Olympic gold medal winner Cody Miller has been described as the Iron Man of swimming and carries a figurine of the superhero with him to... competitions. But in an exclusive interview the American shares why he had to overcome body confidence issues around his "sunken chest", believes the mental focus involved in rising to the top in the sport can become unhealthy, and how it felt to have the pressure of not letting down his idol Michael Phelps when they teamed up for the relay at Rio... as a British rival threatened to spoil the last dance for the most decorated Olympian of all time.