Wednesday morning run - 15km easy

Cut another 5km out of my traditional Wednesday medium long run. I don't know why, but I felt extremely flat this morning. Not too uncommon for me on a Wednesday, but considering that the past few days have been quite a bit easier in terms of both volume and intensity, I was quite surprised. Just never really 'warmed-up' this morning. Didn't even bother strides at the end. 15km in 4:21 min/km, averaging 129 beats per minute.