Oscar Pistorius is not your typical world-class athlete. He was born without fibulae – the bone joining the knee and the ankle – and his legs were amputated below the knee when he was 11 months old.

Fitted with carbon fibre blades on his legs, the 20-year-old South African holds world records for disabled athletes at 100, 200 and 400 metres. Now, he wants to be able to compete with fully able athletes in the 2008 Beijing Olympics. However, the International Association of Athletics Federations (IAAF) announced on Monday that Pistorius is ineligible for the Olympics because they believe his prosthetic limbs give him an unfair advantage.

If you blinked with surprise at that explanation, you're surely not alone. How could a legless runner possibly have an advantage? According to the IAAF, studies have shown that Pistorius' j-shaped blades provide approximately a 30 percent advantage because he expends less energy than fully-limbed runners.

Witness this video footage of Pistorius competing in a 400-metre race in Rome in July 2007, where he sprints from last place to second place in the final stretch. Presumably, the other runners couldn't keep up because their legs got tired.

Wherever you stand on the IAAF's decision (I support it – the Paralympics were created for people like Pistorius), we're entering a new era when performance enhancing drugs (PEDs) aren't the only considerations in trying to maintain fair competition. Now, we have to consider the effect of performance enhancing modifications (PEMs).

Let's say you find Pistorius' story to be inspiring and you think he should be able to compete in the Olympics. How do you think his competitors will feel about that, particularly anyone he beats? And if you allow "blade runners" like Pistorius to compete, what about a discus thrower who uses a prosthetic arm to hurl the disc further than any human arm?

Elio Locatelli, the director of development for the IAAF, explained that they need to block devices like Pistorius' blades in order to protect the purity of sport. "Next will be another device where people can fly with something on their back," Locatelli said.

Of course, Locatelli is attempting to over-simplify the debate of what physical enhancements we should and shouldn't allow in sports. Few people would argue that an NHL player should be allowed to wear rocket skates, but what about athletes who get laser eye surgery to give themselves better than normal eyesight? Some have argued that the famous "Tommy John surgery" – where a ligament in the elbow is replaced with a ligament from elsewhere in the body – allows baseball pitchers to have enhanced throwing endurance. Tommy John himself pitched for 15 more seasons after his surgery, retiring in 1989 at the age of 46.

Pistorius has announced that he will appeal the IAAF's decision and he is not ready to give up his dream of competing in the Olympics. Whatever side you're on, the line separating what PEMs should and shouldn't be allowed in sports is only going to get blurrier as modern technology continues to innovate and amaze.

Feedback or column suggestions? Send them to the-5-hole@hotmail.com.