Coaching during the game

[SP]

Just how much impact can a coach or manager have during a game?  I never liked the Tony Pullis style of shouting the bleedin obvious throughout the entire match but some tactical interaction surely must be good.

During the really pantomime defending in the first half Billy McKinley was hurling some sort of message to Sidwell but I'm not entirely sure I heard correctly.  Sounded something like "Tell them to start effin well defending" - if so, I'm not convinced that message is particularly helpful.