I am training for my first mountain ultramarathon :-) Unfortunately, I live in a completely flat location --- the biggest hill is about 20 meters. I use the hill extensively during my runs, but I am afraid it may not be sufficient to prepare for 2-8km climbs.
Today I extended my workouts with running stairs (42 floors, about 130 meters). Is it a good idea? What other exercise could I add to my workouts?