No easy answer to question that won't be going away any time soon

EUGENE, Ore. -- And now we come to the time in the Olympic trials when we pose the question: Just what is a performance enhancer, anyway?

Most people would suggest that steroids and human growth hormone qualify as performance enhancers, but what about less clear examples? What about swimsuits that affect drag and buoyancy so much that world records are falling like airline stock prices? What about athletic shoes that weigh so little they might as well be made of helium? Or high-tech sleeves that cut your sprinting time from that achieved with simply bare arms?

Or how about this?

Say doctors amputated both of your legs when you were a child. Say you were fitted with carbon-fiber prosthetics -- prosthetics that look more like blades than legs -- that help you sprint at near-Olympic speeds. Say there were bio-mechanical surveys, some of which showed the artificial limbs give you an unfair advantage over someone with two normal legs, while others indicated they do not.

Should you be allowed to compete in the Olympics?

That's the question facing Oscar Pistorius, the South African sprinter who is trying to run in the Beijing Olympics this summer. He has yet to qualify in the 400 meters but is a good bet to be named to the South African relay team. But one athlete's inspirational story is another athlete's unfair advantage -- at least it is if you're the athlete who winds up missing the Olympic team. Track's international governing body first ruled Pistorius ineligible for the Olympics because it believes the Cheetah prosthetics he wears give him an unfair advantage. That ban was overruled by the Court of Arbitration for Sport in May.

"It's great because everybody is aware of Oscar," Paralympics high jumper Jeff Skiba said of the attention on Pistorius. "I get questions every day, 'What about that guy with the blades on two legs?' It's not like it used to be, where you would say, 'Paralympics,' and people would say, 'What is that?' Just the awareness is great. It's opening up doors. I think it's a real positive thing."

Skiba can identify with Pistorius. He was born without a fibula in his left leg, and the limb was amputated when he was 11 months old. Nonetheless, he developed into a good enough athlete that he could dunk a basketball in high school while using his prosthetic limb as his non-jumping leg. Track coaches encouraged him to try the high jump, and he became so accomplished, he won the Washington state high school championship. Within two months of being fitted with another prosthetic, he was able to leap 2 inches higher, clearing 7 feet. His personal best is 7 feet, 0½ inch, achieved at the Azusa Pacific International last month.

He competed in an exhibition at the U.S. track and field trials over the weekend and will compete in the Paralympics in Beijing, but his goal is to improve enough to qualify for the Olympic trials in 2012 and possibly reach those Games in London. He says competing in the Olympic trials has been his goal ever since he leaped 6-10 in high school and learned the qualifying height for the U.S. trials is 7-2½.

Skiba, now 24, wears a significantly different prosthetic than Pistorius. It is heavier and has a straight design, and he says it doesn't return energy the way the Cheetah leg supposedly does. But the key question is this: Does it give him an unfair advantage?

"Speaking from experience for myself, I'm definitely not at an advantage," Skiba said. "Especially in the high jump, where I'm taking off from my sound leg.

"If anyone has any controversy with me, I'd be happy to do any bio-mechanical study of my leg and how it affects my jumping. I'd be more than happy and open to that."

Skiba says his 2-inch improvement in the high jump was due as much to additional training as to the new prosthetic. While the limb does provide an advantage over his previous artificial limb, he maintains that whatever advantage it gives him only gets him back to where an able-bodied athlete would be.

"If I have one side of my car that can go 100 miles per hour and the other only goes 50, I'm not going to go 100. I'm only going to go 50," he said. "I can only go as fast as my good leg will go."

Skiba says he has tried leaping off the artificial leg and he has been unable to jump anywhere near as high with it. But what if he found out the artificial leg did offer an advantage?

"I can tell you from experience they wouldn't," he said. "But I don't know, that's one thing that could happen. I guess my approach would be if I can't compete, then what do I need to do to compete? Because I don't want to be at an advantage. I want to be at a level playing field with everyone else. It's the same thing with the whole doping thing. You don't want anyone with an advantage. I'd want to be as legit as possible."

But what if Nike designers developed a prosthetic that could be slipped on and off normal legs like a shoe? Would it be a performance enhancer? Or just a really, really nice shoe?

Everyone wants a level playing field. The problem is, as technology advances, one question only gets harder and harder: Just what is a performance enhancer, anyway?

Jim Caple is a senior writer for ESPN.com. He can be reached here. His Web site is at jimcaple.net.