CHICAGO -- The amazing thing about the Chicago Bears' NFL rushing lead is they've built it mostly against defenses that are waiting wherever they plan to run. For an offensive lineman, the only possible advantage can be that if he should happen to forget a play, he can always ask the opponent across from him.

"We don't fool many people when we go into a game," center Jay Hilgenberg said the other day as he prepared to face the Washington Redskins Sunday at RFK Stadium. "They know what we run out of certain formations. There's not much finesse about it. It's just power football."

It's no surprise that blockers perform heavy lifting. NFL teams do not stock offensive lines with men who could wear small cars on neck chains because the position is sedentary. Their job is what airports call people movers, only without the conveyor belts and instrumental music.

The Bears' linemen know where the people they must move are going to be. They are going to be in the way. It's much easier to move a defensive lineman if the blocker can cut him off before he gets in the way of the runner.

That is the problem. Defensive linemen don't use marked trails. Sometimes they charge straight ahead. Sometimes they run at angles, or slants. Sometimes they cross in front of each other, in stunts. They don't even line up in the same place every time.

"When they shift a defense," tackle Jim Covert said, "your assignment can change three times in the space of three seconds." So finding the defenders to block and actually blocking them are demanding both mentally and physically, sort of like trying to write a symphony during a workday at the loading dock.

"You have to concentrate and you have to communicate," Hilgenberg said. "When the defense is jumping in different sets, you have to be able to react together as a unit. You've got to play with your head up."

It helps that the Bears' offensive linemen have been playing as a unit since 1985. Hilgenberg, Covert and guard Mark Bortz -- the left side -- all have been to Pro Bowls. Tackle Keith Van Horne and guard Tom Thayer are having good seasons on the right side.

They've had to play well to keep the running game from slowing to a trot. Defenses don't just anticipate Bears running plays. They gang up against them. "Defenses pack up on us because they don't really respect our passing game at all," Hilgenberg said. They put eight men on the line of scrimmage, and even with a tight end and a blocking back, the offense has only seven blockers.

"You aren't going to make that big play as often," Hilgenberg said. "There are going to be a lot of plays where things don't work out as you'd like. You've just got to keep going hard."

Passing more would be an option, but Coach Mike Ditka calls the plays, and he takes pride in running well when running appears foolhardy. Occasionally he lets offensive coordinator Greg Landry call plays. "Greg's a little more at ease in passing situations," Ditka said, so Landry called them when the Bears needed a three-minute field goal drive to tie Detroit last week.

The Bears opened up their offense enough against Detroit for Jim Harbaugh to have career highs of 23 completions and 39 attempts. But those are pretty low highs, and the Bears still ran 34 times for 164 yards.

They're the only NFL team with more rushing yards than passing yards, 1,972 to 1,951. They've run 4.3 times more per game than the No. 2 Giants, and their average rushing game of 164.3 yards is 16.5 ahead of the second-place Eagles. In fact, when they slumped to 143.8 yards a game the last four weeks, against almost exclusively eight-man fronts, they still were running at a rate that would rank third in the league. While the league rushing average has gone down this season, the Bears are nine yards a game ahead of last year's leaders.

"You can still run the ball against eight people on the line," Van Horne said. "It narrows down your play selection, but there are things that do work."

Giving the ball to Neal Anderson is always a good bet. He's fifth in NFL rushing with 853 yards and second in scrimmage yards with 1,298. Primarily a blocker, fullback Brad Muster averages 5.1 yards a carry with 560 rushing yards.

The Bears are patient about staying with the run. The stunting, bunched-up defenses "get real frustrating," Van Horne said. "But you've got to understand that because of that style of defense, it's going to be like that. You've got to keep attacking them. Sooner or later, they'll stunt away from the play and you'll get a big one."

When they do work, Thayer said, "you get on a roll. It's actually sort of fun, banging away at them."

Even when the offense is rolling, though, it's exhausting work. For Hilgenberg, it's more mentally draining than physically tiring. "I never sleep very well after the games," he said. "I'm just wound up. I'm always thinking of things you wish would have gone a little better."