The American's  appeal to the Court of Arbitration for Sport (CAS) on doping charges was rejected, three weeks before the United States holds its Olympic trials.

 

The three-man CAS panel upheld the four-year ban given to the 26-year-old sprinter earlier this year by another arbitration panel.

 

Gatlin, whose ban will not expire until July 25, 2010, had hoped to have it reduced to two years, giving him a chance to defend his 100m Olympic title.

 

He said: ''I will continue to fight for my right to participate in the great sport of track and field in a time frame shorter than four years."

 

The initial arbitration panel that reduced Gatlin's possible eight-year ban to four years essentially had offered up a blueprint for how Gatlin might conduct the appeal - eliminating his first doping offense in 2001 - but the CAS arbitrators did not agree.

 

CAS secretary general Matthieu Reeb said: ''Justin Gatlin wanted to participate in the Beijing Games, the IAAF (International Association of Athletics Federations) wanted to see a life ban imposed on him, but the CAS panel has unanimously decided that four years was the right sanction."

 

Gatlin said: ''I have never been involved in any intentional doping scheme.

 

"'And I think that CAS would not have rejected IAAF's position unless it also believed that I had not participated in any intentional doping.''

 

Gatlin, who once held himself up as a role model for clean competition, has said he does not know how steroids got into his system before an April 2006 test, when he tested positive for excessive testosterone.

 

At the time, Gatlin was coached by Trevor Graham, a Jamaican coach who used to work with Marion Jones and Tim Montgomery and who was recently found guilty of lying to federal investigators.

 

Despite not getting the eight-year ban it sought, the IAAF still looked at the decision as a victory.

 

President Lamine Diack said: ''This result demonstrates the IAAF's determination to remove the scourge of doping from our sport.

 

''We will fight as hard as necessary, and commit all the resources necessary, to ensure that this is done.

 

"There is no place for doped athletes in our sport.''