“In all nature structure determines function” – William Herbert Sheldon, father of somatotyping
“Form and function are a unity, two sides of a coin” – Ida P. Rolf, biochemist and fascial genius
“Conjunction junction, what’s your function?” – Schoolhouse Rock, how us 30+s learnt grammar
Structure and function are intricately connected. Our posture is the structure in which we move and function in the world. For example, when our ancestral primates chose to become bipedal, the hip joint changed to allow for increased mobility and centered weight bearing. For a more present day example look no further than your smart phone. Yes, that little device has created quite a number of neck and upper body problems, leading to what health care professionals like to call “text-neck.” Side note: Did you know that just a 15 degree bend in your neck to look down at your phone more than doubles the weight of your head. Physics people- no wonder your neck is tight. If you’re reading this right now on your smart device just lift up the phone to eye level and see the difference in effort for those neck and upper back muscles. Ok, stepping off my soapbox now. Basically, how we use our bodies impacts how our bodies form. And the form of our bodies impacts what we can and cannot do. My personal journey with posture has been one from ignorance, to militantism, to defeat, and now to hope. I spent a long time trying to “correct” my posture by “standing up straight” and “sucking in my gut,” as my mom used to tell me. Ultimately, I just resigned myself to the fact that I lacked enough strength and motivation. But now I know better.
Posture is not a position you hold, but rather a state of balance.
Let’s take a look at our friends, Jaun, Sara and Bruno to explain it better.
At first glance, who seems most balanced? Sara looks like she may be developing some of that text-neck and possibly back pain. Bruno is trying really hard to stand up straight. He may eventually get tired, or just live with constant discomfort and tightness in his upper back. Now Juan, he’s not perfect, but I think out of the group he seems most balanced and comfortable. I have a disclaimer: not all people named Juan, Sara and Bruno stand like this. Not all ladies are Saras and not all gentlemen are either Bruno or Juan. These postures are not the only postures out there. This is a google image for educational purposes. Ok, so back to the picture. What else indicates that Juan’s muscles and joints may have less stress on them? This is where we go back to the books to explore what us professionals like to call base of support and alignment. Juan is stacked up over his base of support (feet) and has reasonable alignment. He’s a little extended in his ribcage- but again, google image. Overall, his pelvis is over his feet, his ribcage is over his pelvis and his head is over ribcage. Sara does not have efficient alignment. Her ribcage is behind her pelvis and her head is in front of her ribcage. And Bruno…well Bruno’s ribcage is already into next week leaving his pelvis and head behind to catch up. Now let’s finally get to the point of the blog: how posture impacts our muscles, specifically our pelvic floor. To demonstrate my point I’ll show you the same picture with the pelvic floor and diaphragm (basically the “thoracic floor”), drawn in.
Okay, I know it’s a little rough, but hopefully you can see what I mean about Juan’s base of support and alignment. His diaphragm (the top red arc), is lined up over his pelvic floor (the bottom red arc). For Sara and Bruno the arcs are not stacked over one another, and there are even some changes in muscle length and shape. When the ideal length-tension ratio of a muscle is changed, it can’t function as well and this leads to weakness. What’s more, the pelvic floor and the diaphragm, along with some other trunk muscles, are part of the “core.” So when the “core” can’t fire efficiently, dysfunctional movement patterns develop that can create pain. To help explain this a bit better, I have one more picture to show the “strength” and direction of the pelvic floor and diaphragm in each position. (Bigger arrows mean more force/pressure production because of better length/tension of the muscle).
So who’s got the the big arrows? Juan! Sara and Bruno just can’t catch a break. Their muscles cannot produce as much force as Juan’s and don’t work together as well. The primary role of the core muscles is to increase intra-abdominal pressure (IAP) in order to keep the trunk stable. For a basic idea think: floppy balloon versus blown up balloon- which is easier to deform? Of course, the body’s balloon has active muscular walls and the top of the balloon (diaphragm) keeps letting air in and out for breathing, but the general premise is accurate. The great thing about our body is its structure is built for this function- to automatically turn the “core” on when we are in an efficient alignment. Think of how babies grow into toddlers and then into children who run, walk, sit efficiently, and with no pain. No one told them how to do that, their bodies automatically learned from guess and test and retest. Sometimes, after pain our muscles do get inhibited and we need to cognitively turn them on, but often changing to a more efficient posture can actually provide the same or even better strength gains.
So this is all great, but how does it apply to real life scenarios. Well, let’s imagine Sara is one year postpartum and came into the clinic because of incontinence. She’s trying to get back to exercise, but feels like she’s weaker than before she gave birth and is “leaking a little” with her box jumps. She may have even been doing her kegels correctly, but she still can’t get over that hurdle. Perhaps, it’s not as much an issue with strength, but more a problem with her alignment. She actually is weaker than before. Before getting pregnant, she was a Juan-like, but after pregnancy, birth and running around taking care of a one year old, that whole posture-thing fell to the wayside. She also may be a teensy-bit stressed leading to shallow breathing and decreased use of her diaphragm- another core muscle. Recent research out of Australia has even linked breathing capacity to incontinence, back pain and GI distress. To see just the impact breathing can have on stress and your bathroom habits check out Nicole’s blog. Since we understand the mechanics of the core and posture a bit better, this isn’t too surprising.
But remember, your pelvic floor muscles can also be too tight because of postural holding patterns. Maybe Sara actually shortened her pelvic floor muscles from doing so many kegels and now it’s not slack but like a tightrope. Maybe Bruno has started taking a lot of crossfit classes and is really working on “standing up straight,” but also noticed since signing up for his monthly membership, it takes him a while to start urinating and ejaculation has become painful. Normalizing posture, by aligning the body over the base of support can help improve the efficiency of the pelvic floor and diaphragm, so the muscles don’t have to work as hard. And when the muscles chill out, then the pain will start to dissipate. Take a look at some other exercises that can help improve the mobility of the pelvic floor. Often, if the muscles have been short for a while they also may need manual work, that’s where the PHRC or any good pelvic floor PT comes in.
So this is a lot to digest in one sitting. Hopefully you are still reading your phone at eye level and haven’t dropped it back in your lap. We’ll have a Posture and the Pelvis: Part Two to teach you how to apply these concepts to your own body. But please, don’t wait with bated breath. Just keep that diaphragm moving in the meantime.