I never liked gym when I was in school. I liked Library.
However, I'm all grown up now and I have a dog. He's not quite the same as gym class. The dog doesn't taunt me or pick me last for team sports but he's annoying all the same. The dog expects to be walked. Every day. The dog doesn't understand anything about me as a writer--the need I have for space and time to loll about reading and doodling and...and...sloth. Brain work that has nothing to with the dog or what the dog wants or where the dog wants to go. The dog--an obvious jock--could care less about my writing life.
Dog guilt gets to me. Bloody exercise vital to health and well-being, blah, blah. Put on my coat and boots. Dog goes berserk with joy. No one in gym class was ever that happy to see me on their team.
Kind of flattering. Besides, walking is supposed to be good for inspiration.