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Regulating Abdominal Pressure

Hopefully we all have a bit of a better idea about how our abdominal muscle functions. If you didn’t yet get a chance to read my last post, go back and review the section on the transverse abdominis, because having that knowledge is key for understanding the following concepts.

I’d like to start by introducing the concept of our abdominal and pelvic cavities – these are the areas where our organs are housed. Or abdominal cavity contains our gastrointestinal organs and pelvic cavity contains the bladder, bowel and reproductive organs. The differentiating line between the abdominal and pelvic cavity is the pelvis, but there is no real “separation” between these two cavities. Now, let’s think about the wall of this cavity – it’s the abdominal muscle! The “lid” of this cavity is the diaphragm and the floor is the pelvic floor muscle.  

  • Diaphragm
    • This muscle is dome-shaped and it separates our chest cavity from our abdominal cavity. It is connected to our sternum, lower six ribs and lumbar spine.  When it contracts, it drops downward and flattens, which helps with inhalation. When it relaxes, it rises up and is involved in exhalation.
  • Pelvic floor
    • Recall that the pelvic floor runs from our pubic bone to our tailbone and forms a sling of muscle that supports or pelvic organs. It contracts and relaxes just like all of our skeletal muscle. It is responsible for responding to increases in abdominal pressure by contracting, thereby preventing leakages of stool or urine. Want more information on the pelvic floor? Click here to read my earlier post:

The reason I bring up the concept of the abdominal cavity is this: we often do very dysfunctional things that affect our ability to regulate pressure in this cavity, which can result in a variety of other problems, including low back pain and pelvic floor dysfunction. You may (or may not) recall that pressure is inversely proportional to volume. This means that as volume of decreases, pressure increases. Think about a piston – as it drops down, the volume in the cylinder is decreased and the pressure is increased.


One thing that I frequently see is repeated bearing down, pushing or perform a Valsalva maneuver. For those of you that aren’t familiar: the Valsalva is performed when you close your airway and try to force air out (i.e. when you’re “bearing down”). When we brace for a lift, our diaphragm drops down as we inhale (just like a piston) to increase the pressure of our abdominal cavity, which serves to stabilize our lumbar spine. Now, this is a good thing, because we need our low back to be as stable as possible when doing a heavy squat or deadlift. But I can’t tell you how many women (and men) I have worked with that are NOT doing this correctly and instead are doing a Valsalva!  Along similar lines, people often don’t realize that they shouldn’t be pushing when they go to the bathroom.  

In both of these scenarios, we are putting repeated and undue stress on our pelvic floor muscle, which can result in dysfunction of this muscle – it may become weak and lengthened, or it may go into spasm in an attempt to compensate and guard against this pressure. In some instances, this repeated downward pressure can be enough to causes pelvic organ prolapse: the bladder, bowel or reproductive organs and literally be pushed out of the rectal or vaginal opening!

Now, on the other end of the spectrum, people can often get in the habit of always holding tension in their abdomen. This can often be the case when we are constantly trying to “hold it in” like you would when you’re posing for a photo. The problem with this type of bracing is that it is static, and our abdominal cavity is meant to be fluid. What I mean is that our abdominal and pelvic floor muscle need to be able to contract appropriately to respond to a variety of stimuli. We aren’t meant to hold any muscle tight for prolonged periods. Consider what happens when we hold our abdominals tight for prolonged periods: there would be a constant pressure in our abdominal cavity, which can compress the nerve and blood supply to our organs! I often find that my patients who are experiencing abdominal or pelvic pain are particularly guarded through their abdomen and pelvic floor, which is a self-perpetuating process: people tend to tense their muscles in response to pain and this further exacerbates their pain by further compressing the abdomen!

Here’s what SHOULD happen:

  • With diaphragmatic breathing:
    • When we inhale, the diaphragm gently drops downward, the abdomen should expand and the pelvic floor should lengthen and relax. When we exhale, the diaphragm rises up to help force air out of our lungs, our abdomen compresses and our pelvic floor gently lifts.
  • With TA engagement:
    • Recall that a TA contraction will draw the navel toward the spine. With this contraction our abdomen narrows and stabilizes, and the pelvic floor gently lifts. There is a slight increase in the pressure of our abdomen as the volume decreases. However, there is no pressure downward during an appropriate TA contraction. Rather, you should feel your diaphragm to prevent downward pressure against the pelvic floor.
  • With bracing for a lift:
    • When preparing to lift a heavy load, we want to increase the pressure in the abdomen to stabilize the lumbar spine without putting pressure downward onto the pelvic floor. I cue my clients to engage their TA, which will narrow their abdomen. Then, you can inhale and close your glottis to increase the pressure in your now-narrowed abdomen. Think of putting outward pressure against your rigid and contracted TA, rather than pressure going downward. What we don’t want to do here is bear down. Can’t tell if you’re doing it right? If your attempt to brace would cause you to pass gas, you’re bearing down!
  • With bowel movements:
    • We should focus on relaxing our pelvic floor as we inhale; the diaphragm gently drops downward, the abdomen should expand and the pelvic floor should lengthen. If this is not adequate to empty your bowels, think about exhaling as though fogging a mirror and gently bulge your pelvic floor downward.

Start to bring some awareness to the pressure in your abdomen throughout the day! Focus on what happens when you breathe, lift heavy objects and use the bathroom and do your best to avoid putting pressure downward. Your pelvic floor will thank you!

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