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Old 07-19-2009
andreasl33 andreasl33 is offline
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Join Date: Mar 2009
Posts: 193
Default Why do tense muscles make the body sink (or do they)?

I have heard that many times, but could not quite grasp the physics behind the statement

"Tense muscles make you sink."

What makes a body float or sink is its density (or mass/volume). Why would tense muscles increase the density of the body and make it sink? After all, virtually any matter our body is made of, is virtually incompressible for practical purposes. 80% of the body is water, which cannot be compressed by the power tense muscles can provide, the same goes for fat or bones. The only thing that is compressible by weak forces (that or muscles can generate) is air. But our body contains air only in the lungs. And as long as the muscles around the lungs don't tense up, I can see no reason why the above statement would be true.

Might there be some other reason? Tense muscles are not able to perform the movements as precisely as relaxed muscles and therefore one sinks? Or we get tired earlier, which slows us down and makes us sink?

Any comments welcome...

Last edited by andreasl33 : 07-23-2009 at 10:54 PM.
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