These people could have saved themselves the bother. Because for anyone in the know, the true mark of a hard-ass athlete right now is the person who braves the mile-long run. Just as HIIT training (short, intense bouts of exercise believed to force the body into a fat-burning state) has taken over from hour-long aerobic classes as one of the most efficient ways to get into shape, experts are now reviewing the significance of short, intense runs. And the mile, long associated with Roger Bannister, who became the first man to run a sub-four-minute mile, in 1954, is where the smart runners are heading.