Dr. Jordan Metzl, a nationally recognized sports medicine physician, author of the Workout Prescription, and creator of the IronStrength Workout DVD, shares how he has become an evangelist of sorts—for prescribing exercise as medicine for injured athletes. (2:18)We head to Central Park to see just what brings runners—and athletes of all kinds—out on a frigid day for a high intensity workout called IronStrength. (25:55)In the Kick, what it takes to run 100,000 lifetime miles, a relay team that you wouldn’t want to see on the track, and how one man dominated seven marathons on seven continents in seven days. (36:03)The Runner’s World Show is brought to you by Blue Apron, the No. 1 fresh ingredient and recipe delivery service in the country. Check out this week’s menu and get your first 3 meals free—with free shipping—by going to blueapron.com/run.And by Aaptiv, an on-demand audio fitness app that you can do at home, at the gym, outdoors—anywhere. Get your first month free when you sign up for a monthly subscription at aaptiv.com  and use the promo code “RUN.”Episode Credits: Host: David Willey Producers: Sylvia Ryerson, Christine Fennessy and Brian Dalek.The Runner's World Show is a proud part of Panoply.Check out our show page here. Follow us on Twitter (@rwaudio) and Facebook (Runner's World Audio).