Training Dose And Effect- Response Relationship Of Motor Control Stabilization Exercises On Pain And Disability In Chronic Non-specific Low Back Pain Patients: A Systematic Review With Meta-regression

Abstract

Motor control stabilization exercise (MCSE) is evident for the management of chronic non-specific low back pain (LBP). The optimal dose for the maximal treatment success-response relationship is, thus, still unknown. PURPOSE: To systematically review the evidence for a dose-response relationship of MCSE on pain and disability in chronic non-specific LBP patients. METHODS: A systematic review with meta-regression was conducted. We searched in relevant scientific databases (Pubmed (Medline), Web of Knowledge, Cochrane). The eligibility criteria for the studies were: RCTs and CTs on chronic (≥ 12 weeks) non-specific LBP patients, written either in English or German and adopting a longitudinal MCSE intervention with at least one pain intensity and/or disability outcome assessment. Meta-regressions (dependent variable = effect sizes (Cohens d) of the interventions (once for pain and once for disability), independent variable = training characteristics (duration, frequency, time per session)) were conducted to reveal the optimal dose required for MCSE therapy success. RESULTS: From the 3,415 studies initially selected, 46 studies on n = 2,661 LBP patients were included in the analysis. N = 1,220 patients received MCSE; the training duration was 6.4 ± 2.3 weeks and the training frequency was 3.4 ± 2.0 sessions per week with a mean training time per session of 44.2 ± 17.7 min. The meta-regressions’ mean effect size was d = 1.7 for pain and 2.1, for disability, respectively. Total R2 was 0.34 and 0.38. Moderate quality evidence (R2 = 0.136) revealed that a training duration of 20 to 30 minutes elicited the largest effect (both in pain and disability, logarithmic association). Low quality evidence (R2 = 0.202) revealed that training 3 to 5 times per week led to the largest effect of MCSE in chronic non-specific LBP patients (inverted U-shaped association). Training duration showed no systematic variance explanation on the effect sizes. CONCLUSIONS: In non-specific chronic LBP patients, MCSE with a training frequency of 3 to 5 times per week (Grade C recommendation) and a training time per session of 20 to 30 minutes (Grade A recommendation) elicited the largest effect on pain and disability. Future work may focus on the definition of a minimum dosage for therapy success.