Well it has scientifically been proven that when a human is really visualizing and focusing on doing a thing in his mind, the mind activates the muscle memory and creates vibration that are at same rate as when doing it in the real world. That is because the subconcious mind can't distinguish the reality from a vision, image, video or reality itself. To the mind its the same even though we consiously seperate reality from a vision, picture etc. It's also the reason why dreams or nightmares sometimes feel so real that when you wake up you realize it only was a dream. I personally once saw a dream where I was practicing jiu jitsu for hours and when I woke up I was sweating like a pig and the whole bed was covered with sweat. NASA has an astronaut program where astronauts go trough different procedures in the their minds that they will perform in the space in order to program the subconscious mind so that these skills will be deeply internalized. Also lot of atheletes visualizes performing before the event, which improves their focus when they actually are performing. So yes, your mind can improve your skills which totally depends on how your mind is programmed from childhood by the enviroment, parents, friends, media etc.