What is Neutral Spine and Why Does Sticking Out In Back Harm?

"Neutral spine" is an often-used phrase in exercise and back pain rehab. What does your spine have to do to be neutral? What does it matter?

In general, (this interesting topic can be involved) think of a line through the crest of your hipbone from back to front. The line from the top bump in back (medical abbreviation is PSIS) to the top bump in front (ASIS) should be approximately horizontal (left-hand figure in the drawing).

If you let your spine slouch so that the front of the hip (ASIS) drops downward and the back of the hip tilts outward in back, the small normal inward curve of the lower back increases (drawn figure on right). The spine is no longer neutral. It is over-arched.

Another way to see the anterior hip tilt when the spine is over-arched is to check the line from the ASIS to where the pelvic bones meet in front, called the symphysis pubis (PS). When you hold your spine in neutral, the line from ASIS to PS will be vertical (left drawing). When the ASIS tilts forward and the behind sticks out in back (right drawing and photo), this is an anterior tilt to the hip. The spine is no longer neutral. It is arched - hyperlordotic.

The anterior tilt is easy to see when people stand arched. It is a little harder to measure. Since some experimental subjects are disconcerted to have measuring devices put on their symphysis pubis (PS), the line can, instead, be drawn from the top of the leg bone to the center of the crest of the hipbone. The blue line in the left drawing is vertical, showing the hip is straight and level. When this line tilts forward in front and back at the bottom, that is an anterior tilt to the hip. Note the arrow drawn onto the photo showing the abdomen sticking out in front and the behind pushed out in back. The photo shows standing with pronounced hyperlordosis - too much arch or inward curve to the lower back.

In my laboratory work, I have identified three ways the spine can become hyperlordotic. The anterior hip tilt is one. Hyperlordosis pinches and compresses the lower spine. By any name - overarching, anterior hip tilt, swayback, hollowback, sticking out in back - hyperlordosis is a common contributor to lower back pain. The area may ache after long standing, walking, running, or lifting overhead. Eventually, (over years) overarching can damage the spine joints called facets and nearby structures.

Holding the hip and spine in neutral and not letting the hip tilt forward happens to use a particular set of muscles - your abdominal muscles. Strengthening the abs does not automatically keep the spine neutral. Tightening the abs also does not move the spine to neutral. Using Abdominal Muscles is Not Tightening or Pressing Navel to Spine explains more of why. Simply moving your own spine on purpose and holding healthful position as you go about your activities is how you keep your spine neutral and not sinking into injurious overarching.

Hyperlordosis during daily movement and exercise, and how to prevent the injuries it causes, have been an area of my laboratory investigations for years. I have done several interesting experimental studies (interesting to me, anyway). Upcoming posts will tell a bit about them.

The book that tells all about fixing the pain of hyperlordosis and how to get more effective abdominal exercise is The Ab Revolution™

Labels: abdominal muscles, fix pain, hip, lordosis, lower back, neutral spine, posture

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