Flexibility of a Split 4 Defense

I am currently the defensive coordinator at Boyd-Buchanan School. I have coached for eight years and in seven of those eight we have been to the state playoffs. In 2002, we finished state runner up and in 2003 we won the Class A State Championship, 26-3. Our starting defensive unit only gave up 14 touchdowns in 14 games, and here’s how we helped achieve success:


Diagram 1.

The split four is a simple gap control defense that has the ability to put eight men in the box versus the run (Figure 1) and the flexibility to change to a 4-3 versus the pass. Our defensive unit was not necessarily big by any means, but we were quick and really pursued well to the ball. Our lineman, although small and undersized in most games we played, made up for lack of size with good technique and a desire to make plays. Our linebackers were also quick and were able to read on the fly, which enabled us to get to the ball and stop the offense from getting up field. The secondary, which consisted of two corners and one safety were great at covering up receivers and making sure we stayed in the correct coverage.

The split four defensive philosophy we use is based on a gap control technique that enables us as a unit to bounce everything to the sidelines where we can use our team speed to make plays. Linemen are aligned as seen in (Figure 1). The tackles are in what we call a “3” technique. The tackles are taught to read hat and make sure they can play or recognize five simple blocking schemes. These blocks that not only our tackles are taught to defend, but the ends as well are the reach, down, pull, trap and double team. The key to success up front is making sure we first make good contact with the man we are lined up on and then recognize and react to how we are being blocked. The end on the TE side plays what we term a tough “6” technique (See Diagram 1.). This needs to be your strongest, most talented lineman. He is responsible for keeping the TE off of the linebackers and also he is required to not get reached. This is a tough situation to put any lineman in, but if you have a good athlete who is big and quick, he could be your anchor at this position. The weak side end plays a “5” technique (Diagram 1). This player is responsible for squeezing the down block and also is required to check the bootleg by the quarterback. This could be a smaller, quicker kid that could play this position. The four linebackers in the split 4 are responsible for checking their assigned gaps and then pursuing to the football. The inside backers Sam (to the strong A gap) and Mike (to the weak A gap) are responsible for everything that comes to those two gaps (Diagram 1). The Will linebacker or weak side outside backer is responsible for outside leverage away from the tight-end side. The rover backer is also responsible for outside leverage to the TE side, but also must cover the TE man, if asked. Linebacker keys are simple because they are basically reading and reacting off of how our defensive lineman read and react. Sometimes a coach may establish a predetermined read for the linebackers based on information from our scouting report.
Diagram 2.

The responsibility of the secondary in a split 4 defense is simple and easy to teach as well as play. The corners align with outside leverage at seven yards from the line of scrimmage and are responsible for deep third vs. the pass. They are secondary run support versus the run. (Diagram 2). The safety aligns at 10 yards and is responsible for deep middle third versus the pass and acts as an alley player versus the run.

Since cover 3 is our primary coverage in a split 4 defense the drops of the linebackers are vital to our success versus the pass. Middle backers drop deep hook-curl zone to their side while the outside linebackers drop to the flats to defend the out route or flare pass (Diagram 3); a variation coverage as a change up in the split 4 would be a man coverage package. (Diagram 4).
Diagram 3.

Diagram 4.

The split 4 is flexible enough to be changed to a 4-3 in passing situations with no personnel changes. The rover now becomes a cover 2 corner, but is still the flat player. Our corner now becomes our 2nd safety in cover 2. (Diagram 5)
Diagram 5.
Diagram 6.

Blitz packages are multiple out of the split four and easy to execute. The pinch-pop stunt (Diagram 6) is a good stunt against the run or pass. The “in-razor” stunt (Diagram 7) is a definite run blitz that is valuable in short yardage situations. Also, the strong gate stunt (Diagram 8) or weak gate stunt (Diagram 9) can be easily adapted to a zone blitz by dropping the defensive end into the flats to defend the pass. In short yardage situations the split four can be reduced to use as a goal line, or 3rd and short yardage package. If you account for all receivers you should be successful.
Diagram 7.

Diagram 8.
Diagram 9.

In the last three years we have seen a dramatic improvement in our defense. There were times in the mid to late 90’s where we had to outscore our opponents. Recently, that has not been the case. Our attitude is now one of pressuring the offense by cutting off running lanes and “flying to the ball” on the perimeter. As a matter of fact, in 2003, 297 of our 760 tackles were for losses of 718 yards. This also resulted in a +19 turnover ratio. Offenses averaged 86.7 yards rushing, 100.1 yards passing, and 9 first downs per game against our defense.

This may not sound impressive but the fact that we played all of our non-region games against higher classifications (1-2A, 2-3A, 1-4A, 1-Division II) gives it a greater statistical meaning. These non-region opponents also made us a better football team and acclimated us to the pressures associated with playoff and state championship games.

As with any defensive philosophy you want to adapt what you do to the athletes you have. Keeping things simple and consistent will give the athletes the ability to be sure of what they are doing and, in turn, will translate to more big plays on defense. The simplicity and flexibility of the split four should enable you as a coach to teach a defense that is sound in technique and reliable enough to put your defenders in the right position to make plays. Remember, offense wins games but defense wins championships!

About the author
Grant Reynolds

Coach Grant Reynolds is the Defensive Coordinator of the Boyd-Buchanan School in Chattanooga. He has been at the school for 8 years and in 7 of his 8 years, Boyd-Buchanan has been to the state playoffs. Last year's team won the state championship. You can reach Coach Reynolds at Reynolds@Boyd-Buchanan.edu