
United States sprint star Erriyon Knighton has been slapped with a four-year doping ban after the Court of Arbitration for Sport (CAS) overturned a previous decision that had cleared him of wrongdoing.
The ruling follows appeals by World Athletics and the World Anti-Doping Agency (WADA), both of which challenged an earlier verdict that allowed Knighton to compete at the Paris 2024 Olympics.
The 21-year-old tested positive for trenbolone, a banned anabolic substance linked to muscle growth, in March 2024. However, an independent arbitrator initially accepted his defense of meat contamination and cleared him to race.
Despite this, CAS concluded that the evidence presented lacked credibility and fell well short of proving the source of the substance.

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CAS rules against meat contamination claim
Knighton had argued that the traces of trenbolone found in his system came from consuming contaminated oxtail. But the CAS panel dismissed this reasoning, stating that there was no proof that imported oxtail in the United States could realistically contain residues at levels high enough to trigger the failed test.
Both WADA and World Athletics stressed that the defense was “statistically impossible,” and CAS ultimately ruled in their favour.
The decision means Knighton, who narrowly missed out on a medal with a fourth-place finish in the 200m at Paris 2024, is barred from competition effective immediately.
He will also miss the upcoming World Championships in Tokyo. The ruling represents a major setback for one of the sport’s brightest young sprinters, who had been tipped as a future Olympic champion.
Adding to the turmoil in athletics, Ethiopian middle-distance runner Diribe Welteji will also be absent from Tokyo. CAS upheld her provisional suspension while a case concerning her alleged refusal to submit a doping sample is being processed. Welteji, 23, was a silver medalist in the 1500m at the 2023 World Championships in Budapest.
With two high-profile absences, athletics faces yet another doping-related storm. The sport’s ongoing struggle to protect integrity and credibility on the global stage continues.
Tags: Erriyon Knighton, World Anti-Doping Agency, WADA, World Athletics, meat contamination, Diribe Welteji, World Championships, Tokyo, Court of Arbitration for Sport, CAS, trenbolone, four-year doping ban.

