The 3×1 Dilemma
While working at Baylor, one of the first questions the defensive staff would get from visiting coaches was, “How do you defend Trips?” The Trips formation stresses the defense to the max. By using a 3×1 scheme, offensive coordinators have a plethora of options to attack a defense. If the defense stays in an Over front and tucks the Mike in the strong side “A” gap, the offensive coaches know that the defense is either in man or spinning to single high coverage.
By kicking the boundary safety to the field, the offense gets a guaranteed one-on-one match up with the boundary corner. Even if the defense is dropping an end, or slinging the weak side backer under the single receiver, the top can easily be blown off if the offense has a stud “X” receiver. Against RPO teams a tucked Mike gives offenses the option to read the field safety. This is where the “Spot Draw” can give fits to a defense that is playing an Over front.

Some teams will stay in an Over Front and “sink” the back side safety into the box. This is still the same concept of kicking to the Trips side, but inverted. Though the Mike is now able to cover down for the “snag” route, the defense has introduced a safety into the box, creating a third level conflict player. When teams do this they are exposing themselves to an even bigger play, the backside post shot. By creating a conflicted player in the secondary, the defense has put a CB in isolation. Most modern defenses are trying to find ways to stay in a two-shell to combat one-on-one matchups in the secondary. By sinking, the defense has eliminated a 5-yard route to replace it with a deep shot.
The point of the “No Huddle Spread” is to limit the options for the defense and make them predictable. By playing with the defense’s box numbers, and keeping the illusion of a 4-1 box, the defense can dictate how offenses will attack it. Running an Under Front gives a defensive coordinator several options of attack, and can actually make the Spread offense predictable. When offensive coaches see a 4-1 box it gives the illusion that the defense is weak in the box, and especially to the boundary.

In reality, there is a 5 and 3 technique to the boundary. These players act as anchors to the boundary and create a sturdy wall. The backside safety (DS) is the alley runner and protects the outside gap while hanging in the “post hole” or curl. The Mike is now allowed to “hip” the defensive end or align right outside the 5 tech., and cover down to the #3 receiver making it harder for QBs to RPO the “Spot Draw”. The Will moves to the middle of the formation, essentially becoming the new Mike. As stated previously, the safety to the boundary (DS) protects underneath the single receiver and plugs the weak side outside gap if the offense attacks the running lanes to the boundary. The Under Front creates a 7-man box for the defense while providing a plus-one in the pass and run.

Here is a look at how TCU defended a same-side Dart play. TCU is in an Under front. Watch how the Mike folds in on the outside shoulder of the pulling tackle, and the Will reacts to the closing DE by fitting on the inside shoulder of the tackle creating a plus-one versus the pulling offensive lineman. The TCU secondary is running what is called a “Special” coverage (I’ll explain this coverage later).
Secondary Play
Running Quarters behind the Under Front to 3×1 formations can create a seven-man box and still protect the boundary corner. The basic way to defend Trips with an Under Front is through a “stress” coverage. Using Quarters’ principles, a defense is forcing the offense to throw the ball to the furthest receiver. Many times an offense will not attack the defense through the air by throwing to the #1 WR to the field.
The best way to attack an offense is to play on the law of averages. Most Spread offenses want to attack the defense in the middle of the field (MOF), or where they can get a one-on-one matchup. Traditionally, offenses have put their best WR at the “X”, or the single outside WR spot (away from the Trips). The modern trend is to put an offense’s best receiver on the defense’s weakest coverage men, the LBs (slots). Running Quarters behind the front seven can help a defense protect its weakest coverage men yet still be solid in their run fits. Here is a diagram of a “stress” coverage:

In a “stress” coverage the field corner is essentially playing a Cover 3 scheme over the top of the #1 and #2 WRs. The Sam helps the FC by carrying #2 vertical until someone crosses his face or he is given a “push” call by the Mike. The Mike and field safety (CS) will bracket the #3 WR. On the backside of Trips, a defensive coordinator can play with the coverage concept using the trio of the corner, safety, and Will.
When offensive coaches see the apparent soft edge to the boundary, their instinct is to attack it. The Under Front, matched with a two-high safety look, gives the defense a plus 1 all around. Playing quarters to a Trips set allows the boundary safety to be aggressive to the run and cover the outside, or “O”, gap. With the averages saying the offense does not want to throw from hash to outside boundary, a defense can protect the box, and eliminate easy throws for the opposing QB.
Defeating Predictability
The worst thing a defense can do is stay predictable. In order to have the advantage, a defense has to be multiple. Where defenses can achieve multiplicity against Trips is how they play the coverage to the three WR side and mixing the concepts to the boundary. One popular example is playing man on #1, and playing a Cover 2 scheme against the #2 and #3 WRs, or “Special”. Here is a diagram of Special “Loose” or what Saban calls Stump:
In Special coverage, the field corner plays man on #1, while the Sam plays a hard flat reading #3 (yet carries #2 vertical until pushed), Mike protects the curl, and the field safety plays over both (always protecting the inside of #3). This particular coverage is great against teams that run “high-low” concepts with their #2 and #3 WRs. By keeping the Mike in the curl it allows him to sit in the hole and fold much quicker versus the run.
Conclusion
A defense must always play on the law of averages when creating a base defense. There are many ways to attack from an Under look. Putting the 5 tech. and Nose to the Trips allows the defense to cover down in the pass while maintaining a full box. No matter how athletic a defense’s Mike may be, it is hard to ask him to plug the “A” gap and relate to the #3 WR removed from the box. This particular front helps tremendously when you play teams like Baylor that split their #3 WR far to the sideline.
3×1 Resources:
Defending Trips:
- Defending Trips — Fitting the Run
- Top Trips Coverages Explained
- Specific Split Field Trips Coverages:
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Coach, to the trios side you don’t bend the DE? If not how do you teach the DE to do both?
Check this article out: https://matchquarters.com/2017/11/03/how-do-you-play-trips-pt-3-defending-the-run/