A disease of unknown etiology that begins before age 16 and is in a heterogeneous group of chronic inflammatory arthritis is called juvenile idiopathic arthritis. It results in inflammation that lasts for at least 6 weeks and involves one or more joints. It is the most common rheumatic and chronic disease in childhood and an important cause of disability in children. It is more common in girls. It appears in three forms: oligoarticular, polyarticular and systemic. It involves several diseases and its exact frequency is not known. Genetic, immunological, and environmental factors play an important role, although the cause and pathogenesis of juvenile idiopathic arthritis are poorly understood. JIA is an autoimmune disease and is an important genetic predisposition of patients in the pathogenesis of the disease. Various abnormalities of the immune system and the inflammatory response of the organism have an important influence on the development and course of the disease. Studies have shown that cytokine networks, regulatory T lymphocytes, and alarmins or molecules associated with damage are of great importance in pathogenesis. A warm, swollen and painful joint, red skin above the joint, and disturbed joint function, are classic signs of inflammation by which arthritis is recognized. The basis of the diagnosis is a comprehensive history, examination, imaging and laboratory findings. In order to restore lost functions and prevent permanent handicap, it is necessary to start the entire rehabilitation program early. Such a program is extremely important. The main goal of rehabilitation is to preserve the child's functional ability and autonomy because JIA is the disease that leaves the biggest handicap in childhood. The objectives of the seminar paper are to investigate the impact of intensive exercise on the patient, his course of illness and his desire to continue exercising, to determine whether the disease affects quality of life, and to discover whether there is a difference in MAS frequency using different diagnostic guidelines.