Correlation Coefficients of Hip Muscle Group Weakness and ‎‎Imbalance with Low Back Pain

Purpose: Hip muscle weakness and asymmetry have been implicated in low back pain, but coexisting impairment does not establish an association with symptom severity. This study examined correlations between hip muscle grades and pain intensity, alongside exploratory bilateral and within-limb grade comparisons.

Materials and Methods: A cross-sectional study included 25 adults with low back pain attending private physiotherapy clinics in Zawia, Libya. Data collection began on 25 February 2019 and continued for three weeks. Bilateral hip and knee muscle actions were assessed using manual muscle testing on a 0–5 ordinal scale. Pain was labelled a visual analogue scale in the source, although its illustration depicts a 0–10 numeric rating scale. Available Pearson correlations and paired comparisons were reviewed; approximate confidence intervals for correlations were derived from reported coefficients and sample size.

Results: Participants comprised 15 men and 10 women. Hip muscle mean grades ranged from 2.20 to 3.32 on the right and 2.72 to 3.40 on the left. None of the 12 hip-grade correlations with pain reached the nominal 0.05 threshold (r = −0.365 to 0.081; P = 0.072–0.987). Hip flexion showed the largest negative correlations: right r = −0.362 (approximate 95% CI −0.662 to 0.039) and left r = −0.365 (−0.664 to 0.035). Hip extension grades were lower on the right than the left (mean difference −0.52 grades; reported P = 0.001). One bilateral internal-rotation output was internally inconsistent. No participant-level imbalance–pain coefficient was supplied.

Conclusion: Lower manual muscle grades and selected between-action or side-to-side differences coexisted with low back pain, but the study did not demonstrate a statistically significant association between individual hip grades and pain intensity. These small-sample findings neither establish muscle imbalance as a cause of pain nor exclude clinically relevant associations. (Open J Biomed Res 2026;5:155-163)