Stability balls - If they do not train stability, what are they good for?

This IS NOT a stability exercise! (its dangerous)

When you walk into the gym, you see loads of people using those large beach ball type things for various (sometimes crazy) exercises.  You probably have heard them referred to as stability balls (or Swiss balls), but the interesting things is that they really do not help when you are training for stability.

In previous posts, I have referred to the definition of stability as "an absence of motion."  When we are talking about stability and exercise, we should be referring to stability of the lumbar spine or low back.  Most people when they are training using these stability balls you will notice they are waving their arms or are shaking like crazy trying to keep balance. This violates the definition of STABILITY!

So if you are not training stability, what are you training?  The answer is that you are training BALANCE (or proprioception for those that understand the term).  The best way to describe balance would be an example of standing on one foot.  As you stand on one foot, you probably find you are swaying and your ankle will roll in and out.  You ARE NOT stable, but if you haven't fallen over, you are balanced.  Now, close your eyes.  Why is it so much harder?  Because your brain cannot give you visual feedback in relation to your orientation in space.  You rely strictly on feedback from the bones, ligaments and little muscles in your foot.  This is termed proprioception, and is different from balance. 

So most of these stability devices (balls, discs etc) should be referred to as BALANCE devices.  When is it appropriate to use these balance devices?  That depends on they type of training you are doing and your goals for training.  If you are looking at training to become more STABLE, this is not the way to go.  If you are looking to improve your balance, these devices may be appropriate.