Whenever someone is about to make a huge jump in mileage, the first things you usually hear about are "burnout" and "stress fractures." It is true that both of these things are possible results of jumping from say 40 miles per week to 80 miles per week over a time span of about a month (much faster that is "recommended" by current ascent methods...other than Molvar's Lydiard interpretation I guess). Is this fear of breakdown preventing people from reaching their potential mileage goals in a quicker fashion? OR is the stress fracture consequence really something that should be a cause for concern? My philosophy has always been to listen to your body, which sometimes means that you can jump 30 miles in one week and feel great, and other times means you need to back off by 30 miles for a couple of weeks. What say you? Paranoia? or something that has been pounded into the average runner's brain for a good reason?