Core Strengthening Effects in Low Back Pain in Overweight Adults (CORE-BACK)

Mechanical low back pain (MLBP) is a common musculoskeletal condition and one of the leading causes of disability worldwide. Overweight and obesity increase the mechanical load on the lumbar spine, alter spinal biomechanics, and contribute to reduced physical function and persistent pain. Excess body weight, decreased physical activity, and weakness of the trunk musculature may further compromise spinal stability, increasing the likelihood of chronic low back pain.

Core muscles, including the transversus abdominis, multifidus, erector spinae, diaphragm, pelvic floor muscles, rectus abdominis, and internal and external oblique muscles, play an essential role in maintaining spinal stability and functional movement. Strengthening these muscles may improve trunk stability, reduce mechanical stress on the lumbar spine, decrease pain, and enhance functional ability. Although several studies have investigated core stabilization exercises, evidence regarding their effectiveness in overweight adults with mechanical low back pain remains inconclusive.

This study was designed as a single-blinded randomized controlled trial to compare the effects of conventional physical therapy alone with conventional physical therapy combined with core strengthening exercises in overweight adults with chronic mechanical low back pain.

A total of 60 participants aged 25-45 years with chronic mechanical low back pain of more than three months' duration, BMI ≥25 kg/m², body fat percentage greater than 25%, and Numeric Pain Rating Scale scores below 7 were enrolled. Participants with non-mechanical low back pain, previous lumbar spine surgery, spinal fractures, spondylolisthesis, osteoporosis, neurological disorders, metabolic diseases, spinal trauma, or other serious spinal pathology were excluded.

Eligible participants were randomly allocated into two equal groups.

Experimental Group

Core strengthening exercises:

Plank Side plank Superman exercise

Conventional exercises:

Bridging Knee-to-chest exercise Back extension Pelvic rotation

Baseline physical therapy:

Therapeutic hot pack Continuous Transcutaneous Electrical Nerve Stimulation (TENS) for 10 minutes

Control Group

Conventional exercises:

Bridging Knee-to-chest exercise Back extension Pelvic rotation

Baseline physical therapy:

Therapeutic hot pack Continuous TENS for 10 minutes

Participants attended three supervised treatment sessions per week for six consecutive weeks (18 treatment sessions). Each exercise was performed for 10 repetitions with a 10-second hold and standardized rest intervals. Participants were advised to avoid heavy physical activities throughout the intervention period.

Outcome measures were assessed at baseline and after completion of the intervention. Pain intensity was evaluated using the Numeric Pain Rating Scale (NPRS). Functional disability was assessed using the Oswestry Disability Index (ODI). Body fat percentage was measured using the Jackson-Pollock three-site skinfold method.

Data analysis was performed using SPSS version 21. Normality of data distribution was assessed using the Kolmogorov-Smirnov test. Because several variables were not normally distributed, non-parametric statistical tests were used. Between-group comparisons were analyzed using the Mann-Whitney U test, while within-group pre- and post-treatment comparisons were analyzed using the Wilcoxon Signed-Rank test. Statistical significance was established at a p-value less than 0.05.

The study investigated whether the addition of core strengthening exercises to conventional physical therapy would provide greater reductions in pain intensity, disability, and body fat percentage than conventional therapy alone in overweight adults with chronic mechanical low back pain. The findings are expected to contribute to evidence-based rehabilitation strategies for managing mechanical low back pain in overweight individuals and assist clinicians in selecting effective exercise interventions for this patient population.