Explanation of Gaps and Techniques

    Before getting into a detailed discussion on any topic, it is important to establish a set of terms to make sure we're all on the same page.  This post will cover two key aspects of defensive football that are vital to our ability to communicate defensive schemes and concepts: Gaps and Techniques.  Nothing revolutionary here, just ensuring we all are working from a common vocabulary.

Gaps

     Gaps are, quite simply, the spaces between offensive players.  Physics tells us two objects cannot occupy the same space, therefore, it is through these gaps that the offense attempts to run the ball.  It is also these gaps that the defense attempts to fill on run plays, and penetrate through on pass plays.

     Gaps are identified by a letter.  The gaps on either side of the center are the A gaps.  The gaps between the guards and tackles are known as the B gaps.  The gaps between the tackles and the tight ends are the C gaps.  The gaps outside the tight ends are the D gaps.

     The offense can create additional gaps by using offensive backs.  A fullback or H-Back is typically employed in this manner.  A full back leading up through a hole on an iso play turns the one gap into two.  This creates one additional gap that the defense must fill.  Similarly, the offense can move gaps along the front.  The backside guard could pull and lead through a hole on the playside.  This reduces the backside gaps by one and increases the playside gaps by one.  Wing backs can used to create additional gaps outside the tight end.  A tight trey formation can be used to create two additional gaps.

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Techniques

     Proper alignment is key to defensive football.  Coaches communicate alignment in terms of techniques.  A technique describes where a defender aligns in relation to the offensive players.  A 0 technique describes a heads up alignment directly over the center.  A 2 technique is a head up alignment directly over the guard.  A 4 technique is a head up alignment directly over the tackle, and a 6 technique is head up alignment directly over the tight end.  Odd numbers describe an alignment on the outside shoulder of an offensive player.  A 1 technique is the outside shoulder of the center.  A 3 technique is on the outside shoulder of the offensive guard.  A 5 technique is the outside shoulder of the tackle and a 9 technique is the outside shoulder of the tight end.  A 2i technique describes an alignment on the inside shoulder of the guard and a 4i technique describes an inside alignment on the tackle.  An inside alignment on a tight end is known as the 7 technique.

     The same numbering system is used to communicate the alignment of line backers as well.  A 0 is simply added to the end of the technique to indicate that the player should align off of the line of scrimmage.

Base Defense - Alignment

     In his 6 years as the Defensive Coordinator at Michigan State, Pat Narduzzi has forged a formidable defense that ranks among the best in the nation in virtually every defensive category.  Today we are going to take a look at the base alignment of Sparty's Over 4-3 defense versus a couple of fronts.

     Pat Narduzzi's defense is based on the famed Miami 4-3.  It's built around speed.  High School safeties are moved to line backer, line backers are moved to defensive end, and defensive ends are moved to defensive tackle.  There is no place for slow players in this system.

"There is no place for big, slow linemen to play.  Our offensive line coach will make out well because all those players will end up as offensive linemen.  We are looking for speed on the defense, and if you do not have speed, you have to play some other position."

     The defensive line consists of 4 players.  Two Defensive Ends, a Tackle (T), and a Nose (N).  The call side defensive end (E) will align on the outside shoulder of the Tight End in what is known as the 9 technique.  If there is no tight end, he shifts down to the outside shoulder of the defensive tackle.  The rush end (R) aligns in a 5 technique on the outside shoulder of the offensive tackle away from the call side.  The Tackle aligns in a 3 technique on the call side.  This technique puts him on the outside shoulder of the Offensive Guard.  The Nose aligns away from the call side in a 1 technique, shading the away side shoulder of the Center.  The ends do not flop from side to side.  The terms "End" and "Rush" simply apply to the technique, not specific positions.  The Tackle and Nose do flip-flop from side to side.  The tackle is always aligned to the call side, while the Nose is always aligned away from the call side.

     There are three line backers in the 4-3 defense: Sam, Mike, and Will.  All three align themselves in two point stances 4 feet from the line of scrimmage.  Same aligns to the call side in a 50 technique.  Will aligns in a 50 technique away from the call side.  Mike aligns in a 10 technique to the call side.  If there is a second detached receiver to their side, Will and Sam will apex, or split the difference between, this receiver and the end man on the line of scrimmage.

     Michigan State's secondary play is based on a quarters coverage concept.  This coverage allows the defense to put 9 defenders in the box versus the run while still placing the secondary in an advantageous position versus the pass.  The corners align tight to the #1 receiver and play press coverage.  They align inside shade of the #1 receiver, forcing an outside release for the pass and preventing the receivers from blocking the safeties on the run.  The safeties align nine yards deep and one yard outside the end man on the line of scrimmage, either a tackle or tight end.  The safeties read the end man for a run or pass read (high hat/low hat).  If they receive a run read, they play force on runs to their side and play cutback and reverse on run action away.

     Below we'll see how these alignment rules bear out against some common offenses.