Therapeutic Exercise Progression in Patients with Nonspecific Low Back Pain: A Systematic Review.

Objective: This systematic review aimed to identify and synthesize the objective and subjective criteria currently used to guide the progression of therapeutic exercise during the rehabilitation of adults with nonspecific low back pain (NSLBP). A secondary objective was to determine whether the use of those progression criteria enhances the effectiveness of exercise interventions compared to protocols without specific criteria. Methods: A comprehensive search was performed across three electronic databases and supplemented by a manual reference screening. Eligible studies were randomized controlled trials (RCTs) including adults (>18 years) with NSLBP where at least one group received therapeutic exercise with defined progression criteria. Study selection and full-text screening were followed by risk of bias assessment using the Cochrane Risk of Bias 2 tool. Results: A total of 47 RCTs met the inclusion criteria. Due to the heterogeneity of included studies, a qualitative synthesis was conducted. Progression criteria were found to be both subjective and objective. Overall, intervention groups using predefined progression criteria showed greater short- and medium-term improvements than controls. However, only a subset of low-risk-of-bias studies confirmed these effects, and long-term benefits were rarely reported. Conclusion: Exercise progression based on specific criteria appears to offer promising benefits, particularly in the short-term reduction of pain and improvement in function. However, limitations persist regarding the direct applicability of these findings to clinical practice. Future research should aim to further standardize methodologies and establish measurable, clearly defined progression criteria for exercise-based interventions in patients with NSLBP.