Intra Abdominal pressure: Good or Bad?

5 Mins
Intra Abdominal pressure: Good or Bad?

Is Intra Abdominal pressure good or bad?

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..pressure sounds terrible and makes sense right? Pressure causes problems?  And while I agree pressure can cause problems, it can also be very helpful. 

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

 

bike2

 

Now look at a bike tire filled. The air pressure is contained and increased, the bike works. Tube walls are also strong and stable to handle the pressure. 

bike1

 
Intra abdominal pressure can be both good or bad. It depends on how the muscles respond appropriately to the increased pressure. This is what we train!
 
Increased IAP helps stabilize the spine when lifting or exerting force
 

If muscles can sustain and stiffen through the entire movement without fatiquing, it will be ablet to resist the internal force. Resisting is what helps create a strong stabilizied foundation to transfer force. 

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


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 often it is used and what exercises are also being done. 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.

If you put on a support and it restricts your breathing, then it is too tight.
We all want the simple answers, yet there are many variables that create a healthy or unhealthy pressure environment.


FIRST ...  we need to recognize that there are different ways a person can engage their core.  This can influence how pressure is distributed. This can affects whether IAP stays more in the abdominal cavity or pelvic cavity.

SECOND .. when a person engages their core, 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/brace to provide a somewhat stiff foundation for lifting and transfereing force.

The key is getting the muscles to respond appropriately to the pressure. 


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 able to stiffen to resist the internal force?
   4. Is the pelvic floor able to coordinate with the abdominal muscles?
   5. How is the person engaging their core?
   6. What kind of breathing mechanics are they doing?

This is what determines whether  IAP is helpful or damaging! Increasing IAP is what helps a person lift more and produce more power!

Even if pressure is put on the pelvic floor..the pelvic floor muscles when functioning well (strength, coordination and endurance) will be able to withstand the pressure.


When the INNER CORE system (diaphragm, transverse abdominals, pelvic floor and multifidus) is reactive, the pelvic floor can lift to resist pressure. This stiffening protects the pelvic floor and helps contain pressure in the abdominal cavity and off the pelvic floor. 

PRACTICE BRACING/ENGAGING: 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 is what contributes to peeing when lifting heavy weights.

FEEL THE DIFFERENCE #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.

FEEL THE DIFFERENCE #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

Copyright 2015 ReCORE Fitness LLC, All Rights Reserved


Yes ladies, peeing when doing CrossFIT or lifting heavy weights is not ideal but will happen when muscles reach their threshold or fatique. Some may only experinece it on a 1 rep max.  This meas that the pelvic floor is not able to sustain the pressure like it should and pressure on the bladder is too much.


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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