When I was eight years old, I took dancing lessons. Besides the standard tap, jazz, and ballet, the studio included a beginner gymnastics class. I refused to do tap, tolerated jazz and ballet, but enjoyed the tumbling. I had good balance and appreciated the capacity of my small body to bend and twist.

One night, I was turning cartwheels in the house—no, probably not a good idea, but kids have a different concept of danger—and I hit my head on a wooden bench. The impact stunned more than hurt me. I sat on the floor and said, “I’m fine, Daddy,” then touched my forehead. Dripping. I vaguely recall being hauled into the bathroom, my blood a left-behind trail of spots in the green carpet.