Throwing arm before acc

ok, i’m a little confused on this, what do you do to “load” your arm when you are in your in windup and when.

I keep hearing something about a 90 degree angle, when do i do it?

Okay, I don’t know what loading is either, so I’ll just skip to the 90 degree angle thing.
90 degrees refers to your arm angle. It is not the only way to have your arm angle, though. Plenty of pitchers throw from three quarters. Then there are some more rare side-armers and sub-marine pitchers. Three-quarters is like in between side-arm and 90 degrees.

I personally pitch from 3/4 because I feel better in all aspects of pitching (control, velocity, movement, etc.). I grew up throwing from 90 degrees, switched to 3/4 a year or two ago, and have been keeping it ever since.

Then, if you want to get technical about stuff, some guys pitch with different amounts of shoulder tilt to keep the ball higher, while still throwing 3/4. But if you don’t understand shoulder-tilt, that’s fine. I personally do not use shoulder-tilt.

Edit: Oh, and your arm angle is where your arm is during the delivery. I’ll try to get some pics.

Edit 2: Okay, here’s a couple pics:
Nolan Ryan, I believe that is a 3/4 angle, with no tilt. http://members.aol.com/fredscards/nolan1.jpg (the colored part of the pic)
Justin VErlander, I believe this is also 3/4, with a bit of shoulder tilt. http://a.abcnews.com/images/Sports/88157548-9abb-4e78-bb3b-e494158b9415_ms.jpeg
Mmkay, I can’t really find and 90 degree arm angles… Or I just can’t decipher a 3/4 and 90 degree.

i meant before you accelerate forward, not your arm slot when you release it.