Slouching and Low Back Pain

There exists a lot of debate related to the mechanisms causing disc herniation and back injury. 

Sitting has well demonstrated associations with low back pain and degenerative disc issues.  In a separate post on this blog I review some articles related to this topic (http://www.backexercisedoctor.com/journal/2010/3/23/prolonged-sitting-association-with-low-back-pain-and-propose.html).

Slouched Sitting

I read an interesting article in the journal Clinical Biomechanics that looked more specifically at the effects of “slouched sitting” on back pain.[1]

The authors started with the premise that that “back sprain and disc herniation can be caused by a prolonged or sudden lumbar flexion.”  To examine this hypothesis, the authors measured relative movements of L5 and pelvic bones when moving into a slouched position in sitting.

The investigation demonstrated the following: [2]

• Stepwise backward movement of the erect trunk (slouching) resulted in forward rotation of L5 with respect to the sacrum and backward rotation of the sacrum with respect to the ilium
• Ventral displacement of L5 with respect to the ilium indicated elongation (or stretching) of the iliolumbar ligaments
• Use of a lumbar support at the level of L5 practically eliminated relative motion between L5, sacrum and ilium and prevented widening of the L5-sacrum angle

All of that sounds technical and complicated.  The illustrations in the article are even technical and a little hard to understand without a degree in biomechanics.  However, there are a few significant take-home points that I got from the article:

• Slouched sitting widens the angle between the L5 vertebrae and the sacrum.  This widening of the angle places increased stress on discs, ligaments and joints.
• Use of a lumbar support dramatically reduces the strain/effects of slouched sitting.

So, do like your mom told you and sit up straight.  Use a McKenzie roll (or other support) if you are going to sit a lot.  Or just try standing more.

 McKenzie lumbar support

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[1] Clinical Biomechanics 19 (2004): 323-329

[2] Clinical Biomechanics 19 (2004): 323-329

Comments

[low back pain]

Hi there,

Wrong sitting habits can definitely develop low back pain.

Thanks,
Donald