The 4-4 uses four down linemen, four linebackers, two cornerbacks, and a safety. Stunts are a common component of this defensive set, usually with some or all of the linemen stunting left or right and the inside linebackers stunting in the opposite direction. A wide range of possible stunts and blitzes are possible. The 4-4, also known as the "stack" defense, relies on quickness, particular quickness in pusuit. In order to run the 4-4 on a regular basis, the interior down lineman must be players of considerable substance.

5-2
The 5-2 is the standard for many coaches at the high school level and is used somewhat extensively at the collegiate level. Consisting of a nose guard, 2 defensive tackles, and 2 defensive ends, it is intended mainly as a run defense. However, it can be effective against the pass as well with five pass rushers and two or three linebackers.

Usually, the down linemen's first responsibility are running lane specific, each man responsible for a certain gap or lane. The default command for lineman is to read and react to the play, with the defensive end's primary concern being containment. Occasionally, a defensive end may be called on to pass defend an area such as the flat. By design, the linebacker's first responsibility is to defend the run, then the pass. But this may be modified for varying puposes. A coach wants his leading tacklers to be down linemen or linebackers. If a defensive back or safety is leading the team in tackles, it is a clear indication that the opposing offenses are getting throughout the first line of defense.

The remaining four positions are the two cornerbacks and the two safeties. An option is to allow one of the safeties to be a "safe safety" meaning that this player seldom has specific duties, and is left to read and react to each play. If in zone pass coverage, the free safety or safety to the TE side has "up" resposibility, while the strong safety has deep third duty. Each corner has deep third duty as well. LBs are 4 to 5 yards off the ball, CBs 3 to 6 yards deep, safeties 10 to 12 yards. Down linemen keep the ball in the corner of the eye, and move on the snap--not the Qbs vocalizations or other personnel movement.

5-3
The 5-3 is even more intent on stopping the run and is designed to make use of a strong middle linebacker. Similar to the 5-2, the 5-3 simply replaces the free safety spot with a third linebacker which lines up on the outside shoulder of the TE, 5 yards deep and parallel with the other LBs. The "best" LB move to the middle LBs position.

Obviously, modifications, or shifts, may be necessary depending on the actual alignment of the offense. For example, let's say the offense opened in a Tripps (3 receiver) set to the defense's right. Basically, all that has happened is the FB and left wide out have been replaced with two new wideouts to the right. So the left CB shifts over with the new WR, and the left OLB shifts over as well. The two remaining linebackers return to their normal 5-2 alignment.

Another variation calls for the 3 linebackers to all shift down to compensate. The TE can be covered by the DE to that side, or the LB to that side. The DE to the Tripps side can cover the flat or slat area, or even be sent on a blitz.

6-2

The 6-2 is the standard short yardage defensive formation. It is often implemented to stop the run.

Basically, the six down linemen are positioned in the gaps between the offensive linemen with the two inside linebackers playing run first, pass second. The cornerbacks and the safety (playing up tight to the line) play pass first, run second, each with deep third responsibilities.