Breeders are changing them dude...They are making them bigger and badder.
Check this 132lb Blue Male Pit named "Goliath", only $12,000!
http://muglestonspitbullfarm.com/males.html
Those are not pit bulls. They're high priced mutts. They had to go and ruin a good breed by bringing in mastiff blood. That is the only way they could make pits go from maximum sixty pounds to those freaks. That is where all the trouble lies. They actually had to bring other dog breeds in to make them that way. Real pit bulls are very small. Most people who see them for the first time are surprised at how small they really are. Those guys are idiots, selling mutts to other idiots. Period.