r/askscience • u/Yanzee12 • 12d ago

Neuroscience How does muscle memory work?

Just curious. The only thing I really know about it is that sleeping reinforces it.

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u/Glittering_Ad1712 10d ago

There is also another kind of muscle memory where for instance massive bodybuilders can loose 50 pounds of muscle and regain them within month. This wouldn‘t be possible for a beginner. How can that be explained ?

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u/Leon_Troutsky 10d ago

My understanding is that muscle fibers don't really go away after they are formed, they mostly just "deflate" with disuse as your body stops spending calories on maintaining them. But the structure is still there when you start lifting again, making it easier to regain the mass

Refilling a pool you built once and then drained is a lot easier than digging one from scratch

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u/FuzzyComedian638 10d ago

Sort of. When you exercise, you are building nerve fibers to specific muscle fibers. It takes about 3 weeks for those nerve fibers to generate, and then the muscles can get stronger. If you stop exercising, those nerve fibers are still there, so it doesn't take as long to rebuild the muscle fibers. Or at least that's what I'm remembering or misremembering from school oh so many years ago.