I ran into a Reddit conversation with elite mile runner David Torrence, and he offered some ideas about training and running.
"forget everything else and just focus on winning no matter what kind of race it is"
"There have been days where I run 10min per mile for 40minutes, because I was just that tired, and I knew I had to let my body recover. I really suggest not getting caught up in the pace of your runs, and rather just letting your body dictate what pace you should run. Some days you feel good, then let your body go faster; some days you feel terrible, and you should let your body run slow. Forcing things is a great way to get yourself hurt or burnt out."
"The longer the race the shorter the warmup"