"100m is longer than I thought." How long did you think it was Alfie, 50m? Also Mr big time runner can't remember what a running track is called, and says his class was the best at running. So he was a super serious runner for his school class. Wow!!
Poor old Alfie is amazed at Logan's sports day idea, because he doesn't understand how people come up with interesting ideas. He probably bought several books on how to have an idea, but couldn't be bothered reading them.