THE MAN emerged from the dark haze beneath Key Bridge shortly after 5.30 a.m. Dressed impeccably in a three-piece suit, he parked his 10-speed bicycle, unlocked the door to the crusty brick building and disappeared between the racks of slender vessels inside.

In 10 minutes, clad in shorts, tee-shirt and sneakers, the man slids his boat into the water and rowed through the mist, down the listless and silent Potomac.

Eric Meyers, 29, has started his day in this fashion for two years.

The workout lasts two hours, ending before the jets begin their thunderous morning descent on National Airport and the commuters clog the Whitehurst Freeway. By that time Meyers is back in business clothes, biking down-town to his job as a lawyer for the National Drug Abuse Council.

But during the predawn hours, and later when he returns to the Potomac Boat House after work, Meyers is enclosed in his own private world - the world of the one-man sculler.

"When you're out there on the water, you're not consciously thinking of anything," said Meyers. "You might have had the worst day in the world but somehow all the problems gradually disappear. It's an internal experience combined with total physical exertion. The two interact and leave you feeling cleansed."

Tom Adams, a 27-year-old crew instructor, also took up single-sculls two years ago because "the aesthetic appeal of the sport cannot be beat. You can look at the trees or the banks and watch the seasons change. It's timeless."

But Meyers and Adams are not solely attracted to single-sculling because of the mystical allure of the river. Both are highly motivated by the competitive aspect of the event and are serious contenders for the national team.

Meyers began rowing in a sweep-oar program, where teams of two, four or eight men work their own individual oar. In 1967, as a freshman at Georgetown University, he rowed on a "sweep-eight" team that dominated the small college circuit and captured the coveted Dad Vail Trophy.

While working for his law degree at Fordham University in New York, he still managed to gain extensive rowing experience with the Potomac Boat Club and the Vesper Club in Philadelphia. In 1971 he earned his degree; he also finished third in the Olympic trials in the "pair-with-coxswain" sweep-oar competition.

After returning to Washington in 1975, Meyers lost one partner to the U.S. Pan-American team and a second to the 1976 Olympic pair-with-coxswain team. It was then that he turned to single-sculling.

"There were different factors involved in my decision," he explained. "Rowing with a team can be an enormous production.With the single-scull you have flexibility. You just have two oars, your boat and yourself. you can just take off when you want."

That's just what Meyers did. Within three months he had won several regional competitions and qualified in time to make the Olympic sculling camp. Twelve scullers were trained and 10 were sent to Montreal. Meyers was number 11.

"But I haven't given up," added Meyers, who has since defeated several members of the 76 team. "The nice thing is that while I've been training and competiting, the sport has become an integral part of me.

"There is something very primitive about single-sculling. Even when the river is polluted and the highways are backed up with traffic, you're really aware of the breeze and being surrounded by water. you feel very close to nature.

But the isolated aspect of the sport does not evoke a sense of loneliness in Meyers.

"There is a big difference between being alone and being lonely. When I think of lonely, I think of some of the faces I've seen on crowded Manhattan subways. But being alone can be a great feeling. You're within yourself and you know just who's powering the boat through the water."

According to Adams, who rowed sweep-oar events for T.C. Williams High School and the University of Pennsylvania, many rowers would rather experience the unity of team sweep-oar or sculling events.

"I know that I got a great deal out of it, the friendships and feeling of group accomplishment," Adams said. "That's why the decision to switch to singles was such as big one. I was fortunate to get good coaching from the start and win my first big race - the Frostbite Regatta. That got me going. What keeps me going, I guess, is the special blend of the competitive and personal sides of this event."

Adams and Meyers are currently in training for a full schedule of national races with ambitions of qualifying for [WORDS - ILLEGIBLE] actually likens their events, an [WORD - ILLEGIBLE] out 7 1/2-minute sprint, to the 830-yard dash in track.

"There's no pacing. You go full throttle until your mind gets fuzzy. You try to keep a grip on your technique and you just keep going."keep going."

Not everyone has to experience that pain, something common to all competitive rowers.

Others might prefer a different experience that Adams had during his first week with single-sculling.

"It was mid-October and I hit the water around 5:30 a.m. Everything was pitch black except for the reflection of the moon on the water. The only sound was from my oars pushing through the river. I just glided along and cut the trail of moonlight in front of me."