I hurt my back on a hard ride Tuesday afternoon. I did kind of a personal time trial to squeeze in 20 miles before a thunderstorm. Good news is that I beat the rain. Bad news is I woke up Wednesday morning and could hardly walk. Just a pulled muscle I think. Nothing a little Motrin won't cure. Needless to say I'm not commuting this week. Hopefully I'll be ready to commute again next week. Not sure why it happened. I think it was already strained before I rode because I felt the stiffness (but ignored it). Sometimes I don't listen to my body too well.