20 Miles of Hills

Saturday I set out on the last of the Marathon Masochist series. This was a 22-mile course, with long hills. My lovely wife rode her bike with me as my support vehicle, and some of those hills are easier to run up than to bike.
I was going to run the whole 22 miles, but that steep downhill after the 6-mile uphill was just too much on the quads. There's no point in injuring myself at this stage. So after I crossed 20 miles, I walked, stretched, and jogged the last 2 miles.
I figure if I could do those 20 hilly miles, the flat course of the marathon should be cake.