An Olympic-class East German track athlete who dected to the West last year claims that she was forced into taking performance-boosting drugs by her former trainer in East Berlin.

The statement by 20-year-old Renate Neufeld -- a sprinter who had been, until late last year, in training with the East German team being assembled for the 1980 Olympics -- marks the first time that a major East German athlete has spoken out on the alleged use of hormone drugs to win medals for her country.

East German athletes, especially women, have achieved extraordinary successes in the last few Olympic games, outperforming athletes from much larger countries -- including the United States in the 1976 Games. This has touched off continuing allegations in the West of widespread illegal use of drugs by East German athletes; claims that repeatedly are denied by East German authorities.

Neufeld, in an interview with the West German sports news service published here today, said her trainer for the TSC sports club in East Berlin first ordered her to begin taking hormone tablets when she was 18, as preparations began for the 1977 summer season. She said she refused at first but later agreed under threat of various reprisals.

The sprinter -- a short-distance speccialist who had helped her club win the East German National Junior 400 meter relay title in 1976 -- said she was given two different tablets two or three times a day for two-week periods a cycle which was repeated after 10-day breaks.

An expert who analyzed tablets she brought with her to the West identified them as anabolic steroids, drugs that add body weight.

Neufeld told the sports agency that she developed painful and odd side effects including a hardening of her leg muscles which sometimes caused difficulty in walking, occasional loss of her voice, a thin growth of hair on her upper lip and -- like other female members of her club -- frequent missing of her menstrual cycle.

By May, 1977, she said, she refused to take any more pills because of the side effects and was not permitted to see a doctor outside the club. Instead, the club doctor ordered psychotherapy, she claimed in the interview.

The athlete said her troubles were increased when she refused to apply for membership in the ruling Socialist Unity Party of Communist East Germany. She said the training money she received as a member of the Olympic squad was withdrawn and that her trainer said this was just a warning. "If I did not basically change my attitude, neither outstanding sports performances nor a good education would be any help," she said she was told. "Instead I would soon be sweeping a factory floor or, at best, be standing behind a factory bench."

By the fall, Neufeld claimed, she had been taken several times by plainclothes secret service men to a police building for interrogation. After that, she decided to defect. She went to Bulgaria on a vacation, linked up with her Bulgarian boyfriend, who now is her husband, and slipped into West Germany from Bulgaria late last year.

She said she brought out with her samples of the two types of tablets she was given in the East and the sports agency said these had been analyzed by Prof. Manfred Donike of the West German Sports Federation as anabolic steroids.

In East Berlin, Reuter news agency reported that a spokesman for Neufeld's former club denied her claims. "It is not the practice here that athletes are forced to take anything," the spokesman was quoted as saying. "She must have her her own reasons for making such allegations."

Asked if hormone tablets ever were used by the club, the spokesman said only "I would rather not make any comment on that."

In mid-1977, an East German woman shot putter, Ilona Slupianek, was disqualified in the European Championship track and field finals in Helsinki because she allegedly was on drugs.

In the 1976 Summer Olympics in Montreal, East German athletes won an astounding 90 medals, including 40 gold medals, six more than the United States which has about 15 times the population of East Germany.

Neufeld said she decided to speak out now because her father, an English teacher in East Berlin, has lost his job since her defection and a sister, a talented team handball player, was expelled from her sports school and club for the same reason.

Nuefeld now lives near Munich with her husband and their 2-month-old baby. Reached by telephone this morning, she said she could confirm everything that appeared in the interview but declined to elaborate further. She said her claims applied only to what she knew about her own sports club and its members and she did not claim detailed knowledge of what goes on elsewhere in East German sports.

The sports agency interview with Neufeld was conducted by Wlli Knecht, a West German specialist on East German sports who also works for "Radio in the Allied Sector" -- or RIAS -- a jointly operated U.S-West German government radio broadcasting operation based in West Berlin that broadcasts into the East.

The sports agency interview was printed on the front page of the staunchly anti-Communist West German newspaper Die Welt this morning and Neufeld also granted an inter-German government rado broadcast-Wednesday.

Asked today if she was paid for the broadcast interview, Neufeld said yes, but declined to discuss it further.Knecht later said that he had paid her and would get the money back from RIAS. He said when he first met Neufeld and her husband after they defected they were very poor and he offered some money as a humanitarian gesture. He added that it was not unusual for people to be paid when they appear on radio or television interviews.