Justin Gatlin participates in Tennessee's pro timing day

Gatlin is the reigning Olympic 100-meter gold medalist. He received a potential eight-year ban for doping violations, but that ban was reduced to four years.

He is appealing the ban in hopes of voiding the first of his two doping violations to be allowed to compete this summer in the Beijing Games.

Gatlin tested positive for excessive levels of testosterone at the Kansas Relays in 2006, his second doping offense. The first came in 2001 when Gatlin tested positive for amphetamines, part of a prescribed medication he was taking for attention deficit disorder.