There are NFL teams that use a zone blocking scheme on running plays, and then there is Denver.
No one has mastered the art of zone blocking like the Broncos, who have used the scheme to churn out 1,000-yard rushers the way Ford turns out automobiles.
In the scheme, the offensive linemen move laterally and are assigned an area rather than a specific man to block. The running back runs patiently behind the linemen and then explodes through the first open crease he finds. The blocking style includes the sometimes controversial cut blocks, which are designed to knock defenders off their feet and create running lanes for the backs.
Zone blocking also tries to influence defenders to overpursue to the play side, thus abandoning their assigned gaps. When that happens, it opens the door for big runs through the vacated spaces.
"It's not very complicated," Broncos coach Mike Shanahan said. "It's a philosophy that we believe in. We're going to stick with it. Even though sometimes it doesn't work, it's a belief and kind of something that the players will consistently work at. Hopefully if you don't get a big play early, somewhere in that third or fourth quarter it'll come."
"They basically try to stretch you out," said Bills center Trey Teague, who started 20 games at left tackle for the Broncos from 1998 to 2000. "One guy gets out of his gap and they cut downfield. Everybody thinks the backs are cutting back. You rarely see them cutting back. They're really cutting and going straight downfield. It just looks like a cutback because the line of scrimmage has moved."
Denver's zone blocking scheme was instituted by Shanahan and Alex Gibbs, who served as offensive line coach from 1995 through 2000 and later became a part-time consultant through 2003. Gibbs moved on to Atlanta last season, but Denver's running game hasn't missed a beat.
The Broncos head into Saturday's game against the Buffalo Bills ranked second in the NFL in rushing, averaging 157.6 yards per game. That includes 200-yard games against the Kansas City Chiefs (221 yards) and Philadelphia Eagles (255 yards).
Since Shanahan took over in 1995, no team in the league has run for more yards (24,532) or scored more points (4,367) than Denver.
The Broncos have produced nine 1,000-yard rushers in Shanahan's 11 years as head coach. He's had great backs such as Terrell Davis, who capped four straight 1,000-yard seasons with 2,008 yards in 1998, and Clinton Portis, the only runner in NFL history to gain more than 1,500 yards in each of his first two seasons. There also were lesser names such as Olandis Gary, Mike Anderson and Reuben Droughns who reached 1,000.
This season, Anderson (871 yards and nine touchdowns) and Tatum Bell (749 yards and five TDs, 5.9-yard average) have a shot to become only the fourth duo in NFL history to rush for 1,000 yards apiece. Kevin Mack (1,104) and Earnest Byner (1,002) of the Cleveland Browns were the last to do it, in 1985.
The Broncos also have added New York Giants castoff Ron Dayne (184 yards, 5.8 per carry) to the mix, giving them a triple-threat rushing attack.
The long-running joke is the Broncos' system is so good they can stick anyone in the backfield and he would gain 1,000 yards. Not everyone believes it's that simple.
"I don't think you can put anybody back there," Bills middle linebacker London Fletcher said. "Those guys running the football are talented. They do a good job of reading their linemen and understanding where the cuts are and where the holes are."
The key to the Broncos' success is the offensive line, which is annually one of the smallest in the league. Anchored by Pro Bowl center Tom Nalen, the line averages just 298.4 pounds. But the group is very mobile and athletic. Right tackle George Foster (338) is the only one who weighs more than 300 pounds, and he runs the 40-yard dash in 4.9 seconds.
"The overweight guys," Shanahan said, "just don't fit into our scheme."
The Broncos' linemen make up for a lack of overpowering strength by playing with excellent technique, timing and precision.
"The offensive line works so well as a unit," Fletcher said. "It's almost like synchronized swimming in that they're all on the same accord. They do an excellent job of being where they're supposed to be, and the running backs do an excellent job of finding those creases."
The Broncos also benefit from having little or no turnover on their offensive line. Besides Foster (a 2003 first-round draft pick), the rest of the starting five have been together at least five years. Nalen, a 12th-year pro, has started 164 consecutive games.
"That consistency and working with the same guys is a huge impact on any line," Teague said. "If you look at the league, the lines that are the best are the ones that have been together for some time."
The Bills, who rank 31st against the run, would appear to be overmatched against the Broncos' rushing attack. But the Bills say they are prepared to take on Denver's zone blocking and cut block tactics. (Cut blocking, which involves hitting below the knees, has been criticized for putting defensive players at risk for injury.)
The Bills have seen it already this season with Atlanta. Of course, the Bills didn't have much success stopping the Falcons, who rolled up 236 yards on the ground during a 24-16 win.
"As a defensive line, we have to stay on our feet," Bills defensive tackle Tim Anderson said. "If we get knocked to the ground on cut blocks or whatever, it's going to open up a lot of holes for their running backs. It's very crucial that we play our responsibilities, play the cut blocks, stay in our gaps and try to get as much penetration as we can."