Dolf Jansen is a runner in the race events that have what official length?
Dolf Jansen: Dolf Jansen (born 25 June 1963 in Amsterdam) is a Dutch comedian, presenter of the Radio 2 program "Spijkers met Koppen" and an active Marathon runner. Marathon: The marathon is a long-distance running race with an official distance of 42.195 kilometres (26.219 miles, or 26 miles 385 yards), usually run as a road race.
42.195 kilometres