Here is another quote from Running Until You're 100.
A few years ago, I met a 93-year old runner who ran in the popular Crim 10 mile race in Flint, Mich. He was just as excited about the race as the 20 year olds, and more mentally sharp than some of the younger runners as he talked about it. A recent news clipping showed a 101-year-old man running a veteran's track meet. He set a world record.
After reading about those two gentlemen, I decided I am a youngster after all!