When Joe Gibbs sat down two years ago to design his one-back offense, he never imagined that one day it might serve as a possible Killer Bee repellent.

But if the Redskins are going to win Super Bowl XVII Sunday, Gibbs' creation will have to take the sting from an aggressive, swarming Miami defense that already has stopped two of the NFL's best offenses during the playoffs.

The one back was created particularly for the 3-4 defenses employed by such teams as the Dolphins. It was Gibbs' reaction to the league's move away from four-man fronts and toward more mobile, quicker outside linebackers who serve as bookends for a three-man line.

"I thought it was the way to go, to offset what defenses were trying to do against the standard two-back, two-wide-receiver, one-tight-end pro set," he said. "I can see moving away from one back in the future, as defenses change. You can't be wedded to one way of thinking for too long in this league."

Yet no team using a one-back set as its basic offense has played in a Super Bowl before. And only a handful of NFL teams use it at all, possibly because it looks so easy to defend. But try to find a Redskin who wants to run with the majority view.

"How can you not like an offense that has gotten us to the Super Bowl?" guard Mark May asked. "What are we, something like 19-4 since we switched to one back? I know when we first began using it, I wondered about it. It seemed to make our job in the line harder, because the defenses could key on the one back. But you noticed how everyone is stopping John (Riggins) right now?"

That's the irony of the Redskins' one-back attack. Gibbs was first moved to design it in part to take advantage of tight end Kellen Winslow's talents as a San Diego pass receiver. Maybe that's why Dallas' Tom Landry still says it is a pass-oriented offense. Yet the Redskins are one victory away from the NFL championship because of Riggins' ability to run effectively out of the set in the playoffs.

"When I came to Washington and said I like a balanced offense, that I don't mind running the ball, I know people laughed at me," Gibbs said. "But this offense can be adjusted to its personnel. Obviously, you go with what you think will benefit your team the most. But now we go into every game trying for balance until we see what is most effective."

With Gibbs as their offensive coordinator, the Chargers set league passing records in 1980, employing the one back more as the season progressed. With Gibbs as their head coach, the 1982 Redskins have refined their running concepts so well that Riggins has become the first back in the NFL to have three straight 100-yard plus playoff games during the same season.

"What we do with motion and formations makes this offense unique," quarterback Joe Theismann said. "Obviously, there is no mystery who is going to get the ball if we have a running play. But do they know what side we are going? Do they know who is going to block them? Do they know what kind of support from the secondary they are going to receive?"

Miami's Don Shula: "San Diego doesn't use the one back nearly as much as the Redskins. And what Gibbs is doing with it varies a lot from what he did at San Diego. Of course, he has Riggins, who is different from any running back he had there. And (Joe) Theismann is much more mobile than Dan Fouts, so they have him moving around more. They want to confuse you, have you make a mistake with a defensive audible and then they capitialize on it."

In the one-back offense, the running back occupies the fullback position, with the halfback becoming a second tight end who goes in motion almost every play. When that tight end becomes a receiver, he runs patterns designed for the halfback. With two wide receivers and two tight ends, Washington can get four receivers into the secondary very quickly, instead of asking one to come from five yards deep in the backfield.

"If you have Riggins and (Joe) Washington in the same backfield," said Joe Bugel, the offensive line coach, "one has to block for the other. We'd rather have a 250-pound tight end, who's already at the point of contact, blocking every play than a 180-pound halfback."

Gibbs: "We played nine 3-4 defenses this year, and I'm convinced that dominating outside linebackers are taking over the game. There is no way a 180-pound back can block Lawrence Taylor, for example. So I'd rather have two tight ends facing those outside linebackers, which makes Taylor have to work to get around a 250-pound player who is used to blocking all the time. That stops Taylor from dominating on the short side."

Bugel says it all makes sense. "Against the 3-4, running backs were getting their necks screwed into their bodies by the outside linebacker coming in from the weak side without anyone to block him. Now we have a tight end on both sides, so which is weak? And have you noticed how much Riggins cuts back and gains yards? That's because we now have a tight end on the weak side to seal off pursuit. Before, he would have cut back right into tacklers."

Joe Washington says the one-back offense "has the running back closer to the line of scrimmage so the linemen don't have to hold their blocks as long. In an I-formation, the halfback only can run pitchouts and sweeps, long developing plays like that. With the one back, you get a lineman to nudge his man out of the way, and you can get to the opening fast."

What about blitzing linebackers? Simple. Have the man in motion serve as a blocker in the backfield when he sees the blitz is coming. Need extra blocking up the middle? Just have that same man in motion cut upfield behind the center and go after the middle linebacker, as the Redskins did against Dallas last week, clearing space for Riggins.

"Just because we use the same one-back look every week doesn't mean we stay the same every week," May said. "Every week, Gibbs is changing things up. Defenses have to guess. Who's going in motion? If the tight end is in motion, is he going to block, is he a decoy, is he a receiver? You can't look just for Riggins."

Theories are fine, but players still have to execute. And this is what faces the Killer Bees Sunday: Riggins has gained 444 yards in three playoff games, Theismann has completed 69 percent of his passes, and the Redskins have committed just one playoff turnover. Riggins has fumbled just once this year on 275 carries and Theismann has thrown just one interception in 125 attempts.

"They are playing high-percentage ball control with the one-back," Shula said. "And at the end of their possessions, they are scoring. They just don't give the ball up."

And when they do, it usually is deep in their opponents' territory. Opponents have had 65 possessions in the last seven games; only three have started inside the 50.

"This is textbook offense right now," May said. "Everything is functioning on full cylinders just in time for the Super Bowl."