Tyson Gay's former coach has been banned for eight years by the US Anti-Doping Agency.
Jon Drummond, a former Olympic relay gold medallist, was found to have possessed, trafficked and administered banned drugs to an athlete he coached.
The ban comes into force on 17 December, the date of the decision.
Earlier this year, former 100m and 200m world champion Gay was suspended for a year after testing positive for a banned anabolic steroid.
That penalty was reduced because he provided information that led to Usada's case against American Drummond, 46.
Drummond helped the United States win gold in the 4x100m relay at the 2000 Sydney Olympics.
Usada chief executive Travis Tygart said: "Coaches have an inherent responsibility to protect athletes, not take advantage of them.
"But to ensure that they receive the support, training and advice they need to win fairly and in accordance with the rules."
Drummond's ban prohibits him from coaching, training or advising athletes.
He is not allowed to participate or coach at any event sanctioned by USA Track and Field or the sport's global governing body the IAAF.