4. Justin Gatlin (9.77 seconds)
Justin Gatlin is an American athlete, who born in Brooklyn, New York and currently lives in Raleigh, North Carolina. In 2000, he attended the University of Tennessee, where he participated in a number of national competitions. In 2002, he became a professional athlete and won a gold medal in the Olympic Games 2004, in 100m sprints. During the same event, he also won a silver medal for the 4x100m and a bronze in 200m. In Doha, Qatar at 2006, he equaled the 100m world record first set by a Jamaican athlete, Asafa Powell in 2005. Originally, it was believed that he had broken the record with a time of 9.76 s. Unfortunately, by a controversial decision, the IAAF ruled that the 9.766 s would be rounded to 9.77s. On the same year, he was banned for 8 years by the Athletics Federation after being proven positive for testosterone. The sentence was reduced to 4 years due to Justin’s cooperation in the investigation. He returned to athletics competition on 2010.