When throwing a change up, you are thinking fastball all the way. You want your arm
action to look exactly like you are throwing a high-powered fastball, because that's what fools the hitter. He sees your arm whipping through,
there, and the ball has that same backward spin of a fastball.
If done right, the batter's first reflex reaction will be: "Fastball! Swing
hard and fast!"
There are many kinds of change-ups. The type I used in college and pro ball is called the
The circle change up involves laying your middle finger, ring finger and pinkie on
the top part of the ball. And you bring your index finger over on the side
of the ball, and bend it like a fish-hook shape, touching your thumb --
making a little circle, which is where the pitch gets its name. Those three
fingers on top, basically, stabilize the baseball. And you "throw the circle."
The spin is backwards, just like a fastball, with a counterclockwise slant.
That can make it break in on a righthanded hitters, away from lefthanded
hitters (and the opposite if you are a lefthanded pitcher).
Obviously, with that many fingers, not to mention half your palm, touching
the ball, it comes out at maybe 10-14 miles per hour off your fastball speed. So, you end up with the ball speed not matching the arm speed. Hopefully,
that mixed effect will mean the hitter will swing too soon, ending up
way out "in front of" the pitch, for a strike or weak groundball.
Like I mentioned above, there are other variations of change-ups, like
the palm ball. But I don't feature any of them. They involve releasing
the ball from a different grip. The change up grips have the same effect, though,
which is to slow the ball down, despite "full fastball" arm motion.