The effects of hamstring stretching exercises on pain intensity and function in low back pain patients: A systematic review with meta-analysis of randomized controlled trials

Objectives: This meta-analysis aims to synthesize the available data on the effectiveness of hamstring stretching exercises in relieving pain intensity and improving function for patients with low back pain. Methods: Google Scholars, PubMed, Embase, Cochrane, MEDLINE, CNKI, Wanfang, and VIP were searched from inception to August 2023. We included randomized controlled trials that investigated the effectiveness of hamstring stretching exercises in patients with low back pain. The primary outcomes assessed were pain intensity, hamstring muscle flexibility, and function. Study selection, data extraction, and assessment of risk of bias were performed independently by two reviewers. Results: Our searches retrieved 344 trials, of which 14 met the inclusion criteria for this review (n = 735 participants). The combined meta-analysis showed hamstring stretching resulted in lower pain scores (standardized mean difference = -0.72, 95% confidence interval: -1.35 to -0.09; I-2 = 89%, p = 0.03) in different categories of low back pain. Subgroup analysis showed that hamstring stretching led to a larger range of motion for cases of back pain with radiating pain (standardized mean difference = 2.39, 95% confidence interval: 1.76 to 3.02; I-2 = 0%, p < 0.001). The combined meta-analysis revealed that hamstring stretching resulted in lower Oswestry Disability Index scores in comparison to regular treatment, particularly in individuals suffering from low back pain across all subtypes (mean difference = -6.97, 95% confidence interval: -13.34 to -0.60; I-2 = 95%, p = 0.03). Conclusions: This meta-analysis demonstrates the effectiveness of hamstring stretching exercises in reducing pain intensity in various categories of low back pain and improving the straight leg raise in patients experiencing back pain with radiating pain. Additionally, it highlights the improvement in function for patients with back pain across all subtypes.