This is your basic square pass supporting run. By lining up to the player with the ball, you are making the defender's job more difficult. In addition of trying not to get beat, the defender must also be wary of you as a passing option.
Overlap run
An overlapping run adds width to the play. This is a very good offensive tool because it pulls apart the enemy defense. As the enemy defensive line is stretched horizontally, piercing passing lanes will usually open up.
Support from the frontline
As unnatural to inexperienced players as it may seem, running back to show support is commonly done at the highest levels of the game. Notice that by dropping back, the attacker brings along his marker. This play will often create the opportunity for a wall pass combination between the ball carrier and the retrieving attacker.
Checking back to the side line
This is a strategic run that not only adds potential depth to the attack, but also pulls an enemy defender out of the current play.
Changing the point of attack
Using short square passes is an effective way of changing the point of attack. Notice how the black players give support by running up from defense as well as by dropping back from the frontline.
Building up attacks
When safely building up an attack, the defensive line must use square and back passes until a good offensive opportunity arises. This forces the enemy team to work by shifting laterally in order to close down angles. The defenders must be thinking in terms of possession rather than force the ball up. They would also need to have a decent level of skill.
