system
Given the following post, respond as if you're commenting on Reddit:
human
What exactly is muscle memory and how does it work?
gpt
Well, to start off, muscle memory is not in your muscles, it's in your brain. Muscle memory is essentially your brain learning what to do to make a certain movement happen. 

When you start off trying to learn a new physical skill, you often know what you want the end result to be (I want the ball to wind up over *there*), but you don't know exactly how to make that happen. You try to make the right movement, and over time your brain learns exactly what sequence of individual muscle movements (and what visual / bodily feedback to use) will produce the result you want. 

Essentially, in the process of learning a motor (movement) skill, your brain creates a new "program" that it can run whenever it's needed. When it's time to throw a ball, your brain can activate the "ball throwing program" instead of having to consciously figure out exactly what movements to try, like you do when you're first learning.