Alongside the Potomac River, muddy and smooth, K Street NW turns into Water Street, coming to a dead end once passing underneath Key Bridge. One block uphill is M Street and the rush of Georgetown. On Water Street, two men flick forward the tips of their fishing rods while eating from a cooler on a lonely river bank.

Near the end of Water Street sits the Potomac Boat Club, a three-floor house with dusty windows. Inside, paneled walls are covered with pictures of winning crews of past years, dating to the late 1800s. Shells are stored in the adjacent sheds. A rower meditates between the shells.

To its members, the club is a sanctuary from the turmoil of urban life. It also serves as a training facility for rowing, a sport that can be as competitive as the surrounding city.

One member, Bob Spousta, has his name atop of the club's sculling ladder that hangs in the shed. He created the ladder a couple of years back to spur intraclub rivalry. No one since has challenged him.

"I thought it would be good for myself and helping other people in the club to challenge themselves a little bit more," says Spousta, 36, who lives in Arlington. "Maybe trying to aspire to be at the top of the ladder would get you to come down here and row harder. It hasn't really materialized."

To challenge Spousta, however, would probably only result in defeat, albeit a good workout. He is a former Olympic trials finalist in the two-man scull and a recent champion of a masters single event in the Independence Day regatta in Philadelphia. Last October, he won the masters single in the prestigious Head of the Charles in Boston, a three-mile, twisting course. He set a record by 32 seconds and beat former national champion Gregg Stone.

Spousta is 6 feet, 200 pounds. The large muscles in his arms and legs are well-defined, his hair is cropped short. He appears to be in excellent shape. But when asked if he considers participating in the 1988 Summer Olympics, he says, "Oh, naw. Realistically? Naw. It would be fun to go, but I know what level I'm operating at. I know physically what I'm capable of."

A year ago this month, he was competing for the same Olympic team as Tiff Wood, Brad Lewis and John Biglow, scullers portrayed in David Halberstam's new book, "The Amateurs." Spousta, who had been to singles trials and made two national teams in a quad, entered a double. Two years before the Olympics, he says he got together with four guys and it clicked. Perhaps the same could happen in 1984 in a two-man scull.

Teaming with Erik Meyers, president of the club, Spousta nearly made the team. In the past, Meyers had doubled with other scullers. But he liked Spousta's determination.

They lost the first qualifying race, but won the repechage to reach the final heat. Even with the field over the first 500 meters, Spousta and Meyers thought they had a chance. At 1,000, however, they dropped off the pace. Paul Enquist and Lewis won the race, then the Olympic gold medal.

"I think we trained as hard as we could," says Spousta, a biology teacher and crew coach at T.C. Williams High School in Alexandria. "We both had families and worked. Our time in the first two races wasn't bad. But, gee, in the final, we really got smashed. I felt embarrassed."

Since the Olympics, Spousta has trained hard on the Potomac, always looking for someone with whom to do pieces (practice races): "Give somebody a little headstart and go after him." When pieces are done right, he says, "Your legs are screaming.

"In my mid-20s, I don't think I concentrated on my rowing enough. I used to run marathons, ride my bike everywhere. I have had more success when I've really concentrated on my rowing."

Asked to describe Spousta's dedication, Chip Lubsen, a club member and silver medalist in the eight in 1984, says, "I don't know. Compulsive?"

In the weight room, Spousta is equally resolute, having lifted for the last six years. There are weight and rowing machines in his basement. The curves of his biceps and calves are evidence of hard work.

If he does have a flaw, Spousta says, it's his technique. But Meyers says, "When we first started rowing, he was admittedly rough. You watch him row now, he's pretty smooth."

In the masters category, made up of older rowers, Spousta is making a name for himself. In the Independence Day regatta in Philadelphia, he faced a strong headwind and was in a small single. Nevertheless, he was surprised not to be pushed harder on the 1,000-meter course. He won easily in 3 minutes 55.3 seconds but says it could have been faster.

But Spousta's last regatta, at the Corning Crew Classic in Tioga, Pa., it was a different race, a different result. The water was terrible, the weather windy and the competition stiff. He lost, but was most upset about how he felt after the race. He was not exhausted -- a sin in rowing.

Spousta first rowed in 1969 as a junior at the University of Massachusetts. His roommate dragged him from the sport of wrestling and Spousta adapted well. As a child, he had ridden in boats, so he always liked the water. He also could get the same individual satisfaction as in wrestling.

Drafted in 1971, Spousta was stationed at Walter Reed Army Hospital and trained for the 1972 Olympics. He tried for the eight- and four-man crews, but discovered his relatively small size would limit him. So he bought his first single shell in 1973.

Now, he is preparing for three regattas this month. He is going to enter a single and quad in the FISA Veterans (Aug. 14-15) and World Masters Games (Aug. 16-18). He will add the double in the U.S. Rowing Association championships (Aug. 24-25).

In the boathouse, solitude is interrupted only by jets flying over from National Airport. Spousta looks upward, saying that if only the airport somehow could be removed, the atmosphere would be perfect. His voice softens, tranquil as the river itself that day. He appears to have lifted his mind from his body, to the water.

"It is a sport that has unique reward just in the feeling of it," he says. "The feeling of the rhythm, flow of the water . . . I didn't feel good this morning, but I came down to take a row and felt better. I'll probably go out and paddle this afternoon."