Brace Yourself to Halt Pelvic Pain
Can you rub your belly and pat your head at the same time? If so, try this: contract your transversus abdominis muscle at the same time as your lumbar multifidus. What's that, you say? It's a new program of muscle strengthening that's been shown to work well for back and sacroiliac pain.

The transversus abdominis muscle is one of several stomach muscles. It wraps around the lower abdomen from front to back like a corset. The lumbar multifidus is a deep back muscle that attaches close to the spine in the opposite (up and down) direction.

Contracting these two muscles at the same time is called cocontraction. The force of this cocontraction is like a nutcracker squeezing the spine and pelvis bones together. This makes the joints of the sacroiliac stiffer and more stable. Another way to look at this cocontraction is that it acts like a very deep corset or brace for the low back.

These new exercises have already been shown to reduce low back pain, pelvic pain, and sacroiliac joint pain. The cocontraction of these muscles also prevents the return of painful symptoms in most patients. We know these exercises work, but why do they work?

To delve into this question, researchers in the Netherlands measured vibration across the sacroiliac joint. Vibration is transferred best when the joints are stiff. Loose or lax joints do not send the vibrations across as well. A second method of measurement involved the use of imaging called real-time ultrasound.

This technology allows scientists to combine three-dimensional sound waves with the fourth dimension of time. This imaging shows the relaxed and contracted states of the muscles. Changes in the shape of the stomach muscles can be viewed as a picture. The abdominal bracing pattern is clearly shown. In all patients, sacroiliac joint laxity is decreased by the contraction of one abdominal muscle along with one low back muscle. In other words, the sacroiliac joint just got stiffer and more stable from cocontraction.

Using these muscles to form a self-brace will be included in new exercise treatments for low back pain. This replaces the previous whole-body approach. New technology may also improve testing before surgery to see which patients will benefit from surgery.
Carolyn A. Richardson, PhD, et al. The Relation Between the Transversus Abdominis Muscles, Sacroiliac Joint Mechanics, and Low Back Pain. In Spine. February 15, 2002. Vol. 27. No. 4. Pp. 399-405.