Defensive Principles

Delay - Deny - Destroy - Develop  
Immediate chase – The moment possession is lost the nearest player(s) try to regain possession or apply pressure on the ball. Players giving immediate 
All defensive training should begin with training of defensive skills in a 1 v 1 setting, and then progress to 2 v 1 training (numbers down and numbers up), 2 v 2 training, and 3 v 3 training. In this way, players will learn improve their own individual defensive skills and learn the proper techniques for working as a team to prevent the opponents from scoring, by learning to prevent them from taking the ball to dangerous parts of the field; or from passing balls into dangerous parts of the field to other teammates; or from allowing target receivers to collect any errant passes which might slip through; or from allowing such receivers who might get a ball in dangerous territory from getting off a shot. The essence of team defense is to use the available manpower to close down as many of the dangerous attacking options as possible, while patiently waiting for mistakes to occur or sufficient backup to arrive that efforts can be made to win the ball back.
chase can also help to delay the attack 
by making recovery runs that deny the opponent the opportunity to play the ball quickly forward.
Delay – The pressuring defender(s) forces the attacking team to slow down so that the defense may organize. While applying pressure the defender must be careful to not over-commit. If he is beaten easily the time for the team to organize is shortened.
Depth – This refers to the immediate organization of players behind the pressuring defender. While the ball is being pressured all other players should be recovering into defensive positions. The positions taken should support the pressuring defender in the event he is beaten. This is called providing cover.
Balance – As the team concentrates their defense in the area of the ball, defenders away from the ball (opposite side of field) must position themselves to cover vital spaces (central areas) in order to prevent attackers from making penetrating runs into these spaces in which to receive the ball for an attempt on goal. All players who are on the opposite side must seek positions in which to provide balance to the defense.  
Concentration – As players recover towards their own goal and organize their defense, the objective is to limit the time and space for the opponent by concentrating their defense in the area of the ball. Defenders also recover centrally towards their goal in order to limit the opponents ability to directly attack the goal.
Control and Restraint – Players must be disciplined and play “under control” when challenging for the ball. Too often players make poorly timed or off-balanced attempts to win the ball. Players should restrain from tackling until they are confident they will win the ball.