One minute I was waving hello to the neighbors during a typical Rollerblading session with my dog, and the next I was flying down a newly paved hill at a runaway speed. Aiming for a soft landing, I steered up a driveway toward a lawn. My feet hit the grass, and I flew about 10 feet through the air before landing and rolling on the ground. I had the wind knocked out of me—a truly painful experience I hadn't had since childhood—but I could tell I hadn't broken any bones. I was just congratulating myself on avoiding a serious injury when I passed out.