|The natural body of Pacquiao vs. Marquez' not-normal body|
Manny Pacquiao still has the same built. So his energy and power will last until the 12th round. What we do not know is, if he can take the punches of Marquez in the early rounds. If Manny is not knocked-out by the 5th round, it will be Marquez who will be knocked-out between the 6th and 8th round. That is, if he is not knocked-out by Pacquiao in the earlier rounds.
Good examples are the bodies of Muhammad Ali and Sugar Ray Leonard that not too muscular. Their muscular opponents became punching bags after the first few rounds and many were knocked-out on later rounds.