Here we can see a 1v1 situation down the wing and in the box there is man-to-man marking. The fullback is able to cross the ball into the box, but...
The back line runs back quickly until reaching the offside line, there they stop.
Defend the box: Only run into the box if the ball is close.
The defenders should wait to run into the box until the ball is crossed or if it is clear that the cross will beat the defence.
The defenders should...