Anyone who prefers to listen to narrative rather than music when working out will be familiar with the problem of media length. At the end of a work-out it’s not so difficult to wait for a three-minute song to come to its conclusion (or indeed cut it off), but for narrative it’s a different matter. Do you get back onto the treadmill for another five minutes, or sacrifice hearing the end of the piece until after your shower?

Researchers are working on a product for narrative – stories, documentaries, plays and the like – that self-edits according to work-out length without compromising the item’s “plot”. This is bound to be a big hit with the Apple iPhone digerati, as well as others whose time to listen varies according to different tasks.