Your Center of Gravity and Your Spine

Center of gravity or mass is the point around which all other parts are equally balanced.
Center of gravity or mass is the point around which all other parts are equally balanced. Brian Hagiwara/Stockbyte/Getty Images

The term "human center of gravity" has implications for all things related to posture, including issues such as swayback and the design of posture exercise programs and more.

Human center of gravity is the average location in a 3-dimensional space, of a person's mass.

You can think of mass as your body's resistance to movement - in other words, its bulk.

Your weight, on the other hand, is the force that your body's mass exerts under the influence of gravity.

In other words, mass is the force of inertia as it applies to your weight. (In outer space, you become weightless, but your mass stays the same. This is because in outer space the force of gravity, which creates inertia, does not act on your body.)

When you stand, the center of gravity is usually located in front of your sacrum bone, at about the second sacral level.

Center of Gravity Explained with an Example

Another way of looking at this is that the center of gravity (mass) is the point at which the body's mass is equally balanced. This point changes depending on one's position (arms up/down, leaning, etc). Watching dancers, gymnasts and tight-rope walkers provide examples of how the human body can adapt to changes in the center of gravity in order to maintain balance, and also how a human being can consciously overcome the effects of gravity and inertia on the body.

Usually, the center of gravity is located in front of your sacrum bone, at about the second sacral level. (The sacrum is made up of five bones fused together vertically.) So when you are on planet earth your weight or mass, is thought to be concentrated at this point in front of your sacrum. The downward pull of gravity (line of gravity) passes through this point, as well.

To understand the difference between theory and practical application of this concept, let’s compare the human body to a baseball for a minute. From a point in the exact center, the baseball is of equal weight and shape all the way around, is it not? So, with any movement of the ball, this center point moves right along with it. Easy.

But when we consider center of gravity in the human body, things get more complicated. As I mentioned before because the body has moving parts (arms, legs, head, various areas of the trunk), every time you do, well, anything, the shape of your overall form changes. And if you carry something like a suitcase or grocery bag or if you wear a backpack, this adds weight to some areas, but not others, changing the center of gravity as it does.

So, we can say that the center of gravity is a constantly changing point in the body that represents where the weight (mass) of the rest of your body is equally balanced in every direction. This point can and does change based on what you’re carrying and how you’re carrying it, as well as the position you take and the movements you make.

My personal take on it this: In an ideal situation I like to think of the center of gravity as the place from which you can operate your whole body as a single unit, while gracefully coordinating the motion of appendages as you go.