Abstract
Background/Objectives: Cesarean birth (CB) is linked to nonspecific low back pain (NSLBP). Different properties of the muscular tissue, including contractile, biomechanical, and viscous properties, may reflect its physiological or pathological condition. This study aimed to measure these properties of lumbar paravertebral muscles (LPVMs) and their relationship with post-CB mothers with moderate-severity NSLBP and match their measurements to those of the controls. Methods: Sixty women were included in this case-control research. They were divided into two equal groups: Group (A) representing cases, consisted of 30 females who experienced CB and complained of moderate-severity NSLBP, and Group (B) representing controls, consisted of 30 healthy females who had never experienced pregnancy with no or mild-severity NSLBP. Results: The statistical analysis between the two groups yielded significant differences in the right and left LPVMs' tone (p = 0.002 and 0.015), relaxation time (p = 0.002 and 0.022), and creep (p = 0.013 and 0.008), respectively. On the other side, there were non-significant differences in the right and left LPVMs' stiffness (p = 0.055 and 0.367) and elasticity (p = 0.115 and 0.231), respectively. The regression analysis's final model indicated a strong overall performance (Nagelkerke: 1.00). Conclusions: The LPVMs of post-CB mothers with moderate-severity NSLBP showed remarkable changes in both contractile and viscous properties: muscle tone notably decreased, while viscosity increased. However, biomechanical properties like stiffness and elasticity showed negligible changes. This fitted regression analysis illustrated the holistic strong effect of LPVMs' properties as risk factors contributing to post-CB NSLBP, emphasizing their consideration in diagnosis and intervention strategies for such cases.