Dear Rick-of-the-future:
When you run more than 15km you need to give yourself more than 3 days of rest. It really, really tears up your legs. It’s only going to hurt like you wouldn’t believe if you run again too soon.
Don’t be a doofus—give it a rest.
–Rick-of-the-past
P.S.—In fact, just adhere to the following chart. And remember to load up on protein after each run!