There are two basic categories of joints: mobile and stable. A mobile joint is one that moves a lot and usually in several different directions like your ankle. A stable joint tends to only move in one direction and resists motion in all the other directions. The knee is a good example of this.

An interesting observation about these two types of joints is how they interact within the body. They always alternate. Ankles-mobile, knees-stable, hips-mobile, low back-stable, mid back-mobile, shoulder blades-stable, shoulders-mobile, elbow-stable, and wrists are mobile again.

This model becomes a great predictor of injuries when you lose mobility in one of the mobile joints. Your body doesn’t lose the need for mobility, it simply loses access to where it is supposed to be. The consequence is the mobility shifting into stable joints, which frequently causes injuries.

An example will make this clearer.

Let’s say you lose hip mobility from sitting for years on end. Your body still needs that mobility whenever you bend over, walk or run. But since it doesn’t have it in the hips anymore, it frequently shifts into the low back.

You probably won’t notice it much for quite some time, but eventually you start to get an achy low back that continues to get worse. You might try stretching, strengthening or medication, but it never seems to go away.

That’s because the low back isn’t the source of the problem. The low back is simply being forced to be more mobile than it should to make up for the hips. Until the hips get better, the back won’t.

This does make treating low back pain much easier though. If you can make the mobile joints mobile again, usually the pain in the stable joints goes away very quickly. Getting the mobile joints mobile again sometimes takes some time, but once they are working properly, the stable joints tend to improve dramatically.

The take away from this is to take care of your mobile joints. Ankles, hips, t-spine (middle back), and shoulders. If you can keep those mobile, you’ll drastically reduce your risk of developing chronic pain in the stable joints.