Try doing some research first wrote:
http://runningtimes.com/Article.aspx?ArticleID=23029Why on earth would you be giving advice/opinions without any "evidence or science". And as the article in the shows, you are dead wrong.
Yeah, I've long suspected that running 70 MPW for a young teenager wouldn't kill them. Even 50 MPW for a 9 year old doesn't seem like a big deal. We are MADE to run, and if we were living in pre industrial times, we would run to hunt down our food, BUT today as a matter of practicality, I would be more concerned about mental burnout than physical burnout when running so much at age 9. My 11-year old son eats up running and would run 7-10 miles a day if I'd let him. I don't let him. He's got one other sport to participate in plus other things that keep him active while he runs 3 days a week on average right now. When he enters middle school, he'll run 5 days a week in season, and that will be new and a step up for him. When in HS, he'll run 6-7 days a week. I'm fine with that progression.