 Dr. Macedo and others involved in the proposed research recently conducted a study that investigated whether simple clinical characteristics could identify patients who benefit more from either motor control exercises or graded activity. Results were statistically significant and clinically relevant demonstrating that a simple questionnaire could help aid the selection of the most appropriate exercise therapy for each individual patient. Therefore, we aim to conduct a randomized controlled trial following a similar approach to the original study to validate in a different sample the results of the effect modification analysis. 