One of my personal goals this year has been to really pull apart the nuts and bolts of my life, look at how things function, and figure out the best way to do things for myself. When you look at how parts of your life either help or hinder productivity for yourself, you figure out how to improve your personal happiness and efficiency.

This is the same reason we pull apart data on player and team performances here at numberFire: we want to get right into the middle of the action and figure out what makes a team tick on the football field. To that end, this offseason, I've specifically conducted a few studies exploring the effectiveness of offensive schemes, from the differences between a vertical and precision passing attack, to the usefulness of a fullback in a rushing offense.

The study today will complete the two halves of an offensive game plan by examining the effectiveness of man blocking/power rushing schemes versus zone blocking/stretch rushing systems. Will the traditional smash-mouth run game provide greater value, or does a finesse approach lend itself to more backfield success?

Backfield Building Blocks

To evaluate these running schemes, I've researched each NFL team's offensive tendencies over the past decade, putting offensive coordinators' blocking and running schemes into two categories: man-power and zone-stretch. I then averaged each scheme's production by our signature numberFire metric, Net Expected Points (NEP), and compared the historical results.

We'll also need a little bit of context about rushing styles to properly analyze this. The first, and perhaps older, style of rushing attack is the man-power. This features a man blocking scheme, where linemen and blockers each have an assigned defender to block. There is a greater specificity needed in this blocking scheme, but if it works properly, it can cause mismatches and dictate the defense's response to the run. The power rushing scheme that goes along with this style of blocking features a lot of between-the-tackles runs and a downhill, straight-ahead mentality. The man-power scheme is often used by teams to stretch a defense vertically, and set up deeper downfield passing attacks. An example of teams who run the man-power scheme include the Arizona Cardinals and Minnesota Vikings.

The zone-stretch is a newer and more complex scheme than its counterpart. This features a zone-blocking system, which requires its linemen to guard zones of the line, rather than have specific man assignments. This allows the linemen to pick up surprises in blitz packages far easier, but the line has to be cerebral and athletic. The zone lends itself very well to a stretch-running game, which does exactly what you'd guess: it stretches the field. Unlike the power run scheme, which aims straight ahead and helps stretch the field vertically, the zone-stretch looks to pull a defense to each sideline so that an athletic and quick running back can take advantage of angles and holes. This lends itself well as a counterpart to a precision passing offense, which works short and wide as well, much like Chip Kelly and the Philadelphia "Blur" offense

From Plan to Practice

Now that we have an idea of what these run games look like on the field, how do they translate to NEP production? The table below shows the averages of each scheme's production since 2004 in NEP categories, adjusted for the strength of the opponents faced.

We see that teams with zone-stretch rushing attacks tend to be a little heavier on the pass in terms of play-calling. This suggests that these teams actually use the run to set up the pass somewhat, relegating the running back to a slightly diminished role in the offense. This seems to run counter to the common perception that, for instance, Chip Kelly's offense gives running backs a massive amount of carries; it's less about the emphasis of play-calling and more about the speed of those teams' offenses. Teams running man-power schemes, however, are more balanced in their play selection, which indicates a desire to keep defenses off balance and spread them out between short and long coverage.

Also of note is that the average zone-stretch team is a much more effective running team, with a fairly impressive -0.12 Rushing NEP (rushing plays are typically less efficient than pass plays, so they have a lower NEP score), in comparison to the man-power's -9.01. This may be due to the versatility of blocking assignments found in the zone blocking scheme, as opposed to the somewhat hit-or-miss approach of one-on-one blocking in the man scheme. Though the zone blocking scheme has been criticized heavily by some old school coaches, it appears to allow for greater consistency in the running attack. This is further supported by the zone-stretch's superior per play Rushing NEP. These teams didn't just rack up more value with more rushing plays; they actually were much more efficient.

On a small side note, it’s interesting to see the difference in Passing NEP production for teams that use these two run schemes. The teams running man-power tended to have much higher Passing NEP production than those running zone-stretch. This is likely a confirmation that man-power tends to be a compliment to a vertical passing offense (which racks up big-play yardage, and therefore NEP, like crazy). The zone-stretch’s companion, however, will have a lower Passing NEP because the precision passing offense doesn’t pick up as many big chunks of NEP at a time.

Flexibility is Key

In almost every single way, it seems that the zone-stretch scheme is superior to the man-power when it comes to rushing effectiveness and efficiency. Teams using this rushing offense produce NEP more effectively – likely due to the versatility of the blocking assignments (allowing linemen to assess threats on the fly and adjust) – and the zone-stretch’s per play efficiency is also greater than the man-power, proving that this is not just a volume advantage for accumulating NEP. In fact, 13 of the top 15 Rushing NEP seasons since 2004 have come from zone-stretch run schemes. The only area in which the man-power scheme trumps zone-stretch for running back value is that the former will have a greater propensity for running the ball in play selection ratios.

Some teams have the personnel to run a man-power scheme very effectively, such as Bill Musgrave’s 2013 Minnesota Vikings: with a top five road-grading offensive line and a fantastic running back in Adrian Peterson, the historical limitations of the scheme didn’t hinder them. However, if you are a coordinator looking to spice up your team’s rushing, or a fantasy owner looking for both value and opportunity from your running backs, bet on the zone-stretch teams. Their complexity is all worthwhile when you see the results.