Running is enjoying a huge rise in popularity at the moment - run clubs are popping up all over the place, plenty of new events are bringing the running community together, while old classics like the Marathon des Sables, the Winter Spine Race, and the ever-baffling Barkley Marathons continues to fascinate us. But ultrarunning is no mean feat - packing, preparation, kit choices and nutrition really can make or break a run. Find out how others have crossed deserts and the Arctic tundra, and how you can prepare for your own ultra.