How do you throw fast? Everyone wants to know! Think about driving along in a car at 10 mph and you are riding along ( without your seat belt ) and the driver slams on the brakes – you slam forward into the dashboard but you are ok. Now do that at 30, you hit the dash really hard because you were moving faster. Now hit a wall at 60. Through the windshield you go. Big car , little you.
Pitching is about making the biggest part of you ( legs and butt) go fast and stop , making the medium part of you ( trunk) go faster then stop, then making a small part of you ( your arm) go faster and stop and finally your smallest part ( hand) goes faster and makes the ball go fast.
Learning the techniques to do this fast, stop, faster, stop is called pitching mechanics. This is what we teach in bits and pieces to teach a kid to pitch. In more familiar terms we get off the mound fast with our legs, then stop on the front leg and make the hips turn faster, then snap the torso and stop the shoulders to make the upper arm go even faster, and then snap the elbow to make the forearm and hand go even faster.
Coaching speed is first mastering the basic movements. Then gradually making each move more and more efficient. It takes time and work. It takes even more time if you spent 4 years copying somebody who did it wrong.