 After initial research showed the blades did provide an advantage, the International Association of Athletics Federations (IAAF) changed their rules to ban the use of technical devices that provide an advantage and ruled him ineligible to compete.Pistorius challenged the ruling with additional research and was reinstated by the Court of Arbitration for Sport (CAS) in 2008, meaning that he can continue to run in non-disabled meets as long as he uses the equipment that was studied in the research.Pistorius's performance in the early non-disabled races raised questions because of two major concerns