When to decrease percentage of the long run?

I ran across the same article when I was studying up on training for long runs. I started running late in life and have only been doing it seriously for about 18 months now. In other words, take my opinion with a grain of salt and some tequila. I ran my first 50-miler last a few weeks ago based on the UA book. I am a slow runner due to my age and inexperience. I think if you are out there pushing yourself in the upper heart zones, you are probably going to get hurt like the article you shared says (or if you increase distance too quickly). On the other hand, I worked some temp jobs this summer where I was up and down ladders and lifts and on my feet all day for 14 or 16 hours. Was I risking injury then? The human body can take quite a bit if it’s conditioned to do so. My long runs (15+ miles) are always 3 hours or more. I take them low and slow like the book says. That means I walk a lot of steep sections, too. I think walking is the bastard child of this sport that few people talk enough about. It’s not sexy, and I think it makes some people feel like less of a “runner”. I believe it’s an absolutely essential tool on your road to longer, faster running. Like I said though, my résumé is an impressive 2 halfs (1 paved, 1 trail), 1 marathon, and 1 trail ultra.