When 26.2 miles just isn't enough – the phenomenal rise of the ultramarathon

They are an almost-impossible test of the human body and spirit, yet the number of ultramarathons has increased 1,000% over the last decade. Adharanand Finn asks what’s behind this rapid increase – and whether racing 100 miles or more is actually good for you

A while ago, I was standing at the office tea point when a colleague who had heard I was a runner asked me if I did ultramarathons – the term for any foot race longer than the 26.2 miles of a standard marathon. He looked disappointed when...