I think the best bet is have someone with a bicycle just ride along with him for some meaningful distance and monitor him. Tell him, "I'm going to ride behind you for the next 100 miles." See what he says or does.
To combat message board spam by non runners, we are making people answer a brief question before they can post on a thread that is over 20 days old.
If you answer this question you will be able to post.
Who of the following is not an American runner?