Control group: m-health-booklet and pain education
pain
Patients allocated to the control group received a login and password for individual access to the smartphone app designed for the study. The app content for this group included two components: (1) an online booklet and (2) weekly messages. The online booklet contained general information about self-management of CLBP, including pain education, advice on healthy lifestyle and sleeping habits, and promotion of physical activities based on the “Back Book” (see Additional file The message component provided 8 messages (one per week), with their contents taken from the online booklet. Messages included information about the benefits of exercise, motivation, and positive messages about coping with pain. Before intervention begins, participants received a yoga mat, an elastic band, and a link to a video tutorial on how to use the app. To increase adherence to the intervention, after the study is concluded, the training function available in the app will be offered to the control group participants if the intervention group proved to be more effective than the control group.