Last year, when I was running the New York City Marathon, picking up the pace for my 26th-mile kick along Central Park South, my high school coach's voice was in my head. I imagined him coaching me to the finish, daring me to victory, and pumping his fist at the end of each race. That voice helped me run faster, and I finished in under four hours. I'm not sure I've ever been so proud of myself.
It's been 14 years since I eagerly awaited my first day of winter track practice in 2003, but the lessons my coach taught me over my seasons on the team feel as fresh and crisp as if it were yesterday, and his voice isn't in my head just when I'm running—it's in my head when I'm taking on other challenges in life, too. Here are the 12 most important life lessons I learned from my high school track coach: