Check out the Advanced Defending Techniques Tutorial:
http://www.youtube.com/watch?v=8Vz3GvMYUlg
It tells you all about jockeying, running jockeys, and jockey press in FIFA 11. There is also a way to combine a running jockey with a secondary press. this is a new way to defend against thru passes. it also allows you to mark players without the ball in an automatic way for the first time in a fifa game. this could be a huge improvement to defense which hopefully makes it harder to score from 1 on 1s.