Duo Blocking

Duo is a downhill run scheme that pairs adjacent linemen into two vertical combo blocks (an Ace block and a Deuce block) without pulling anyone across the formation. Unlike Inside Zone, which steps laterally to stretch the front and open backside cutback lanes, Duo attacks straight ahead. Each combination uses a post man to set a vertical anchor under the defensive tackle's chin and a drive man to generate hip-to-hip vertical displacement before climbing to the second level with four hands, four eyes discipline.

The running back's read keys the frontside inside linebacker (Mike) rather than a down lineman:

Bang (Inside)

If the Mike steps outside, scrapes toward the perimeter, or gets washed into the offensive line's double-team, the back hammers the ball straight downhill through the playside A-gap or B-gap.

Bounce (Outside)

If the Mike triggers downhill to plug the interior gap, the Deuce combination seals him inside and the back bounces off the tackle's outside hip into the off-tackle C-gap or D-gap alley created by the tight end's kickout block.

How Duo compares to its two closest relatives:

Duo vs. Inside Zone

On Inside Zone, linemen step toward the call side and work to overtake defenders horizontally, while the back reads the first down lineman past the center to bang, bounce, or bend back across the grain. On Duo, linemen step vertically to drive the down linemen backward rather than laterally, eliminating the backside bend and isolating the decision on the Mike linebacker.

Duo vs. Power

Both schemes build a vertical double-team at the point of attack and kick out the playside edge defender. Traditional Power pulls the backside guard to lead through the hole on the Mike while the inline tight end kicks out the end (or vice versa); Duo keeps all five linemen home, securing two full interior double-teams and making the running back's eyes replace the pulling guard by making the Mike wrong.

Personnel adaptations across formations:

11 and 12 Personnel

With an inline tight end creating a 6- or 7-man surface, the tight end turns out the playside edge defender (or combines with a second tight end/wing on a Tre double-team), giving the running back a true outside bounce lane.

10 Personnel (Spread)

With a 5-man surface and no tight end, offenses either lock the tackles on the defensive ends and work one interior combination, or attach a perimeter RPO (such as a glance or bubble) to hold the unblocked edge defender.

Playbook Examples

• Duodownhill run behind two vertical interior double-teams with the running back reading the Mike linebackerLincoln Riley