Proof for this. Behavioral studies, perhaps? Crime reports.
What the hell? Crime reports and behavioral studies. Shee-it. You have video support...or maybe you don't watch MMA?
I'm not really sure why all this discussion is taking place, really. The difference in damage (and perceived threat) between punches from an untrained guy on top of a heavier, struggling opponent aren't gonna be much difference than the top guy's aggressive cross-face attempts, elbows, and head-posting while trying to keep position (on top). All the dude on the bottom knows is that he's taking damage to the head/face.
If the gun wasn't pulled until they were on the ground (a big "if"), then it's reasonable to think it was likely pulled when Trayvon wasn't striking Zimmerman much at the time because:
- It'd be difficult to unholster a weapon while taking blows to the head. As the bottom guy, it'd be pretty hard to not cover up with both hands/arms if you're taking hard blows to the face.
- It's not easy to keep throwing even halfway-effective punches while maintaining top position when the guy under you is squirming and trying to get up, especially if the bottom guy is heavier.
These facts are moot, though, because even if Trayvon stopped throwing punches for a few seconds (long enough for Zimm to draw his weapon) to post on an arm to re-establish his position or just to posture up and take a few breaths or whatever, it's still reasonable for Zimm to think he's in a life or death situation.
I think Zimmerman deserves all the blame in the world for being in the position he found himself in when he was under Trayvon, but don't blame him for using his weapon once he was in that position. Though I hate the message that other wannabe neighborhood watch nerds might take from the outcome of this tragedy, I agree with one of the comments above where it was chalked up to being an anomalous occurrence that isn't nearly worth all the time we've invested in it.