Am 01.08.2010 18:16, schrieb Orchid XP v8:

>> The thing with muscles is, they never actually hold something still
>> unless they're totally slack. When they're contracted, they actually
>> twitch at a high frequency
>
> Individual fibers twitch, yes. A single "muscle" contains rather a lot
> of individual fibers though, all twitching in a coordinated pattern. The
> net result is more or less contant tension.
>
> I'm told this is why when you try to lift something too heavy, you start
> shaking. You run out of fibers to twitch.
>
> (Related... I'm told that if *all* the fibers were to twitch at once,
> the muscle would probably tear itself from its attachment points. Which
> perhaps explains why people undergoing convulsions sometimes display
> superhuman strength.)

Hm, I didn't know /that/ (and I'm still doubtful about it). Still, the 
result is only "more or less constant" tension, so there /is/ some 
inevitable net twitching.

If it's true though, then the energy you burn to hold something steady 
is actually the energy you need to overcome the friction in your muscles.

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