protecting our spine all throughout our practice and life. That idea is still commonly taught in yoga classes, but it doesn’t actually stabilize our spine and it doesn’t help us access our true core. We’ve got to let go of the tuck and embrace the un-tuck!!

  • John

    I’m curious where this series will go once you get past the basics. It’s one area where individuals are radically different. For example, I know people who’ve found doing yoga variations of crunches radically improves the health of their back but for me it’s completely the opposite (and yes, my technique is good, and my “core” is strong.

    Also, the problem often seems to be more a case of technique than strength, it’s not that people need more “core strength” but that they need to learn to move more efficiently.

    • Hi John! Totally agree that a “strong” core is much more about things like coordination, efficiency, and proper firing of muscles than just sheer muscular “strength”. For sure! And about crunches, newer research has shown that repeatedly flexing the spine against gravity like that actually creates wear-and-tear on the spine and especially the intervetebral discs. Some people you know may have experienced some temporary decrease in their acute back pain (?) from doing crunches, but we now know that in the long term, crunches really aren’t an appropriate practice for spinal health. Bummer man. 🙂

      • John

        Ok, you’re in the “crunches not good” camp. Fair enough 🙂 Me, I’m not so sure it’s as simple as one rule for every one, particularly not given how often “what we now know” from newer research turns into “what we used to think” as a result of even newer. How many decades is “temporary release”? I’m in the “crunches not good for me” camp (using crunches to cover all the various crunches like yoga abs exercises around). I know some one who uses leg raises (which I thought every one had agreed were outright evil) to keep their back pain free, they have done for decades, following expert advice. I’m open to the idea something else would help them even more, but I’m also open to the possibility that their body’s needs are just different to the average.

  • Todd

    Hey Jenni, Lots of things we shouldn’t do or shouldn’t cue. What should we do?

  • colleen

    Thanks Jenni– that is definitely helpful. That’s what I thought… There is so much conflicting information out there in the yoga world! I definitely don’t want to be giving incorrect cues to my students– so making sense of it all is important to me. I’m interested in the ‘correct’ core exercises that would not create wear and tear on the spine as you described in your comment above. I look forward to your future posts!

  • Renee

    Great article, I wonder if you have additional recommendations for pregnant yogis? I’ve read the tailbone tuck protects and strengthens against the lower back’s tendency to arch as space is created for the uterus. I’ve also heard “core work” during pregnancy can cause diastasis recti, but that it’s important to keep the transverse abdominals strengthened. Any suggestions?

    • Hi Renee! Congratulations on your pregnancy!! 🙂 It’s true that traditional “core work” can contribute to diastasis recti (especially if we don’t know how to turn on our transverse abdominus, which my next blog post will address!) And the advice to tuck your tailbone during pregnancy to protect against the lower back’s tendency to arch is outdated. The “arch” in the spine that can happen during pregnancy isn’t coming from a pelvis that is tilted forward – it’s coming from a rib cage that is lifted up and tilted backwards. The best thing we can do for our core, especially during pregnancy, is to un-tuck our pelvis to neutral and to “tuck” our rib cage back down where it belongs. My teacher Katy Bowman has a TON of great info on how to align your body during pregnancy in this blog post – the whole post is great, but you could at least watch the 2 min video for some easy and helpful tips. http://www.katysays.com/mama-baby-alignment/ 🙂

  • Kathryn Strauss

    Thank you, thank you, thank you Jenni!!!!!!! I appreciate all of your wisdom and the knowledge you share! Can’t wait till your next post. The pelvis tucking cues in yoga classes are one of my pet peeves! Especially because people with low back pain are often told to tuck in order to relieve or help the problem. It is probably just making it worse. I really want to pick your brain regarding the training you did with Katy. I’m super interested in it!!!! I’m so lucky to be able to go to your class, Jenni!!! You are such a blessing! ❤️

  • Hiii Lovely Kathryn! Thank you so much for your amazing and supportive comment! It is so awesome to know that people appreciate the info I try to offer with these posts. Even though the suggestion to tuck your pelvis to help with back pain is sooo outdated, the news that it’s unhelpful hasn’t made it to everyone yet, so it is still a common suggestion to hear (which is why I wanted to write this blog post!) I would love to share about my experience with Katy’s training and am really excited that you’re interested in doing it – omigosh!! Maybe you could FB message or email me and we could meet for lunch or coffee or a dog walk and chat about it? YAY!

  • awesome article very well explained and researched and thanks for pointing out that just because you have abs doesn’t mean you have a strong core!

  • sandra
  • Finally some decent information about the core.
    Most people have no idea what the “core” actually means. It’s more then just your abdominals popping out. It’s the inner strength and balance it brings.

  • Finally some decent information about the core muscles.
    Most people have no idea what the “core” actually means. It’s more then just your abdominals popping out. It’s the inner strength and balance it brings.

    Personally I’m not into yoga but you bring forward some good points about this!

  • Finally some decent information about the core muscles.
    Most people have no idea what the “core” actually means. It’s more then just your abdominals popping out. It’s the inner strength and balance it brings.

    Personally I’m not into yoga but you bring forward some good pFinally some decent information about the core muscles.
    oints about this!

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