get a stopper (eg. dalembert, o neil, etc) and use their stopper skill and block those dunkers... another is jump 1st when u think that the player is going to dunk over you, if ur late... just accept the fact that he has dunked on ur face!
up physical defense to at least 70, always use defensive crouch inside of 14 feet(oops, is that prejudicial against keyboard players), superstar block instead of regular blocks.
i get in front of em as they are driving and press take charge, and occasinally will knock him aside or get a travel called on him. sometimes get a charge called, only got dunked on, rarely
i have my physical defense on like 40 and i can still stop em, i just have a guy that can swatt waiting in the paint, then user superstar block and send it flying!