The diaphragm has been getting a lot of play in the interwebz these days, and with good reason. It’s the most proximal muscle in the body, holds up internal organs, links in with the psoas to the hip, controls breathing, fights against the dark side of the force, is a creative genius like Kanye, and totally references Breaking Bad every chance it gets.
It’s a main muscle involved in powerlifting, where the goal of getting your air and squeezing down on it makes the intraabdominal pressure skyrocket and increases spinal stability. An article in the European Journal of Applied Physiology by Brown et al showed powerlifters had greater diaphragm thickness compared to a control group, showing that it has the ability to respond to load in a similar manner as other skeletal muscles. This also shows that if it could respond to hypertrophic stimulation, it could also atrophy in the presence of injury or dysfunction.
For my anatomy nerds out there THIS ARTICLE describes the major attachments and functions of the diaphragm, and for those who want the condensed version, I’ll lay it out here:
When breathing, the diaphragm depresses into the abdominal cavity. The pelvic floor undergoes a concomittant lowering during this phase, which allows for the increase in lung volume into the abdominal cavity. The downside comes if the person has any pelvic floor alterations, which makes these muscles resist descending, and essentially hold the diaphragm up. This tends to affect everything as a domino effect.
The pelvic floor is pretty much what it’s called: it’s the muscle tissue at the bottom of the pelvis in and around all the happy areas. It responds to core contraction by either elevating or depressing, based on what’s required. When doing a max lift, it tends to rise. When breathing deep and gently, it depresses in line with the breathing. The medial fibers of the glute max bind into the fibers of the pelvic floor, which means when you’re doing any kind of hip extension work you’re also getting some PF work in there.
Spinal, SI joint, core, or diaphragmatic disturbances or damage can affect the pelvic floor as much as any other area, which makes it pretty important to know about.
The connection between the pelvic floor and the diaphragm is one that doesn’t get as much play in most strength and conditioning articles.
I’ve been fortunate to work with a number of women who have had significant PF dysfunction following childbirth, some who have had to have surgical repair and some who haven’t. In each case, there’s some presence of diaphragmatic disturbance, coupled with thoracic restriction, and even a few with rectus diastasi, which is where the two sides of the rectus abdominis (the six pack muscle) separate horizontally.
This is all well and good, but what the heck does all this have to do with pushing and pulling?
Think of the two ways you can move an object. You can either push it there or pull it there. Essentially, the goal in breathing is to increase lung volume, creating a negative pressure inside the lungs compared to the pressure of the atmosphere, and pulling air into the system. The way this is commonly accomplished is to have the diaphagm push down and the ribs to push out to increase the lung volume.
Now the problem comes in when the diaphragm is supposed to press down, but it doesn’t. We know it’s important, and that in an ideal state, it’s going to drive down and push into the core, and to get reflexive movement out of the pelvic floor and other core muscles to allow this to happen without smashing your colon all over the third period wall. This is your classic belly breathing.
When belly breathing, your entire abdomen should expand evenly and universally. If you were to hook your fingers under your lower ribs and breathe in, the diaphragm should push your fingers back out rather quickly, if not immediately.
If not, you may not be getting your diaphragm to push down properly. Go ahead, give it a try now. Hook your index and middle fingers under your ribs, and take a deep breath in and see what happens. Now do the same thing but slouch like crazy in your chair, or standing, or whatever the hell you’re doing right now. Did it change what happened in your diaphragm? Most likely it delayed it or made it nearly impossible to depress the fingers back out.
This is essentially the diaphragm pushing into the core to get the respiration, but what about if the diaphragm is dysfunctional? How do you breathe?? FOR THE LOVE OF GOD, HOW DO YOU BREATHE!?!?!??!?! That’s for the pull.
Remember earlier when I said your pelvic floor depresses when you breathe in, but that it’s linked to the diaphragm directly through fascia and other muscle attachments? It has the ability to pull the diaphragm down, along with some other core muscles, in order to get your to breathe if you ever lose control or strength in the diaphragm.
Another reason why dysfunctional PFs can lead to a little sneaky action after coughing.
If the diaphragm is pushing down, you will get equal expansion of the abdomen as the cavity is filled and all abdominal muscles are working together. In a dysfunctional diaphragm, you’ll see the lower portion of the abdomen (immediately below the belly button) expand out first and significantly more than the rest of the abs.
Can you fix this? Absolutely. It just comes down to looking at how the core looks when it moves. Does it move uniformly or fairly evenly or does it create a bulge in one place or another? Ideally, you want to aim for an equal press out from the core.
In some instances, you may need to get some specific work done to make sure everything is firing properly, which is where a physiotherapist trained in pelvic floor work comes in really handy, especially if you work with a lot of females who have a history of core issues from pregnancies.
In most instances of low back, shoulder or hip pain, I look at breathing as part of the assessment. I have found some people respond relatively quickly from simply altering breathing mechanics. The one that stands out the most was a young guy who had recently had surgical repair from a shoulder dislocation and had lost a significant amount of flexion. Having him go into a full segmental flexed posture with the opposing leg forward and focusing on diaphragmatic deep slow breathing, he immediately gained some new range of motion through the shoulder and even seemed genuinely shocked that all it took was some breathing drill.
So in conclusion, the act of belly breathing can be accomplished by the diaphragm pushing (bueno!) or by the pelvic floor and lower core muscles pulling (no bueno!!), which will both result in you continuing to breathe (ie. stay alive), but will alter how your core works and probably have some nasty side effects along the way.