A STOCKBROKER by trade and father of two young sons by avocation, Tony Salah has precious little time for recreation. But he's serious about fitness and likes to play as hard as he works. So each Sunday morning in the fall, he packs his gym bag and joins several thousand other area residents who devote intensely competitive hours each week to soccer.

"I may not run as much as some of the players, but the action is constant in soccer. It's impossible to be bored," says Salah, a former high school player who relishes his position as goalie, his team's last line of defense.

"Soccer is one game where the action really is non-stop. I work very hard all week, and playing competitive soccer helps keep my body as sharp as my mind."

Hailed 15 years ago as the sport of the future, soccer has so far failed to become a major commercial success as a spectator sport in this country. But there's no denying its popularity among young players. Anyone who's seen the thousands of kids clad in matching shirts and shorts and chasing a checkered ball on fields across the country can testify to that.

Soccer, which has 11 players to a side, including a goalkeeper (the only player allowed to touch the ball with his hands), is amazingly simple to learn and maddeningly difficult to master. Still, the most difficult part for most new players is the non-stop running required in the two 45- minute halves. Scoring is accomplished by kicking or heading the ball into the opponent's goal in this usually low-scoring game.

Youth soccer has been around long enough now that the pioneer American soccer players have grown up and the soccer boom has reached the adult recreational ranks.

"We've been at a 'no growth' stage for the past several years," says Montgomery County adult soccer coordinator Jim Wilshire, citing the effects of a funding cap. But "if we were allowed, we probably could double our program within a year."

Like many other local jurisdictions, Montgomery offers men's, women's and co-rec (co-ed) soccer, but demand far surpasses the limited supply of teams and fields. And a lot of that demand is coming from women.

In such sports as softball and football, strength requirements can relegate women to second-class status in co-rec games. But soccer relies on speed, stamina and proper positioning, regardless of sex.

John McLaughlin, Arlington County women's soccer coordinator, describes the new female soccer player this way: "These aren't just football widows anymore who're looking for something to do while their husbands sit glued to the football games each weekend. Now we're seeing more Yuppies who play because they're serious about fitness and have enjoyed soccer as youngsters and still like to play the sport."

Luanne Bloom, a congressional aide who plays halfback for the Fairfax Astros, a women's team, falls into that category.

"I'm very serious about fitness, so soccer fits my needs perfectly," Bloom says. "I could run five miles a day by myself, but by playing soccer for 11/2 hours I cover the same ground and get the enjoyment associated with playing a team sport. Some games like softball are just social, but soccer offers a real opportunity to keep fit."

No matter the level of a player's skills, somewhere there's a team for them. In most every jurisdiction, leagues are separated into expert, recreational and masters (over-30 or 35) categories.

And then there is the league that most soccer experts consider the finest amateur outlet in the area -- the District's National Soccer League, founded in 1926. Its champion last year, the Espana Soccer Club, won the U.S. Soccer Federation Tournament in July, making it the top amateur soccer club in the country.

The league fields teams composed mostly of foreign nationals, international students and recent immigrants, according to league president Luis Del Agula.

"This is one of the best leagues in the country," says Del Agula, whose league plays year round (indoors in winter). "We only have a few American players and only a handful from the embassies."

And these guys aren't in it just for the exercise of kicking a ball around. "This is a league for serious players only," says Del Agula. "To our players, only the competition offered by soccer is important. They enjoy playing, but they enjoy winning more." REAL FOOTBALL

Whether you're a budding Pele destined for World Cup play or simply a weekend warrior, there's plenty of recreational soccer available in the Washington area. Here's a sampler of adult leagues. D.C.

NATIONAL SOCCER LEAGUE -- The 14- team National Soccer League begins its season on September 15 at fields throughout the District. All games are played on Sunday. This is a very competitive, expert league, warns league president Luis Del Agula. Players may call 362-4873 to request a tryout for an established team.

WASHINGTON AREA WOMEN'S SOCCER LEAGUE -- plays games on Saturday afternoons on fields throughout the District and Northern Virginia. League play begins this Saturday. Team registration is closed, but individuals still may join existing teams. The cost is approximately $20 per person. Call 978-0848 or 532-0278. MARYLAND

ANNE ARUNDEL COUNTY

CO-REC LEAGUE -- Up to 20 teams can be accommodated in this male-dominated (95 percent of the players are men) co-rec league. Games begin Sunday. The season lasts 10 games, and there is a postseason tournament. The A and B leagues play Sunday mornings and afternoons, but the masters (over-30) league plays on Thursday nights. Call 621- 9552 if interested in joining an established team.

MONTGOMERY COUNTY

MEN'S LEAGUE -- Team registration is closed for 24 open and 18 masters (35-and- over) men's soccer teams. Games begin Sunday, but individuals may call 468-4176 if they wish to join an existing team.

CO-REC & WOMEN'S LEAGUES -- Team registration closes Friday for women's and co- rec (co-ed) leagues. The franchise fee for women's teams is $290; co-rec teams cost $320. There's room for 20 women's teams in open and masters (30-and-over) categories. Forty teams will comprise the co-rec league. Women play eight games, and co-rec teams play nine games. Individuals wishing to join a team should call 468-4176.

PRINCE GEORGE'S COUNTY

MNCPPC LEAGUE -- The Maryland National Capital Park and Planning Commission will run six-team men's, women's and co-rec leagues on Sundays at Mount Rainier Recreation Center. Team franchise fees cost $300 and registration closes September 21. League play begins on Oct. 6. For further information about joining an exisiting team or starting your own, call 699-2401. VIRGINIA

ALEXANDRIA

Team registration closes September 16 for men's, women's and co-ed soccer leagues. Games are played on weeknights throughout Alexandria. Call 838-4345 for further information about registration costs or joining an exisiting team.

ARLINGTON COUNTY

WOMEN'S LEAGUE -- A 24-team women's league begins play on September 8. Games are played on Sundays at Thomas Jefferson and Kenmore Intermediate schools in Arlington and George Mason High School in Falls Church. The fall season is 10 games. Team registration is closed, but individuals still can join an established team. Call 532- 2088 for information.

FAIRFAX COUNTY

MEN'S LEAGUE -- The Northern Virginia Soccer League is a 40- league which plays its games on Sundays at locations throughout Fairfax County. League play begins Sunday for the 11-game regular season. Team registration is closed, but players interested in joining an established team may call 528-1443 or 560-9098.

WOMEN'S LEAGUE -- The Fairfax Women's Soccer Association has already ended team registration for its 36-team league. Games begin this Saturday at various locations throughout Fairfax County. The FWSA offers masters (over 30), recreational (Class A through C) and and an expert class that involves local and regional travel. The cost for individual players is $23 for the 10-game fall season. There is also an all-star game after the season. Call 573-7958 for information.