Rules changes, safety measures and spread offenses have forced coaches to overhaul their approach to one of the most elemental facets of football: tackling. But at the top programs in the nation, opinions differ on the best method.

Washington defensive coordinator Pete Kwiatkowski can rattle off the commands: Head across. Eyes through the near number.

The essential phrases for tackling that Kwiatkowski learned as a defensive lineman at Santa Barbara (Calif.) High and at Boise State in the 1980s share traits with the ideal takedown described six years ago by then Patriots linebacker Jerod Mayo, who played high school ball in Hampton, Va., and collegiately at Tennessee in the 2000s. “Eyes up, head across, bite the ball,” Mayo told SI. “Then bring your hips through and grab cloth in the back. That’s old-school, Pepper Johnson–style tackling.”

Mayo is recalling a technique that coaches like Kwiatkowski have spent the last decade trying to eliminate—not just because it puts the head and neck at risk, since they’re driven into the chest of a charging runner, but also because it left so much room for improvement. As the 1987 Big Sky Defensive Player of the Year, Kwiatkowski planted plenty of ballcarriers by planting his face into their near numbers; now he can’t believe he ever considered that the best approach. “It’s like wrestling,” he says. “If you’re going for a single-leg or a double-leg takedown, you don’t put your head on the guy’s thigh. You put your head to the side [of the leg] so you can get in deeper [with the shoulder].”

The game hasn’t given Kwiatkowski and his peers much choice but to evolve. Concerns over head injuries prompted the 2013 targeting rule that can get a tackler thrown out of a game for contacting a defenseless player above the shoulder or for leading with the crown of the helmet. Offensive schemes have also spread the field, which means missed tackles have a greater chance of turning into touchdowns.

But while the incentives for sound, effective tackling have never been greater, under a variety of recent safety rules players have less time than ever to practice in pads and master new techniques. That’s why Rocky Seto, a former USC and Seahawks assistant, wound up studying how rugby players tackle while working for Pete Carroll. It’s why Tennessee defensive coordinator Bob Shoop invented drills last season that would allow his banged-up defense to maintain some semblance of tackling fundamentals. It’s also why Baylor equipment director Jeff Barlow received new marching orders from first-year coach Matt Rhule: Go buy some robots.

Old-school tackling methods just as aiming the 'eyes through the near number' are falling out of fashion as injury awareness rises and targeting penalties become commonplace. Gregory Bull/AP

Defensive coaches are as passionate about their tackling methods as gumbo cooks are about their roux. And just as those chefs have definite ideas about the use of butter and flour, defensive coaches are adamant about the tackle’s key ingredients: where to make contact and how to bring down the ballcarrier.

All the coaches interviewed by SI agreed on one thing: Never lead with the head. Seto, who helped hone the rugby-style methods that have been adopted by several major college programs, believes that tackling changed for the worse in the late 1970s and early ’80s, after advances in design made helmets strong enough to protect the facial bones of headfirst hitters. While quizzing former players such as linebacker Dick Butkus, who retired in 1974, Seto found that self-preservation instincts had led players to go in with their shoulders before then. “As soon as the face masks improved, coaching techniques and principles changed,” Seto says. “Get your head across. See what you hit. Eyes to the ball. In essence, putting your head in the line of fire. That messed up the fundamentals of the game. The game was meant to be played with our shoulders and having good leverage. We got away from that for about 30 years. The game is correcting itself.”

Then, in the late 2000s, new medical data about the long-term dangers from head injuries encouraged coaches to further rethink their approaches. Now, nearly every one agrees that the tackler’s shoulder should hit the ballcarrier first—just as it did in the days before seemingly indestructable face masks. What coaches can’t agree upon is where that shoulder should land and what should happen next.

Alabama coach Nick Saban played defensive back at Kent State in the early 1970s, when tacklers mostly led with their shoulders. Saban has always taught defenders to track the near hip, plow a shoulder into the ballcarrier's near shoulder, wrap him up and drive him to the ground. This allows for a chest-high hit while keeping the head out of the tackle. The approach has proved remarkably effective. According to data tracked by Pro Football Focus, Bama has been the nation's second-most-efficient tackling team over the past three seasons, behind Air Force. The Crimson Tide had 1,845 tackles and 437 assists with only 273 missed tackles, well below the FBS average of 349.6 during that span. When Saban sees coaches teaching defenders to send their shoulders into the thigh, he wonders how a tackler can generate power while bending that low. “There’s no game that anybody plays bent at the waist on their toes,” Saban says.

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Seto would politely demur, citing what Seahawks coaches call the hawk tackle—in which the defender hits the ballcarrier’s thigh with a shoulder, grabs him and either spins him or powers him to the ground. Kwiatkowski teaches that series at Washington, and former Ohio State defensive coordinator Chris Ash talked Buckeyes coach Urban Meyer into adopting it before Ash left to take over at Rutgers. Seto had been trying to persuade the Seahawks to adopt shoulder tackling when a comment from a visitor from the University of Birmingham—not UAB, the one in the United Kingdom—earlier this decade led him to video clips of rugby tackles. Seto saw players hitting ballcarriers hard enough to knock the breath from them, but the tacklers weren't launching themselves or leading with their heads. They had efficient leverage and their heads to the side of the contact zone. This was a concept he could take to All-Pro DBs Kam Chancellor and Richard Sherman. “They have to really believe that this is going to help their career,” Seto says. “Not just to make them safe, but to make them more effective.”

The Seahawks bought his pitch and even released an instructional video on their rugby-style tackles before making a second straight run to the Super Bowl in 2014. The hawk drew the most media attention, but coaches also took notes on the profile tackle (a shoulder-to-chest tackle, which Saban would prefer) and the compression tackle (a two-on-one tackling method, usually with a combination of a hawk and a profile).

By that point Kwiatkowski had already made his own rugby connection. He worked at Boise State when the NCAA implemented its harsher punishment for targeting. Knowing he wanted to help his players to aim lower and keep their heads to the side of the ballcarrier to avoid ejections, he called on a college buddy who belonged to the Snake River Rugby Club. He helped Boise State coaches understand the leverage involved in rugby tackling and showed them drills. Kwiatkowski and the rest of Chris Petersen’s staff had moved to Washington by the time the Seahawks released their video, and they found themselves running on a parallel track with their local NFL team. “When we started doing this, we weren’t sold on the fact that getting the head behind versus in front was going to be a more efficient tackle. But now we know,” Kwiatkowski says. “When you shoulder punch and you get your foot in the ground and you tackle low, you’re way more efficient at getting guys on the ground.”

More college teams are teaching defenders to lead with the shoulder, as rugby players often do. Erick Rasco

No matter the technique, the challenge every FBS coach faces now is finding a way to teach it. In 2015, the Big 12 began limiting its teams to one full-contact practice a week during the season. Last year the Ivy League ceased full-contact practices altogether. This year the NCAA banned two-a-day practices. And sometimes coaches simply don't have enough healthy players to risk hitting much in practice. By mid-October, Tennessee’s Shoop had lost four starters for the season and had three others sitting with injuries. “Our Achilles heel was giving up a lot of big plays,” he says. “Some of them were because of missed tackles.” So Shoop had his players drill more on their footwork and positioning, which can help solve issues that lead to extra yards. Lunging to hit from too far away, for instance, can cause a missed tackle just as often as a poor wrap-up or minimal leg drive.

Programs across the nation are seeking better ways to practice tackling without contact. One way is to treat tackling as they treat blocking. For decades offensive line coaches have obsessed over step length, step angle, head placement and hand placement—and they’ve learned to teach them all without contact drills. A reach block has a very specific set of instructions. So does a down block. On the other hand, tackles were often improvisational reactions to the ballcarrier’s movement that drew from a few basic tenets. “I don’t care how he gets there,” says Rex Norris, mimicking coaches he heard through the years. “I just want him to make the tackle.” Then Norris pauses. “An offensive line coach would never say that [about a block].”

Norris was the coach at Kentwood (Wash.) High for 11 seasons before he left in 2015 to marry his first sporting love with his second. He had discovered rugby at Arizona State in the 1980s, and he had coached it at the youth level when he wasn’t coaching football. Norris now serves as head of football at the ATAVUS rugby and football academy in Seattle, and he consults with high school, college and pro teams about the science of tackling. Working with Kwiatkowski and schools including Michigan State and Rutgers, Norris studies tackling data and video and helps coaches design practice plans that focus on the facets that need sharpening.

Norris and Seto agree that coaches can drill players on the finer points of tackling with no pads involved at all. Simply working on tracking the ballcarrier’s near hip—as Alabama players do nearly every day—helps players be in far better position to make the tackle. Also, no contact is necessary to perform footwork drills that ensure the tackler’s near foot is staggered in front so he can adjust if the ballcarrier changes direction. Kwiatkowski has a rule at his practices that tacklers are not allowed to “tag off” ballcarriers in noncontact situations. The defender must work through every step of the process until the point at which he would make contact.

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Equipment innovations have also helped coaches drill technique without making players drill one another. Tackling dummies still exist, but new products are available at every price point. One of the simplest is the Tackle Wheel, a foam donut as tall as five feet that a coach can roll down the yardline. Hawk tacklers work on shoulder-to-thigh contact by hitting it, then practice spinning the donut to the ground as they would a ballcarrier.

The Shadowman, meanwhile, is a dummy with clearly marked strike zones for the chest and thighs. It sits inside a rubber ring that slides along the ground and has a harness attached. As a coach pulls the ring, the tackler must track the moving dummy, hit it with the proper shoulder and drive it in the right direction. A solid hit will pop the dummy off the ring and onto the ground. The Shadowman doesn’t offer the resistance of a real ballcarrier, but it does force the tackler—who can wear full pads or just a helmet—to approach correctly and hit the proper strike zone.

Schools with a heftier budget can afford more advanced options. When Rhule arrived at Baylor from Temple, he wanted to teach his defenders to blast ballcarriers in the chest. “If you want to cause turnovers and knock people backward,” he says, “hitting them low doesn’t really do that.” So Rhule asked his equipment director, Barlow, to find a device that would allow the Bears to simulate a game-speed tackle.

Barlow called Baylor’s sales rep at dummy and blocking sled-maker Rogers Athletic. The rep recommended the MVP-DRIVE—the MVP standing for Mobile Virtual Player—based on a device pioneered at Dartmouth, where coach Buddy Teevens banned live tackling in practice in 2010. He ultimately replaced human ballcarriers in some tackling drills with a self-righting, motorized dummy designed by students in the school's engineering program. Now Rogers has similar devices on the practice fields at Texas, Notre Dame and Georgia, and in NFL camps.

Baylor received its first MVP-DRIVE shortly before camp opened this month. The 190-pound dummy (retail price: $8,295) can cover 40 yards in seven seconds, and it can spin 360 degrees to evade a tackler—if the coach or manager handling the remote control has been practicing. “The players look at it like a pop-up dummy,” Barlow says. “All of a sudden they see it moving and their eyes get wide.” Bears coaches plan to use the battery-powered dummy as a kickoff returner, which would allow coverage team members a rare out-of-game opportunity to make a tackle on that play. The MVP-DRIVE can play other positions as well. “You can use it as a receiver, and a DB reacts off of it,” Barlow says. “It can break on a post. It can do a corner route. It can do a straight go route. That thing hauls butt.”

Whether a team uses a robot, a foam dummy or noncontact drills, the goal remains the same: Execute one of football’s two fundamentals. The team that figures out how to do that in the safest, most efficient manner could rule the sport.