John Sanders looks like he's been kicked in the head by a horse.

That's because he has been kicked in the head by a horse. But a black eye and hugely swollen cheek are not enough to keep the 50-year-old doctor from galloping 30 mph down an arena nine times as big as a football field, trying to hit a tennis-size ball with a wooden mallet while seven other riders are trying to do the same thing.

Polo. The word conjures up images of an "athletic, rich, Old World style," says an executive of Ralph Lauren's successful fashion company, Polo. But while polo players concede to being an altogether gutsy, dashing and exceptional group of people, they argue that the sport today is played by workingmen, not the idle rich.

"You can tell just by looking at us that this isn't the jet set," says Jack Wittemore, a stockbroker, of his fellows, who include a lawyer, a dentist and a real-estate developer.

There are about 500 polo players in the area, and the country is enjoying something of a revival of interest in the sport. Besides the free Sunday-afternoon polo on the Mall near the Tidal Basin, where Sanders, Wittemore and cohorts play, there are five nearby clubs that charge only modest fees for an afternoon of watching.

Polo began in Persia in the first century A.D., as training for mounted soldiers, and became a sport of the nobility. The British came across it in India in the 19th century, and since then wherever the British have gone, polo has been as standard as tea and stiff upper lips. Today, Argentina boasts the world's top players, followed by the U.S. and Britain.

Similar in broad outline to hockey, though lacking a goalie, polo is played by two teams of four players each. A match consists of four to six 7 1/2-minute periods called chukkers, with a score made by hitting the ball through the goal at the end of the field. A horse plays a maximum of two chukkers, so players must bring several horses to each match. Even without understanding the subtleties of the game, it's a beautiful spectacle; and when the game is at top speed, its beauty is enhanced by its danger.

Many of the area's polo-playing "working stiffs" say they've found a level of intensity in polo that isn't present in other sports.

Sanders, who took up the sport 15 years ago, when he finished his medical training, says he spends $4,000 a year on the game -- "less than I spend on malpractice insurance and less than some people spend on gold." That figure is usually cited as the minimum; of course, depending on how many horses you have, how good they are and how much traveling you do, expenses can get into the five- and even six-figure range -- over a long term: It takes a year and a half to train a polo pony, and in spite of a player's prowess, it's conceded that the game is "75 percent horseflesh."

Lawyer Joseph Muldoon, 48, head of the Potomac Polo Club, started playing nine years ago, and has become such a fan that after he broke his cheek in a match, he was playing ten days later, "with wire and Teflon in my eye socket." Several players have tales of finding themselves under their horses, counting the various crushed parts of their bodies.

Retired Colonel William West, who rode with the Army's last calvary squadron in 1945, now referees the Sunday-afternoon games at the Mall. He knows why the players keep coming back for more:

"It leaves a euphoria no other game I ever heard of does. There's something about tooting down a field on a good pony -- the rapport between the pony and player. There just isn't anything else like it."

Ami Shinitzky, 37, a native of Israel, was a professor of philosophy in New York before he started playing polo seven years ago. He found the game "such a terrific release for frustration" that he gave up philosophy and moved to Maryland to devote himself to horses. He now publishes the official magazine of the United States Polo Association and several equestrian newsletters. The game "still has an image of being rich and aristocratic that keeps people away," he says, "but it's quite democratic in this country. Which is not to say wealth isn't present."

The biggest news in Washington polo this year is the appointment of Christian Zimmerman as executive director of the Inter-American Development Bank. Zimmerman, former chairman of the Argentina Polo Association, has promised to bring some of his countrymen to the area to demonstrate how the game is really played. As for polo's dangers, "I've broken my shoulder, leg and arm at least five or six times. Nothing serious," he says.