The Crowbar Effect and Low Back Pain

Sometimes I like going back through some of the research articles I have previously read.  I find that I can always refresh or learn something new/again from many of these articles.

One of my favorite articles explains a "Crowbar Effect" that occurs in the low back with slouching.  This is exactly what most people experience when they sit! 

When we sit in a slouched position, the pelvis rotates posterior (hips roll backwards) and spine moves forward as we lose the lumbar curvature in the back.  As the curvature is reduced, the back stiffens and is akin to a "bar."  Ligaments that attach from the spine to the pelvis act as a fulcrum around L5 causing the proposed "Crowbar" effect.



They also propose that two conditions must be fulfilled for the crowbar effect to occur:

1.  Loss of lumbar lordosis (lumbar curvature)

2.  Body weight placed behind the ischial tuberosities (those bony bumps you sit on).

If you look at figure 4 in the article, it has some great diagrams to show "good" and "bad" sittinng.

If you work at a desk job, or you happen to do a lot of driving (sitting) this article pertains to you! 

The article can be viewed for free here