Niners' dominant O-line

The San Francisco 49ers' quick jump from irrelevance to repeat Super Bowl contenders under coach Jim Harbaugh has left fans of other mediocre teams wondering why their franchises can't make the same timely transition by simply making a coaching change. Well, part of the Niners' secret to success has been their incredibly productive offensive line, something most mediocre teams don't have.

"They've been the dominant line in the NFL for the past two years," ESPN analyst Damien Woody said. "They just seem to impose their will on people. They've got a lot of different runs and formations, but the thing that never changes is their physicality and smarts."

Staying healthy has been a key, too. All five starters have started every game this season, which means they can communicate at times with simple glance or nod, notes Jerry McDonald of the San Jose Mercury News.

"Sometimes we get up there and the line knows the offense so well we know when [Colin Kaepernick] is going to kill it and audible to something else," tackle Alex Boone said.

That sort of communication level could be critical in the noisy dome Sunday when they battle the Atlanta Falcons.