For many people, mechanical low back pain (LBP) is a long-term, function-limiting condition rather than a short-term, self-limiting condition. Exercise is one of the primary non-surgical approaches used worldwide for managing LBP. Specifically in people with chronic LBP, exercise has been found to be as efficacious, if not more efficacious than 1) no treatment, 2) usual care, and 3) many other treatments, such as massage or laser therapy. Despite the growing body of evidence for the beneficial effects of exercise, however, there is limited evidence about 1) which exercise is best for which person, 2) how long the effects of different exercises last, 3) which types of exercise people will adhere to, and for how long, and 4) the mechanisms underlying the effects of different types of exercise.