Proper timing is necessary to produce speed and accuracy, and to avoid strain and injury.
A pitcher's body rotates around the foot he keeps planted firmly on the mound. The ball, held overhead in his extended arm, is like a rock whirling on the end of a string. Just as a twirling rock on a long string has more angular momentum than the same rock on a short string (that is, it's more likely to travel farther and faster), the ball in the hands of a tall pitcher can be launched with more speed. (Fastball pitchers are traditionally lanky fellows.) And since the pitcher actually steps downhill, moving off the crest of the mound as he throws the ball, the height of the mound also affects the force of the pitch.
Bringing the "Heat".
By varying grips, wrist spins, and pitching motions, the pitcher can make the ball curve, rise, drop, change speeds, or just plain GO FAST. Speed is the most important aspect of the pitcher's game, and "go fast" is what a hardball is designed to do. The raised red cotton stitching that holds the cowhide covering of the ball together serves more than just an ornamental function. Without it, the ball wouldn't travel as far or as fast. When the ball is airborne, the stitching disturbs the "boundary layer," the paper-thin layer of air closest to the surface of the ball. As the ball spins, some of this slightly turbulent air rotates with the ball.
At high speeds, the air stream friction against this rotating turbulence is less than it would be against the actual surface of the ball. There is a drastic overall decrease in drag, making it possible for a major league "flame-thrower" to hurl the ball at speeds of 90 to 100 miles an hour. This leaves the batter with less than half a second to decide whether he will swing, hold up, or dive for cover. (This same "boundary layer" effect explains why a golf ball, which normally travels over 200 yards on a drive, would travel only 50 yards without its characteristic dimples.
