Regular physical activity promotes health. An inactive lifestyle may alter gene expression, influence negatively on several organ systems and thereby cause chronic disease and increase mortality. These conditions may be reversed by regular activity and in creased level of physical fitness. Physical activity and fitness also parallel QoL, reduced depression and improved social welfare. Patients with chronic pain report reduced physical function, lower muscular strength and aerobic fitness. There is an urgen t need to investigate these aspects in large scale epidemiological studies and in prospective cohort studies. Through the establishment of a long term interdisciplinary research collaborative with scientists from physical exercise, clinical research, epid emiology, outcome assessment, pharmacology and molecular biology at the Faculty of Medicine, NTNU including international collaborators, physical activity, pain and general health and genomics will be targeted. In the first phase of the collaborative, one will scientifically investigate how physical activity may cause, modulate and prevent chronic pain, general health, major diseases as well as improvement of Quality of life (QoL). In the next phase the collaborative will embark on intervention studies. T he Nord-Trøndelag Health Survey (HUNT), the largest population based health study in Norway, is the basis for the collaboration in this phase of the research. The study material will consist of data from HUNT-2 and HUNT-3 (study I) supplied by two studies . One will test physical activity and capacity of a representative cohort of approximately 10000 participants (study II), a representative sample of HUNT-3. Furthermore, a prospective follow-up study (study III) of 3000 participants followed over a five y ear period, a representative draw from the 10000 cohort and HUNT-3. The overall goal is to establish a long lasting collaborative to investigate the effect of physical activity and capacity on health.