Individuals with childhood-onset physical and developmental disabilities often have special needs around exercise and physical activity. However, most books on this topic are written for exercise science experts who may not always be the frontline service provider. This book provides clear and evidence-based information on how to evaluate, train, and foster physical activity and fitness in individuals with childhood-onset disabilities safely across the lifespan. It is written for frontline service providers, such as clinicians and other rehabilitation professionals, as well as individuals with childhood-onset physical and developmental disabilities and their families. The authors thereby respond to specific needs and enable multiple parties to lead more physically active lives. Themes include physical fitness and activity assessment and training, safe engagement, measurement of activity levels and progress, and responses to pain. It includes disorder-specific chapters that apply the general principles of physical activity training to specific diagnoses including autism and juvenile arthritis.