While watching American football, I frequently hear about "one gap" or "two gap" techniques when referring to defensive linemen. I found this terminology to be a bit unclear, so I looked for an explanation online. I found a few articles like this one.

What is the primary difference between these techniques? It seems that the way the defensive linemen are lined up and their defensive responsibilities are the main factors. My understanding is that one gap defender is lined up between two offensive linemen and only worries about the gap between his opponents, while a two gap defender is lined up directly across from an offensive lineman and has to defend the space on either side of the blocker. From the diagram, it seems that 3-4 defensive linemen would tend to be two gap defenders, while 4-3 defensive linemen tend to be one gap defenders. Is my understanding correct?

Is there a simpler way of explaining these techniques?


Yes, your understanding is correct on the responsibilities of the two techniques.

One Gap vs Two Gap

The one-gap lineman is only responsible for the one gap in the offensive linemen and he typically lines up directly in this gap on the defensive line. The two-gap lineman is technically responsible for the gap on either side of the offensive lineman that he is lined up across from. The main purpose of the one-gap technique is for the defensive lineman to get past the offensive lineman and either sack the quarterback or tackle the ball carrier behind the line of scrimmage. On the other hand, the main purpose of the two-gap technique is for the defensive line to "clog" the line of scrimmage which allows for the more athletic linebackers to make plays on the outside of the play or gives them time to support in case of a run up the middle.

3-4 vs 4-3

However, not all 3-4 defenses exclusively use the two-gap technique and not all 4-3 defenses use the one-gap technique. Often 4-3 defenses can drop a single linemen into pass coverage leaving the other three defensive linemen playing a two-gap technique. Also, when playing the 3-4 and expecting a run play, defenses will often bring two linebackers to the defensive line just before the snap of the ball in support. In this case, all five defenders will play a one-gap technique, this is sometimes referred to as a 5-2 defense though there is not much difference between the 5-2 and the 3-4.

Explaining the Techinque

As far as having a better way to explain it to the player, I think the way you stated it is pretty good. However, it is important to note that with the one-gap technique the main objective is to get into the backfield and make a tackle or generally cause havoc. But with the two-gap technique, your main objective is to "clog" the line of scrimmage (draw double teams, prevent holes from opening, etc...) so that the linebackers can run free to the ball carrier and make the tackle. For this reason, linemen who play the two-gap technique are less likely to accrue lots of statistics for tackles, fumbles, etc... This is the main reason that many high-profile defensive linemen in the NFL do not like to play in 3-4 defensive schemes.


As much football as I watched, I had previously not gotten very far into learning about d-line assignments until my son began playing DT in school. From my non-expert understanding, the difference with 1 gap and 2 gap is 2 gap linemen are more concerned with eating up blocks than are 1 gap linemen and 1 gap linemen are more concerned with penetrating the o-line than 2 gap linemen.

1 gap linemen tend to get more sacks. 3-4 linemen tend to be bigger, slower and stronger.

If you look at how a 3-4 defense lines up on most plays it will make most casual observers ask, "Uh, what's the difference between 3-4 and 5-2?". And they have a good point.

So think about 3 d-linemen up against either 5 o-linemen or 5 OL and a TE. You're going to generally rush at least 4. If the NT and 2 DEs can each take up 2 blocks that leaves the OLBs (who are in basically the same starting position as 5-2 DEs) in great shape. Or the pressure can come from the middle instead (you're never quite sure where the 4th guy is coming from with a 3-4 defense, that's the whole point of the 3-4), but you get the point. And it takes a big, strong guy to take up those blocks and plug those holes.

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