It is estimated that 8 out of 10 people suffer from low back pain at some point in their life.  While most episodes are self-limited and resolve spontaneously, approximately 20% of low back pain episodes recur within 6 months of their initial occurrence.  The subset of patients with low back pain who continue to experience chronic symptoms is so large that chronic low back pain (CLBP) (defined as low back pain for > 3 months) has been acknowledged as the most common cause of disability in individuals between 45 and 65 years old. [3, 4]\(\)Most of the time CLBP is non-specific meaning there is no evidence of structural abnormalities, however, discopathies are observed in 26–40% of patients, being this the second most common cause of CLBP. [5, 6] Societal and economic costs of CLBP are high, with most of these costs attributed to productivity loss due to incapacity.  Medical and surgical interventions may also be too expensive and catastrophic for patients suffering from CLBP. 
Important studies have demonstrated that exercise reduces pain and improves function in patients with CLBP. [9–11] Clinical implementation of exercise programs as a treatment for CLBP is challenging due to the lack of outcome consistency. Many of the differences in outcomes are due to the wide variety of exercise programs available, the use of supervised programs versus non-supervised programs, the low patient adherence to exercise programs, and the inconsistent recommendations of intensity and duration of programs. Patients suffering from CLBP report several barriers preventing them from following a regular exercise program going from the lack of motivation to the absence of self-involvement in the treatment.  A well-established affordable and accessible exercise program, that combines supervised with self-management interventions, and that focuses on strength/resistance and coordination/stabilization would be the perfect option to manage CLBP.
Mobile health (mHealth), referred to as the use of mobile phone applications for health-related measures, has emerged as an accessible tool for health care that offers psychological and medical assistance remotely reducing health care use, emergency room visits, and unnecessary expenses. Mobile apps related to health, promoting self-care and self-management, have greatly increased in the last couple of years.  Recently a study evaluating an app for chronic pain revealed mHealth is efficient for treating chronic pain, with better results observed in patients more engaged to the app.  There are currently multiple apps in the market trying to address CLBP, however many of them are low quality and lack evidence on their effectiveness. [15, 16]
Limbr (pronounced “Limber”) is the first mobile phone app developed to treat chronic lower back pain using the Back Rx rehabilitation program. The Back Rx program was developed in 2004 and has shown great success in preventing and treating CLBP. [11, 17] It consists of a 15-minute exercise program that combines yoga and pilates exercises promoting strength, coordination, and stability. Limbr was released to promote patient adherence to the program, encourage self-management, provide videos demonstrating the correct exercise technique, and offer professional coaching support and supervision. This pilot study is intended to evaluate the effectiveness of Limbr in treating low back pain in patients with discogenic CLBP and evaluate patient adherence to the Back Rx program, laying the basis for future randomized trials.