advice from hal higdon on facebook:
OF THE DAY: There are three ways to improve as a runner: 1) run more
miles; 2) run what miles you run faster; or 3) continue to run the same
number of miles at the same pace, assuming consistency will allow you
some improvement. It will, but the other two routes maybe offer a more
effective way to achieve your performance goals. Be aware, however, that
when you run farther and also run faster, you may increase your risk of
huh. that was quick.