Tweaked back, with an inverted portent?

I strained my back last Thursday which showed that, while my basketball reflexes return, they do so to an older body. On the drive home, I watched a grey squirrel fall out of a tree—perhaps a twenty foot drop—and kept the car still as it limped to the grassy sward nearby. My weekend was spent chasing children of suddenly superhuman speed, and realizing that I, too, am an aging squirrel.