Ummm... Yesterday I rode 5 miles doing errands and today I only did 10 miles running errands (shoe store, grocery store), and my quads are really sore. Hmmm...
Granted, I haven't ridden much at all lately, but still. I'm not in bad shape. I guess my legs just have forgotten what that crazy riding thing is all about (might be the 20 lbs of food I was hauling).