This week we are lucky to be joined by Rob again to have an in-depth discussion about what sort of impact ultra-endurance events have on the human body. Rob has just returned from a 160km run in New Zealand and has now competed in some of the world's biggest ultra races. We discuss the sort of injuries people can experience, when it is time to go long and why, how to step up in distance, the mental challenge of ultra-events and the sort of impact that ultra-endurance sport can have on your weight.