It’s pretty simple. Eighty-percent of a pitcher’s success is determined by the movements she makes in the last twenty-percent of the pitch. But…
The majority of kids look pretty good if you take photos at the start and mid-point of a pitch. Suddenly it all crumbles and they look weak at finish.
The secret is this. The movements at the very beginning are going to avalanche. They are going to put her in the position to be powerful at finish, or for everything to domino into a crushing failure. No matter how aggressively she wants to finish, if she is struggling to get the core back in line, to get the hips into a power position, to recover a glove hand which is flailing to the side, or to keep from falling off to the side, no aggressive finish is possible.
Eighty-percent of the pitch is spent getting everything ready to explode at finish. When done correctly, this kid is a blur at release. Unfortunately, for most kids, eighty percent of the movements are so inefficient that many parts of the body get out of place, so she spends the last 20-percent trying to recover those things, attempting to get the ball in the general direction of the plate, or simply trying to keep from getting hurt.
If you are spending most of your time working on the last 20-percent, frustration is guaranteed. She is guaranteed to fail if the movements leading up to that point are not free, natural, and balanced.