Sergey Koplyakov from Belarus made the Soviet national team in 1976 and won his first international tournament medal, a 4×200 m freestyle relay silver, at the 1976 Olympics. Koplyakov next competed at the 1977 European Championships, winning gold in the 4×200 free relay and bronze in the 4×100 free relay. Koplyakov established himself as one of the world’s top 200 freestylers in 1978, winning a bronze in the event at the World Championships. He also won silver in the long freestyle relay at the 1978 World Championships. In 1979, Koplyakov became the first man to swim under the 1:50 mark for the 200 metre freestyle, clocking his only world record of 1:49.83 in East Berlin. At the 1980 Olympics, with the Americans absent, Koplyakov was the heavy favorite in the 200 free gold and won easily, nearly a full second ahead of fellow compatriot Andrey Krylov. He also won a 4×200 freestyle relay gold and medley relay silver at the 1980 Olympics. Koplyakov finished his swimming career after the 1981 European Championships, where he won three golds – in 200 freestyle and in both freestyle relays. Domestically Koplyakov won seven Soviet titles – three in 200 freestyle (1978-79, 1981), one in 100 freestyle (1979), one in 4×100 free relay (1978), one in 4×200 free relay (1978) and one in the medley relay (1978). After retiring from competition, Koplyakov has worked as a swimming coach in his native Belarus, as the long time coach of Dynamo Minsk.
Personal Best: 100 m freestyle – 51.34 (1980); 200 m freestyle – 1:49.81 (1980).