Looking at Tom McMillen, shooting hook shot after hook shot at Fort Meade in a rumpled sweatsuit with "Washington Bullets" stenciled across the front, one wonders what the other candidates for Congress from Maryland's 4th District are doing for their daily exercise.

Surely their health and fitness club isn't as exclusive as the Washington branch of the National Basketball Association, a select group of 12, men only, please. Entering the final season of an 11-year career, McMillen must juggle basketballs and briefings as he runs for office in the November 1986 election.

"Unless you're independently wealthy and can afford not to work, everyone has to have a job. This just happens to be mine," said McMillen, 33. "People think of basketball as this all-consuming thing but it's not like you're running on a court for eight hours a day."

Actually, a sprained ankle has kept McMillen off the court for much of the Bullets' training camp so far. As a precautionary measure he also will miss tonight's exhibition game in Worcester, Mass., against the Boston Celtics, a fact that was bothering him more yesterday afternoon than the speech he was scheduled to give before the AFL-CIO last evening.

"I'm just trying to get all of the soreness out, doing things like contrasting baths of heat and cold," he said. "I guess I can get some work done, but I'd rather be making the trip and playing basketball."

According to McMillen, the keys to his dual life are scheduling and priorities, a fact that is reflected in his daily routine. Awake and on the road by 7:30 a.m., McMillen is in communication with his office by car telephone while en route to the first of the Bullets' two daily practices. There are more calls to make from 11 to 1, when most of the team eats lunch.

After the team's second workout, which usually lasts until 4, McMillen goes to his office and works into the early evening, leaving to give speeches or make other appearances. The end of the evening is devoted to reading a number of issue papers and then bed before it all begins the following day.

"This is the worst part of the season, time-wise and I'm still able to keep things going," McMillen said. "The only consequence so far has been that my free time is minimalized because every day there's something to do."

The regular season and its frequent road trips affords even more of an opportunity to get things accomplished, according to McMillen. "What do you do really?" he asks. "You get up and drive to the airport, and I can do work then. I take a briefcase on the airplane and get things done and when we get to the hotels I can write letters or make phone calls."

Of course, McMillen isn't the first athlete to make the foray into the political arena. Others include Sen. Bill Bradley (D-N.J.) and Rep. Jack Kemp (R-N.Y.), who ended their careers with the New York Knicks and Buffalo Bills, respectively. Like them, McMillen began laying the groundwork for his political future early. Although he only recently announced his candidacy, he had formed a staff and opened an office 10 months ago.

"Then we were preparing to run against Mrs. Holt (Marjorie Holt, a long-time incumbent who chose not to run for re-election). Now it's a different ballgame. It's not simpler. We'll have to work just as hard, but it's more wide open.

"No matter who I may face, I'll be running scared. There's a lot of things from sports that you bring into the legislative arena: like being prepared for any situation or knowing that if you go into a game feeling sure that you're gonna win, that's when you usually get beat."

In McMillen's case, the parallels are brought closer to home because he feels that "basketball brings me more energy to put into my other work and vice versa," a factor that came into play last season when he averaged nine points a game, including a 13-game stretch during which he established a season high in points six times. During the period ending Jan. 27, he was named the NBA player of week, averaging 22.4 points in four games.

That stretch made the decision to play another season easier.

"As a candidate, the visibility I get from playing basketball is just an offshoot compared to the enjoyment," he said. "Those are the key ingredients, that I still enjoy the game and can contribute to the team."