Pistorius has been the subject of criticism because of claims that his artificial limbs give him an advantage over runners with natural ankles and feet. In November 2007, Pistorius was invited to take part in a series of scientific tests at the Cologne Sports University under the guidance of Professor of Biomechanics Dr. Peter Brüggemann.
After two days of tests, Bruggemann reported on his findings on behalf of the IAAF. The report claimed that Pistorius's limbs used 25% less energy than runners with complete natural legs to run at the same speed, and that they led to less vertical motion combined with 30% less mechanical work for lifting the body.
Based on these findings, on 14 January 2008, the IAAF ruled Pistorius's prostheses ineligible for use in competitions conducted under the IAAF rules, including the 2008 Summer Olympics. Pistorius called the decision "premature and highly subjective" and pledged to continue fighting for his dream. His manager Peet van Zyl said his appeal would be based on advice from United States experts who had said that the report "did not take enough variables into consideration".
After a two-day hearing, on 16 May 2008, the Court of Arbitration for Sport upheld Pistorius's appeal and the IAAF council decision was revoked with immediate effect. There was no evidence that he had any net advantage over able-bodied athletes.
In response to the announcement, Pistorius said: "My focus throughout this appeal has been to ensure that disabled athletes be given the chance to compete and compete fairly with able-bodied athletes. I look forward to continuing my quest to qualify for the Olympics."
