BRET CONTRERAS, PhD, CSCS, *D, is a teacher, innovator, personal trainer, bestselling author, researcher, international lecturer, and lifter. Best known for his glute training methods, he has established himself as the world’s leading expert in gluteal muscle functioning and development, strength training, and program design. In addition to developing a comprehensive glute training system, Bret discovered and popularized the barbell hip thrust exercise and invented the Hip Thruster and Skorcher machines. He is the author of bestselling books Bodyweight Strength Training Anatomy (Human Kinetics, 2014) and Strong Curves (Victory Belt, 2013) and has published over fifty peer-reviewed studies on strength training. He has also contributed to well-known industry publications including Men’s Health, Men’s Fitness, Oxygen, and Muscle & Fitness. Bret owns and operates the Glute Lab Gym in San Diego, California, and continues to publish articles and coach clients remotely on his website, bretcontreras.com.

GLEN CORDOZA is one of the most published authors in the world on the topics of MMA, jiu-jitsu, Muay Thai boxing, and fitness with twenty-six books to his credit. These works include co-authorship with MMA superstars Randy Couture, BJ Penn, Anderson Silva, Fedor Emelianenko, and Lyoto Machida and jiu-jitsu legends Eddie Bravo and Marcelo Garcia. He also co-authored Power, Speed, Endurance by Brian MacKenzie, as well as the New York Times and Wall Street Journal bestselling books Becoming a Supple Leopard and Deskbound by Kelly Starrett. In addition to his accomplishments as an author, Glen has a 12–0 professional Thai boxing record and a 3–1 professional MMA record and holds the rank of black belt in 10th Planet Jiu-Jitsu.