Symmetry and linearity of trunk function in subjects with non-specific low back pain

Objective. To investigate the effect of a standard rehabilitation program on the symmetry of trunk kinematics in subjects with non-specific low back pain. Design. Assessing lumbar spine kinematics in the cardinal planes using dynamometry. Background. Previous evaluations of trunk symmetry focussed more on anatomical rather than functional symmetry. Correlation of functional symmetry with low back pain was occasionally performed, but only for base line evaluations. To the best of the authorʹs knowledge, there is no study examining the effect of exercise on the functional symmetry of the trunk, especially in non-specific low back pain subjects. Methods. Two groups of young male subjects whose working conditions incurred long daily hours of sitting and standing participated in the study. Muscles of the lumbar spine were initially evaluated in the cardinal planes using dynamometry. The same parameters (maximum isometric torque, dynamic torque, angular velocity and range of motion) were then repeatedly measured throughout a standardized strength protocol lasting for 12 sessions over a four-week period. Results. As pain gradually disappeared over a one-month period of rehabilitation, certain factors of the trunk kinematics exhibited convergence towards perfect symmetry while others showed oscillations. Moreover, global right–left data for certain trunk kinematics exhibited near-perfect linear relationship. Conclusion. Functional symmetry of the trunk in the coronal and transverse planes can be used to assess the progress of rehabilitation programs of non-specific low back pain subjects.