A person stands on an image of Brazil's interim President Michel Temer during a demonstration against the impeachment of Brazil's former President Dilma Rousseff on Copacabana before the opening ceremony of the Rio 2016 Olympic Games in Rio de Janeiro, August 5, 2016. REUTERS/Carlos Barria

A person stands in front of a banner which reads "Temer out" in reference to Brazil's interim President Michel Temer during a demonstration against the impeachment of Brazil's former President Dilma Rousseff on Copacabana before the opening ceremony of the Rio 2016 Olympic Games in Rio de Janeiro, August 5, 2016. REUTERS/Carlos Barria

U.S. Olympic athlete Connor Fields walks his BMX bike to a training hill, at the Olympic Training Center in Chula Vista, California, United States, June 13, 2016. REUTERS/Mike Blake

A satellite photo provided by DigitalGlobe dated June 16, 2016 of the BMX Center in Rio de Janeiro, Brazil, being prepared for the Rio 2016 Olympic Games. DigitalGlobe/Handout via REUTERS

The landing marks from the tires of BMX bikes are shown on the training track at the Olympic Training Center in Chula Vista, California, United States, July 1, 2016. REUTERS/Mike Blake

U.S. Olympic BMX athlete Connor Fields works out at a training facility in Carlsbad, California, United States May 20, 2016. REUTERS/Mike Blake

U.S. Olympic BMX athlete Connor Fields works out doing squats with a broken hand during a training session at a facility in Carlsbad, California, United States May 20, 2016. REUTERS/Mike Blake

U.S. Olympic athlete Connor Fields (R) powers through a turn while training with New Zealand athlete Trent Jones at the Olympic Training Center in Chula Vista, California, United States, July 1, 2016. REUTERS/Mike Blake