Low back pain is the most prevalent health problem in Switzerland. Exercise is the most effective means of primary and secondary prevention. In acute low back pain, it is recommended to reduce exercise and sporting activities but maintain a daily physical activity as usual as possible. Exercise is however effective in subacute or chronic low back pain. It reduces deconditioning and breaks the downward spiral of chronicity. Sporting activities have been little studied but could promote long-term adherence more than a prolonged exercise program. It seems reasonable to advise against sports involving heavy loads to lift or sudden changes of direction. However the notion of pleasure must remain a priority.