Football basics
What Is a Gap in Football? A, B, C and D Gaps Explained
If you’ve been around a youth practice, you’ve heard a coach yell “fit your gap” a hundred times. Most kids nod. Plenty of them couldn’t tell you where their gap actually is.
A gap is the space between two offensive blockers. Every run play is aimed at one, and every defender on the field is responsible for one. Learn the gaps and the rest of run defense, and most of the run game, starts making sense.
Where the gaps are
Count out from the center, one side at a time.
| Gap | Where it is |
|---|---|
| A gap | Between the center and the guard |
| B gap | Between the guard and the tackle |
| C gap | Between the tackle and the tight end, or just outside the tackle when there’s no tight end |
| D gap | Outside the tight end |
Every side of the line has an A, B and C gap, so there are two A gaps, one on each side of the center. A side with a tight end also gets a D gap. Some programs number the holes instead of lettering the gaps. The idea is the same.
Why every defender owns a gap
A run defense works when every gap has a defender in it. If two players fill the same gap, another gap is empty, and that empty gap is exactly where a good running back is going.
That’s why coaches talk about “gap responsibility.” Before the snap, each defender should know which gap is his. After the snap, his job is to get there and hold it.
On offense it’s the mirror image. A run play is built to hit a specific gap, and the blockers’ job is to keep that space open long enough for the back to get through it.
Add a blocker, add a gap
When the offense puts a tight end on the line, the line gets wider and there’s one more gap to defend. Bring in a second tight end and there’s another. The defense now has to account for it, usually by moving a linebacker over or bringing a safety down closer to the line.
That’s why formation matters before the snap. The offense can create a gap the defense doesn’t have a player for, and the run goes there.
What to look for before the snap
- Find the tight end. The side he lines up on is the side with the extra gap.
- Count the box. Compare the defenders close to the line with the number of blockers the offense has. If the defense has more players in the box than the offense can block, someone is coming free on a run.
- Watch the linebackers. Where a linebacker lines up often tells you which gap he’s thinking about first.
- Look for late movement. A linebacker sliding over or a safety walking down late usually means the defense just noticed a gap it was short in.
How to teach gaps to young players
- Walk the line. Put five kids in a row as linemen. Call out “A,” “B,” “C,” and have another player step into that space.
- Ask it every rep. “Where’s your gap?” before every snap, until the answer is instant.
- Make them say it, not just do it. A kid who can name his gap out loud is a kid who will be in it when the ball moves.
FAQ
How many gaps are there in football?
With five offensive linemen and no tight end, there are six: an A, B and C gap on each side. Each tight end on the line adds a D gap on his side.
Which gap is the A gap?
The A gap is between the center and the guard, on either side. It’s the shortest path to the quarterback, which is why pressure through the A gap gets home so fast.
Who is responsible for each gap?
It depends on the defense’s call. The front and the coverage decide who fills which gap. What never changes is that every gap needs someone.
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