Would it be possible for him (or anyone) to be competitive at the marathon distance if he's not starting to train for it until 35?
It would be entirely possible for him (not just anyone) to be competitive at marathon distance. The problem is though he just can not get/stay healthy.
I remember reading "Running with the Buffalos" when it first came out and in their Wetmore comments on Adam:
"If there's a weakness, it's his durability...He's got three out of the four. If he's got durability and can do ten years of one-hundred-plus-mile weeks, he'll have four out of four, and he'll be hard to beat..."
Wetmore claimed that Adam had the determination, talent, and courage but had yet to show the durability...how prophetic and amazingly accurate, that truly turned out to be.
Its a shame for Adam, he seems like a nice guy, obviously is extremely talented and a very hard worker, but he is not by any means the first elite runner to lack the necessary durability. Just a shame. I would hope he could get things together and fully recover, but things do not seem to be heading that direction. He has a good future no matter what though.