Walking in NYC (at least in this neighborhood) is not good cross-training for running. I find that I spend so much time dodging smokers, that it becomes a Slalom course, I speed up to jump around one smoker I'm behind, only to find myself behind yet another one. Within a few moments I'm running up the block to get away from them all. So, walking in NYC is not good cross-training for running. It's more like speed-work. Sheesh.