Stability: Clearing Up a Confusing Term! — Jenni Rawlings Yoga & Movement Blog

To consider balance in a yoga setting, picture yourself standing in tadasana (mountain pose) on your yoga mat. You can probably imagine that if you were to stand with your feet hip’s distance apart or even wider than that, this would be a relatively stable position for your body because your “base of support” is rather wide. If someone were to come up and give you a little push from the side, you’d first sway in response to that perturbation then re-settle back into your original tadasana.

But if you were to stand with your feet all the way together so the inner edges were touching, this would narrow your base of support. You’d have less leeway for how far your center of gravity could sway in response to a perturbation and still return to equilibrium afterward.

And what if you were to lift one foot off the floor so that you were standing on one leg (e.g., in tree pose)? That would be even less stable because you’d be removing a point of contact with the floor! Can you imagine being pushed from the side while in tree pose? Instead of maintaining your equilibrium in that single-leg balance, there’s a good chance you’d have to come out of the pose by setting your leg down.

Is “balance” always what people mean when they use the word “stability” in a yoga, movement, and fitness context, though? Most certainly not! Let’s turn our attention to some other common uses of the word “stability” – and see whether they align with the scientific definition of the term.

#2: STABILITY AS A SYNONYM FOR STRENGTH

It’s quite common to hear the words “stability” and “strength” paired together as though they were the same or very similar concepts. While stability is certainly related to strength, these two terms aren’t actually synonymous. To communicate clearly about the body and movement, we want to be sure to understand the difference between these qualities.

The scientific definition of stability is the definition we just covered in the last section: the ability to return to equilibrium after a perturbation. The scientific definition for strength, on the other hand, is that strength is a measure of force production. Whereas a good way to measure (postural) stability would be to see whether someone could stand on one leg for 20 or 30 seconds, a good way to measure strength would be to see how much weight someone could lift.

Although there’s a certain amount of strength required for standing on one leg (especially in the lateral hip muscles of the standing hip!), the movement attribute that generally plays a more dominant role here is balance/stability. And while picking up a heavy weight does involve some level of stability, the movement ability that’s truly playing the starring role here is strength.