A University of Wyoming human performance researcher is co-author of a study that says the prosthetic legs of double-amputee sprinter Oscar Pistorius give the South African a 10-second advantage over a 400-meter race.

Matthew Bundle of UW and Peter Weyand of Southern Methodist University found that Pistorius, who has been cleared to compete against able-bodied athletes, runs the distance 10 seconds faster than he would if his prosthetic limbs behaved like normal legs.

Their conclusion will be published today in the Journal of Applied Physiology.

Bundle is the director of UW's biomechanics laboratory. His area of research is human movement/locomotion and muscle function.

"My interest is in the upper limits of human performance," Bundle said Wednesday in a telephone interview.

He said he and other researchers became involved with the Pistorius case in December 2007 after the International Association of Athletics Federations banned him from able-bodied competition because of his prosthetic limbs.

The IAAF had concluded, on the basis of other tests conducted at the University of Cologne in Germany, that Pistorius' J-shaped, artificial lower limbs, called "Cheetahs," gave him a competitive advantage over intact-limb competitors.

But in May 2008 the ban was overturned on appeal to the Court of Arbitration for Sport in Lausanne, Switzerland.

The study to be published today is a point-counterpoint debate by researchers who served on the appeal team but differed in their conclusions.

The team of investigators performed a second set of tests at Rice University in Houston, where they evaluated the effects of sprinting on artificial legs that weigh half as much as an intact lower leg.

The lightweight carbon-fiber prostheses "allow Pistorius to swing his legs faster than anyone we've ever seen, including some of the fastest men in human history," Bundle said Wednesday.

The 22-year-old Pistorius remains eligible for the 2012 Olympics, and it remains to be seen if the new study changes that, Bundle said.

The newly released conclusion from Weyand and Bundle analyzes scientific evidence and quantifies the competitive advantage provided by Pistorius' "Cheetah" limbs.

"Pistorius' sprinting mechanics are anomalous, advantageous and directly attributable to how much lighter and springier his artificial limbs are," Weyand said in a statement. "The blades enhance sprint running speeds by 15-30 percent."

The CAS ruling cleared Pistorius to compete at the 2008 Beijing Olympics, but he failed to run the required qualifying time of 45.95 seconds. His personal best is 46.25.

He also failed to meet the qualified standard ahead of this year's world championships in Berlin.

Pistorius won gold medals in the 100, 200 and 400 at the Paralympics in September.

Pistorius, known as "Blade Runner," still hopes to qualify for the 2012 London Olympics.

Weyand and Bundle say the lightweight blades allow Pistorius "to reposition his limbs 15.7 percent more rapidly than five of the most recent former world record-holders in the 100-meter dash."

"The springy, lightweight blades allow Pistorius to attain the same sprinting speeds while applying 20 percent less ground force than intact-limb runners," the pair found, according to the statement. "The springy blades reduce the muscle forces Pistorius requires for sprinting to less than half of intact-limb levels."