How are my brain and fingers able to do this?

Part of my life has been focused on being a musician. I have been playing guitar for many years and the playing style I use most is called shredding. That basically means that I play complex scales and licks at a very fast speed. I use a metronome to time my progress and I have gotten to a point where I can sweep a 9 note arpagio per 1 second and I don't just slop through it. Each note is pronounced and articulate. How is the brain even able to acomplish this?