My most realistic worry about the triathlon was that I would injure myself running. My preparation was working my way up to running 2 1/2 miles three times a week, but all on a track, which is softer than the road and flat. I am very pleased that I have been only a little sore. This morning I felt well enough to go back to running, though after 2 miles my legs started to feel sore and I stopped.
What amazes me is that when I practice I run a mile in about 14 minutes (slower than that today). In the triathlon, after swimming and biking, I ran 3.1 miles at 13 minutes a mile. That is still very slow, but it amazes me that instead of being tired and slow I was significantly faster. I've never run that fast in practice; I think my best time for two miles was around 26 min. 30 sec.