Kechi and I have started going to the gym again, but one thing that takes getting used to these days is that even when I’m not hitting the gym, I’m staying active. This week, I’ve walked over five miles with Karate three times, with 2.5- and 3.5-mile days interspersed. It’s a relatively modest achievement, but it’s a big deal for someone my size—and then for me, personally...