I've been thinking that I should change my running schedule, because my heavy runs are now defined by pace rather than distance. I've decided to make the change.
Before I ran the SLC half marathon in April, I ran light 5-mile runs on both Monday and Tuesday, and I ran a heavy intermediate 10-mile run on Wednesday and a heavy 13-mile long run on Saturday. The heavy runs were heavy because of distance not pace. Now that I'm running faster, I want to be sure I follow the heavy/light schedule. My heavy runs are now Tuesday and Saturday. Those runs are shorter than they were before the half marathon, but they are heavy because of my faster pace. My light runs are now Monday and Wednesday and are light because of a slower pace and if need-be a shorter distance than the 5 miles I did before the half marathon. Hopefully after a few months, my body will have adapted to my faster pace, and I'll be able to increase the distance of my heavy runs while keeping my faster pace.