Before Oscar Pistorius won the ticket to the London Olympic Games, the IAAF banned prosthetics from participating in the Olympic Games. The reason is that the leopard blade prosthesis has high strength, low density and strong elasticity. It can rebound 97% of the energy when running. 
It is the responsibility of IAAF to create opportunities for fair competition
 the wearer runs faster and faster, and the speed of the later range is beyond the reach of normal people.