Exercise has played a central role in rehabilitation of subjects with low back pain. The research in this field has intensified since the 1980s. Low back pain has been associated with both physically stressful and sedentary occupations. There is no clear association between low back pain and physical activity during leisure time. Many studies have shown that subjects with back pain have impairments in muscular and connective tissue, functional limitations in muscular strength, endurance, speed, and neuromuscular functions, and physical, social and psychological disabilities. The ultimate aims of the exercise-based programs are to reduce and prevent these impairments, functional limitations and disabilities. The results of controlled studies with exercise programs have shown a positive effect on physical impairments and functional limitations for subjects with chronic low back pain. The outcome of exercise programs has not been so positive for disability, defined as an inability or a limitation in performance in social interactions including occupational activities.