Why can’t you hear a pterodactyl go to the bathroom?
Because the “P” is silent.
The Psoas
Sometimes a hypertonic or tight muscle can cause a lot of problems.
One of the muscles that often gets hypertonic is the psoas.
The Hip Back Connection
The psoas is the only muscle that has a direct attachment from the spine to the lower extremity.
Meaning it has quite the influence on the low back and the leg.
When it's tight it can increase lordosis and place excessive extension stress on the lumbar spine. This concept, the lower crossed syndrome, was made popular by Vladimir Janda almost half a century ago.
The Breathing Connection
Possibly more important is the connection of the psoas to our diaphragm (both physically and neurologically).
A view from below. Notice how the psoas goes right into the diaphragm. (image source)
Or as Tom Myers puts it, the psoas is where breathing meets walking.
A wonderful picture from the side of the diaphragm/psoas connection from Tom Myers and Anatomy Trains (image source)
In this manner, it's impossible to address the psoas without first addressing breathing.
How to Address Breathing
Crocodile breathing is an easy way to improve breathing patterns.
This alone may help normalize positive hip mobility tests, improve tissue extensibility, and decrease pain.
Set a timer for 2 minutes. Breathe into your low back.
Onto the Psoas
As mentioned above, the psoas can't be mobilized without the diaphragm.
So we essentially take the above breathing drill and add a little bit of a stretch on the psoas (and rectus femoris).
I cannot emphasize the importance of pelvis positioning and breathing with this stretch.
An excessive lordosis/anterior tilt or breath holding will lead to an ineffective exercise.
The breathing helps with muscle inhibition and provide a dynamic stretch on the psoas.
When performed correctly a deep internal stretch should be felt on the psoas with each breath.
An Alternative, Progression, or Regression
If this stretch is too difficult, try the traditional 1/2 kneeling variation. But make sure to perform it with correct technique. This may be the #1 incorrectly performed exercise of all time.
Take Home
Assess if you have a restricted psoas
Learn to breathe better
Stretch the hip for 2 minutes a day.