What does it take to be a successful runner of extreme distance and why do people do it?

David Greig is the Artistic Director of the Lyceum Theatre in Edinburgh and an internationally successful playwright. He's also an ultra-marathon runner who has twice completed the punishing 96 mile West Highland Way as well as many other long-distance races. He took up running fifteen years ago when he stopped smoking and running has since become an endorphin-fuelled obsession.

For One to One, David is speaking to two fellow runners. Today he meets former world hill running champion, Angela Mudge. Born with birth defects that affected her feet, Angela spent the first two and half years of life almost continually with her lower legs and feet in plaster. Despite this, she went onto be a hugely successful long-distance runner. Her most memorable race was when she became the first woman to break three hours when she won the Sierre-Zinal - 'the race of the 4000m peaks'.

But why do they do it?

Producer: Karen Gregor.