To combat the inner resistance of patients, clients, or employees, strong arguments are just as necessary as strategies for behavior change and successful training concepts. This practical book provides physiotherapists, fitness trainers, (sports) physicians, and experts in workplace health promotion with knowledge from sports and nutritional physiology as well as training methods, helping them to sustainably and appreciatively manage the inner resistance. It offers fitness and health professionals across all fields practical tools for performance diagnostics, planning and conducting individualized training, fundamentals of performance-enhancing nutrition for both mind and body, as well as psychological principles for increasing motivation. Questionnaires, measurement tools, and numerous supplementary materials for download assist in the development process.