Typical coverage areas for midfielders in 7v7 in a 2-3-1 formation. Midfielders are "lawnmowers" because they should be covering the most grass and should always be moving. Left and right mid are responsible for tracking back defensively, but still staying wide to provide outlets for passes. Outside mids should also be ready to run up the field quickly into space or with the ball.  Offensively you don't want to move to far central, unless defending a specific player. Center mid is consider the maestro, conducting play in the middle of the field.  Coverage wise they are considered "box to box", not dropping to far back defensively unless necessary and not pushing too far forward offensively unless the right opportunity to present itself occurs. Center mids should look to pass the ball wide and to the striker and then move to offer support.