How does Iowa's defense do it? Understanding college football's most consistent unit

IOWA CITY, Iowa — Four years of film study and fundamentals culminated in one legacy-defining moment for Iowa defensive end Ethan Hurkett last fall.

The Hawkeyes led rival Iowa State 20-13 with 1:23 to play. The Cyclones faced a fourth-and-1 at their own 40. Hurkett crouched outside the left tackle’s shoulder and noticed the Iowa State tight end’s motion across from him. He knew what was coming. At the snap, Hurkett crashed inside and tackled Cyclones running back Cartevious Norton for a 2-yard loss to preserve the win for Iowa.

Hurkett earned the glory, but the game-sealing moment was a portrait of Iowa’s defensive philosophy. Defensive tackles Logan Lee and Yahya Black took on double teams and held their ground, which left Norton without a lane. Defensive back Sebastian Castro shifted from slot coverage to containment with the tight end motion and followed Hurkett directly to the ball.

Every Iowa teaching point was on display in those few seconds. Pre-snap identification. Gap sound. Perfect technique. Violent hands. Disengagement from blockers. Leverage. Pursuit angles. Swarm to the football.

“That’s how we’re built,” assistant head coach Seth Wallace said. “It might seem simplistic, but the level of fundamental execution is on a different level, like it is on a completely different level. You can ask our opponents, and they would tell you that Iowa plays with unbelievable fundamentals and fundamental execution in what they’re asking their guys to do.”

That play in Ames provided another tile in Iowa’s timeless defensive mosaic. Created by former defensive coordinator Norm Parker in 1999 and passed down to his protege and successor, Phil Parker (no relation) in 2012, the same core concepts have fueled one of college football’s most consistently excellent defenses in the past two-plus decades. And since a minor scheme shift six years ago, Iowa has ranked among the nation’s elite.

Iowa also led the FBS in yards per play allowed (4.4) during those six seasons. That the Hawkeyes regularly perform so well opposite an offense that spent last year near the bottom of several national rankings might seem miraculous. To defensive coordinator Phil Parker, who won the Broyles Award last year as the nation’s top assistant coach, the yards are secondary to one other statistic.

“I think the biggest thing is about not letting people score,” he said.

Stable geniuses

If there’s a secret to Iowa’s defensive success, it starts with continuity. Parker has coached the secondary since head coach Kirk Ferentz hired him in 1999. Wallace, who also serves as assistant defensive coordinator and linebackers coach, was a graduate assistant under Norm Parker from 2006 to 2008 and rejoined the program as a full-time assistant in 2014. Defensive line coach Kelvin Bell played at Iowa beginning in 2000, returned in 2012 as a graduate assistant and joined the on-field staff in 2016. Assistant defensive line coach Jay Niemann arrived in 2019, and both of his sons were multi-year starting linebackers at Iowa. Analysts Tyler Parker (Phil’s son) and Shane Viilo have worked with the defense for at least 10 years.

Norm Parker’s initial design called for a four-down, split-safety base defense, and that hasn’t changed in 26 years. It’s set as an under front, which means the line shades its alignment to the wide side of the field. Iowa coaches ask their defensive linemen to largely occupy two gaps, taking a lateral first step at the snap to defend the run. Behind them, the Hawkeyes rarely stray from a two-high safety shell in zone coverage, which means they line up with seven defenders in the box.

Iowa rarely recruits four- and five-star performers, which shapes part of its defensive ideology and its detail-oriented approach. It wants its linemen to tie up as many blockers as possible with the fewest number of defenders to protect the secondary from surrendering explosive plays. That has become almost a mission statement for Phil Parker, and the numbers bear it out.

During an 11-year period, Iowa is 74-26 and allows 13.9 points per game when it gives up two or fewer plays of 25-plus yards. In the 41 games since 2013 when Iowa has allowed three or more explosive plays, its record is 22-19 with 23.9 points allowed. Last year, Iowa gave up just 15 plays of 25-plus yards all season, including only two on the ground.

That type of philosophy leads to shortcomings in other areas. Iowa willingly eschews tackles for loss to remain gap-sound against the run. Also, the defense can leave short openings in pass routes. But with proper pursuit angles and a premium on tackling, the Hawkeyes force opposing offenses to attack them with patience.

“The biggest indicator for us defensively has been the plays of 25 yards or greater,” Wallace said. “If you’re able to keep your safeties opposite each other in case the ball was to break the second level and get both safeties there to converge on the tackle, then all you’re doing is just living to play another down. I know that gets some bad pub sometimes that we’re bend-but-don’t-break, but there are times where we do have to make that decision.”

Unselfish play

Aaron Taylor won the Lombardi Award and twice earned consensus All-America honors while playing offensive line at Notre Dame. He serves as chairman of the Joe Moore Award voting committee, tasked with recognizing college football’s top offensive line.

But Taylor also appreciates what a defensive line can do, Iowa’s two-gap scheme in particular.

“It’s one of the most glorious displays and an homage to football fundamentals that I’ve ever seen,” said Taylor, a college football analyst with CBS Sports. “It’s almost like a love story to fundamentals. It’s this incredible, simplistic return to what the basis of the sport is. It’s a game of blocking and tackling, and the way they coach, the way they practice, the way they show up on Saturdays, it’s simplicity at its finest. It’s been deadly effective.”

Iowa’s system forces the defensive linemen to cancel the opening — or gap — on both sides of an offensive lineman. A defensive tackle, for instance, is responsible for a primary gap on one side of a guard and a secondary gap on the other side. For defensive linemen, tackles for loss are not the core objective; it’s about tying up blockers and creating disruption.

“In high school, nobody two gaps,” Bell said. “Usually you’re big enough, strong enough to dominate the guy that’s in front of you. But to understand that and play with technique and what we do up front, it allows for us to do some of the creative things that you see on the back end because we’re covering more than one gap.

“That takes an unselfish kid, that takes a disciplined kid, which is probably why you may see it take guys a little bit longer to reach the field than what you would see from other guys.”

From hand placement to pad level, Bell places a premium on details. He often begins meetings with a quip or a quote, but his blunt honesty about the style of play offers no surprises from the day players arrive on campus. As they grow, players appreciate the candor.

“With the way we play defense, this style we play, you’re going to be in a dogfight every game,” defensive end Deontae Craig said. “If you’ve got to suck up a double team so one of your guys can come free, that’s what you’ve got to do. We might not get the stat, we might not get the award or the recognition, but at the end of the day, people in this building know how hard we work up front.”

For opposing offenses, battling against a proficient two-gap front can be frustrating and exhausting.

“The whole defense is so smart,” Purdue center Gus Hartwig said. “They’re getting their hands on, they’re making contact. They’re not sitting there playing passively, and they’re aggressive, and they’re not ever out of their gap. They’re very consistent. They know what they’re doing, and they’re just overall very sound players.”

“It drives offensive coordinators mad because when you’re good at the fundamentals, you don’t have to find the weakness in the offense because they’ll give it to you,” Taylor said. “That’s been the approach of what Phil Parker has been able to do on that side of the ball. And, man, the season that they had last year is a testament to just how effective that can be because they did it by themselves largely.”

It might be thankless work, but the recognition comes later in a paycheck. Since 2011, NFL teams have drafted 12 Iowa defensive linemen, including five in the first three rounds. Seven Iowa defensive linemen are currently on NFL rosters.

During a season when its offense foundered, Iowa’s defense arguably played better than ever in 2023. (Nirmalendu Majumdar / Ames Tribune / USA Today)

The erasers

If selflessness is the primary tenet for Iowa’s defensive linemen, the key word for the linebackers is responsibility. To an Iowa linebacker, the line never makes a mistake. The linebackers are the erasers and are expected to make every situation right.

Nick Jackson discovered it takes time to learn Iowa’s defense well enough to take on that responsibility. After four years at Virginia, Jackson spent his first month at Iowa overthinking and getting subbed out on passing downs. Once he figured it out, Jackson played faster, eventually eclipsing 100 tackles for the fourth time in his career.

“I wasn’t used to having a seven-man front,” said Jackson, who is now 114 tackles shy of setting an FBS record. “I was used to like everybody had their gap, conceptually.

“Honestly, you take pride in it. It’s just one of those things that you want to hold that standard. You don’t want to have to bring somebody in the box, and you don’t want to have to play extra.”

Jackson’s development coincided with Jay Higgins’ rise from solid to spectacular. A reserve in his first three seasons, Higgins tied a school record last year with 171 tackles and became the Hawkeyes’ third middle linebacker since 2017 to earn first-team All-America honors.

“The middle linebacker at Iowa has to be unique in the way that you do things,” Wallace said. “You’ve got to be able to have a transparent way of communicating with everybody. You’ve got to have a unique leadership style where you’re dealing with different personalities, different positions and then you’ve just got to have a level of humility and an inner arrogance.”

Higgins carries himself differently than All-America predecessors Josey Jewell and Jack Campbell, who led by example. Based on statistics, Iowa linebackers usually receive more acclaim than their teammates up front. But in the Iowa defense, every position carries equal importance.

“As much as my mom thinks I just go run to the ball, there’s a lot more to the game,” Higgins said. “You can’t just run to the ball. You can’t just do what you want. You have a lot of people counting on you to do your job.”

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Geometry in motion

Questions to former players and even current assistants about Phil Parker’s fiery demeanor may provoke sarcastic comments or smiles, but no one dismisses his ability to mold a secondary.

During the past 15 seasons, Parker has coached 16 defensive backs to All-Big Ten status, more than any other program. Eleven of those were unanimous selections — three more than Ohio State produced. Of the 13 honorees for Big Ten defensive back of the year, six have been Hawkeyes. And none of those six held another power conference offer to play that position as a high school prospect.

“He’s the best secondary coach I’ve dealt with — bar none,” Ferentz said. “Now that he’s a coordinator, he’s fantastic, too. We’re lucky.”

Iowa’s defense is built from back to front, but that description doesn’t tell the whole story. One of the many Norm Parker quips that remains with the program is “Rob Peter to pay Paul.” The Hawkeyes do everything to protect their secondary from giving up explosive plays.

Iowa lines up almost exclusively with two deep safeties and plays quarters zone coverage, where each defensive back defends one-fourth of the field, on about 80 percent of its snaps. All eyes are on the quarterback and the ball. Phil Parker was a three-time first-team All-Big Ten safety at Michigan State, and his demands are non-negotiable. Those include smart, disciplined players competing with great effort and attitude. They must be tough mentally and physically, or they won’t play. No exceptions.

Phil Parker’s teaching points begin with specific yardages across the field: the distance from the sideline to the hash marks, then inside the hash marks. He drills into every defender to memorize the distance from the tops and bottoms of the painted numbers to the sideline (nine and seven yards, respectively).

“As soon as you get here, Coach Parker is teaching your dividers,” Iowa safety Xavier Nwankpa said. “Rules, like where the ball is placed on the field, how far you can get, how close to the line you should get, things like that.”

If a defender is even a step in the wrong place, they receive a tongue lashing.

“That’s the foundation of our defense,” said Riley Moss, the 2021 Big Ten defensive back of the year and now a starting cornerback with the Denver Broncos. “It starts with basic fundamentals, even like how wide the field is. Once you get that stuff down and what we need to look for, eventually he’ll put you on the field, once he’s confident that you can do your job.”

Earning Parker’s trust takes time, but he has started nine defensive backs as true freshmen. He’s also willing to evolve when necessary.

After years of playing as a 4-3, which meant the defense’s strongside linebacker covered the slot, Parker shifted to a 4-2-5 during the 2018 season. The move came after Wisconsin went to a three-receiver package late in their matchup and slot receiver A.J. Taylor burned linebacker Nick Niemann for the game-winning touchdown. Although Niemann ran a 4.51 40-yard dash time at his pro day years later, Wallace called it an “athletically unfair” matchup.

With most teams regularly employing three-receiver packages, Parker began to use his “Cash” defender as a slot corner/outside linebacker. The first three defenders to play “Cash” (Amani Hooker, Dane Belton, Cooper DeJean) became NFL Draft picks, while current starter Sebastian Castro might play the position better than anyone.

Before making the switch to a 4-2-5 in the middle of 2018, Iowa had two interceptions in its first four games. The Hawkeyes finished with 20 that season. From 2018 onward, they have 93 interceptions, six more than the second-closest FBS defense (Oregon) over that span.

“We are pretty good at self-scouting ourselves and having a little bit of humility and knowing where we need to get better and maybe do some things differently,” Wallace said.

In an expanded Big Ten without divisions, Iowa will face diverse offensive styles. Yet the staff believes its defense can adapt to any system it faces, from forcing pass-happy Maryland to throw six interceptions in 2021 to holding 2023 national champion Michigan to 213 total yards. That self-awareness is essential this year for Iowa’s potential as a College Football Playoff contender.

“We’re trying to figure out what we can do better, but we’re not going to reinvent the wheel here with our defense,” Wallace said. “And here’s why: because it has stood the test of time.”

(Top photo: Jeffrey Becker / USA Today)