Many pitchers don’t complete their upper-half rotation during the throw. We see this even at the pro level and it especially happens when the pitcher is trying to complete an off-speed pitch. Oftentimes, the mental effort of throwing a breaking ball will see the pitcher overthink and overtry which will lead to incomplete upper half rotation.
But completing your upper-half rotation can lead to bad habits like flying open. That’s why it’s important to think a certain when when completing the throw. Try to drive your throw-side rib cage or lat muscle at the target through your body. This will help to prevent flying open.
We use two different drills to teach upper-half rotation — the pivot pick-off and the roll-in. Each drill teaches the body to create hip-to-shoulder separation but it’s important to finish the throw properly. Take your throw-side ribs to the target by completely turning your upper half upon finish.
Performing these plyo throws before a game can help remind the body to finish the pitch while completing upper-half rotation. And you’ll get the added benefit of a longer reach towards the target, so you’re more likely to throw strikes, it will add perceived velocity to the pitch and you’re more likely to manipulate the ball for off-speed pitches.