I've always been a vocal opponent of endurance training. I mention things about stress fractures, lowered testosterone in men, lowered thyroid function in women, blah blah blah.
Then I read a quote in a book from Brian MacKenzie when asked if endurance sports were good for you:
“Good for you physically? No. But you’ll recover. And I assure you: if you run 50K or 100 miles, when you finish, you won’t be the same person who started.”
That certainly made me stop and think.
Athletes at the competitive age aren't exactly the epitome and sanity and health. We push ourselves further than conventional wisdom or even science would say is smart.
However, irregardless of what direction your competitive spirit takes you, it will change you.
If you're an endurance fan, save your joints, muscles and mobility by checking out Brian MacKenzie's new book Power Speed Endurance: A skill based approach to endurance training.
Ferriss, Timothy (2010-12-14). The 4-Hour Body: An Uncommon Guide to Rapid Fat-Loss, Incredible Sex, and Becoming Superhuman (Kindle Locations 7978-7979). Random House, Inc.. Kindle Edition.