I trained for my first marathon all last summer, mostly just by running a lot. And then, when that didn't feel like quite enough, running even more.
Now I'm about fifty days away from my second marathon and I'm taking a more balanced approach to the training. I've been adding more strength training and core exercise in addition to the running. In part because the weather this time of year makes it hard to just run a lot, and also because I'm focused more on performance and not just completing the race this time around.
I'm finding that my abject neglect of upper body workouts really shows. Running 20 miles is no big deal but 20 pushups just about kills me. So I guess it's good to be working on that aspect of my fitness. I hope it all pays off in February.