Fitness: The Complete Guide, Edition 8.6.6 is the official textbook used for ISSA’s Certified Fitness Trainer program; it’s a large, comprehensive reference that covers all the core knowledge needed to pass the CFT exam and train general-population clients safely and effectively.What the book isIt is ISSA’s in‑house course text, often shipped with their Certified Fitness Trainer (CFT) package and referenced throughout the online curriculum.The 8.6.6 designation is simply the specific edition/version of the text; content is broadly similar to the “Fitness: The Complete Guide” textbook you’ll see referenced for ISSA CFT in general.Main topics coveredThe book is designed as a full curriculum rather than a casual read, and typically includes:Anatomy and physiology, muscle anatomy, and basic biomechanics.Metabolism and energy systems; principles like overload, specificity, reversibility, periodization, and overtraining.Exercise programming, assessments and fitness testing, special populations (older adults, medical conditions), emergency procedures, and program administration.Nutrition fundamentals, caloric needs, weight management, supplements, and behavior/motivation basics.How it’s typically usedIt functions as both an exam-prep manual and a reference you can go back to when writing programs, doing assessments, or working with special populations.ISSA expects CFT candidates to be comfortable with anatomy/physiology, program design, basic nutrition, and safety concepts at the level presented in this text.