It’s an early-spring Saturday afternoon in Midlothian, Virginia, and in a backyard buzzing with activity—kids on a zipline, flying baseballs, careening scooters—a race is afoot. The challenger: a freckled 7-year-old boy wearing the head-to-toe maroon of Virginia Tech. Accepting that challenge: a mom in black running tights, long blond hair pulled into a loose bun, smile incandescent. At the boy’s call, they scrabble down the wooden stairs of the back porch, dodge family members, and sprint up the driveway. There’s a few seconds of silence as the pair disappears around the front of the house, and then the boy rounds the corner again, yelling, “I beat Aunt Kiki running! I beat Aunt Kiki running!”

The loser pretends to breathe hard, hands on knees, and then protests teasingly, “Hey, I wasn’t running the tangents!” But Keira D’Amato doesn’t seem too disappointed. After all, just three months prior, at age 37, she set a new American record for the marathon in Houston, besting a time that had stood since 2006.