This is very short story, which show the strength of visualization.
In a groundbreaking experiment, piano players were divided into two groups. One group was told to physically practice. While the other was told to “mentally” practice by visualizing playing the piano.
In both groups, the same physical changes in the brain were found in the motor cortex. And after three days their accuracy was exactly the same regardless of how they practiced.
That’s the strength of visualization. It’s a way to activate the areas in your brain as if you were actually performing the action itself.
P.S.: Notes on visualization, 2017