Brian is the author of the New York Times bestseller Unbreakable Runner, as well as the book Power, Speed, Endurance and the program that inspired it at PowerSpeedEndurance. He is a world-renowned strength and conditioning expert and a co-founder of XPT Life. Mackenzie and his program have been featured in Runners World, Men's Journal, The Economist, Tim Ferris's New York Times bestseller The 4-Hour Body and many other leading publications. Brian works with several CrossFit Games athletes, including champions Rich Froning, Jr. and Annie Thorisdottir. He has also coached and is married to Erin Cafaro-Mackenzie (2X Olympic Gold Medalist in Rowing – W8+) and has guided world and Olympic champions and performance innovators like Laird Hamilton, Taylor Ritzel (2012 Olympic Gold Medalist – W8+), Sara Hendershot (2012 Olympian – W2), Jamie Mitchell, Koa Rothman, Koa and Alex Smith, Nathan Florence and Elliot Sloan. 


Andy is a Professor of Kinesiology at the Center for Sport Performance at California State University, Fullerton. He has a Ph.D. in Human Bioenergetics and is the founder and director of the Biochemistry and Molecular Exercise Laboratory. Andy works directly with professional athletes in the NFL, MLB and UFC and played a major role in Helen Maroulis’s run to gold in the 2016 Rio Olympics. He is a co-host of the popular training podcast Barbell Shrugged, which has more than 300,000 followers, and has been featured in countless magazine articles, television shows and other podcasts. One interviewer called him “the Tony Stark of human performance.” 


Phil is an Emmy-nominated writer who frequently contributes to The Inertia, SUP the Mag and Canoe & Kayak. He is the co-author, with Dr. Kelly Starrett, of the forthcoming books Flight Plan and Waterman 2.0, and is also collaborating on Game Changer with University of Michigan football performance director Dr. Fergus Connolly and Bridging the Gap with Sue Falsone, the first female athletic head trainer in Major League sports. His other books include Whistle Stop, which Larry King said, “I can’t put down,” and Our Supreme Task, which The Times Literary Supplement called “Illuminating.”