Few teams seem to adopt zonal marking. A system where players mark space instead of going man for man. The problem being, with the players being static and having a standing jump, players who are attacking the ball and having a running jump, will win the header every time.
One team to use zonal marking is Manchester City. With players lining up on the six yard box, two either side of the penalty spot and nobody on the post, teams exploit them from corners. Even with the power City have in the air, they are vulnerable from set pieces with their zonal marking. 
This has been proven so far this season with Martin Skrtel?s goal for Liverpool against City, Niklas Moisander?s header for Ajax and Siem De Jong?s double against Manchester City which, unless a miracle happens, will see the end of this years Champions League campaign.
A team not to use the zonal marking system is Manchester United. They mark man for man. A system that has worked well for the most dominant team of the premier league era. A system that has few critics.
Even with the flaws zonal marking has, teams continue to adopt the system. With a good delivery and players timing their runs, chances will be created.
Source: DSG
Source: DSG