"Baywatch," that weekly salute to the dedicated men and women of lifeguarding - and to swimwear - remains the most popular American television show in the world. But sex is still not the universal language of television.

Action is.Paul Krumins, who surveys syndicated television shows for Copley Entertainment, analyzed the phenomenon: "Kicking butt," he said, "plays everywhere."

No genre has proved as enduringly popular around the world as the old-fashioned good guy vs. bad guy show - as long as somebody gets pounded into submission.

If you turn on a television set in France, Italy, Germany, Brazil, Israel or a number of other countries, the odds are excellent that you will run into an episode of "Highlander," "Hercules," "Xena," "Kung Fu" or any one of more than a dozen other hour-long action shows. They are aired on American television too, but abroad the shows that bash are a smash.

"Highlander," an epic in which a Scottish warrior, originally killed in battle in the 14th century but brought back to life to wage weekly sword battles as an "immortal," is in its fifth season and going strong in about 90 countries.

"Hercules" and "Xena," which chronicle the adventures of two mythic pre-Hellenic superheroes in high-camp style, accompanied by plenty of flying bodies, are newer, but they have grown into international hits, sold in 20 and 15 countries, respectively.

"The thing about all these shows is that locale doesn't really matter," Krumins said. "What you need is somebody beating up bad guys. That transcends translation. It can also help if a show has some sci-fi element, like `Highlander' does. That translates well too."

So hungry are international broadcasters for American-style action shows that they often put up a share of the production costs. Generally, Krumins said, one of these action hours costs about $1.2 million.

The American production company usually puts up one third, with one European broadcaster accounting for a second third and a South American, Asian or Australian company putting up the final $400,000.

"For the U.S. studio it's an excellent deal," Krumins said. "Even if the show bombs, the production cost is not drastic. If it hits, it's all upside."

In the case of "Highlander," it was a French television company, Gaumont, that initiated the series. A 1986 movie of the same name was not a big hit in the United States, but the rest of the world ate it up.

A production executive at Gaumont got the idea six years ago that the movie could be made into a series. After some dealmaking, an American-based company, Rysher Entertainment, took on the task of producing and syndicating the show. Gaumont remained a partner.

"Highlander," which is shot half the year in Vancouver and the other half in Paris, caught on all over the world. Ken Gord, one of the producers, said the show strives for international flavor. Its star, Adrian Paul, is British. Guest stars are from Canada, Italy, Austria and other countries.

The show also dips into world historical events. The Highlander has already turned up in the American Civil War and the French Revolution. An upcoming episode has him battling some immortals from the Bronze Age.

But the real international appeal lies in the combat. The immortals favor swordfighting - "It's an intimate form of fighting," Gord said - and just about every episode climaxes in a ritual decapitation. It seems that immortals can die only if beheaded. (The chopping takes place off screen.)

This year Rysher created a second action adventure show, "F/X," based on the film about a movie special-effects man caught up in crime-solving. The series costs more to produce than any other hour-long show on television, said its executive producer, Steve Downing. It is already sold in 98 countries.

Action shows turn up mainly on independent television stations which have hours to fill, usually on weekend nights. "Xena" and "Hercules" are simply rushing into the international void left when broadcast networks, worried about the federal mandate that limits the amount of violence they show, stopped making heavy action series.

Suddenly syndicators have an easy market. "These shows still have to be sensitive to whatever limitations on violence specific stations may have, but they surely can get away with more than a network show can," Krumins said. And they need not score superhero ratings in the American market to survive.

The highest-rated action series this season, "Hercules," has averaged only about a 6 rating (each rating point represents 931,000 households), which would target it for cancellation if it were a network prime-time show. But because of its international appeal, "Hercules" actually is considered a runaway success.

But Krumins offered a warning: "The market is getting glutted with these things." After all, he said, "France can only take so many action shows."