Center of gravity

[S.Teebas]

Lots of styles believe their center of gravity resides in different places. I think some think its below the naval, some near the waste, some higher.

Out of curiosity, where does your school say it resides? Please mention which style you practice in your post.

[TjD]

depends on what im doing, and what someone else is doing to me :)

[Braden]

I don't think the different theories are as to where it resides, so much as to where you should try to 'condense' it.

Below the navel, though.

[S.Teebas]

I don't think the different theories are as to where it resides, so much as to where you should try to 'condense' it.

Braden do you care to elaborate on what you mean by 'condense it'?

[Braden]

Just in the sense that, if you went out and shoved someone who's walking down the street, you'd probably find that although in the strict physical sense, they "have" a COG, they're probably going to be poorly balanced - their body isn't connected in any martially-meaningfull sense to a certain location of the body. 'Condense' seems like a good metaphor to describe a body which is connected and settled into a certain spot.

[OdderMensch]

i like it. I've always used "settled" to descibe that.

oh and in the WC I practice the cog is just above the knees, due to the adduction, and the body placement.

[BrentCarey]

I don't understand the question. The true COG is not a matter of interpretation or style. It is a matter of physics. COG varies according to sex and body mass distribution (fat and muscle). Also, body position affects COG. Since the human body is not a static object, the COG varies depending on the current configuration of limbs, spine, and head.

I'm sure someone will contest this and contend that there is an absolute COG. Well, try this. Lay down on a balance beam (or something similar) with your body rigid like a teeter-totter balanced on the beam. If you are a male, the balance point (or COG) will probably be right about at your tailbone.

Now reach your hands above your head (or actually away from your feet). Your new COG will now be several inches ****her up the back. Now tuck your knees up to your chest. This moves the COG up several inches again. Now lay back down horizontally again with your neck straight, hands at your side, and rebalance yourself (probably at about the tailbone). Once you have rebalanced, tuck your chin to your chest. This will shift your COG down about an inch or so.

Where ones COG resides vertically is not much of a concern while you are standing anyway. Since actual COG moves around with every motion we make, we are much better off letting our subconscious mind compensate for the variations without rationalizing a specific point.

Did I miss the point of the question?


Best regards,

Brent Carey

[Braden]

BrentCarey - I think you must be strictly right, which is why I introduced a more subjective idea like a 'condensed' center.

Despite strictly physical concerns regarding COG, you can approach two people who are overtly standing in a similar posture, and press with your palm on their chests; and with one you feel the force press straight through where you press, and the person lean or stagger backwards; while the other you feel their body solidified at some point. Surely, this is a dynamic thing, with respect to how said person might be moving and what pressures they are under. In this sense, I assume the original question asks where the movement principles of your martial training encourage you to solidify this point.

[BrentCarey]

Braden,

Ahh . . . I see what you are talking about. I would consider this to be a matter of leverage. I can see that it would be useful to think of this as condensing. That is probably a good way to explain it.

Best regards,

-Brent

[S.Teebas]

Since actual COG moves around with every motion we make..

What can stabilize this?


BrentCarey, a good post and i agree with your scientific view point. Interresting metaphore Braden.

[BrentCarey]

Originally posted by S.Teebas
What can stabilize this?

Well, as long we are moving our joints, the CG will move unless we counter balance it. Unfortunately, when some people begin to tip over, they attempt to shift their CG by increasing the moment of a limb.

Simply put, while tipping over, the person may extend an arm or leg to try to stay more upright. This generally puts the person off balance and dangerously overextended. By thrusting a leg out to counterbalance, the acceleration of the leg will tend to drive the rest of the body in the direction of the fall. Also, most people will instinctively put a hand out in the opposite direction to counterbalance the leg. Therefore a net improvement in CG location is not gained.

It makes more sense to shift or flex the leg(s) under the body to compensate for the shift as this keep the body stable with minimal drama.

Here is some food for thought. When you lower your stance, your CG actually shifts higher in the body, but lower to the ground.

Anyway, like I said, the brain does a pretty good job of compensating for the shifts without us having to do anything special. I don't believe it is important to rationalize the location of the CG at any given moment. This is important in airplanes, but not humans.

Best regards,

-Brent