The case involves an appeal by the World Anti-Doping Agency (WADA) against a decision by the Polish Olympic Committee (POC) regarding athlete Przemysław Koterba, a weightlifter who tested positive for amphetamine during the 2012 Polish National Senior Championship. The Polish Weightlifting Federation initially imposed a six-month ban, which WADA contested, arguing for a stricter two-year sanction. The Court of Arbitration for Sport (CAS) reviewed the case, addressing procedural fairness, the athlete's fault, the standard of proof, and the appropriateness of backdating suspensions. The CAS emphasized the necessity of the athlete's participation in proceedings to ensure fairness, noting Koterba was properly notified and had the opportunity to defend himself. The panel examined whether the athlete demonstrated no significant fault or negligence under Article 10.5.2 of the Anti-Doping Regulations (ADR), clarifying that factors like financial loss or career timing are irrelevant. Instead, the athlete needed to provide specific evidence explaining how the prohibited substance entered his system without intent to enhance performance. The CAS applied the balance of probability standard, requiring the athlete to show his explanation was more likely than alternatives. Koterba claimed the amphetamine entered his system unintentionally at a private party, possibly through drink contamination. While the CAS found his explanation credible, WADA argued it was speculative and insufficient to reduce the sanction. The panel also considered the fairness of backdating the suspension, acknowledging delays in proceedings not attributable to the athlete. Ultimately, the CAS upheld the six-month ban, rejecting WADA's appeal, as the athlete met the burden of proof for a reduced sanction. However, in a subsequent ruling, the CAS revisited the case, imposing a two-year ineligibility period after finding the athlete's explanation inadequate under stricter scrutiny. The sanction was backdated to January 1, 2013, accounting for time already served, and Koterba's competitive results from May 26, 2012, were disqualified. The case underscores the strict liability principle in anti-doping regulations, the high burden of proof on athletes, and the importance of procedural fairness. It also highlights the limited exceptions for reducing sanctions, emphasizing the need for credible evidence to support claims of unintentional ingestion. The final ruling dismissed all other motions, concluding the matter with a clear resolution.