As members of a unit (element to platoon level) take an overwatch posture, other members advance to cover; these two groups continually switch roles as they close with the enemy. This process may be done by "leapfrogging" by fireteams, but is usually done within fireteams along a squad/platoon battle line to simulate an overwhelming movement towards the enemy and make it more difficult for the enemy to distinguish specific targets. This is where bounding overwatch comes into play.