Stability and low back pain

We are regularly confronted with the communication from the patient in practice: I have back pain because I have instability and I now have to practice my back and stomach muscles to regain stability and get rid of my symptoms. What is instability and what is necessary for stability?

What is stability - instability

Unfortunately, there are many different definitions of instability of the lower back. The definition that we now apply is: instability is when with a minimum of force too much movement in a joint is possible, for example from vertebra to vertebra. Excessive displacement causes irritation of tissues, resulting in lower back complaints. For example because a joint becomes overloaded, or muscles react too violently.

Different back muscles

The muscles in the back, also in the lower back, can be divided into: a - long superficial strength muscles (erector trunci), which can make a lot of strength for a short period of time and are quickly tired, b-short deep muscles (multifidi), which can make a reasonable tension for a long time. The muscles that are most suitable for ensuring stability in the lower back are the muscles of group b. They can make fine corrections and maintain them for a long time.

Causes instability

Instability in the lower back can come from various causes. We mention two. 1- When the condition of an intervertebral disc (medical: discus intervertebralis) deteriorates, for example due to prolonged overloading or through hernia, it becomes a bit flatter. The result is that relatively more joint-play between vertebrae is possible: a form of instability. 2- When someone goes through a period of low back pain, and then recovers properly, then in some people it turns out that muscle group b no longer functions properly. It is not clear how this is coming, so for now we will have to consider it as a given.

Treatment instability

The best way to deal with these types of instability is to exercise the muscles of group b. This exercise is done with technical and coordination exercises for which concentration is required. In the first instance it is a training of the nervous system that must control these muscles again. That only works well when the muscles of group a are spared as much as possible. The advice is therefore to stop strength training for the back muscles for the time being. In our practice for musculoskeletal medicine, tests are performed on forms of instability, and the role of the back muscles. If this is found, the stability can be restored in most of the people.

References
Richardson C, et al. Therapeutic exercise for spinal segmental stabilization in low back pain. Churchill Livingstone 1999.
Richardson C, et al. The relation between the transversus abdominis muscles, sacroiliac joint mechanics, and low back pain. Spine 2002 4: 399-405.
Panjabi MM. Clinical spinal instability and low back pain. J Electromyogr Kinesiol. 2003 Aug;13(4):371-9.