Arm Strength/Injuries?

I’m a pitcher that uses mostly arm but I’m trying to incorporate everything else. I don’t understand why everybody says that you should squat a lot.
When I work out, I usually work out my shoulders, triceps, and biceps. Then chests and core. Then I do a little bit of leg press after.
Here’s some videos of me pitching btw.
I honestly don’t see when you use your legs except when you start the chain of kinetic energy. I don’t see the explosive power that you might need when pitching.
Can someone just kind of explain it to me? Don’t mean to talk too much :stuck_out_tongue:
And also, if you watched my videos, does it look like I might injure my arm like that? Because a lot of people have told me that I might but I don’t usually feel sore after. However my friends say it might just be because of strength.

When I was a kid I used to go to the original Yankee Stadium every chance I got, and I would watch the pitchers. I noticed that the Yankees’ Big Three rotation all did the same thing: they drove off the lower half of the body, using the legs, the hips and the torso in one continuous (and seamless) motion, and that was how they were generating the power behind their pitches. It seemed that the arm and shoulder were just going along for the ride, and when they delivered the pitches it was just effortless—using the whole body took a lot of pressure off. And not a sore arm in the bunch. I saw just how they were doing this, and I made a note of it and started working on it on my own. As I practiced this essential aspect of good mechanics I found that not only was I getting more power behind my pitches, I was also throwing harder—and faster—than I had been doing, with less effort. I was a snake-jazz pitcher, but somewhere along the line I ended up with an 81MPH four-seamer which my pitching coach told me was, for a finesse pitcher, a fast ball!
This is what you need to do—work on getting your whole body into the action. It will pay off handsomely, believe me. Elsewhere in this section one of the other posters describes the “Hershiser drill”, which concentrates on getting the hips involved—look for it. :slight_smile: 8)

How about this…

At the end of your stride, you plant the front leg which has to put on the brakes and stop the forward motion of the front hip. It’s this “putting on the brakes” that takes strength. Planting on a bent front leg takes even that much more strength. Having a faster tempo takes even more strength. So, part of the strength you need allows you to perform these mechanics well and part of the strength you need allows you to do this repetetively over the course of a game without tiring too soon.