TUMBLING world records are part of the Olympic experience, but just how much have swimmers or runners improved over the past 100 years? In Beijing, new records have been set in the most glamorous events in athletics and swimming—the men's 100m sprint and freestyle. Jamaica's Usain Bolt cruised to victory, taking his own 100m sprint world record down by three-hundredths of a second to 9.69 seconds. In the century or so since official records began, the quickest time has fallen by just under a second—a 9% improvement. But in the pool, Australia's Eamon Sullivan covered 100m in the heats (although he lost in the final) in a world-fastest time of 47.05 seconds, 19 seconds (and 28%) quicker than the record-holder of 1905.