LAUSANNE, Switzerland  (AFP) — United States (US) sprinter Erriyon Knighton, a double world 200 metres medallist, must serve a four-year ban, the Court of Arbitration for Sport (CAS) ruled on Friday after rejecting his argument that he consumed steroids in imported beef.

Knighton won bronze aged 19 at the 2022 World Championships in Eugene, Oregon. A year later he took silver in Budapest.

He tested positive on March 26, 2024, for epitrenbolone, an anabolic steroid, in an out-of-competition test and was provisionally suspended from April to June 2024.

Knighton was initially cleared by a US tribunal, which accepted the theory of food contamination in time for Knighton to run in the Paris Olympics, where he finished fourth in the 200m final.

After the Games, the World Anti-Doping Agency (WADA) and World Athletics appealed to CAS, arguing, according to the court’s press release, that Knighton’s “explanations of a meat contamination scenario fell short of the required proof of source and were statistically impossible.”

CAS took their side.

“There is no proof that would support the conclusion that oxtail imported into the USA would be likely to contain trenbolone residues at the level required to have caused the Athlete’s Adverse Analytical Finding,” said the court statement.

WADA welcome the decision, saying: “WADA is pleased with the outcome and we will continue to appeal cases to CAS when we feel justice has not been served.”

Knighton’s four-year ban, the court said, will include the period from 26 March 2024 to 12 April, 2024.

He had not been selected for the US team for the world championships in Tokyo, which start on Saturday.