I'll tell you what I know. For several years, (a while ago) I got massages weekly. They did not harm my running. They felt good. I liked talking to Sandy who told all the stories of the local running community. I wasn't injured during that time, but I wasn't training at PR level either. So, above all I know massage does no harm.
Does massage do any good? I have been trying to devise a double blind study, but I can't figure out how you can have someone give a massage with out knowing it to some one who doesn't know if he is getting a real massage or a placebo massage.
Massage is nice. They feel good. At least afterwards. But how do I know about the injuries I didn't get or if the injury that went away would have gone regardless of the massage?
Maybe placebo massages would be cheaper?
Tom