Non-specific low back pain lasting for 12 weeks or more is termed as non-specific chronic low back pain (NSCLBP). Motor control impairment subgroups exist in non-specific chronic low back pain (NSCLBP) as per a multidimensional classification approach. The changes in sitting lumbar posture were revealed between two such subgroups- flexion pattern (FP) and active extension pattern (AEP) and healthy individuals, although, the functional spinal movement was not investigated. This study was performed to explore whether NSCLBP subgroups displayed regional spinal kinematic differences, as distinguished from healthy individuals, during functional tasks.

A total of 78 subjects comprising 50 NSCLBP (27 FP, 23 AEP) and 28 healthy individuals were considered for this observational, cross-sectional study design. Their spinal kinematics was examined using 3D motion analysis during functional tasks [reaching upwards, step down, step up, lifting, and replacing a box, stand-to-sit, sit-to-stand, bending to retrieve (and returning from retrieving) a pen from the floor]. The mean sagittal angle for the total thoracic, total lumbar, upper thoracic, lower thoracic, upper lumbar, and lower lumbar regions between groups were distinguished.

During most tasks, the notable changes were observed in the lower thoracic and upper lumbar regions between NSCLBP subgroups. The tasks like stand-to-sit-to-stand and bending (and returning from) to retrieve a pen from the floor portrayed significant changes between the FP and healthy group in the lower thoracic region. All important outcomes revealed that the FP group should operate in comparatively greater flexion.

It was concluded that the thoracolumbar spine discriminated between FP and AEP, and FP and healthy groups during functional tasks. In the FP individuals, more kyphotic thoracolumbar postures were observed which may provoke pain. Alternative mechanisms may occur in AEP as no notable differences were observed between AEP and healthy groups.