Step 1

The most basic concept in defense is the force. There are 3 basic forces: home, away, and straight up. Home and away refer to sides of the field; home is the side where our stuff is, and away is the other side. Look at the two players marked number 1, with blue being offense and red being defense. Blue is trying to score in the top endzone.

Step 2

Let's assume that our stuff is on the right sideline. If the defender forces home, or stands to the left, then he effectively cuts off that side of the field. This means that players 4,5, and 7 are "open side" throws whereas 2, 3, and 6 are "break side" throws. The difference is that the open throws are much easier because there's nobody in the way. Player 1 doesn't worry about the open side throws because his team is responsible for those. More on that later.

Step 3

Now the defender switches sides to force away. When this happens, players 2, 3, and 6 are now on the open side while players 4, 5, and 7 are on the break side.

Step 4

A straight up mark takes away down field throws, and takes away the center. In a straight up mark there is no longer a open side or break side, but players 2, 5, 6, and 7 are easier throws than players 3 or 4.

Step 5

To demonstrate how this is effective, lets look at a basic offense, the vertical stack.

Step 6

Here, the defnder is taking away the left side of the field. The cutters (players 2, 3, 4, 5, and 7) want to run to the other side of the field to get the disc. Player 5 makes a cut and gets thrown to.

Step 7

Could a cut on the other side be effective? Yes, but its a much harder throw, because player 1 tries to take away that half of the field and the thrower has to get the disc over his own players. Most of the action happens on the open side for this reason.

Step 8

So how does this "force" concept help the defense? Let's add the other players and see.

Step 9

Since the offense is going to cut to one side, the defense knows where to stand. This makes throws much harder to complete as the defense already has a step on the attacking players.

Step 10

It's important not to get mixed up about which way the force should be. If player 1 sets up incorrectly like is shown here..

Step 11

Then the defense is automatically a step behind the offense! Throws to the break side are now very easy for the offense because it's totally unguarded.

Step 12

When one break throw happens, the whole defense is out of position, so this usually results in lots of up field passes for the offense. For this reason, it's very important to hold the force!