Jeff Horowitz is a certified running, cycling, and triathlon coach and a personal trainer who has run more than 200 marathons and ultramarathons across six continents. Formerly an attorney, he quit law to pursue his passion for endurance sports. He currently teaches running at the George Washington University and works with runners from ages 14 through 80. Horowitz is the author of Quick Strength for Runners, Smart Marathon Training: How to Run Your Best Without Running Yourself Ragged, My First 100 Marathons: 2,620 Miles with an Obsessive Runner, and Ageless Strength: Strong and Fit for a Lifetime.