When Oscar Pistorius made his dramatic debut in the men's 400-meter race in London last Saturday — becoming the first double amputee to compete alongside able-bodied athletes in Olympics history — some people might have wondered if the South African's artificial legs gave him a competitive edge over the other sprinters.

But if you ask the prosthetics-wearing athletes themselves what it takes to run with carbon-fiber feet, they'll tell you it's much tougher than you can imagine.

Perhaps the misconception arises from how effortless the top runners make their movements seem. Such skill is possible only after long, difficult training — not just physically, but mentally.