JOE DE SENA is the founder of Spartan Race, as well as a legend in endurance and adventure racing circles—he completed the 135-mile Badwater Ultramarathon, raced the 140.6 miles of Lake Placid Ironman, and finished a 100-mile trail run in Vermont, all within one week. He lives in Vermont.
John Durant is the author of The Paleo Manifesto, and has been ranked as one of The 100 Most Influential People in Health & Fitness by Greatist. He is the founder of Wild Ventures, a venture group specializing in consumer health products and technology.