Your Training Recovery Ratio

To optimise your running, you need to find the ideal balance between running and recovery. 
Your running is the stimulus required for your body to adapt in order to improve, but this requires recovery to allow improvement to a higher level. Hans Selye, a Canadian physiologist, espoused his General Adaptation Syndrome which basically stated that if you stress a body and let it recover, its performance will be enhanced. Miss out on the recovery, and it will become exhausted. An athlete may withstand a relatively great load of a particular exercise for which he or she has been trained, but more easily succumbs to other stressing agents such as colds and bacterial infections than the normal healthy person. A number of hard training weeks require a recovery week to allow supercompensation and subsequent improvement. Even if you have a hard day/easy day schedule, although energy levels will recover, muscle tissue repair will not. The ideal pattern is generally 3 hard weeks followed by an easy week. In summary, to ensure that you are optimizing your training from the point of adaptation, go hard day/easy day, 3 weeks hard/1 week easy and also have a couple of recovery periods throughout the year (say of 3 weeks duration each). The effort you put in to your running is too important to devalue by not giving yourself sufficient recovery.