Back after a four-year doping ban, the American sprinter Justin Gatlin will compete against Jamaican superstar Usain Bolt for the first time at the world athletic champs in South Korea on the weekend.
Bolt succeeded Gaitlin as Olympic 100m champion in Beijing in 2008 after Gatlin received an eight-year ban in 2006, later halved to four, for testing positive to a substance believed to be testosterone.
At the time, Gatlin who was Olympic and world champion was coached by Trevor Graham, whose stable also included the disgraced Marion Jones.
The 100m field in Daegu will also include British sprinter Dwain Chambers, who has served a two-year ban after testing positive to steroids in 2003.
