Intraabdominal pressure: Good or Bad?

5 Mins
Intraabdominal pressure: Good or Bad?

This is a hot topic lately. The common thought being; intra-abdominal pressure (IAP) is not good for you... therefore any support worn around the belly must be harmful...assuming it increases IAP, meaning it must put pressure on pelvic floor, causing prolapse, hemorrhoids, displacement of organs and diastasis. Agh..it sounds terrible and makes sense right? Pressure causes problems?  And while I agree pressure can be bad, it can also be helpful.


FIRST ...  we need to recognize that there are different ways a person can engage their core.  There are many incorrect ways and only 1 correct way. This affects whether IAP stays more in the abdominal cavity or pelvic cavity.

SECOND .. when a person engages their core correctly, IAP does increase slightly. When a person lifts a heavy weight and engages the core more, IAP increases even more.

Does that mean engaging the core is bad for you? Well we know that isn't true. The core needs to engage to provide a foundation for lifting and moving.


The questions we should be asking is:
   1. What is causing the IAP?
   2. Where is the IAP going when a person engages their core (abdominal, thoracic or pelvic cavity?)
   3. Are the core muscles strong?
   4. Is the pelvic floor lifting like it should when core engages?
   5. How is the person engaging their core?
   6. Are they using proper breathing mechanics?

This is what determines whether  IAP is helpful or damaging!

IAP does NOT automatically put pressure on the pelvic floor


When the CORE stabilization system (diaphragm, transverse abdominals, pelvic floor and multifidus) is reactive, the pelvic floor will lift when the TVA engages. This protects the pelvic floor and helps contain pressure in the abdominal cavity and off the pelvic floor.  It is this pressure when increased that helps stabilize the spine (lock it into place) when exerting force.

PRACTICE CORRECT WAY TO ENGAGE: Lift pelvic floor, breathe out as you engage abs. Where does the pressure go?  Up in the Abdominal Cavity off the pelvic floor. (If you are having trouble figuring out how to do this, you need to reconditioning your core)

Cavity engaged

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IAP is what helps stabilize the spine so a person can lift heavier weights safely


If the pelvic floor is not responding (lifting) when the TVA engages (see pic below), then IAP may get pushed downward and put more pressure on the pelvic floor (like when a person has a bowel movement)..this of course is not a good thing. This is what contributes to peeing when lifting heavy weights.

PRACTICE WRONG WAY #1: Breathe out while engage abs in and "bear down" (like having a bowel movement) - where does the pressure go? Yes, down to the pelvic floor.

PRACTICE WRONG WAY #2: Hold breath, "bear down" without engaging the abs (belly bulges out instead). Where does the pressure go? Yes, down to the pelvic floor and out to the belly button. 

cavity pressure

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Yes ladies, peeing when doing CrossFIT or lifting heavy weights is not a good thing. This can mean that the pelvic floor is not engaging like it should and pressure on the bladder is too much.

Picture a flat bike tire. Without the proper amount of air pressure, the tube walls are flimsy and weak.

 

bike2

 

Picture a filled bike tire, when air is contained and increased, the tube walls are strong and stable.

 

bike1

 
Increased IAP helps stabilize the spine when lifting or exerting force
 

It is very difficult to increase too much IAP into the abdominal cavity when lifting weights. Especially when the walls (spine, muscles an fascia) are strong and stabilized. If someone who does not have a strong core decides to try and lift a very heavy weight, yes...they are at risk for lifting with incorrect alignment, pulling a muscle, causing a hernia or a herniated disc.

So is  IAP good or bad?

It depends on your breathing
It depends on your muscles ability (strength) to contain the pressure
It depends on where the pressure is going
It depends on what is causing the IAP


Learning to direct intra-abdominal pressure correctly will help:

  • reduce stress on pelvic floor
  • use core muscles efficiently
  • breathe efficiently
  • stabilize the spine

To say that all abdominal binders are bad for you..is also a big assumption. Its like saying all ankle braces are bad for you. Again, it depends on what it's being used for; how it works, how much pressure is applied, how it is used and what the claims are. A person can wear an ankle brace too tight and restrict blood circulation and restrict too much motion.  There is a science to taping an ankle correctly. The same goes for abdominal supports, they can work differently! Some are flexible, some are stiff, some are fully adjustable, some are not, some are tall, some are short. It's very possible to wear an abdominal support and have the same amount of IAP applied as when someone engages their core. Its possible to have less, its possible to have more.   Again many variables, many differences.

We all want the simple answers, yet there are many variables that create a healthy or unhealthy pressure environment.


SOURCES

Bartelink, D.L. (1957). The role of abdominal pressure on the lumbar intervertebral discs. Journal of Bone and Joint Surgery [Br], 39, 718-736.
 
Sullivan, M.S. (1994). Lifting and back pain. In Twomey, L.T., & Taylor, J.R. Physical Therapy of the Low Back. (2nd ed.). New York: Churchill Livingstone, 329-356.
 
Thompson J,  O'Sullivan PB, Briffa NK, Neumann P (2006)Differences in muscle activation patterns during pelvic floor muscle contraction and Valsalva maneuver. Neurourol Urodyn., 25(2):148-55.
 
Cobb W, Burns J, Kercher K, Matthews B, James Norton H, Todd Heniford B. Normal intraabdominal pressure in healthy adults. J Surg Res. 2005;129:231–235. doi: 10.1016/j.jss.2005.06.015.
 
O'Dell K, Morse A, Crawford S, Howard A 2007 Vaginal pressure during lifting, floor exercises, jogging, and use of hydraulic exercise machines.Int Urogynecol J Pelvic Floor Dysfunct. Dec;18(12):1481-9. Epub 2007 May 22.

 

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