What is the optimal training frequency? Most runners, at some point in their running careers, contemplate this question. The answer to the question depends upon who you ask and what particular training philosophy they follow. Conventional training wisdom suggests running more frequently results in better performance. In line with this philosophy conventional training advice suggests to gradually increase training frequency until you are running 6-7 days per week. Conversely, Power Running suggests that there is no one training frequency that is right for all or most people and that less frequent training is better for runners with average genetic talents. But, how do you go about figuring out who is right? I suggest looking at what the research has to say, as this paper does.