If a pitcher throws every pitch at the same speed, no matter how fast that is, she gets pounded by the third inning. Batters rely and depend on timing the pitcher's motions to make that big decision - when to pull the trigger and start their swing. To be a successful pitcher, you must take that advantage away form the batters.
One tactic a winning pitcher will use is to throw off-speed pitches. Many pitchers will throw a certain pitch for an off-speed pitch and that is all. I have found it is effective to throw all of your different pitches at different speeds, from one pitch to the next.
Taking Something Off the Heater
Let's take the fastball, the pitch you throw with your fastball grip. That same fastball can be thrown at say, 55, 45 and 40 mph. Now your one single fastball can be disguised to look like three different pitches.
That same pitch, when thrown at a different speed, from one pitch to the next, forces the batter to have to stop and decide exactly when to start her swing.
Hitting the Wall
This is the best way I have ever found to train a pitcher to throw one pitch at different speeds (an off-speed pitch). It will require a solid concrete wall, a piece of chalk and a tape measure.
Find a concrete or foundation brick wall (preferably with no windows). A handball court wall is ideal. DO NOT USE A STUCCO WALL - a stucco wall is only around 1-inch thick and will be damaged.
Draw a strike zone on the wall with chalk, the strike zone representing the pitcher's height.
Now draw a line across the box dividing the zone into top and bottom halves. For this drill, the pitcher should only throw to the top half of the zone.
Have the pitcher throw at the top half of the zone at 100 percent full speed. Have her keep throwing and backing up to the point the ball just reaches her without hitting the ground. Draw a line on the ground where she starts that pitch. Now we have established the 100 percent mark.
Next, measure the distance from the wall to the point of what would be the regulation throwing distance for the pitcher's level of play, then subtract two feet. Draw a line at that point. You want the distance to be from the rubber to where the batter would hit the ball, usually around two feet in front of the back tip of home plate.
Now, have the pitcher throw her slowest change-up several times and draw a line at an average distance where the ball comes back and hits the ground. Now we have established the 40 percent mark. (The percentage is not accurate but I will use this as an estimate for argument's sake).
Now measure the distance between the 40 percent mark and the 100 percent mark. Divide that distance into three equal parts and draw a line at what would be the 60 percent and 80 percent distances. Now have the pitcher return to the 100 percent mark and throw from there.