Athletics/News:Oscar Pistorius is set to take his case to the Court of Arbitration for Sport (CAS) after he was blocked from competing in this summer's Olympic Games.

The International Association of Athletics Federations (IAAF) yesterday barred the double amputee from participating in Beijing because his prosthetic legs were deemed an unfair advantage.

The World athletics' governing body announced their decision yesterday morning after studying the findings of a two-day independent scientific investigation held last November.

They now believe there is "overwhelming scientific evidence" that the 21-year-old South African's 'Cheetah' blades are technical aids in clear contravention of IAAF rules, and as it stands he will be denied his dream to compete for his country at the 2008 Games over 400 metres.

No appeal has yet been formally lodged but Pistorius's agent Peet van Zyl revealed yesterday his "natural feeling" was that the fight to compete was not over yet, with CAS's decision considered final and binding.

"We would have to sit down with our legal team in terms of the way forward," he said.

"I am disappointed, but the natural feeling from our side would be to appeal the verdict and see what avenues we can take forward. Oscar wants to prove that he isn't getting an advantage."

The IAAF's statement said: "It is evident that an athlete using the 'Cheetah' prosthetic is able to run at the same speed as able-bodied athletes with lower energy consumption.

"Running with prosthetic blades leads to less vertical motion combined with less mechanical work for lifting the body.

"As well as this, the energy loss in the blade is significantly lower than in the human ankle joints in sprinting at maximum speed.

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

IAAF communications director Nick Davies insisted that his organisation were left with little choice but to ban Pistorius.

He said last night: "The IAAF has nothing but the highest respect for Oscar and his achievements, but we have an obligation to ensure that the IAAF rules are not broken.

"In this case, we believe there is now overwhelming scientific evidence, that did not exist before, that his blades give him a major advantage."

Pistorius volunteered to undertake independent scientific tests under the supervision of Professor Peter Bruggemann at the German Sport University of Cologne, with the IAAF picking up the €50,000 bill.

Pistorius agreed with the choice of laboratory and appointment of Bruggemann, acknowledged as one of the foremost experts in the world.

But Van Zyl yesterday appeared to suggest he had spoken to experts who contradicted the Cologne findings. He said: "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.

"We were hoping that they would reconsider and hopefully do some more tests."

An IAAF official said last night the world governing body had been concerned about the implications of prosthetic aids.

"It's for the future," he said. "It's about what might happen in 20 or 30 years."

Pistorius, whose legs were amputated beneath the knee when he was 11 months old, has worn the blades for four and a half years.

Although he has raced only twice against able-bodied runners overseas, his manager Van Zyl said he had competed more against able-bodied athletes than disabled. The IAAF doesban all prosthetics and athletes have completed marathons with artificial legs or feet.

In response last year to concern in the disabled community about the new IAAF rule, US council member Robert Hersh went on national radio to explain that the ban on springs and wheels was designed to ensure athletes did not get an unfair advantage.

A statement from the International Paralympic Committee said it acknowledged the scientific validity of the tests. "However, the use of an assistive device should not only be considered in solely biomechanical terms."

"It is recommended that further investigations take into consideration other aspects such as an examination of the energy loss or generation of the corresponding knee and hip joints as well as the impact of the amputation site contact with the prostheses."