Thiago Machado Vilela Pereira (born January 26, 1986 in Volta Redonda, Rio de Janeiro) is an international competition swimmer from Brazil. He became known in his native country after winning the silver medal in the 200 m individual medley at the Pan American Games in Santo Domingo, Dominican Republic in 2003.

Pereira's biggest success came one year later, when he won the world title in the same event at the 2004 FINA Short Course World Championships. After that, Pereira won six gold medals in the 2007 Pan American Games in Rio de Janeiro, Brazil, breaking the record of five gold medals won in one Pan American Games edition, held by Mark Spitz. He also broke the 400 individual medley world record in short course later that same year. A resident of Belo Horizonte he represented his native country at the 2004 Summer Olympics in Athens, Greece, where he reached the final of the 200 m IM, finishing in fifth place. In the 2008 Summer Olympics in Beijing, China, he also reached the final of the 200m IM, finishing fourth.

Michael Fred Phelps (born June 30, 1985) is an American swimmer who has, overall, won 16 Olympic medals—six gold and two bronze at Athens in 2004, and eight gold at Beijing in 2008, becoming the most successful athlete at both of these Olympic Games editions. In doing so he has twice equaled the record eight medals of any type at a single Olympics achieved by Soviet gymnast Alexander Dityatin at the 1980 Moscow Summer Games. His five gold medals in individual events tied the single Games record set by compatriot Eric Heiden in the 1980 Winter Olympics and equaled by Vitaly Scherbo at the 1992 Summer Games. Phelps holds the record for the most gold medals won in a single Olympics; his eight at the 2008 Beijing Games surpassed American swimmer Mark Spitz's seven-gold performance at Munich in 1972. Phelps' Olympic medal total is second only to the 18 Soviet gymnast Larisa Latynina won over three Olympics, including nine gold. Phelps also holds the all-time record for most gold Olympic medals, at 14.

Maria Emma Hulga Lenk (January 15, 1915 – April 16, 2007) was a Brazilian swimmer and to date is considered one of the greatest Brazilian female athletes.

At the age of 17, she was the first Brazilian and South-American woman to participate in the Summer Olympic Games, at the 1932 Summer Olympics, in Los Angeles.

Born in São Paulo, Maria Lenk was the first Brazilian in history to set a world record in swimming. On November 8, 1939, in Rio de Janeiro with a time of 2:56.0, she beat Jopie Waalberg's previous record of 2:56.9, for the 200m breaststroke event. This record lasted almost 5 years, until Nel van Vliet, from the Netherlands broke it on August 17, 1946, with a time of 2:52.6.

In the same year, she also broke the world record for the discontinued category of 400m breaststroke, with a time of 6:15.8.

She also participated in the 1936 Summer Olympics, in Berlin, where she reached the semifinals of the 200m breaststroke event. In this occasion, she also became the first woman in the world to swim the Butterfly stroke in an official competition. At the time, the Butterfly stroke was used as a form of swimming the Breaststroke, and not yet recognized as a separate swimming stroke. Lenk's account of the event was that at the time she subscribed to a German specialized magazine that ran a story on David Armbruster's and Jack Sieg's work in developing "a new way of swimming the Breaststroke". She became interested and started practicing the stroke by herself in her training sections. In 1936, she and Jack Sieg were the only two people that were prepared to use the technique in the Breaststroke events at the Summer Olympics.