It was the easiest first day of any of my 21 ski seasons in Jackson, Wyoming: two hours on intermediate-level groomed runs at the Jackson Hole Mountain Resort. Still wearing a cast after surgery seven weeks earlier to repair a shattered wrist, I enjoyed taking it easy. Except the next morning revealed that I hadn’t taken it easy enough: I awoke unable to stand up straight and feeling like an ice pick was embedded in a long-ago herniated disc.