The book starts with assessment in pediatric exercise science, which is discussed in 13 sections as follows: 1- Ethics in paediatric research: principles and processes; 2- Interpreting exercise performance data in relation to body size; 3- Anthropometry, physique, body composition and maturity; 4- Muscle strength; 5- Maximal intensity exercise; 6- Pulmonary function; 7- Cardiovascular function; 8- Aerobic fitness; 9- Field tests of fitness; 10- Physical activity; 11- Effort perception. In part II developmental aspects of pediatric exercise science are presented between sections 12 and 23: 12- Growth and maturation; 13- Developmental biodynamics: the development of coordination; 14- Motor development; 15- Muscle strength; 16- Exercise metabolism; 17- Maximal intensity exercise; 18- Pulmonary function; 19- Cardiovascular function; 20- Aerobic fitness; 21- Loco-motor economy; 22- Oxygen uptake kinetics; 23- Tem-perature regulation. Physical activity, fitness and health issues are discussed in part III in 7 sections (from 24 to 30): 24- Physical activity, physical fitness, and health: current concepts; 25- Physical activity, physical fitness and cardiovascular health; 26- Gene-physical activity interactions and their role in determining cardiovascular and metabolic health; 27- Physical activity, physical fit-ness, and bone health; 28- Physical activity, physical fitness, and social, psychological and emotional health; 29- Sport, physical activity, and other health behaviours; 30- Systematic promotion of physical activity . Then, in part IV chronic health conditions and physical activity matters followed from section 31 to 36: 31- Exercise testing in congenital heart disease; 32- Exercise, physical activity, and asthma; 33- Exercise, physical activity, and cystic fibrosis; 34- Exercise, physical activity, and eating and weight disorders; 35- Exercise capacity and training in cerebral palsy and other neuromuscular diseases; 36- Exercise, sport, and diabetes mellitus. Finally, in the last part the elite young athlete is examined in detail between sections 37 and 48: 37- The elite young athlete; 38- Hor-monal responses and adaptations; 39- Aerobic training; 40- Maximal intensity exercise and strength training; 41- Young athletes with a physical or mental disability; 42- Current concepts on the aetiology and prevention of sports injuries; 43- Aetiology and prevention of injuries in physical education classes; 44- Aetiology and prevention of injuries in youth competitive contact sports; 45- Aeti-ology and prevention of injuries in youth competitive non-contact sports; 46- Upper extremity and trunk inju-ries; 47- Lower-limb injuries in sporting children; 48- Injuries to the head and cervical spine.