ST. PETERSBURG -- The planet's best athletes, not to mention its most famous aerobics instructor, have descended on the most beautiful city in Russia for a two-week festival of sports. Swimming pools, basketball courts and even the beach in front of the Peter and Paul fortress are primed for action in the Third Goodwill Games, which get underway on Saturday.


Who is faster, Leroy Burrell or Carl Lewis? Can American college hoop players perform even half as well as their Dream Team counterparts? How many records will Sergei Bubka set? How much zing does Jackie Joyner-Kersee have left? These questions and more will be answered over the next fortnight. The Games run through August 7.


The Games were founded in 1986 as a protest against tit-for-tat Olympic boycotts by the United States and the Soviet Union in 1980 and 1984, which kept those countries' athletes from competing against one another. And Russian-American competition remains the cornerstone of the Games: Without exception, each event will feature competition between an athlete of the U.S. and Russia, with the rest of the field drawn from the world's top athletes.


There are no qualifying heats in the Goodwill Games. Each competition is for the gold. The advantage of that format is that the stars compete head-to-head, instead of dropping in early rounds to unknowns as they often do in the Olympics. The past two Goodwill Games -- 1986 in Moscow, 1990 in Seattle -- saw athletes set a total of eight world records.


Basketball fans will see how a "pre-Dream Team" U.S. squad fares against a field of international giants, including the national teams of Russia, Croatia and Brazil. The U.S. team includes Corliss Williamson and Scotty Thurman of Arkansas, and Cherokee Parks of Duke. The medal games will take place Thursday, and will be the last time these teams can test themselves against each other before basketball's world championship in Toronto.


After the Goodwill Games, the U.S. team heads home to play an exhibition game on July 31 against Dream Team II, a collection of National Basketball Association stars. The professionals, not the collegiates, will represent the U.S. in Toronto.


Track and field events, meanwhile, will attract more than a half-dozen world-record holders, in what sports journalists expect to be that sport's event of the year.


In a field heavily dominated by U.S. sprinters, the grudge match of the Games could well be Monday's men's 100 meters, which pits Leroy Burrell against Carl Lewis, who Burrell has replaced as the world-record holder.


The women's 100 meters will feature Gwen Torrence of the U.S. and Russia's Irina Privalova in a battle for the title of the world's fastest sprinter. In the 110 meter hurdles, two of the world's greatest -- Colin Jackson and Tony Jarrett, both from Britain -- will face each other Thursday.


A host of major and minor events will surround the Games, ranging from fireworks and street fairs to an aerobics class led by Jane Fonda at the Lesgaft Academy of Physical Culture.


Tickets for the games can be bought at kiosks on St. Petersburg's streets, and should be available at venue box offices two days before any event.


Entire Goodwill Games tour packages can be bought from Moscow's Intercity Service (tel. 248-6163 or 248-5473, fax 248-2904).