6 Reasons Why the Diaphragm may be the Coolest Muscle in the Body

I have a small confession to make-- I love the study of human anatomy. Always have. It was studying human anatomy and physiology that made me shift my undergraduate degree at Gordon College away from "Biology" and into "Movement Science" (which has now become "Kinesiology"... Who would have known that years later, "Movement Science" would have been the coolest name for a major ever? Am I right fellow PTs?). The human body is fascinating and incredible. So, it should come as no shock to you that I have favorite muscles. In PT school, my favorite muscles were the ones with the most fun names... like the Gemelli brothers (who are small hip external rotators) or Sartorius (a thigh muscle...best, if sung to the tune of "Notorious"). Of course, you know that now the pelvic floor muscle group ranks pretty high on that list...but the diaphragm, well... it just takes the cake. Here are some of the reasons why the diaphragm really is so cool.

1) We can contract our diaphragm voluntarily--but it also will contract without us consciously telling it to. How cool is that? You can activate your diaphragm by taking a long, slow, breath expanding your ribcage 360 degrees and allowing your belly to relax. But, before I brought your attention to your breath, you were using the diaphragm without even thinking about it!

3D View of The Diaphragm

2) The diaphragm helps to mobilize the ribs, lumbar spine and thoracic spine. The diaphragm attaches to the 1st, 2nd, and 3rd lumbar vertebrae, the inner part of the lower 6 ribs as well as the back of the sternum at the xiphoid process. The central tendon of the diaphragm then attaches to the 3rd lumbar vertebrae. During inhalation as the diaphragm flattens to allow the lungs to fill with air, the diaphragm will "pull" slightly on each of those attachments, effectively giving you a gentle mobilization. The ribs will also move during inhalation and exhalation to allow space for the lungs to fill.

3) The diaphragm is a key member of a team of muscles which help to create dynamic postural stability. You knew that would be one of my bullets, right? I think I mention this in almost every post...but... the diaphragm works together with the pelvic floor muscles, abdominal muscles (transverse abdominis) and low back muscles (multifidus) to pre-activate and provide support to the body during movement. Together, these muscles make up our "anticipatory core" and are important muscles for healthy pain-free movement patterns. Now, no post on the diaphragm would be complete without an excellent video explanation by Julie Wiebe, PT, who is amazing and has done so much to help advance the understanding of dynamic stability in PT practice.

The Diaphragm And Our Internal Pressure System

4)Retraining proper firing of the diaphragm can help to reduce urinary incontinence AND low back pain.  Now, that is pretty cool, right? Excellent research by Paul Hodges and colleagues has shown altered firing patterns of the diaphragm in people with low back pain or urinary incontinence.  Amazingly, when people re-established proper firing of the diaphragm leading to full excursion, both low back pain and bladder problems reduced   This is likely due to the relationship between the pelvic floor and diaphragm in controlling intraabdominal pressure within the abdomen and the pelvis.  Proper breathing helps to restore the optimal pressures needed to control movements and support the pelvic organs. This relationship is so huge that problems with breathing and continence are more correlated with low back pain than obesity and physical activity. 

5) Slow breathing with the diaphragm can calm down the nervous system.  The breath is so connected to the autonomic nervous system. When a person is fearful or anxious, the sympathetic nervous system (fight or flight response) is activated, and a person will take quick shallow breaths to bring oxygen to the muscles as quickly as possible (think: being chased by a bear)  the parasympathetic nervous system (rest and digest) is activated when in a more calm or relaxed state (yes, I am oversimplifying all of this... I know). In that state, a person will take slow calm breaths (think: sipping a cup of tea after a great massage).  The cool thing is that we can use our breath to help us move toward a more relaxed state. Slow breathing will help calm stress, anxiety and promote a person being in a more parasympathetic state. And guess what? There's an app for that! The Breathe2Relax app for iphone/android allows a person to program in his or her breath and then takes you through a guided breathing exercise.

6) Slow breathing with the diaphragm can reduce pelvic pain. As we discussed previously, the pelvic floor and diaphragm are coordinated and work together to control pressures through the pelvis. As the diaphragm is activated during inhalation, the pelvic floor relaxes to accept the contents of the abdomen/pelvis. As we exhale, the diaphragm returns to its rested position and the pelvic floor activates slightly. Long slow breaths then encourage complete relaxation of the pelvic floor and thus can help decrease pain for people with tender pelvic floor muscles.

So, there you have it! I bet the diaphragm just moved up a few notches on your favorite muscles list (you know you want one!). If you need more reasons, and enjoy "nerding-out" with Anatomy, check out these studies:

• Exploring the postural function of the diaphragm using MRI

• Breathing problems and incontinence as risk factors for low back pain

• Changes in position of the diaphragm in people with and without chronic low back pain

• The effect of abnormal breathing patterns on functional movements (FMS screen)

• Diaphragmatic breathing may help improve lower limb venous return (decreasing swelling) in patients with congestive heart failure (CHF)

• Diaphragmatic breathing and respiratory muscle training helps to improve breathlessness and quality of life in patients with chronic obstructive pulmonary disease (COPD)

What's YOUR favorite muscle? Did I miss any reasons why the diaphragm is amazing? Let's chat together in the comments below!

~ Jessica