The probability that a contaminated pork burrito led to the US Olympic 1500m medal prospect Shelby Houlihan’s failed drugs test is “very close to zero”, the court of arbitration for sport has ruled. In a 44-page verdict, which outlined the reasons why Houlihan was banned for four years in June, Cas said her claim she had unwittingly ingested the banned substance nandrolone by eating the meat of an uncastrated boar from a Mexican food truck “simply cannot be accepted”. Houlihan told the court that she had only eaten three quarters of her beef burrito, having found it “uncharacteristically greasy”, and said she may have been given a pork one by accident. Cas dismissed Houlihan’s claims, saying: “The explanation presupposes a cascade of factual and scientific improbabilities, which means that its composite probability is (very) close to zero. “First, the athlete would have had to have been served pork at the food truck despite ordering beef. Second, the pork consumed would not have been ‘normal’ pork product ordered by the food truck, but uncastrated boar. Third, uncastrated boar enters the food chain through completely different channels than pork. “It is rather difficult for an uncastrated pig to ‘slip through’ the multiple checkpoints. In principle, boars can be easily detected because of their big testicles.” Cas quoted experts who said that for an uncastrated boar to end up in the normal pork supply chain, it not only had to be cryptorchid – a specimen with undescended testicles – but have had elevated androgen levels, “which would be abnormal for 6-month-old pigs”. The court said: “The concentration of nandrolone in the athlete’s urine was 2-3 times higher than the highest values reported in the scientific literature after the ingestion of much more significant quantities of meat of mature (uncastrated) boar. “Finally, in his expert witness report, Prof McGlone states that the chance of a cryptorchid ending up in the normal supply chain in the United States is far less than 1 in 10,000. As a result of her failure to establish the origin of the nandrolone in her system, the athlete cannot benefit from a plea of no significant fault or negligence.” Houlihan, who finished fourth in the 1500m at the world championships in Doha in 2019, had a lengthy array of witnesses who pointed to her good character. She also told Cas she had refused to wear carbon-plated “super spikes” in Doha as she thought they would give her an unfair advantage – a decision that may have cost her a medal. Speaking in June, Houlihan said: “I did everything I could to prove my innocence. I passed a polygraph test. I had my hair sampled by one of the world’s foremost toxicologists.” However, Cas said that “neither the hair analysis nor the polygraph results are sufficient for the athlete to rebut the presumption that the anti-doping rule violation was intentional”.