Just a quick note to pass on a great article that explains one of the basic ideas of “my” running plan (a plan largely taken from Running Science, of course):
Split it up (Unevenly): Elite runners typically follow a lopsided polarized plan, in which they devote about 75 percent of their training time to easy running, 10 percent to threshold work, and 15 percent to very hard efforts. Tempo runs are important, but that middle-intensity zone is still the smallest.
As the article notes, most runners tend to run too fast on their slow days, and too slow on their fast days. So, stay polarized.
Check out the whole article here.