This is a tactic used by
soccer teams in order to lure the other team
offside. In soccer, offside is when an offensive player is behind the second to last defenseman when the
ball is passed to him.
To intiate an offside trap, your team has to be in the
proper formation. The most commonly used formation is the
sweeper or "diamond" formation. It is in the shape of an elongated diamond, with the
latitudinal sides being the ones elongated.
The actual trap is iniated by the back
defenseman or sweeper. As the ball is about to be
kicked, the sweeper runs forward in order to draw any
offensive players, that are behind their man, offside. It is a very good trap and is used by many
professional teams.
There are, however, many things that can hamper the trap. A particularly
fast forward doesn't need to be behind the defense. Another is a
mistimed run by the sweeper when moving forward. The last is common at all levels of the game, an
incompetent referee or linesman.
Despite many things that can make it useless, the offside trap is very effective at stopping an opponent's attack even before it happens.