'Never again,' swore Peter Walker on completing a Costa Rican cycling adventure billed as one of the toughest - and muddiest - in the world. Two days later, he was dying to be back with the chain gang.
Ever since the first Rocky film, fans have been running up the most famous steps in America in homage to their boxing hero. And their stories are just as inspirational as that of their idol, Sarfraz Manzoor discovers.