Speed and athleticism are always immediately mentioned when talking about SEC defenses, but there’s a mental side that’s often overlooked.

For Alabama linebacker Nico Johnson, it’s the first thing he notices when he sees youngsters competing in practices. Their speed is always impressive, but the way younger players are dissecting and learning defenses these days has Johnson shocked. It also has defensive coordinators around the league giddy with the thought of not having to simplify things for youngsters.

“The more recruits that come in, year in and year out, it seems like they’re smarter and faster figures,” Johnson said. “It just keeps going and going.

Alabama linebacker Nico Johnson says today's young SEC players enter the league with an impressive grasp of defensive schemes. Marvin Gentry/US Presswire

“I don’t know how it’s happening, but it’s happening.”

That accelerated learning is one of the main reasons Johnson thinks the SEC has been so dominant defensively, and why the conference will continue to be for years to come. Since 2007, the SEC has had at least two teams ranked in the top 10 nationally in total defense, including having four ranked in the top five in 2011.

Johnson says the way players respond to coaching and changes in defensive schemes have been enhanced since he arrived in Tuscaloosa in 2009. The senior-to-be said it was amazing to see younger players, like linebackers C.J. Mosley and Trey DePriest, pick up things so quickly, and admitted they were much farther ahead during their first camps than he was.

And Johnson thinks that it’s going on all around the league.

As the SEC looks to earn its seventh straight national title, teams are looking to continue the tradition of having the staunchest defenses around. Like Johnson, Georgia coach Mark Richt believes that will start with the quicker breed of players who have entered the league.

Richt said he thinks the SEC’s defensive success should absolutely be attributed to the type of athletes who circulate throughout the league, but he also thinks the speed with which athletes adapt to the college level helps. He sees what he and his coaching staff are doing being duplicated at the high school level by coaching staffs, but he also sees younger athletes understanding the game more, especially in the Southeast.

Explaining schemes has almost become a thing of the past.

But it isn’t just preparation that will go into making sure SEC teams return to their defensive perches in 2012. Richt and Johnson agreed that it comes down to having the right mindset -- to be better than those before.

At Alabama, that won’t be easy. The Crimson Tide had one of the all-time best defenses in 2011, ranking first nationally in total defense, rushing defense, passing defense and scoring defense, and will lose a host of players who made all that possible.

Linebackers Courtney Upshaw and Dont'a Hightower are gone. So is defensive tackle Josh Chapman and defensive backs Mark Barron, Dre Kirkpatrick and DeQuan Menzie. It seems like Alabama will be in a rebuilding mode similar to 2010, but Johnson disagrees. With a handful of juniors and seniors returning, Johnson said Alabama’s defense will be far from inexperienced, and will feed off the talk of possibly resembling the 2010 squad.

“We want to make ourselves better than the defense last year,” Johnson said. “We want to create our own identity.

“We know what we’re capable of, and we know what can happen if we don’t do our job 24/7. We use that ... to keep us motivated to keep us going, because we don’t want that to happen anymore.”

But what about the other top defenses? Well, there isn’t much drop-off …

LSU returns nearly everyone who helped the Tigers rank second in total defense. What’s scary is that while Morris Claiborne is gone at cornerback, Tyrann Mathieu could be better this fall, and Tharold Simon could be just as deadly in coverage.

LSU must replace two linebackers, including leader Ryan Baker, but returns three starting defense linemen, including ends Barkevious Mingo and Sam Montgomery, who combined for 16 sacks in 2011.

Georgia loses star cornerback Brandon Boykin, but returns 10 starters, including top pass-rusher Jarvis Jones, from a defense that ranked fifth nationally last season. In order to keep its edge, Richt said his players must eliminate complacency and can’t think 2011’s success will propel them.

“We don’t want to rest on any accomplishments of the past,” Richt said. “I don’t think our coaches will allow that. I don’t think our leaders will allow that.”

South Carolina and Florida are in similar situations. The Gamecocks ranked third nationally in total defense, while Florida was eighth. South Carolina loses playmakers in defensive end Melvin Ingram, Spur Antonio Allen and cornerback Stephon Gilmore, but welcomes back six starters and a hefty line that features Jadeveon Clowney, Devin Taylor and Kelcy Quarles, or 22.5 tackles for loss and 14 sacks.

South Carolina also returns most of its front seven, including linebackers Shaq Wilson and Reginald Bowens, who combined for 96 tackles last season.

The Gators lose defensive tackle Jaye Howard, but should be equipped with all of their remaining defensive parts, including rising star Matt Elam at safety. Dominique Easley will be recovering from a serious knee injury he suffered at the end of the season, but the Gators added depth up front and moved Sharrif Floyd back inside.

The SEC’s top defenses from a season ago return enough talent in 2012 to keep their names near the top of the national rankings. The talent will always remain in the SEC, but the idea of maintaining the tradition of defensive dominance for players keeps teams at the top of the defensive charts, Johnson said.

“I don’t see how anybody in any other conference can compare to it, because of what we do year in and year out,” he said. “We take pride in it, and it makes me feel good that people do look at us like that. We want to go out and prove to every team that’s not in the SEC that it’s no fluke that we’re that good.”