AIR FORCE ACADEMY, Colo. (AP) _ Andrew Gearhart of Brockport, N.Y., placed first in the final round of the under-17 men's foil competition at the U.S. Junior Olympic fencing tournament.

Luka Popper, a U.S. citizen who lives in Munich, West Germany, placed second, and Marc Pavese of New York placed third in the foil competition Monday.

In the under-20 women's epee competition, Rachel Haugh of Portland, Ore., placed first; Janel Obenchain, Chicago, placed second, and Lisa Posthumus, San Diego, placed third.

The U.S. Fencing Association also announced two fencing teams that will represent the United States in upcoming international competitions.

Members of the men's foil team, which will compete in March at the Cadet Continental Championships at Mexico City, are: Gearhart; Dave Brown, Rochester, N.Y.; Pavese and Popper as first alternate.

Members of the women's epee team, to compete at the world championships next month in Athens, Greece, are: Haugh; Tracey Goodnight, Portland; Chanel Summers, Los Angeles; and Obenchain as first alternate.

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LOS ANGELES (AP) - Rosa Mota, 1988 Olympic gold medalist and two-time winner of both the Boston and Chicago marathons, has entered the March 5 Los Angeles Marathon.

Mota, a 30-year-old runner from Portugal, won the 1988 women's Olympic marathon in 2 hours, 25 minutes and 40 seconds.

At the Los Angeles Olympics four years earlier, she collected a bronze, finishing behind Joan Benoit Samuelson and Grete Waitz.

Mota has been the fastest woman in the Boston Marathon for each of the past two years. She had won the Chicago Marathon in 1983 and 1984.

The 5-foot-1, 99-pound Mota will be contending for the $300,000 Coast-to- Coast Challenge bonus offered to an athlete who wins both the marathon in Los Angeles and the Nov. 5 New York Marathon.

In the LA race, she'll also be shooting for a $250,000 bonus for a world record.

William Burke, president of the LA Marathon, said in a prepared statement Monday: ''We could not be more pleased. Rosa is excited about returning to Los Angeles for the first time since the 1984 games. Excellence is always her trademark and that means that spectators and our television audience can expect a great women's race.''

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BEREA, Ohio (AP) - Valerie Kepner, a Baldwin-Wallace junior, has ended her streak of successful consecutive free throws at 69, nine short of Calvin Murphy's world record of 78, as Baldwin-Wallace defeated Mount Union 70-58.

Kepner made her first but missed her second attempt Monday. She holds both the women's world and NCAA records for consecutive free throws, said Baldwin- Wallace spokesman Kevin Ruple.

Murphy set the world record for consecutive free throws in 1981 when he played for the Houston Rockets in the NBA, Ruple said.

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NAIROBI, Kenya (AP) - Italians won three of five matches played on the opening day of the $25,000 Kenya Open Tennis Tournament.

Ugo Biagianti defeated Kenya's Eno Polo 6-3, 6-3, Edoardo Mazza beat Glenny Schaap of Holland 6-4, 7-6 (7-3) and Fabio di Mauro downed fellow Italian Enricho Cochi 7-6 (7-5), 6-1.

In other matches Monday, Xavier Daufrene of Belgium, the sixth seed, was upset by Austria's Thomas Buchmayr, 6-4, 6-3, and Sacha Nensel of West Germany defeated Dennis Langasken of Belgium 6-2, 6-3.