How the run and pass games in football are tied together by "flow" — Part 3

Flow is like the Force in “Star Wars” — a ubiquitous entity that can be credited or blamed for any event at a given time.

In Part 1 of this series, we discussed what flow meant in the context of the run game. Split flow (three threats strong, two weak) is often associated with concepts like zone blocking. Load flow (four strong, one weak) is usually tied together with man or gap runs, such as power.

This also informs how defenses fit the run in two-back sets, both in the box and on the perimeter with run support. Against split-flow runs, the defense aims to be evenly distributed because the No. 3 (running back) can set the strong side in either direction. 

Against load flow, the defense needs to have an extra run-fitter overlap and set a wall for the defense. This gives the defense an additional player at the point of attack, and the wall player is responsible for the running back cutting back to the weak side, which would then cause a split distribution.

In Part 2, we touched on the way the flow of a concept can influence the pass protection being used. A split-flow run needs a balanced pass protection (half-slide) on play action so that one or both backs can release into a route if needed without exposing holes in the protection to any blitzers or slanting linemen.

A load-flow run concept is tied to load flow protection concepts (full-slide, rollout and sprintout) in which linemen or the quarterback have to account for the weak side in the protection or the type of drop back used. The weak edge can be exposed in play-action concepts, so teams will use a “waggle” fake to get the quarterback on the move toward the passing concept.

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We’ve spent a good amount of time talking about the way flow influences the movements of players inside the box and up front, and that foundation will allow us to examine how zone coverage works in response to the flow of an offense. This will also give us a look at what it means when the offense gets into single back for the run and pass games.

Let's establish some relevant definitions for Part 3 of this series:

Glossary

• Distribution: The way coverage defenders (linebackers and defensive backs) relate to receiving threats as they move across the field.

• Pushing/Overlapping: In stopping the run and covering the pass, this is the process of moving players over one space in the distribution to handle what the offensive concept is.

• 4 to 1st Crosser: A coverage rule that lets a defender know he is responsible for the second threat on the weak side, whether it’s a running back flaring out or a drag route crossing the field. This rule is used against two-back offenses and trips formations.

• Wall of the Defense: When an offense threatens to overload the strong side, the defense needs a player in the middle of the flow who can overlap to the strong side AND fall back to the weak side, depending on the distribution. In coverage, this player must also carry routes up the field.

• Retracing: Against a trips formation or load flow, any crossing route coming back toward the weak side will pull the underneath coverage defenders back with it, landing them in their natural coverage positions. This allows a defense to keep good leverage (body positioning) on the routes being run.