Gray Cook is a physical therapist, strength coach, author, lecturer and founder of Functional Movement Systems. He consults with professional and university coaches and athletes, and teaches various aspects of physical therapy, sports medicine and performance enhancement. Cook is the author of 'Movement: Functional Movement Systems—Screening, Assessment, Corrective Strategies' (2010) and 'Athletic Body in Balance' (2003), and the creator or co-creator of over a dozen DVD packages for exercise consumers, fitness professionals and rehabilitation clinicians.