These areas or zones are general guidelines for where on the pitch the midfielders should be responsible for attacking and defending.  Of course this is dependent on where the other team's players are positioned.  Midfielders should consider themselves as "lawnmowers" who have to be able to cover the majority of the pitch for long periods of time both defensively and offensively. Typically, midfielders move up and down the pitch together in order to provide areas to pass into as well as support each other defensively.

When attacking, wide midfielders will need to move towards the boundary in order to create space.  The center midfielder can drift to either side in order to provide support.

When defending, wide midfielders will need to compress closer to the middle of the field in order to stay goalside on an attacker and to protect the goal.