One strange thing I've noticed about running is the different after-effects of fast versus slow running. Last week, I did a slower, easy run, and the next morning I woke up stiff. Yesterday, I did a few fast intervals and this morning I woke up feeling good.
You would think that slower running would put less strain on the body, but it often doesn't seem that way. It could be that slower running puts more strain on the bone and joints, while faster running loads the muscles more.
This led me to wonder about the relationship between slow running and injuries. I came across a running discussion board the other day, and I noticed that the same people who were talking about their injuries also had slow race times. It's easy to think that the injuries are what's limiting them from going faster, but what if it's the other way around? What if the slow-paced training leads to both greater injuries and slower race times?