A less active environment, changes in leisure activities, poor posture among adolescents, restlessness in the classroom, learning difficulties - there are many reasons why more exercise in schools is needed today. This book aims to present a wide range of arguments as to why more exercise in primary and secondary schools not only makes sense, but is absolutely essential. The focus will be on the much-discussed question of whether the concept of the 'active school' is also recommended for secondary schools.