ARLINGTON, Texas – Iowa State’s football facility saw more than its usual trickle of traffic this offseason. Matt Campbell estimates 35-40 college and pro teams passed through Ames on a defensive pilgrimage of sorts. The Cyclones, entering Year 4 of Campbell’s regime, have become a unexpected testing ground of defensive innovation.

Faced with the task of stopping the Big 12’s daunting group of Air Raid behemoths, Campbell and his defensive coordinator, Jon Heacock, started to experiment early in the 2017 season. The result is, perhaps, the future of defensive football in an era where offenses dominate with speed and exploited matchups in space.

“The petri dish model has come from a conference where the offense challenges you every week and trying to find an answer when you don’t have maybe the exact same skillset of some of the elite teams in your conference,” Campbell told 247Sports. “I think that’s where, for us, we had to go to work and figure out how do we give ourselves a chance to be successful. We had to do that in a short period of time and then had the ability to take that model and really build off it and grow off it.

“The conference is what forced it to happen.”

Iowa State’s system is somewhat hard to define, and that’s by design. Schematically, the Cyclones ran a 4-3 or a 4-2-5 when Heacock arrived with Campbell in 2016. Following a ho-hum non-conference stretch the next year, the Cyclones all but threw out their defensive playbook. Heacock’s directive was to get his best players on the field. The result: A 3-3-5 that put three defensive linemen, three linebackers and five defensive backs in the lineup.

In this alignment Iowa State’s third safety served as a robber of sorts, a defender that could hunt in the middle of the field or act as a extra middle linebacker when called upon.

The transformation worked – quickly.

Texas sputtered to just 312 yards of offense when the Cyclones debuted the defense following its bye week. The rest of the Big 12’s struggled to catch up in the time since. Iowa State hasn’t exactly stymied the league’s Air Raid maestros, but it's held most of them well below their scoring averages.

Opponent 2017 vs. ISU 2017 PPG 2018 vs. ISU 2018 PPG Oklahoma 31 45.1 37 48.4 West Virginia 20 34.5 14 40.3 Texas Tech 13 34.3 31 37.3 Oklahoma State 49 45 42 38.4

The Cyclones’ defensive alterations so profoundly resonated throughout the league that Texas defensive lineman Malcolm Roach, a sophomore at the time, remembers his defensive coordinator, Todd Orlando, “adopting their style a bit” the next week. Orlando borrowed the concept of the middle safety to help create Texas’ lightning package.

Campbell said his defense is built with an offensive mindset. In other words, the Cyclones look to create matchups that put their defenders in the best position as opposed to reacting to what the offense does. This can be accomplished in several ways, but Iowa State’s efforts largely center around two positions – their third safety and SAM linebacker.

Labeled a STAR in Iowa State’s system, a position which will be manned in 2019 by preseason All-Big 12 selection Greg Eisworth, the extra safety can play everything from nickel to middle linebacker to robber. Eisworth is a defensive back with linebacker-like tendencies. The SAM linebacker is viewed in similar fashion. That defender must be athletic enough to occasionally cover in the slot while also retaining the physicality to spin down and provide Iowa State the option of a four-man front when called upon.

Given that pair’s flexibility, the Cyclones can realistically line up with anywhere from two to four linebackers on any given play. That allows Iowa State to constantly have eight capable defenders against the pass from down to down, as opposed to a four-man front that limits a team to at most seven.

The Cyclones are additionally advantaged since the offenses often won’t know which defender(s) will commit to attacking the run. Iowa State’s linemen are able to stunt, twist and loop on most plays because Heacock can send a number of different linebackers as the team’s fourth gap stuffer. It can cause havoc on an opponent’s blocking scheme, while allowing the Cyclones’ free linebackers to either plug gaps or flow over the top.

“It allows us to create matchups in our favor,” Campbell said.

Iowa State’s system is an odd combination of pressure and a bend-but-don’t-break attitude. The Cyclones finished 30th nationally in tackles for loss and 39th in sacks last season. Much of that production came from Iowa State’s linebackers, which are allowed to attack aggressively if sporadically – Heacock mixes who comes from down to down. Iowa State’s starting linebackers finished second, third and fifth on the team in tackles for loss. The SAM, which was Willie Harvey a season ago, also finished second on the team with 3.5 sacks.

It helps that the Cyclones excel at stopping the run. Iowa State finished ninth nationally in yards allowed per rush last season, thanks in large part to a dominant defensive line and a scheme that can flummox quarterbacks given that Iowa State can show five people in the box and realistically come with seven on any play.

That element of unexpectedness allows Iowa State to get away with a smaller third safety instead of an extra lineman. The additional athleticism on the back end, plus a pair of deep safeties, is a big reason why Iowa State finished 26th nationally allowing just 14 plays of 30-plus yards. Only one other Big 12 school (Kansas State, 41st) ranked within the top 65 in that category.

Baylor put up 505 yards of offense against Iowa State last year, outgaining the Cyclones by 150 yards. But the Bears sputtered in the red zone and left Ames staring at a 28-14 loss.

“I think Coach Heacock is one of the great defensive coordinators in college football,” Baylor head coach Matt Rhule told 247Sports. “That defense is designed in a way where they’re taking away the big run play as well. The robber safety is always showing as an extra defender. People are having a hard time trying to find a way to run. I think if people could run the ball against them they’d have a lot of success.

“Nobody’s found a way to do it.”

Iowa State hasn’t finished among the top half of the Big 12 recruiting rankings since Campbell arrived in Ames. Yet entering the 2019 season, the Cyclones led the Big 12 with four defensive preseason All-Big 12 selections.

One of those players, linebacker Marcel Spears, said a big part of the defense’s success is that the Cyclones “don’t have like a major player.” Everybody in Iowa State’s system must work in concert for the team’s offensive coordinator-stumping system to function. Spears has seen teams adopting some of what the Cyclones do defensively. He called it a “compliment.” But fellow preseason All-Big 12 teammate, JaQuan Bailey is quick to point out not everyone has a coach like Heacock: “That dude is like a genius.”

Campbell doesn’t mind sharing. Among Iowa State’s visitors this spring were Clemson defensive coordinator Brent Venables, fresh off a national championship. Yep, Iowa State is out front in the defensive world of college football.

Just don’t expect anyone to ever fully copy the Cyclones’ magic.

“We’re not a defense you can minor in,” Campbell said. “We’re a defense you have to major in with some of the adjustments and what we’ve got to do. It’s been flattering that we’ve got a lot of questions in it. But we’re unique.”