Matt Biondi, winner of four gold medals in the University Games, will not be able to swim in his final race Friday night because of an infected boil on his leg, a spokesman for the U.S. team said today.

A fifth gold medal, swimming a leg in the 400-meter medley relay, would have tied a University Games swimming record.

Keith Brantley of Gainesville, Fla., gained the first gold medal in the men's track and field competition. Brantley ran the 10,000 meters in 29 minutes 11.24 seconds, to 29:11.71 for runner-up Jesus Herrera of Mexico. Soviet women won the day's other track and field events, Natalia Lysovskaya the shot put and Alexandra Grigorieva the 5,000-meter walk.

Bob Condron, press officer of the U.S. team, said Biondi's injury occurred Tuesday, before he won the 100-meter freestyle final. "He was shaving his leg and cut himself," Condron said. Swimmers routinely shave their legs to improve their speed.

After cutting himself, Biondi won two more gold medals before the injury became infected so badly Biondi was limping and finally restricted to his room.

In competition today, before attention turned to opening of the track and field portion of the Games, swimming world-record holders Michael Gross of West Germany and Igor Polyanski of the Soviet Union won events. A strong day in the pool gave the Soviets a 10-medal lead over the United States after the sixth day of the 12-day competition.

Stacy Shupe, 19, of Cerritos, Calif., won the women's 800-meter freestyle to earn her second gold medal, and Svetlana Kopchikova of the Soviet Union took the gold in the women's 200-meter individual medley.

Gross won the 200-meter butterfly in 1:57.88, or 0.84 off his world record.

Polyanski, who set a world record of 1:58.14 in the men's 200-meter backstroke in East Germany last March, broke the Games record of 56.64 to win the 100-meter backstroke in 56.26. The 18-year-old trailed Mark Rhodebaugh, 21, of Cincinnati before coming on in the final 50 meters. Rhodebaugh held on for second and Soviet Sergei Zaboltnov earned the bronze.

Kopchikova triggered a medal rush for the Soviets by winning the 200-meter medley in 2:18.11, breaking the Games record of 2:18.23.

Shupe took the lead at the 650-meter mark and coasted to victory in the 800-meter freestyle with a time of 8:45.87. She had earned her first gold medal Sunday in the 800-meter relay.

The United States team of Michelle Donahue, Kathryn Smith, Mary Meagher and Jenna Johnson won the women's 400-meter medley relay in a Games record 4:11.24.