Original articleEffects of low back pain and of stabilization or movement-system-impairment treatments on induced postural responses: A planned secondary analysis of a randomised controlled trial

•Subjects with low back pain responded to induced balance perturbations.•Assessed before and after stabilization or movement-system-impairment treatments.•Electromyography responses not improved by either treatment.•Physical treatment may not transfer to benefit impaired postural responses for low back pain.

BackgroundMotor retraining for non-specific chronic low back pain (LBP) often focuses on voluntary postural tasks. This training, however, may not transfer to other known postural impairments, such as automatic postural responses to external perturbations.ObjectivesTo evaluate the extent current treatments of motor retraining ameliorate impaired postural coordination when responding to a perturbation of standing balance.DesignPlanned secondary analysis of a prospectively registered (NCT01362049), randomized controlled trial with a blinded assessor.MethodSixty-eight subjects with chronic, recurrent, non-specific LBP were allocated to perform a postural response task as a secondary assessment one week before and one week after receiving either stabilization or Movement System Impairment (MSI)-directed treatment over 6 weekly 1-h sessions plus home exercises. For assessment, subjects completed the Oswestry disability and numeric pain rating questionnaires and then performed a postural response task of maintaining standing balance in response to 3 trials in each of 4 randomly presented directions of linear surface translations of the platform under the subjects' feet. Integrated amplitudes of surface electromyography (EMG) were recorded bilaterally from the rectus abdominis (RA), internal oblique (IO), and external oblique (EO) muscles during the postural response task.ResultsNo significant effects of treatment on EMG responses were evident. Oswestry and numeric pain ratings decreased similarly following both treatments.ConclusionsStabilization and MSI-directed treatments do not affect trunk EMG responses to perturbations of standing balance in people with LBP, suggesting current methods of motor retraining do not sufficiently transfer to tasks of reactive postural control.