Associations of Weight-Bearing Lunge Test Performance and Occiput-to-Wall Distance With Chronic Low Back Pain Intensity in Older Adults

Purpose: We investigated whether weight-bearing lunge test (WBLT) performance and occiput-to-wall distance (OWD) were associated with chronic low back pain (LBP) intensity in older adults.Materials and methods: This multicenter cross-sectional study included 208 outpatients with chronic LBP (mean age, 74.5 years) assessed between April 2024 and March 2025.LBP intensity was assessed using the Numerical Rating Scale (NRS).Multivariable linear regression analyses were performed with NRS score as the dependent variable.Model 1 included WBLT performance and OWD, whereas Model 2 additionally included age, sex, body mass index (BMI), symptom duration, and appendicular skeletal muscle mass (ASM) as potential confounders.Receiver operating characteristic (ROC) analyses for moderate-to-severe pain (NRS ≥ 4) were conducted as exploratory secondary analyses.Results: In Model 1, lower WBLT performance (standardized β = -0.414,t = -5.470,p < 0.001) and greater OWD (standardized β = 0.190, t = 2.513, p = 0.013) were significantly associated with greater LBP intensity.After additional adjustment in Model 2, lower WBLT performance remained significantly associated with greater LBP intensity (standardized β = -0.465,t = -5.981,p < 0.001), whereas the association between OWD and pain intensity was attenuated and was no longer statistically significant (standardized β = 0.143, t = 1.720, p = 0.088).Exploratory ROC analyses identified cutoff values of 0.9 cm for WBLT and 4.5 cm for OWD for moderate-to-severe pain.Conclusion: In older adults with chronic LBP, lower WBLT performance remained significantly associated with greater pain intensity in the fully adjusted model, whereas the association between OWD and pain intensity was not statistically significant.However, OWD showed higher discriminatory ability in the exploratory ROC analysis and was significantly associated with pain intensity in an additional sensitivity analysis.Both measures may provide complementary clinical information, although the cross-sectional design and missing data warrant cautious interpretation.