Anterior Pelvic Tilt and the Diaphragm

Anterior pelvic tilt has been well known in the strength and conditioning and physical therapy world for a long time.

What no one realized was that the muscles usually implicated in anterior pelvic tilt, the hip flexors, in particular the psoas, are not really the muscles that cause the anterior pelvic tilt. 

They just tend to get overactive due to the position they get put in to after the anterior pelvic tilt has already been established. 

This is an important point. The psoas does not cause an anterior pelvic tilt. The overwhelming size and strength of the right diaphragm compared to the left diaphragm causes anterior pelvic tilt because the pull from the right diaphragm rotates our lower spine to the right. This starts the process of the pelvis getting stuck anteriorly.

So trying to stretch or massage the psoas by itself is only a half-measure at best, and sometimes completely useless. 

The following video should demonstrate why trying to address an anterior pelvic tilt through stretching a psoas is usually ineffective. You can fast forward to 2:08 in the video and hopefully discover…..

  • The illiacus (a hip flexor) is continuous with the quadratus lumborum. The QL, considered the most posterior abdominal muscle though often thought of as a lower back muscle, is often overactive and painful in both anterior and lateral pelvic tilts. 
  • Pay particular attention to the fact that the psoas and the diaphragms (plural) are completely inseparable. They are essentially the same muscle. As the anatomist pulls on the psoas, the diaphragm moves, too.
  • So the psoas, illiacus, QL, and diaphragm are all basically one functional unit. I find it ironic that only the first three muscles are talked about in anterior pelvic tilt, yet it’s the diaphragm that actually causes it! Very rarely does anyone try to fix the left diaphragm. But that’s what needs to be done.

Quite simply, the idea of trying to stretch your way out of an anterior pelvic tilt isn’t sound.

The diaphragm has to be involved in any solution because it is the primary driver of the anterior pelvic tilt.

Anterior Pelvic Tilt and the Diaphragm


human diaphragms and anterior pelvic tilt

We have two diaphragms, the left and right, and the right is MUCH bigger and stronger.

Interestingly, an anterior pelvic tilt is not usually found on both sides.

Normally it’s found just on the left. This is easily displayed through PRI testing. Usually the left side of the pelvis is forward compared to the right side of the pelvis.

The reason it’s usually found just on the left is actually quite simple.

The right diaphragm exerts a strong rotational pull on the lumbar spine that can’t be fully counter-balanced by the smaller left diaphragm. 

Over time the weaker left side loses its ability to oppose the rightward pull. When this happens the lower spine and sacrum get pulled to the right and the left side of the pelvis goes with it. 

You end up in what Postural Restoration calls the left AIC pattern. 

Sometimes both sides of the pelvis rotate forward and you will end up with a bi-lateral anterior pelvic tilt, but dealing with the bi-lateral pelvic tilt isn’t much different from dealing with the left sided anterior pelvic tilt.

It all starts with breathing!

After all, the primary purpose of the diaphragm, the actual muscles that causes the tilt, is respiration!

Why Stretching the Psoas Fails

Stretching the psoas fails because the psoas doesn’t exist in isolation from the quadratus lumborum, illiacus, and most importantly, the diaphragm.

And as I mentioned, it isn’t the cause of the anterior pelvic tilt. It’s a victim, yet also stands accused by years of misunderstanding.

The only thing that will quiet down an overactive psoas, and get you out of an anterior pelvic tilt, is restoring diaphragmatic breathing. 

Of course proper diaphragmatic breathing is dependent on proper rib position, otherwise known as the left ZOA.

If anything you do to resolve an anterior pelvic tilt doesn’t involve normalizing diaphragmatic breathing, it’s bound to fail in the long run.


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