Jarring is a rule for when a player slams his or her rods against the wall of the foosball table in an attempt to distract or jar the foosball loose from the other players possession. The rule is that there is no jarring allowed at any point during a game. This is not the same as when a player on the opposite team moves his or her foosball rods back and forth in an attempt to play defense. The key this rule is when a player hits the wall of the table with enough force to jar the ball or distract the opponent. That is why this is a subjective rule that may be called more strict by certain foosball player.