Apr 8th: 6 miles in 00:54.
Apr 10th: 6 miles in 00:49.
I am trying to increase my cadance from ~160 to ~180. Supposedly higher cadance with shorter stride distance actually lowers impact on joints while achieving higher speed. It seems to be working so far: I haven't finished 6 miles in 50 minutes since last September. I did feel a bit more strain on outer calf muscles and had to loosen my shoe laces, but these went away today.