“I had not reversed time, or gotten any younger. But I had shown, at least to myself, that time and age are not walls but fences, and fences can be jumped.” That’s a conclusion from Peter Sagal’s splendiferous book on running. When I did my Jogging Big Year, back in 2016, I used to complain all the time. Now, I’m running even slower and only half the distance, and the weight is stacking on. Isn’t motivation mysterious?