The Sydney Olympics, due to start in just over five weeks, will be the launch pad for a revolutionary new shoe devised by Calgary University's Human Performance Laboratory.The construction of the shoes, which are said to improve performance by up to four per cent - the equivalent of a four minute gain for Canada's Olympic marathon runners - was based on special shock-absorbing technology.Research discovered that muscles tighten to lessen vibrations in surrounding leg tissue. A soft, shock absorbent sole was the best defence against such energy depletion, researchers discovered. However, they went even farther with the study and adjusted the shoe to each athlete's vibrational frequencies, which vary depending on training and build.Subjects were required to be strapped to a suspended bed that swung like a pendulum, causing their heels to hit the wall every two seconds. Their pain could lead to a definite gain though, according to Calgary University's Beno Nigg. "We think we will see some world records," he said.