COMPARATIVE EFFICACY OF LOW-FREQUENCY CURRENT WITH AND WITHOUT HEAT IN THE MANAGEMENT OF CHRONIC LOW BACK PAIN

Abstract

Background: Chronic low back pain is a major cause of disability. Electrotherapy using low-frequency current is often used in physiotherapy; heat is frequently added with the assumption it enhances therapeutic effects. However, evidence comparing low-frequency current with heat versus without heat in back pain is limited. Methodology: This randomized controlled trial was conducted at Health & Wellness Physio Rehab Center from January 2024 to April 2025. Sixty adults with chronic non-specific low back pain (duration ≥ 3 months) were randomized into two groups: the experimental group (n = 30) receiving low-frequency current plus superficial heat, and the control group (n = 30) receiving low-frequency current without added heat. Treatment sessions were delivered three times per week for 12 weeks, with baseline, 6-week, and 12-week assessments. Primary outcomes were pain measured by VAS (0-10) and disability by Oswestry Disability Index (ODI %). Secondary outcomes were lumbar range of motion (flexion / extension in degrees) and functional test (sit-to-stand time). Data were analyzed using SPSS version 26, using repeated‐measures ANOVA (group × time), post hoc pairwise comparisons, effect sizes (Cohen’s d), and checking assumptions of normality (Shapiro-Wilk) and sphericity (Mauchly’s test). Results: Fifty-six participants completed the study (experimental n = 28; control n = 28). There were no baseline differences between groups (p > 0.05). Repeated measures ANOVA showed significant group × time interaction for VAS (F (2,108) = 7.42, p = 0.001) and ODI (F (2,108) = 9.15, p < 0.001). At 12 weeks, mean VAS reduction was 3.5 (SD 1.1) in the experimental group vs 2.1 (SD 1.0) in the control (between-group p = 0.002, Cohen’s d = 1.33). Mean ODI reduction was 15.6% (SD 6.0) vs 8.3% (SD 5.5) (p = 0.001, d = 1.27). Range of motion and sit-to-stand also improved more in the experimental group (p < 0.05). No serious adverse effects reported. Conclusion: Adding superficial heat to low-frequency current therapy provides greater improvements in pain, disability, and function over 12 weeks than low-frequency current alone in patients with chronic low back pain. Physiotherapists should consider combining heat with low-frequency electrotherapy for better outcomes.