OSAKA -- When the late Abebe Bikila represented Ethiopia in the men's marathon at the 1960 Rome Olympics, he shrugged off shoes in favor of his own bare feet. He took the gold, but were he running today, he might not make the same choice.

Shoe technology has advanced greatly over the past several decades, and today's runners expect the right pair of shoes to give them a leg up.

It was the introduction of ethylene vinyl acetate, a foam polymer, in the mid-1970s that really set the ball rolling. Until that time, the standard midsole for running shoes was made of rubber. But when that was replaced by EVA, running shoes became lighter, more flexible and more shock-absorbent.