It appears many coaches follow a more or less standard training philosophy, with 1 interval, 1 tempo, and 1 long run per week (with minor variations). I was wondering if any coaches out there employ a training system of short, hard bursts of overtaxing the system for a week or two, such as by performing 4-6 hard sessions per week and then following up the hard week(s) with a very easy week? Has anybody seen a benefit to this?