Updated

The IAAF ruled Monday that double-amputee sprinter Oscar Pistorius is ineligible to compete in the Beijing Olympics because his prosthetic racing legs give him a clear competitive advantage.

The International Association of Athletics Federations had twice postponed the ruling, but the executive Council said the South African runner's curved, prosthetic "Cheetah" blades were considered a technical aid in violation of the rules.

"As a result, Oscar Pistorius is ineligible to compete in competitions organized under IAAF rules," the IAAF said in a statement from Monte Carlo, Monaco.

Pistorius, known as the "blade runner," announced last week that he planned to appeal any adverse decision, including taking the case to the Court of Arbitration for Sport in Lausanne, Switzerland.

Athletics South Africa said it would immediately apply the decision, further complicating Pistorius' future since he will not be able to set legal Olympic qualifying times in his own country.

"That's a huge blow," said Pistorius' manager, Peet Van Zyl. "He has been competing in South African abled-bodied competition for the past three years. At this stage it looks like he is out of any able-bodied event."

The decision was reached in an e-mail vote by the 27-member IAAF Council. The vote count was not disclosed but was believed to be unanimous.

The IAAF endorsed studies by German professor Gert-Peter Brueggemann, who conducted tests on the prosthetic limbs and said they give Pistorius a clear competitive advantage over able-bodied runners.

"An athlete using this prosthetic blade has a demonstrable mechanical advantage (more than 30 percent) when compared to someone not using the blade," the IAAF said.

The federation said Pistorius had been allowed to compete in some able-bodied events until now because his case was so unique that such artificial protheses had not been properly studied.

"We did not have the science," IAAF spokesman Nick Davies said. "Now we have the science. We are only interested in competitions that we govern."

Davies stressed the findings only covered Pistorius' specific blades and did not necessarily mean that all lesser-abled athletes would automatically be excluded.

The ruling does not affect Pistorius' eligibility for Paralympic events, in which he was a gold medalist in Athens in 2004.

"It's unfortunate because he could have boosted team athletics at the Olympics at Beijing, because he had the potential to qualify," said Leonard Chuene, president of Athletics South Africa.

Chuene said the federation would respect the ruling.

"There's not much we can do," he said. "It rules him out with immediate effect. We use the IAAF rule book. If we had our rules and our own competition, it would be easier. It is a huge problem."

Pistorius finished second in the 400 meters at the South African National Championships last year against able-bodied runners.

The runner worked with Brueggemann in Cologne for two days of testing in November to learn to what extent the j-shaped carbon-fiber extensions to his amputated legs differed from the legs of fully abled runners.

Brueggemann found that Pistorius was able to run at the same speed as able bodied runners on about a quarter less energy. He found that once the runners hit a certain stride, athletes with artificial limbs needed less additional energy than other athletes.

The professor found that the returned energy "from the prosthetic blade is close to three times higher than with the human ankle joint in maximum sprinting."

Based on these findings, the Council ruled against Pistorius.

The findings are contested by the Pistorius camp.

"Based on the feedback that we got, the general feeling was that there were a lot of variables that weren't taken into consideration and that all avenues hadn't been explored in terms of coming to a final conclusion on whether Oscar was getting some advantage or not," Van Zyl said. "We were hoping that they would reconsider and hopefully do some more tests."

The IAAF adopted a rule last summer prohibiting the use of any "technical aids" deemed to give an athlete an advantage over another.

Ossur, the Icelandic company which is a leader in the production of prosthetics, braces and supports and also made Pistorius' blades, has said the blades do not provide an edge over able-bodied athletes.

Pistorius has set world records in the 100, 200 and 400 in Paralympic events.

Pistorius was born without fibulas — the long, thin outer bone between the knee and ankle — and was 11 months old when his legs were amputated below the knee.

He began running competitively four years ago to treat a rugby injury, and nine months later won the 200 meters at the 2004 Paralympic Games in Athens.

Pistorius competed in the 400 at two international-level able-bodied meets in 2007. He finished second in a B race in 46.90 seconds at the Golden League meet in Rome on July 13 and, two days later, was disqualified for running out of his lane in Sheffield, England.