Correlation between Pain, Back Function, Lumbar Flexibility, Hamstring Flexibility, and Pain Pressure Threshold in Subjects with Chronic Non-Specific Low Back Pain: A Cross-Sectional Analysis

Abstract

Background: Chronic nonspecific low back pain (CNSLBP) is a multifactorial condition in which pain, back function, lumbar mobility, hamstring flexibility, and pain sensitivity may be interrelated. This study aimed to examine the association between pain, pressure pain threshold (PPT), back function, hamstring flexibility, and lumbar flexion/extension mobility in patients with CNSLBP.

Materials and Methods: Thirty-four subjects with a mean age of 31.32 ± 0.99 years who were diagnosed with CNSLBP were recruited.  Pain intensity was measured using the Numeric Pain Rating Scale (NPRS), Pain pressure threshold (PPT) using a pressure algometer (PA), functional disability using Oswestry disability index (ODI). In addition, lumbar flexion and extension flexibility were measured using the Modified-Modified Schober's test, and hamstring flexibility using Active Knee Extension test (AKE) and a bubble inclinometer. Spearman’s correlation coefficient analysis was performed.

Results: A negative correlation was found between pain and lumbar flexion (r = -0.51, p = .002) and between pain and lumbar extension (r = -0.36, p = .038). An inverse correlation was also detected between pain and the right (r = -0.50, p = .003) and left (r = -0.55, p < .01) hamstring flexibility, while Lumbar extension correlated positively with the right (r = 0.59, p < .01) and left (r = 0.52, p = .002) hamstring flexibility. 

Conclusion: Subjects with CNSLBP demonstrate multi-factorial, inter-related outcomes supporting the use of a multi-factorial approach to assessment in future research.