Effects of breathing exercises on pain, disability, range of motion and muscle endurance in patients with chronic low back pain, a randomized controlled trial (Preprint)

BACKGROUND Mechanical chronic low back pain is a common musculoskeletal condition that significantly affects daily function, work productivity, and quality of life. Routine physical therapy is widely used for its management; however, interest has grown in adjunct approaches such as breathing exercises due to their potential role in pain modulation, trunk stability, and functional improvement. OBJECTIVE This study aimed to compare the effects of routine physical therapy with and without breathing exercises on pain intensity, lumbar range of motion, functional disability, and muscle endurance in patients with mechanical chronic low back pain. METHODS A single-blinded randomized controlled trial was conducted on 132 patients with mechanical chronic low back pain, who were randomly allocated into two equal groups. Group A received routine physical therapy, while Group B received routine physical therapy combined with breathing exercises for four weeks (12 sessions). Outcomes including pain (VAS), lumbar range of motion, functional disability (Modified Oswestry Disability Index), muscle endurance, and FEV₁ were assessed at baseline and follow-up. Data were analyzed using SPSS version 25, applying non-parametric tests and linear mixed models, with statistical significance set at p < 0.05. RESULTS A total of 132 patients with mechanical chronic low back pain were analyzed. Compared with routine physical therapy alone, the addition of breathing exercises resulted in a greater reduction in pain over time (group × time effect: F = 50.6, p < 0.001). Patients receiving breathing exercises also showed significantly superior improvements in lumbar range of motion across flexion, extension, side flexion, and rotation (time and interaction effects: p < 0.001). Functional disability, assessed by the Modified Oswestry Disability Index, decreased more markedly in the breathing exercise group (mean reduction: 42.4 vs 28.3; F = 4.34, p = 0.005). In addition, trunk muscle endurance (anterior, posterior, and lateral plank tests) improved significantly more in patients receiving breathing exercises compared with routine therapy alone (interaction effects: F = 524–2138, p < 0.001). CONCLUSIONS It is concluded that he addition of breathing exercises to routine physical therapy resulted in superior improvements in pain reduction, lumbar mobility, functional disability, trunk muscle endurance, and pulmonary function. CLINICALTRIAL IRCT Registration number = IRCT 20200901048579N1