[From exercise physiology to sports medicine]

Physical activity causes marked circulatory and metabolic adaptations, and results in marked alterations in e.g. skeletal muscle and connective tissue. Strengthening of skeletal- and heart-muscle, an improved oxidative capacity and an increased hormone sensitivity not only lead to an improved overall functional level in elderly and in frail patients, but also contribute to improvement in risk factors for development of inactivity related diseases. Patient groups can achieve pronounced both general and more disease specific improvements through regular physical activity, and better knowledge as regards to how exercise can be used correctly as therapy in rehabilitation, in preventing loss of function and disease development, and in training of the chronically sick is needed. Exercise leads to a large amount of overuse injuries in connective tissue. Through usage of in-vivo techniques it has become possible to study tissue (e.g. tendon) adaptation to physical loading and training more closely. A deeper understanding of the underlying mechanisms behind the development of overuse injuries is crucial for diagnostic and treatment regimens not only in sports medicine, but also in more general terms within disease prevention and treatment.