My femural stress fracture was in the shaft of the bone, not the neck. The only pre-fracture symptom was a vague pain deep in the thigh after a long hilly trail run that I wrote off as quad soreness. The truth came out, however, after finishing a flat 30K road race a few days thereafter (poor planning on my part, obviously) when my leg collapsed under me after crossing the finish line. Interestingly, there was no discomfort during the race -- guess my working muscles held things together. This was mid-March. So much for Boston that year! My orthopedist said to not do anything that hurt, so I rode my bike a lot, took stairs one at a time, was able to hike in the Rockies by the end of June, and resumed running mid-August. Wouldn't you know that my calcaneus would be the next to go (in Oct of the same year), and then my tibia a couple of years thereafter, despite starting on a regimen of Fosamax. Now I do as much of my training on trails, grass, or the track and limit my road miles as much as I reasonably can.