A trap block in football is a type of block in which the offensive line allows a defender through the offensive line to be blocked by a rotating blocker. This play moves the blocker out toward one side of the field to cover an unmarked defender. The defender is purposely left uncovered so that the block can swoop in from the other side of the field to push him off of the field and out of the current play. Sometimes the tight end will execute the trap block.
Many blockers utilize the trapping left or trapping right strategies depending on the side of the field that the trap block is occurring. Players step with their left foot when trapping left, and their right foot when trapping right. Blockers also hit the defenders left or right shoulder depending on which way they are trapping.
The blocker needs to be fast on his feet and aggressive. His play starts when he moves, but isn't finished until the defender is out of the way of his teammates. He is the one responsible for making a lane for his teammate to get through without the defender stopping him. Blockers during this play formation need to be able to see the field at a glance and know their move and their opponent's move in order for it to run successfully.