Pretty sure they don't really have a 'break'.
They have been doing double sessions according to a few accounts, and have been in most days since Christmas due to the congested fixture list. I am sure they will have been working on set pieces.
But like I say, as much as it's Silva's doing, the players are the ones who go out on the pitch and have to deliver at the vital moment. I'm not sure all the coaching in the world can get Zouma to learn he has to move towards the ball rather than wait for the opposition to get there...
Of course hard work pays off. But then the players have to do it when it matters and our 'lionhearts' (as
@deipnosophist regularly says) are adept at not doing it when it matters.