As an ex-NFL fullback, Daryl Johnston appreciates the power-run philosophy the 49ers have implemented this season.

Johnston said it bears little resemblance to the vaunted ground game in which he played with Hall of Fame running back Emmitt Smith and the Cowboys in the 1990s.

Then again, some of what the 49ers have done this season doesn't look like, well, anything other NFL teams are doing.

A formation with six offensive linemen and two fullbacks? How about three tight ends bunched to one side? Or a formation with four tight ends, one being an offensive lineman moonlighting at another position?

"They'll throw some unique formations at you," said Johnston, a Fox television analyst who has been in the booth for the 49ers' past two wins, against the Buccaneers and the Lions. "In the Tampa game, they had the three tight ends out there to one side. It's just not traditional.

"It's not what we ran (in Dallas). You know, we had our offense, and here's what we're going to run, and whatever you do defensively, we're coming at you. This approach is more, we like to run the ball, but we're not going to beat our heads against a brick wall to do it."

In other words, the 49ers are taking a cerebral approach to playing smashmouth football, using motion and unique personnel groups to create mismatches, often by overloading one side of the line.

The recent results have been stunning. In their past three games, the Niners have collected 580 rushing yards - their highest three-game total since 2006 - while averaging 6.4 yards a carry. San Francisco has had back-to-back 200-yard rushing games for the first time since 1998.

Johnston said the 49ers' offensive staff has been adept at identifying a weakness in an opponent's run defense and then exploiting it.

"They decide where they feel good about running: 'Is our matchup between the tackles better? Is our matchup better on the outside to the perimeter?' " Johnston said. "And then they are really gearing that run scheme to not really account for what they do defensively, but to attack it and take advantage of it. It's pretty impressive."

Tight end Justin Peelle, a 10-year NFL veteran who played with three other teams before signing with San Francisco this season, said the Niners' power-running attack is unique.

On Tuesday, Peelle laughed as he recalled 330-pound nose guard Isaac Sopoaga, lined up at fullback, going in motion earlier this season. And right guard Adam Snyder lining up at fullback.

"Putting a defensive lineman in motion? That was a first for me," Peelle said. "Having our starting guard line up at fullback? That was a first for me, too. But it's just a way of finding different ways to run the plays that we're good at. The defense knows what's coming. It's not like we're going to release Snyder on a seam route."

At this point in the season, opponents know the 49ers want to run. How they establish their ground attack each week, however, remains a bit of a mystery.

"This approach is completely different," Johnston said. "You're going to see them do some similar things from week to week that you can watch on film. But there's going to be something that a defense does that they're going to take advantage of."