Mark Verstegen is recognized as one of the world's most innovative human performance experts. As the founder and president of EXOS, he directs teams of specialists to train U.S. Special Operations Forces personnel and some of the biggest names in sports. Verstegen serves as director of performance for the NFL Players Association and is an advisor to numerous leading performance-oriented companies. His first book, Core Performance, revolutionized how people train. He lives in Arizona.
Pete Williams is the author or coauthor of a number of books, including Mark Verstegen's five book Core Performance franchise. An avid endurance athlete, he's the author of Obstacle Fit and coauthor of Paddle Fit and lives in Central Florida.