18 yo, 5'10"

Currently at low 80s, looking to get faster
my goal is 90 mph eventually

I know there has to be something I can improve
stride, shoulder separation, etc


This is something I just love talking about because I learned it many moons ago—“The Secret”. In a nutshell (think Brazil nut), it involves getting the whole body into the action. I learned it from watching the Yankees’ Big Three pitching rotation of the late 40s to mid-50s and seeing just what they were doing and how they were doing it; they were all driving off the lower half of the body, using the legs, the hips and the torso in one continuous motion to create a nonstop flow of energy all the way through the shoulder and arm to the fingertips, thus generating more power behind their pitches so they could throw harder with less effort. I started working with it and found that I was doing the same thing those three pitchers were doing, and because I was a natural, honest-to-gosh sidearmer it came easier for me.
And incidentally—or perhaps not so incidentally—a good part of the secret has to do with the fact that most batters have no idea that the lower half of the body is the real key to the pitcher’s power! They focus on the upper half, looking for that much-desired fastball they can blast out of the ballpark and across the street and right into Aunt Minnie’s kitchen window, and unless they are good low-ball hitters they are often suckers for such pitches. Now, a good place for you to start would be the “Hershiser” drill which aims at getting the hips fully involved and establishing the connection between lower and upper halves of the body; it requires no special equipment, just a fence or a wall.

So I should work on leading with hip instead of opening early and leading with leg?
that was something I thought I saw

In addition to leading with the front hip, you need to get your center of mass (think “hips” or “butt”) moving forward sooner. Doing so will help your overall timing, put more energy into “the system” and make you quicker to the plate.

I know it has been a while since this, but I noticed something recently while pitching.

While warming up, I focused on leading with hip, and my velocity definitely shot up with no effort.
Through the game, that’s the only thing I really thought about, and speed stayed up.
Then, I got kinda pissed off at a bunch of errors in a row (never yelling at fielders of course, they are not trying to mess up. still frustrating). I found myself moving forward way faster, and my speed spiked up again.

I think that in one day, my speed jumped at least 5 mph, maybe more. For the first time in a while, I actually felt like I was fast.