Rugby, that most English of English sports, seems to be taking root in American soil.

Rugby's popularity among adults--as participants and spectators--is increasing nationally as well as locally. In Northern Virginia four adult teams with about 200 players participate in the 28-team Potomac Rugby Union, which extends from Baltimore to Fredericksburg.

And area officials point to the growing number of high schools offering rugby. Starting with Langley High School in 1975, six Northern Virginia high schools with 300 players offer rugby as a club sport.

"High school rugby is very exciting today," said Art Steffen, a player on the Western Suburbs team who helped establish three of the high school teams. "A lot of high school rugby players give up football and other sports because rugby is a 'lifetime sport.' You know if you're a high school football player your career is going to be limited to college intramural sports if you don't get a scholarship. But if you played high school rugby, you've been indoctrinated into a sport where you can find teams to play on 10 to 20 years with maximum participation."

The four adult teams--George Mason University, NoVa, Winchester and Western Suburbs--gather on Saturdays to play the rough-and-tumble sport that is the forerunner of American football.

A rugby team has 15 players, each trying to advance a "bloated football" on a field about 100 yards long, without tossing the ball forward to a teammate. Ideally, a team's eight-member "pack"--the defense--will push the opposing team's pack away from the ball. Players can use their hands, shoulders, upper torsos and most other parts of the body to push other players away from the ball. This gives the seven backfield players an opportunity to pass laterally while running upfield toward the goal line. If the opponents fail to tackle the approaching "backs" and stop the movement of the ball, the team will score a "try"--rugby's equivalent of a touchdown. In rugby, a player can be tackled on most parts of the body except the neck or head.

Wearing traditional rugby shirts, shorts, knee socks and metal-cleated shoes, the players push and tackle each other without protective padding except for a plastic mouthguard.

The 80-minute games are fast and furious, punctuated with frequent stops to, among other things, assess penalties. Dropping or throwing the ball forward (called "knock-on") and "high tackling" are penalties. A key point in the game is a "scrum down," which happens when a penalty is called. At that point, the two packs line up and the ball is thrown between them. The packs then attempt to get the ball by pushing the other pack away.

But rugby is somewhat of a gentlemen's game. At traditional post-game parties, players who only moments before were throwing each other to the ground often share a beer or a joke.

And although many Americans think of rugby as a rough sport, much of that is myth, say rugby players. The typical rugby match does not have the bloodletting and fist-fighting of, say, an ice hockey match. And contrary to popular belief, rugby does have rules--one rule book is 70 pages long--which are enforced by a referee and two sideline judges. Although many rugby players--or "ruggers"--are husky, inordinate size and strength are not prerequisites, as in American football.

"Nobody is too small and no mind is too large to play rugby," joked Jeff Shumaker, a player for the Western Suburbs team. Shumaker, who is 5-feet-7 and weighs 138 pounds, has played rugby nearly nine years.

"Most of the people who play rugby are intelligent," added Steffen, 29, a 6-foot-2, 195-pound, 10-year rugby veteran. Among his fellow players on Western Suburbs' squad are computer analysts, teachers, government administrators, a painter, a writer and a nuclear engineer.

Adult club members pay dues that range from $40 to $50 a season. "If you play 10 games, that's only $4 a game and all the beer you care to drink. And you get to travel and do things you wouldn't normally do. You get a chance to meet people from a lot of walks of life. At $4 a game, that's quite a value," said Matt Godek, a player-turned-referee who owns a rugby and soccer supply store in Merrifield.

High school players also pay dues, which vary among the schools, because rugby is not an officially sanctioned varsity sport in local high schools. The clubs operate independently of the school systems, finding their own coaches, officials and fields.

The six Northern Virginia high school teams compete in a spring schedule against teams in Maryland and the District.

Bill Savage, curriculum specialist for athletics with the Fairfax County public school system, says rugby is not likely to become an official sport for some time.

"We don't have the resources, that's one reason," Savage said. "For another, we don't have the interest. In order to add a new sport, we must have over half the schools in the county interested in participation. We are at the point where we can't continue to add sports: When we add one, we'll have to look at deleting something."

But Steffen says rugby is an inexpensive sport: "You don't need hundreds of dollars worth of equipment to play. You get a $25 shirt, some shorts, a pair of cleats, a mouthpiece, a ball and 29 other players and you've got a rugby match.

"When resources for sports such as football become even more costly, schools will need to turn to inexpensive sports such as lacrosse, soccer and rugby. These are sports you can always do."