In 2020, when Tokyo hosts the Olympic Games, it will also host the Paralympic Games. Japan has traditionally lagged behind in the development of artificial limbs - one man trying to change that is prosthetic leg engineer Ken Endo. He has done very promising work on robotic limbs at the MIT Media Lab, with a particular focus on artificial legs for athletes. Endo's conviction is that "disabilities lie not in humans but in technology". We speak with this visionary engineer.