Quantified biomechanical properties of lower lumbar myofascia in younger adults with chronic idiopathic low back pain and matched healthy controls

Abstract

Background: Non-specific chronic low back pain (LBP) is a prevalent condition that is poorly understood with respect to possible altered physical properties. Five biomechanical properties of stiffness, frequency, decrement, creep, and stress relaxation time of the L3-L4 myofascial tissue were quantified using the MyotonPro® in chronic idiopathic LBP and matched normal control subjects.

Methods: Measurements were obtained in the resting prone position on the left and right sides (initially and after 10 min rest) in 25 chronic LBP participants (16 female, 9 male) and 25 age- and sex-matched control subjects. Surface electromyography measurements were simultaneously conducted to ensure a resting state.

Findings: Female LBP had significantly greater median decrement (p < 0.001) and stiffness (p < 0.010) than female controls. In female LBP patients, BMI correlated with decrement (p < 0.010) and creep (p < 0.050); creep also correlated with decrement (p < 0.050). Significant male versus female differences were found in all five properties in both LBP and control subgroups, except decrement in control males versus females.

Interpretation: This study showed that greater median decrement was found in LBP female subjects suggesting decrease in elasticity in the lumbar myofascia. Most of the biomechanical properties differed significantly by gender. This study further documented that right-handed dominance might correlate with greater right-sided lumbar myofascial stiffness.

Keywords: Biomechanical properties; Decrement; Idiopathic low back pain; Linear elastic; Stress relaxation time; Viscoelastic.