http://www.boxing.com/news/comments/brandon_rios_the_uppercut_explained Short interview, but some great nuggets in here: The uppercut has always come naturally to me. You have to set it up. I like to come in with a jab right hand. When I get inside, I bend, lean a little back with my weight on my right foot and fire my right uppercut straight up the middle. I like to follow the uppercut with a left hook, a left uppercut to the body and then I finish with a straight right down the middle. The left uppercut is arguably the hardest punch in boxing to master but Rios maintained that the big difference is you are getting weight on the front leg and turning the back foot. But right or left uppercut, Rios stresses, You have to come straight up with it. And he and his mentor, Robert Garcia, are adamant about changing levels with your shots as in head, body, head. Pacquiao has gotten very spiritual. Very Christian. And that is fine. But he really doesnt want to hurt the other guy anymore. And in boxing, as much as we might be friends and respect the other guy you have to want to kill him when you are in there. Not really but you know what I mean. When I go in there I dont care who it is. I want to destroy them. You have to have that attitude.
I would say the trailing uppercut is the toughest punch to land from anywhere but chest-chest anyway. You only see the real masters land that punch from anywhere but phone-both range.
