I am very often asked to give a new mother an exercise to fix her separated abdominals. I decided to write this article in response to that question, as Diastasis Recti Abdominis (or DR as I will call it for simplicity) is a misunderstood, under-researched and often mistreated condition. What I am finding in my search for answers is that there is no quick fix; DR is a whole-body problem needing a whole-body solution. Healing your abdominals may not be as simple as a single exercise, but it can be a journey that is rewarding for the entire body and your overall health.
What is DR and is it normal?
You have a line of connective tissue running from your sternum to your pelvis called the linea alba (see a cross-sectional view below). This long ligament connects the two halves of your abdominals, and it is this connective tissue that stretches to create the separation between the two halves in a DR. The linea alba is almost like the waistband in your pants; it has a lot of stretch in one direction (sternum to pubic bone), but if you put too much pressure on the horizontal direction it can tear and cause distortions in the fibers. A DR is usually defined as a separation greater than 2cm (or 2 fingers width) and can occur at any place along the length of the linea alba (just above or below the belly button is common). It also has a depth; so the wider and deeper your DR, the longer it will take to heal.
What is DR and is it normal?
You have a line of connective tissue running from your sternum to your pelvis called the linea alba (see a cross-sectional view below). This long ligament connects the two halves of your abdominals, and it is this connective tissue that stretches to create the separation between the two halves in a DR. The linea alba is almost like the waistband in your pants; it has a lot of stretch in one direction (sternum to pubic bone), but if you put too much pressure on the horizontal direction it can tear and cause distortions in the fibers. A DR is usually defined as a separation greater than 2cm (or 2 fingers width) and can occur at any place along the length of the linea alba (just above or below the belly button is common). It also has a depth; so the wider and deeper your DR, the longer it will take to heal.
Remember that your body is amazing and fabulous and has evolved this way over millions of years…so I would like to believe that your body is meant to stretch this way *to a point* to accommodate your growing baby and it can be a natural process to heal it. Unfortunately you can stretch connective tissue so far that it loses its ability “bounce back”, and you may need additional help in the recovery process. If you are concerned about your DR or have any adverse symptoms (pelvic/back pain, incontinence, bulging in the front of your abdomen, etc) I would strongly recommend seeing a Women’s Health Physiotherapist to advise you in your rehabilitation.
Up to 99% of women have been shown to have DR by their third trimester of pregnancy[i]. Depending on the research this drops from 35%[ii] to 56% immediately postpartum. It has been shown that without any intervention, your abdominal separation at 8weeks is pretty much what you can expect to have at a year postpartum[iii]. The research is still severely lacking on what impact exercise can have on helping you heal your DR or how long it can take[iv].
While we are waiting for some awesome DR research to be produced, we can use a bit of logic in designing our postnatal programs so that they encourage abdominal wall healing by:
a) Not doing things that will make our DR worse by increasing load or strain to the area. Removing the stress factor from the injured connective tissue will promote healing and allow the body to do what it does best…heal itself without us getting in the way.
b) Make sure everything surrounding the site of injury (so your whole body) is functioning properly so that load, strain and pressure are evenly distributed and ALL of the muscles required for posture and stability are doing their jobs. If you think of it like a sprained ankle, a comprehensive exercise rehabilitation program will improve proprioception and motor control in the area and help to prevent re-injury, but it has nothing to do with healing the actual ligament that has been stretched/torn. It is all about restoring optimum control, balance and strength to the area to make up for any damage to the connective tissue.
Diastasis Recti (as well as many pelvic floor issues) is often a condition of excess pressure. To understand more about healing your DR, we need to talk a bit about Intra-abdominal pressure.
Up to 99% of women have been shown to have DR by their third trimester of pregnancy[i]. Depending on the research this drops from 35%[ii] to 56% immediately postpartum. It has been shown that without any intervention, your abdominal separation at 8weeks is pretty much what you can expect to have at a year postpartum[iii]. The research is still severely lacking on what impact exercise can have on helping you heal your DR or how long it can take[iv].
While we are waiting for some awesome DR research to be produced, we can use a bit of logic in designing our postnatal programs so that they encourage abdominal wall healing by:
a) Not doing things that will make our DR worse by increasing load or strain to the area. Removing the stress factor from the injured connective tissue will promote healing and allow the body to do what it does best…heal itself without us getting in the way.
b) Make sure everything surrounding the site of injury (so your whole body) is functioning properly so that load, strain and pressure are evenly distributed and ALL of the muscles required for posture and stability are doing their jobs. If you think of it like a sprained ankle, a comprehensive exercise rehabilitation program will improve proprioception and motor control in the area and help to prevent re-injury, but it has nothing to do with healing the actual ligament that has been stretched/torn. It is all about restoring optimum control, balance and strength to the area to make up for any damage to the connective tissue.
Diastasis Recti (as well as many pelvic floor issues) is often a condition of excess pressure. To understand more about healing your DR, we need to talk a bit about Intra-abdominal pressure.
Intra-abdominal pressure (IAP)
Think of your abdominal region as a fluid filled cylinder. The walls of the sac are made of the Transversus Abdominis (TrA) and the connective tissue it attaches to in the front and back, the floor is the pelvic floor and the respiratory diaphragm is the ceiling. All of these “postural” muscles have an extremely important role in core stability. If you make the abdominal cylinder smaller (by lifting pelvic floor and contracting TrA for example) you will increase IAP. Increasing IAP can be a good and very important natural mechanism of the body, as this extra pressure is what creates a “girdle” or “corset” around the lumbar spine to effectively stabilize the area[v].
The problems with IAP arise when we start to increase the pressure in the abdomen TOO MUCH and TOO OFTEN. The excess pressure places mechanical stress on the abdominal wall, which starts to wear and tear on the weakest links; usually the connective tissue that holds us together. A lot of pressure in the abdominal area will usually push down on the pelvic floor and force pressure outwards, straining the linea alba. Connective tissue that is over-stretched can lose the ability to rebound and become permanently changed, so this excess pressure can be very damaging.
Think of your abdominal region as a fluid filled cylinder. The walls of the sac are made of the Transversus Abdominis (TrA) and the connective tissue it attaches to in the front and back, the floor is the pelvic floor and the respiratory diaphragm is the ceiling. All of these “postural” muscles have an extremely important role in core stability. If you make the abdominal cylinder smaller (by lifting pelvic floor and contracting TrA for example) you will increase IAP. Increasing IAP can be a good and very important natural mechanism of the body, as this extra pressure is what creates a “girdle” or “corset” around the lumbar spine to effectively stabilize the area[v].
The problems with IAP arise when we start to increase the pressure in the abdomen TOO MUCH and TOO OFTEN. The excess pressure places mechanical stress on the abdominal wall, which starts to wear and tear on the weakest links; usually the connective tissue that holds us together. A lot of pressure in the abdominal area will usually push down on the pelvic floor and force pressure outwards, straining the linea alba. Connective tissue that is over-stretched can lose the ability to rebound and become permanently changed, so this excess pressure can be very damaging.
| DR can be caused or exacerbated by excess IAP, and when this pressure is continually raised in the postpartum period it can get in the way of abdominal healing processes. Pelvic floor issues are present in 66% of women with DR, so finding out what is causing this excess pressure is extremely important for the entire core[vi]. Many males also experience DR and other high pressure related conditions (hernias for example), showing us that we don't need a growing baby to have excessive levels of IAP damaging our core. We need to figure out what habits we have in our Western culture that create such high internal pressures to have any hope of naturally healing our bodies. |  |
Here are some things that can increase IAP:
Of course some of "the above" are inevitable. But we can definitely make an effort to reduce excess IAP and strain to our abdominals during pregnancy and the early postpartum period. To reduce the IAP we need to look at our cultural abdominal habits, the way we train and use our abdominals, and our whole-body alignment.
Start working on these 3 Steps to promote healing throughout your "core cylinder":
1. Stop sucking in
“Sucking in” has become normalized in our Western culture (think of the action you would do if someone was taking a picture of you in your bikini) and many people even confuse this action with stabilizing their core. In a neuro-muscular sense “sucking in” is very different to core stability, and can be debilitating when it becomes a long-term habit.
When you “suck in” you are effectively using pressure to draw your organs and belly in and up towards your diaphragm. Think Physics 101: every action has an equal and opposite reaction, so you draw your insides up, pressure is forced downwards (and outwards). Remember those weak links taking the brunt of these extra forces; icky for your pelvic floor, no good for your DR, and creates “bad habits” in your muscle patterning (example: every time you go to lift something, instead of your body naturally contracting your inner abdominals and lifting pelvic floor to create stability through your lower spine, you suck your guts in and up, creating pressures down and out, having the exact opposite effect of the natural muscle reaction to such a task).
Sucking your stomach in once is pretty harmless. Doing it for 30 years (from the time your dance teacher trained you to stand up straight and suck it in) can create lifelong habits that will increase your IAP and strain your connective tissue.
Toddlers are fantastic to watch for their ability to use their abdominals in the way they were designed to function. Observe them moving around, and how they let their lovely soft bellies hang out, but when they go into a more difficult position or plank-type pose they naturally contract and you can see the amazing strength and tone in their core. I only hope we can find more ways for the next generation to keep this natural strength and ability.
As a culture we need to start valuing true inner strength and supple, tension-free bellies rather than some fictional appearance that culture and media teach us to strive for. The extra stuff on your belly may just be needed to feed your growing child, and any excess can be taken care of with a healthy diet and a variety of whole-body movement. Please remember that when you “suck in” you are only temporarily trying to hide whatever is hanging out on your abdomen, at the expense of your internal organs, breathing, and very important connective tissue. Learn to let your stomach “go” and allow the abdominals to stabilize the way they were designed to (without us trying so hard), and your entire body, including your DR, will see the benefits.
2. Relearn how to naturally use your abdominals
“By the time toddlers are upright and walking they will have all of the core strength they will need in their lifetime.”
-Kathleen Porter, Natural Posture Solutions[vii]
Post-birth is the perfect time to re-learn how to use our abdominals in the way they were designed to be used. This time of healing and restoration can be ideal to take us back to a place where we had incredible strength and natural muscle patterning without years of modern technology and culture affecting the way we move. To accomplish this we must start from scratch, ignore the big bulky muscles for a while and rediscover our true “inner core”. Something you will need as a mother in more ways than one.
- Holding the breath (especially while lifting or exercising)
- Dysfunctional breathing patterns
- Abdominal exercises with improper technique or “too much too soon”
- Improper posture/alignment
- Sucking your stomach in
- Straining for bowel movements
- Carrying a baby
- Pushing a baby out
- Sneezing and coughing
Of course some of "the above" are inevitable. But we can definitely make an effort to reduce excess IAP and strain to our abdominals during pregnancy and the early postpartum period. To reduce the IAP we need to look at our cultural abdominal habits, the way we train and use our abdominals, and our whole-body alignment.
Start working on these 3 Steps to promote healing throughout your "core cylinder":
1. Stop sucking in
“Sucking in” has become normalized in our Western culture (think of the action you would do if someone was taking a picture of you in your bikini) and many people even confuse this action with stabilizing their core. In a neuro-muscular sense “sucking in” is very different to core stability, and can be debilitating when it becomes a long-term habit.
When you “suck in” you are effectively using pressure to draw your organs and belly in and up towards your diaphragm. Think Physics 101: every action has an equal and opposite reaction, so you draw your insides up, pressure is forced downwards (and outwards). Remember those weak links taking the brunt of these extra forces; icky for your pelvic floor, no good for your DR, and creates “bad habits” in your muscle patterning (example: every time you go to lift something, instead of your body naturally contracting your inner abdominals and lifting pelvic floor to create stability through your lower spine, you suck your guts in and up, creating pressures down and out, having the exact opposite effect of the natural muscle reaction to such a task).
Sucking your stomach in once is pretty harmless. Doing it for 30 years (from the time your dance teacher trained you to stand up straight and suck it in) can create lifelong habits that will increase your IAP and strain your connective tissue.
Toddlers are fantastic to watch for their ability to use their abdominals in the way they were designed to function. Observe them moving around, and how they let their lovely soft bellies hang out, but when they go into a more difficult position or plank-type pose they naturally contract and you can see the amazing strength and tone in their core. I only hope we can find more ways for the next generation to keep this natural strength and ability.
As a culture we need to start valuing true inner strength and supple, tension-free bellies rather than some fictional appearance that culture and media teach us to strive for. The extra stuff on your belly may just be needed to feed your growing child, and any excess can be taken care of with a healthy diet and a variety of whole-body movement. Please remember that when you “suck in” you are only temporarily trying to hide whatever is hanging out on your abdomen, at the expense of your internal organs, breathing, and very important connective tissue. Learn to let your stomach “go” and allow the abdominals to stabilize the way they were designed to (without us trying so hard), and your entire body, including your DR, will see the benefits.
2. Relearn how to naturally use your abdominals
“By the time toddlers are upright and walking they will have all of the core strength they will need in their lifetime.”
-Kathleen Porter, Natural Posture Solutions[vii]
Post-birth is the perfect time to re-learn how to use our abdominals in the way they were designed to be used. This time of healing and restoration can be ideal to take us back to a place where we had incredible strength and natural muscle patterning without years of modern technology and culture affecting the way we move. To accomplish this we must start from scratch, ignore the big bulky muscles for a while and rediscover our true “inner core”. Something you will need as a mother in more ways than one.
The first step is learning how to properly contract your Pelvic Floor and TrA without sucking in or overusing the “big guns”. Our smaller, postural muscles (like TrA and pelvic floor) normally work without conscious contraction needed. The body is in fact so amazing that if you move your arm, your core muscles will activate just before your arm muscles to stabilize the spine. Unfortunately the research has found that for people with back pain or general trauma in the area of the core (eg pregnancy/childbirth), often this mechanism is no longer working[viii]. So your body tends to “splint” with the big muscles instead of activating the small subtle stabilizers, thus creating a cascade of negative effects to your core stability.
If you’ve been splinting your core or have developed some abnormal patterning (kind of like any bad habit really), you will often need a period of retraining to remind your brain and body how/when to use these subtle stabilizers. This is a lot easier said than done, and I strongly recommend seeing a professional (Physios/EPs with access to Real Time Ultrasound can be very helpful here) to guide you through the process.
To get started try the following exercise:
To get started try the following exercise:
- Get on your hands and knees with hands under shoulders and knees under hips
- Flex and extend your spine a few times (cat stretch) and find middle/neutral
- Many or us that live with a tucked tailbone will still be tucked here. Try this: Without letting your ribcage drop to the floor, let your coccyx (bottom of your tailbone) float up towards the ceiling and think of spreading your sit bones.
- Many people that feel they have a "big curve" in their lumbar spine are actually just letting their ribs thrust forward, so really be conscious of having a stable rib cage while letting your bum "go" (rather than forcing over-extension of your low back).
- You should look something like the picture below (left):
 |  |
- Now the fun part. Hold your spine where it is and let your abs "go". That's right, no more sucking in. Let all your abdominal contents relax toward the floor and breathe.
- As you exhale, you should feel the natural lift of your abdomen away from the floor (not forced and your spine shouldn't move).
- Add a pelvic floor contraction to this natural breathing pattern. Inhale, let everything relax, and exhale, gently lift pelvic floor. As you lift pelvic floor you should feel a gentle lift of your abdomen away from the floor, almost like a piece of glad wrap inside those big bulky muscles is ever-so-slightly tightening around your waist (TA contraction).
- So your PF and TA should be able to work without any movement happening in your pelvis or spine, without any big bulky muscles contracting (no bums please), and it will really feel like you’re not doing anything. Because it’s supposed to be natural and we’re not supposed to have to think about it. Except sometimes we do. So practice this a few times a day until your body remembers what it feels like to use those lovely little stabilizers!
Once you’ve done a bit of retraining/corrective exercise on your abdominals and you’ve had an adequate period of rest to allow your DR to heal, (this can take 6 months depending on the person, please don’t rush it!) you can build your way back to your old workouts or favorite core exercises as long as you ensure that you are layering your abdominals properly. This means that TA and pelvic floor fires first, and that you never feel your abdominals “popping” (pushing outward) or downward pressure on your pelvic floor. Think of how your abdominals feel if you were lying on your back and suddenly decided to jack-knife yourself to sitting…most people "pop" with this movement. “Popping abdominals” means that you are either doing an exercise that is too hard for you at this point in time, you are holding your breath, or you haven’t mastered those inner muscles yet. That’s fine, just back off to an exercise you know you can do well and take baby-steps back to those bigger/harder exercises.
Once your abdominals are “retrained” and/or if you are in a proper alignment (see the next point), the magical thing about the body is that you should not have to consciously contract your abdominals. Modern life often takes us out of these good habits and alignments, so a daily dose of corrective exercise certainly won’t hurt. But I DO NOT think you should ever walk around contracting your abs all day, that will do more harm than good and mess with these amazing natural processes.
3. Work on your Whole Body Alignment
Theoretically, when your bones are in the “right place” in respect to each-other and the ground, your core and postural muscles should work naturally – meaning you shouldn’t have to consciously contract them. When you were a kid running around I’m sure you didn’t think about lifting your pelvic floor before you jumped, right? We can take our bodies back to this magical place of natural stability but it will take a move back towards natural alignment.
The other great thing about natural alignment is the way the body distributes pressure throughout the system. Katy Bowman, a biomechanist, a valued teacher and role model of mine, explains this much better than me, please see these posts for more info:
http://www.katysays.com/under-pressure-part-1/
http://www.katysays.com/under-pressure-part-2/
To sum it up: good alignment=natural distribution of pressures=less pressure on our DR and pelvic floor, allowing the core to heal naturally.
Dodgy alignment + carrying a child = excess IAP = more pressure pushing on the linea alba and pelvic floor, preventing it from healing and closing.
There is an ideal alignment for the human body that would have been the norm for our ancestors living in nature. Shoes, chairs, desks, cars, computers, etc have changed much of our alignment, which is why we often need an exercise regime to try and put us back where we belong. We also need to look at what we are doing all day long to exacerbate these alignment issues, as one hour of exercise does not take away the negative effects induced by 8-hours of sitting and staring at a computer screen.
*If you are wanting to find more ways to work on your alignment, please see "next steps" below.
To start working on your alignment, try this simple awareness exercise:
 |  |
- Check out the picture on the left. This is where many of us normally live, exacerbated further by pregnancy and carrying around a child (the ball is my pretend baby).
- The picture on the right is more of a natural alignment, notice how you can draw a line through the centre of the foot, knee, hip and ribcage. Imagine the diaphragm and where it would be in relation to the pelvis. Our core muscles function best when we are in this alignment and the diaphragm sits on top of the pelvic floor with a neutral pelvis relative to the ground
- SO…stand by a mirror side-on. Check out where your ribs sit in relation to your pelvis and your pelvis in relation to your feet. See if you can back your pelvis up over the centre of your ankle joint without falling over backwards, and then bring your ribcage balanced over the pelvis.
- Understand the natural alignment, play with it and become aware of how you stand (and carry your child) in relation to how you should be standing. Do not try to force yourself into “natural alignment” if your body doesn’t go there yet. Be aware that it can take years of work to be able to get yourself there, but the closer you get the better you will feel.
- If you feel unable to get into a better alignment I would highly recommend getting some bodywork done (find a KMI or Myofascial Release practitioner near you) and combining it with some corrective exercise (find a trusted exercise professional or start with Katy’s snackbytes on the Restorative Exercise website). Even tension in the bottom of your feet and the top of your neck can affect your pelvic floor so remember to treat the body as a whole!
So it’s not too hard right? We only need to learn to let something go we may have been holding our entire lives, use muscles we haven’t properly engaged since we were carefree children, and work on our entire body alignment. Simple really.
Our body has amazing, untapped potential and I firmly believe we can heal most DR and pelvic floor issues naturally. But like anything else in life it needs to be seen as a process. The same way that developing good nutrition and eating habits can be a process of discovery and invention. Or the way mindfulness and meditation can continue to improve your mental and emotional state the longer that you practice. The physical body and movement is no different. Like anything good in life, there is no quick fix or short answer, no single exercise that is going to put us back together after having a child. And if someone tells you there is, I hope it raises red flags for you after reading this article.
Postnatal rehabilitation can be an amazing time to rebuild our bodies from the inside-out, find that inner strength that we are so badly going to need, and nurture and love our bodies for everything that they are and all that they have the potential to become.
Enjoy the journey and let me know how you’re traveling xx
The next steps:
References
[i] Fernandes de Mota, P.G., Pascoal, A.G.B.A., Carita, A.I.A.D.C., & Bo, K. (2015). Prevalence and risk factors of diastasis recti abdominis from late pregnancy to 6 months postpartum, and relationship with lumbo-pelvic pain. Manual Therapy,20(1), 200-205
[ii] Candido, G., Lo, T., & Janssen, P. (2005). Risk factors for diastasis of the recti abdominis. J Assoc Chart Physiother Womens Health, 97: 49–54
[iii] Coldron, Y., Stokes, M.J., Newham, D.J., and Cook, K. (2008). Postpartum characteristics of rectus abdominis on ultrasound imaging. Man Ther. 2008, 13(2), 112–121.
[iv] Benjamin D.R., van de Water A.T., & Peiris C.L. (2014). Effects of exercise on diastasis of the rectus abdominis muscle in the antenatal and postnatal periods: a systematic review. Physiotherapy, 100(1), 1-8.
[v] Hodges PW, Eriksson AEM, Shirley D, Gandevia SC. (2004) Intra-abdominal pressure increases stiffness of the lumbar spine. J Biomech, 34 (3), 347-53
[vi] Spitznagle, T.M., Leong, F.C., and Van Dillen, L.R. (2007). Prevalence of diastasis recti abdominis in a urogynecolgical patient population. Int Urogynecol J Pelvic Floor Dysfunct, 18(3), 321–328
[vii] Katheleen Porter, quoted from Liberated Body podcast: http://www.liberatedbody.com/kathleen-porter-lbp-042/
[viii] Hodges P.W, Richardson C.A. (1996) Inefficient muscular stabilization of the lumbar spine associated with low back pain. A motor control evaluation of Transversus Abdominis. Spine, 21(22) 2640-2650.
Our body has amazing, untapped potential and I firmly believe we can heal most DR and pelvic floor issues naturally. But like anything else in life it needs to be seen as a process. The same way that developing good nutrition and eating habits can be a process of discovery and invention. Or the way mindfulness and meditation can continue to improve your mental and emotional state the longer that you practice. The physical body and movement is no different. Like anything good in life, there is no quick fix or short answer, no single exercise that is going to put us back together after having a child. And if someone tells you there is, I hope it raises red flags for you after reading this article.
Postnatal rehabilitation can be an amazing time to rebuild our bodies from the inside-out, find that inner strength that we are so badly going to need, and nurture and love our bodies for everything that they are and all that they have the potential to become.
Enjoy the journey and let me know how you’re traveling xx
The next steps:
- Look for my “Restore Your Core and Pelvic Floor” 30-Day Online Program launching next year! Sign up to the newsletter here and/or like my facebook page to keep updated.
- Look for more awesome info and “movement snacks” on Katy Bowman’s website: http://www.restorativeexercise.com
- For a more comprehensive exercise program that encompasses the principles listed in this article, check out MUTU systems: https://mutusystem.com
- Nothing beats 1:1 care. Please go see a healthcare professional trained in postnatal care, and if you’re having any pain/issues make sure it’s a Women’s Health Physiotherapist!
References
[i] Fernandes de Mota, P.G., Pascoal, A.G.B.A., Carita, A.I.A.D.C., & Bo, K. (2015). Prevalence and risk factors of diastasis recti abdominis from late pregnancy to 6 months postpartum, and relationship with lumbo-pelvic pain. Manual Therapy,20(1), 200-205
[ii] Candido, G., Lo, T., & Janssen, P. (2005). Risk factors for diastasis of the recti abdominis. J Assoc Chart Physiother Womens Health, 97: 49–54
[iii] Coldron, Y., Stokes, M.J., Newham, D.J., and Cook, K. (2008). Postpartum characteristics of rectus abdominis on ultrasound imaging. Man Ther. 2008, 13(2), 112–121.
[iv] Benjamin D.R., van de Water A.T., & Peiris C.L. (2014). Effects of exercise on diastasis of the rectus abdominis muscle in the antenatal and postnatal periods: a systematic review. Physiotherapy, 100(1), 1-8.
[v] Hodges PW, Eriksson AEM, Shirley D, Gandevia SC. (2004) Intra-abdominal pressure increases stiffness of the lumbar spine. J Biomech, 34 (3), 347-53
[vi] Spitznagle, T.M., Leong, F.C., and Van Dillen, L.R. (2007). Prevalence of diastasis recti abdominis in a urogynecolgical patient population. Int Urogynecol J Pelvic Floor Dysfunct, 18(3), 321–328
[vii] Katheleen Porter, quoted from Liberated Body podcast: http://www.liberatedbody.com/kathleen-porter-lbp-042/
[viii] Hodges P.W, Richardson C.A. (1996) Inefficient muscular stabilization of the lumbar spine associated with low back pain. A motor control evaluation of Transversus Abdominis. Spine, 21(22) 2640-2650.
