On Youtube, look at sections .02 and .10 &.11.
This is what you’re doing to yourself:
YOU’RE WORKING AGAINST YOUR BODY’S NATURAL BALANCING SENSORS.
Your stride leg/foot posture is forcing a landing that places your compete body in a starting position that adjustments and counter adjustments forces a motion by you in an attempt in throwing the baseball as hard as you can. Thus, your throwing arm makes an “up & over” motion that tries to compensate for your initial off-balance stride reach and stride foot plant … all the while your upper body tries to handle the throw the ball, then your glove arm/hand tries to compensate by recouping the bodies balance. In the section of your video… .10 & .11 notice how your glove hand whips up to your chest like you’re trying to catch a bag of groceries.
Whatever it is that you’re trying to do, is not working - IF you continue with this kind of delivery.
Here’s my suggestions:
First off, move your target a lot closer to you, say 30 feet. Knock down the velocity stuff … throw at only one third game speed.
Second, concentrate on bringing that stride leg out, easy does it, and plant your stride foot right off the instep of your pivot foot, then stop and hold that position, no arm action, just lower body control here.
Third, now take a baseball in your pitching side hand and bring it up to the high cock position, but don’t throw yet.
Fourth, stretch out your glove arm in a relaxed way and point it towards your target.
Fifth, with the same motion, throw your baseball by exchanging your pitching side shoulder with your glove arm shoulder, bringing in the glove to about your lower chest. … as your going through this posture, bend your stride leg a little letting it accept your forward motion of your upper body. Do not allow that glove arm to SWING OUT to the side. Bring it straight back.
HOLD that finished posture for just a few seconds and notice how balanced you are. Your glove should be tucked somewhere near your lower chest and glove side hip, along with your pitching shoulder completely buried into the target with your glove side shoulder facing somewhat to your backside.
NOTICE THE COMPLETE BALANCE THAT YOUR BODY IS SENDING YOU, WITHOUT YOU EVEN CONCENTRATING ON IT.
Repeat this drill over and over again until it’s as natural for you as getting out of bed in the morning. You’ll not only have a 100% improvement in your delivery posture, but you increase your strike % ten fold.