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The Anatomy of Core Stability

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By Kelly KaneThe Core in Pilates

Many teachers know the buzz word “core stability” and see that working the back and abs helps their clients transition out of back pain, but they may not know exactly why. Here, Kelly Kane, founder of the Kane School of Core Integration in New York City, provides a detailed look at the core muscles and how they work together to support the back and the whole body.

As humans we move in an upright relationship to gravity. We sit, stand, walk and run, often while carrying heavy loads such as our kids, bags and backpacks. When we do these activities we need to stabilize our pelvis and our low backs, and use the flexibility and strength of our hips to change levels, locomote and mobilize.

Unfortunately when the hips are tight and mobility in the hip joint is limited, movement is taken up the skeletal chain into the sacroiliac joints, sacro-lumbar junction and lumbar spine. The protocol for creating healthy backs should be to find good drop and glide of the femur bone at the hip joint, while strengthening the core stabilizers. In the Pilates venue we call this hip dissociation/differentiation and core stability.

Core Stability
The Core in Pilates refers to the muscles of the pelvic floor, the transverse abdominus, the lumbar multifidi and the diaphragm. This group of muscles encases our organs and supports our upper extremities and spine, but specific attention must be paid to strengthening these muscles.

Stability means absolutely no movement. Core stability assumes both the lumbar spine and pelvis remain immobile. In pelvic stability, the bones of the pelvis are stabilized in either a posterior or neutral pelvic position while the upper and lower extremities load the stabilizing muscles. Even the smallest rotation of the pelvis during movement means that the core stabilizers are working unevenly. Challenging the core stabilizers by loading the head, arms and legs on a stabilized pelvis will make these muscles stronger.

Lumbar stability
is stability of all five vertebrae of the lumbar spine. When the vertebrae are stabilized in neutral pelvis, the small lumbar multifidi and the transversus abdominus (TVA) work in opposition to each other to stabilize each vertebra (see diagram below). When assessing lumbar stability, it is vital to assess the stability of each spinal segment. It is possible to have segmental stability in all but one of the spinal segments. The trick is strengthening the core stabilizers so that all of the spinal segments are stabilized. In a posterior pelvic orientation lying supine the low back muscles are taken out of the equation, but the lumbar vertebrae are stabilized because the abdominal muscles push the lumbar vertebrae into the ground, inhibiting their movement. In neutral pelvis the ASIS and the pubic ramus are level in the coronal/frontal plane. For most people the lumbar vertebrae will be arching anteriorly, assuming a natural lordotic curvature. For our purposes we will talk about core stability, as it relates to the Pilates repertoire, in neutral pelvis.

Muscles of the Back

The Core Stabilizers
Pelvic Floor
The most important of the muscle of the pelvic floor for postural support is the levator ani (see diagram below) which is comprised of three very different units. The pubococcygeus originates at the left and right pubic tubercles and courses posteriorly, running lateral to the genitals. The two sides meet behind the anal opening and then bifurcate as it runs up the anterior surface of the coccyx. The iliococcygeus arises from the lower aspect of the two iliac fossa and inserts at the coccyx. The ischiococcygeus runs from the two ischial tuberosities to the coccyx. Pelvic floor strength is primary for low back health because it is literally the inferior anchor of the spine: all three aspects of the levator ani attach to the tailbone. These muscles form a cup or a diaphragm that has the capacity to contract in and up. The pelvic floor muscles support the inferior organs of the pelvis, such as the bladder, prostate, uterus and rectum.

Muscles of the Pelvic Floor
Strength and balance in the pelvic floor is greatly affected by pelvic orientation (neutral, anterior or posterior). To feel this for yourself, try sitting on a chair feeling your SITS bones. Come into neutral pelvis by bringing the ASIS and the pubis in the same plane. You will probably feel as though you are a little forward on your SITS bones. Contract your pelvic floor by pulling the right pubic bone to the right tailbone, the left pubic bone toward the left tailbone, the SITS bones together, close the anal and vaginal opening or condense around the base of the penis and pull everything up. Now tuck the tailbone under and sit on the back of your SITS bones, taking a posterior orientation, and contract the pelvic floor in the same way. You will probably feel more contraction around the anal opening. Do the same thing in an anterior pelvic orientation by rocking forward on your SITS bones and contracting the pelvic floor. You will most likely feel more contraction in the anterior pelvic floor around the genitals. When you are executing your Pilates exercises with a neutral pelvic orientation you will be more likely to recruit the pelvic floor evenly front, sides and back.

Transversus Abdominus 
The transversus abdominus (TVA) is the deepest abdominal muscle. It literally forms a girdle that encases our organs and supports our spine. At the pelvis, it attaches to the inguinal ligament, the iliac crest and the sacrum. It also has attachments to the lumbar spine by way of the thoraco-lumbar fascia. At the thorax it attaches to the inner surfaces of ribs seven through twelve and has fibers that interdigitate with the diaphragm. A healthy TVA is said to contract whenever we move; when we lift our arms, walk, turn our heads. When it contracts it axially elongates the spine and assists in spinal flexion and rotation. It also aids in respiration and contracts when we laugh, sneeze, cough or forcefully exhale. When the TVA contracts with the lumbar multifidi, it stabilizes each of the lumbar segments. It is the muscle that reduces the diameter of the waist and helps us “scoop.”

The TVA is extremely important to low back health. When it contracts and axially elongates, it literally decompresses the lumbar spine. As an intervertebral stabilizer, it protects the low back and the intervertebral disks by “stiffening” the spine so that it can sustain loading.
Hip Disassociation/Differentiation
The hip joint is the articulation between the femoral head and the acetebulum of the pelvic hemisphere. The femoral head is a ball and the acetebulum is a cup. The hip joint is happiest when the ball literally spins in the cup. When the hip flexes the ball scoops out the cup, as if a melon scooper were scooping out a melon. In hip flexion the scooping happens posteriorly, in abduction the scooping happens medially, in extension the scooping happens anteriorly. When there is an incapacity to scoop, mobility is reduced and the mobility will be taken up or down the skeletal chain. When executing this scooping action the pelvis half has to diassociate/differentiate from the movement of the femoral head. The capacity to stabilize the core allows the pelvis to stay in one position while the femoral head scoops or drops and glides in the socket.
 The Pilates Core | Hip Disassociation/Differentiation
The action of hip disassociation/differentiation happens when you reach your ischial tuberosities or sits bones as you descend to sit in a chair. The pelvis stabilizes and the femur heads scoop out your pelvis creating a deep crease at the front of the hip, as the photo at right demonstrates. This action is also the action that keeps the back happy when you are change levels to pick something off the floor. There should be the same action of pulling the abdominal muscles in, engaging the pelvic floor, reaching the sits bones back while mobilizing through deep flexion of the knee and hip joint to change levels. The action of deep knee and hip flexion requires sufficient strength through the quadriceps, hamstrings and gluteals. Many people don’t have adequate strength in their legs to squat 30-50 times a day to pick up the kids toys, get goodies out of the bottom of the fridge or lift a heavy bag of groceries. Correct biomechanics and a deep understanding of the core stabilizers and how to get good hip disassociation/differentiation are primary to any Pilates practice. 

Kelly Kane, founder of the Kane School of Core Integration, has been teaching Pilates for more than a decade. She studied with Romana Kryzanowska, Hila Paldi and Irene Dowd, and completed the training program at the Pilates Institute in Santa Fe, two years of the BodyMind Centering teacher-training program and a certification in massage from the Florida School of Massage. Her manual therapy repertoire includes Structural Integration, CranioSacral Therapy and Visceral Manipulation, and she cultivated her manual perception skills through three years of human cadaver dissection at the New Jersey School of Medicine and Dentistry. Her expertise also includes GYROTONIC® and Continuum Movement.  

Illustrations ©Elijah Leonard

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Posted on Monday, January 22, 2007 at 08:10PM by Registered CommenterAmy Leibrock in , | Comments48 Comments

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Reader Comments (48)

JW as I said in my deleted post I never said Pilates was perfect. It has it's limitations. A very important one to remember is that it was made for reasonibly HEALTHY bodies. It can be used for rehabiliation in certain instances but certainly not all. It is not a perfect cure for everything. Jay Grimes summed this up perfectly when he said,

Pilates teachers are not physical therapists. We do not have the education that a PT does, and we should not be trying to do their work. We do not diagnose or treat or cure. We teach exercise for reasonibly healthy bodies, and if someone comes in with a condition that suggests a need for medical attention, we should tell them that.

Due to the lawsuit (I will not go into that) many unqualified people can call themselves Pilates teachers and many do untold damage to peoples bodies. Unfortunetly it has been my experience that there seem to much more of people who fit this criteria then qualified teachers with 600+ hours of quality practical training. Your well known teacher that you speak of may fall under the poorly trained category.

Alot of non-pilates people forget or are ignorant that NOT ALL PILATES is the same.

I can only speak for myself and others that I know when we have had no problems with Pilates. It cured my lower back pain and I have had no problems since. Dancers who practice the Classical method properly are famous for having no problems or injuries when performing. This is the main reason why they loved the method so much and embraced it.

It is simplistic also to say that by corrective, the movements are reflective of the way we should be moving. That is not what I said at all nor is it the total sum of what the term corrective actually means. Is it not natural to have strong abdominals? Whilst the hundred strenghtens them and is corrective by way of making them stronger it is certainly not reflective of the way we should be moving is it? It is statements such as this that leads me to question your credentials on understanding things. I do not expect such simplistic statements from someone with your claimed level of knowledge.

Please specify your exact role or even better tell us your place of business so we can research your credentials. Do you have a website?

With regard your comment,

We should be able to take the foundations of what they put forth and use that to build and modify where needed based on our current and evolved perspective on the human form, experience and movement alike. If we can't do that objectively without biased for each discipline, then we have failed in fulfilling the spirit of each of those pioneers. None of them would have let their work remain static in its conception.

You will find that Power Pilates and Peak have done exactly that whilst staying with the classical mantra. They have altered certain moves to make them safer. Yes Joseph Pilates would have evolved his method but do you know HOW he would have evolved it. Romana has also made some changes to Pilates too so it has not remained static as you have put it. Joe used to pulse and push down on peoples heads. He would also heavily stretch them to the point of agony sometimes. No-one teaches like that today.

Regarding evolving, what is already happening is that some organisations have changed the method so much that it resembles little of the original. Not only that these versions are much more boring and alot less effective then then the Classical version. This is a case of DE-evolving the method. This is not the way foward and it's usually done by people with no real understanding of what Pilates is. This is also why I envy Gyrotonic as it's creator is still alive shaping and moulding his method whilst still having total control over what goes on in his disipline. I could probably make some changes to Gyrotonic and think I'am improving it. However I would almost certainly de-evolve it and make it worse because I do not understand Julio Horvaths creation. You are not the first person who talks like this about Pilates and other disiplines. The PTs in the 90's beat you to it.

March 12, 2009 | Unregistered CommenterJames

We need to stop the Pilates bashing, he said, she said commentary that seems to be an ongoing part of these discussions.

This is just non-productive and has nothing to do with the original topic which I can't even tell you what it is by reading the recent posts.

I can tell you that no two Pilates teachers practice the same. To judge an industry based on a few experiences with clients is unfair. Pilates as an industry can not be responsible for everyone that wants to call themself a Pilates teacher. Even the consumer doesn't know the difference until they can make comparisons.

Pilates can be an option that can be used to correct movement issues and developmental problems. That is not to say that if taught improperly it could cause injury. That can be said for anything. It is no different than choosing physical therapy, surgery or whatever method a client would like to try to feel better in their body. Some teachers are successful using that method and some aren't. Some surgeons are better than others, some teachers are better, etc. Everyone chooses the level of excellence they would like to practice at and that is what separates them from the rest of the herd.

Until you experience any of these teachers first hand, it is polite to ask questions, try to understand their thought process or assume they may have something new to offer.

If you are not a Pilates teacher, practioner or whatever you want to call yourself, it is important to be respectful to those of us who have found success and choose to teach the Pilates Method as our profession.

I am done posting on this site. JW, you are exhausting.

Good Luck to all!

March 12, 2009 | Unregistered CommenterStacey Redfield

As I posted Stacey you had already put your comment up. Everything you just said was true. Please do not leave because of JW narrow mindedness. He is not worth it. I have enjoyed reading your posts Stacey. You have alot to other myself and others who read this site. Please don't go.

March 12, 2009 | Unregistered CommenterJames


My viewpoint (not judgment) comes from experience with about two dozen teachers from whom I've taken with, my own kinesthetic/anatomic understanding of what they were teaching me to do, as well as my clientele (teachers and students alike).

March 12, 2009 | Unregistered Commenterjustwondering

To James (a classical teacher/enthusiast..?): I am curious to know your take on Kelly's article and the information she presents. Would/do you use the information? Who are your clients? Where would you place the boundary of "healthy enough to practice pilates" as you stated that it has helped your back?
Thanks, Carole

March 12, 2009 | Unregistered CommenterCarole Amend

JW I think that the overwhelming majority of those responding are saying that it is through our work and experience teaching the method developed by Joe Pilates that we are basing our opinions, not on hearsay or just accepting his word as gospel, but because we use his system every day on many bodies and it works, period! But that does not mean that you are wrong or right, and you as a person should be respected even if there is disagreement with your opinions. So shame on everyone if you were dishonored, that is not cool!.

March 12, 2009 | Unregistered CommenterLA

I have made the decision to heavily edit this thread due to posts that violate our Community Guidelines, specifically items 2, 3, 4 and 8. You can review the guidelines here.

March 12, 2009 | Registered CommenterPilates-Pro

Impersonating other people in the Pilates-Pro.com forums is in direct violation of our Community Guidelines. If we suspect a site user is impersonating someone else, we reserve the right to block his or her access to the site. Please use courtesy in these forums and refrain from personal attacks and from soliciting personally identifiable information.

Thank you.

March 12, 2009 | Registered CommenterPilates-Pro

JW -- just some show of support. I like your questions and your take on things. I may not agree with everything you say (and how boring would that be, if I did?) but I like your input. I think you bring up questions that need to be asked. I'm Romana-trained and how I wish that she were here to participate in this discussion. Whether you stay or go, I wish you the best.

March 12, 2009 | Unregistered Commenterdropshot

Hey, I have a question to anyone who has "registered" with pilates-pro. Can you edit your posts once they've been posted? As an anonymous user I don't have that capability.

I ask because that 'letter' supposedly from me was at first just the one paragraph with james' signature at the end. Then it was replaced with my signature and two more paragraphs added to the beginning.

March 12, 2009 | Unregistered Commenterjustwondering

Thank you for taking 'my' apology letter down... I'm not quite ready to go.:)

March 12, 2009 | Unregistered Commenterjustwondering

JW, please email me directly and I can address your question.


March 12, 2009 | Registered CommenterPilates-Pro

This forum for discussion about Pilates is also open to the general population. How must we sound to those folks who are looking to learn about Pilates?
I for one would hope that even though we might not agree with each other we can act like mature professionals, stay on point and not degenerate into name calling vitriolic behaviour.
Can't we have a healthy debate and acknowledge each other with respect, even though we don't agree. We are after all merely discussing differing protocols for movement, not trying to resolve world hunger. And at the end of the day we will still be teaching and doing things in our own style.

March 13, 2009 | Unregistered CommenterLA

I just heard that Peak Pilates was acquired by the Mad Dog/Spinning Organization. I wonder how that will effect their teacher training program and if they will be marketing even more heavily to the fitness sector? To which I say..... Uh Oh.
I think that poses the concerns that have been at the heart of all the discussions with JW, going back several months ago,the ones that have generated the most posts... where he is questioning the quality and quanity of education and training (or lack thereof) in the Pilates profession. Or more precisely, are instuctors teaching from a true base of knowledge, understanding and experience or are they reciting from a learned script and teaching a list of exercises

March 13, 2009 | Unregistered CommenterLA

I just heard that Peak Pilates was acquired by the Mad Dog/Spinning Organization. I wonder how that will effect their teacher training program and if they will be marketing even more heavily to the fitness sector? To which I say..... Uh Oh.
I think that poses the concerns that have been at the heart of all the discussions with JW, going back several months ago,the ones that have generated the most posts... where he is questioning the quality and quanity of education and training (or lack thereof) in the Pilates profession. Or more precisely, are instuctors teaching from a true base of knowledge, understanding and experience in a profound movement system that is adaptable to each individual or are they reciting from a learned script and teaching a list of exercises?

March 13, 2009 | Unregistered CommenterLA

Woops, how'd that happen

March 13, 2009 | Unregistered CommenterLA

hi JW,

i like to read your comment on pilates.i believe that is important to respect the body the way the body is.I haven't try feldenkreis or gyrotonic but been experiencing with different kind of yoga and few pilates style> there so many different pilates out there, can u recommended one which one is closer to that ideal??i have problem figuring out except for some that claim that they're respect the natural body curve.pls send me private massage through my email.

many thanks,

May 20, 2009 | Unregistered Commenterafi39

Hello Afi39,

If you would like a contempory approach with lots of physical therapy influence then Stott Pilates is a good choice. Physicalmind style of Pilates is more grounded in the Classical choreography but they also adhere to a neutral spine (natural curve).

Here is their website


They are drawn from Eve Gentrys (Pilates elder) teachings so are more rehab based then a Classical school.

Others on this site can give you advice regarding their schools too.

Hope this helps

May 21, 2009 | Unregistered CommenterJames

To James, you forgot to mention my school!!

I'm from BASI Pilates which stands for Body Arts and Science International. Our organisation prides itself on updating the way we teach Pilates using the most up to date scientific research availible. There are many Physical therapists and other people with Alphabet soups after their names involved the running of BASI. In fact there were 3 PTs in my class when I was training. They all remarked how amazed they were at the improvement in their patients when they took up Pilates in addition to their rehab schedule.

I remember my first class with Rael Isacowitz (head of BASI). He really emphasised to us that every exercise must be understood and legitismised, scientifically. Based on the most modern research availible. He is a man I have tremendous respect for. I can't remember exactly what his degree and furthur education was in but I know it was something to do with movement. He has also been practising the method for over 30 years!

May 26, 2009 | Unregistered CommenterNisreen Sheriff

To Pilates-Pro, I'am confused as to why my comment was deleted as there was no insults or anything to bring down the tone of the board. It was just information.

I ask please that the following post be allowed to stay up.

Sorry Nisreen I did forget to mention BASI. Stott Pilates also has alot of Physical therapists involved in the running and updating of the way they teach Pilates. The UK organisation Body Control Pilates also has many PTs involved in the organisation and evolving of their curriculum.

Brent Anderson president of Polestar Pilates is a physical therapist with a PHD in the subject.

Even many Classical trainers are PTs. Alycea Ungarro author of two best selling books 'Pilates in motion' and 'the Pilates promise' is a Physical therapist. So is the infamous Sean Gallagher as well as many others in the field.

In the 90's when Pilates came to the fore it was embraced by many from the world of Physical therapy. In fact so many became involved in Pilates many Classical enthusiasts accused them of diluting and changing what Pilates is! However that is another debate!

May 26, 2009 | Unregistered CommenterJames

Hi James,
Please email me off the board and I can explain it to you.


May 26, 2009 | Unregistered CommenterAmy Leibrock/Editor

I am glad you re-posted your comment.
You write:
"In the 90's when Pilates came to the fore it was embraced by many from the world of Physical therapy. In fact so many became involved in Pilates many Classical enthusiasts accused them of diluting and changing what Pilates is! However that is another debate!"

It is another debate...a very important one. Thank you for mentioning it and for your other comments as well.

One does not need to be a PT to be a pilates teacher. I can say with quite a bit of certainty that I would not have learned what I know now had I gone to PT school.

May 26, 2009 | Unregistered CommenterCarole Amend

I have deleted comments that violate our community guidelines. Please review them, and if you have any further questions, please email me at editor@pilates-pro.com.

This thread has strayed very far from the original topic, so I'm going to close it to further comments.


May 27, 2009 | Registered CommenterPilates-Pro
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