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Background: Motor 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., Objectives: To evaluate the extent current treatments of motor retraining ameliorate impaired postural coordination when responding to a perturbation of standing balance., Design: Planned secondary analysis of a prospectively registered (NCT01362049), randomized controlled trial with a blinded assessor., Method: Sixty-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., Results: No significant effects of treatment on EMG responses were evident. Oswestry and numeric pain ratings decreased similarly following both treatments., Conclusions: Stabilization 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., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background: People with low back pain (LBP) exhibit impaired anticipatory postural adjustments (APAs)., Objective: To evaluate whether current motor retraining treatments address LBP-associated changes in movement coordination during tasks that do and do not require APAs., Design: Prospectively registered randomized controlled trial with a blinded assessor., Setting: Outcome evaluations occurred in a university laboratory; treatments were carried out in outpatient physical therapy clinics., Patients: Fifteen subjects without LBP and 33 subjects with chronic, recurrent, and nonspecific LBP., Intervention: Twelve subjects with LBP received stabilization treatment, 21 received movement system impairment-based treatment, for more than 6 weekly 1-hour sessions plus home exercises., Measurements: Pre- and post-treatment, surface electromyography (EMG) was recorded bilaterally from trunk and leg muscles during unsupported and supported leg-lifting tasks, which did and did not require an APA, respectively. Vertical reaction forces under the contralateral leg were recorded to characterize the APA. Oswestry disability scores and numeric pain ratings were also recorded., Results: Persons with LBP demonstrated an impaired APA compared with persons without LBP, characterized by increased premovement contralateral force application and increased postmovement trunk EMG amplitude, regardless of the task. After treatments, both groups similarly improved in disability and function; however, APA characteristics did not change (ie, force application or EMG amplitude) in either task., Limitations: Treating clinicians were not blinded to treatment allocation, only short-term outcomes were assessed, and main effects of treatment do not rule out nonspecific effects of time or repeated exposure., Conclusions: Movement impairments in persons with LBP are not limited to tasks requiring an APA. Stabilization and movement system impairment-based treatments for LBP do not ameliorate and may exacerbate APA impairments (ie, excessive force application and increased post-movement trunk muscle activation)., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background Context: Classification schemas for low back pain (LBP), such as the Treatment-Based Classification and the Movement System Impairment, use common clinical features to subgroup patients with LBP and are purported to improve treatment outcomes., Purpose: To assess if providing matched treatments based on patient-specific clinical features led to superior treatment outcomes compared with an unmatched treatment for subjects with chronic recurrent LBP., Study Design: This study is a randomized controlled trial., Patient Sample: Subjects (n=124) with LBP (≥12 months) with or without recurrences underwent a standardized clinical examination to group them into one of two strata: ineligible or eligible for stabilization exercises based on the Treatment-Based Classification schema. Subjects underwent additional clinical tests to assign them to one of the five possible Movement System Impairment categories., Outcome Measures: Questionnaires were collected electronically at Week 0 (before treatment), Week 7 (after the 6-week 1-hour treatment sessions), and 12 months. Using the Oswestry disability index (0-100) and the Numeric Pain Rating Scale (0-10), the primary analysis was performed using the intention-to-treat principle. Secondary outcomes included fear-avoidance beliefs and psychosocial work-related and general health status., Methods: After subjects were categorized based on their particular clinical features using both the Treatment-Based Classification and Movement System Impairment schemas, they were randomized into one of two treatments using a 3:1 ratio for matched or unmatched treatments. The treatments were trunk stabilization exercise or Movement System Impairment-directed exercises., Results: Of the patients allocated to treatment for this study, 76 received a matched treatment and 25 received an unmatched treatment. After treatment, both groups showed a statistically significant improvement in the primary outcome measures and almost all the secondary measures; however, the matched treatment group did not demonstrate superior outcomes at Week 7 or 12 months, except on one of the secondary measures (Graded Chronic Pain Scale [Disability Scale]) (p=.01)., Conclusions: Providing a matched treatment based on either the Treatment-Based Classification or the Movement System Impairment classification schema did not improve treatment outcomes compared with an unmatched treatment for patients with chronic LBP, except on one secondary disability measure., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Unlabelled: Interventions that target trunk muscle impairments in people with LBP have been promoted; however, the treatment effects on muscle activation impairments during postural tasks remain unclear. Thus, our objective was to evaluate the effects trunk stabilization vs. general strength and conditioning exercises on the automatic postural response in persons with chronic low back pain (LBP). Fifty-eight subjects with chronic, recurrent LBP (n = 58) (i.e., longer than six months) were recruited and randomly assigned to one of two, 10-week physical therapy programs: stabilization (n = 29) or strength and conditioning (n = 29). Pain and function were measured at 11 weeks and 6 months post-treatment initiation. To quantify postural following support surface perturbations, surface electrodes recorded electromyography (EMG) of trunk and leg muscles and force plates recorded forces under the feet, to calculate the center of pressure. Both groups demonstrated significant improvements in pain and function out to 6 months. There were also changes in muscle activation patterns immediately post-treatment, but not at 6 months. However, changes in center of pressure (COP) responses were treatment specific. Following treatment, the stabilization group demonstrated later onset of COP displacement, while the onset of COP displacement in the strengthening group was significantly earlier following treatment. Despite two different treatments, clinical improvements and muscle activation patterns were similar for both groups, indicating that the stabilization treatment protocol does not preferentially improve treatment outcomes or inter-muscle postural coordination patterns for persons with LBP., Clinical Trial Registration Number: NCT01611792., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Observational cross sectional study. To examine the inter-rater reliability of novice raters in using the Movement System Impairment (MSI) approach system and to explore the patterns of disagreement in classification errors. The inter-rater reliability of individual tests items used in the MSI approach is moderate to good; however, the reliability of the classification algorithm has been tested only preliminarily. Using previously recorded patient data (n = 21), 13 novice raters classified patients according to the MSI schema. The overall percent agreement using the kappa statistic as well as the agreement/disagreement among pair-wise comparisons in classification assignments were examined. There was an overall 87.4% agreement in the pairs of classification judgments with a kappa coefficient of 0.81 (95% CI: 0.79, 0.83). Raters were most likely to agree on the classification of Flexion (100%) and least likely to agree on the classification of Rotation (84%). The MSI classification algorithm can be learned by novice users and with training, their inter-rater reliability in applying the algorithm for classification judgments is good and similar to that reported in other studies. However, some degree of error persists in the classification decision-making associated with the MSI system, in particular for the Rotation category., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Study Design: Observational, cross-sectional reliability study., Objectives: To examine the interrater reliability of novice raters in their use of the treatment-based classification (TBC) system for low back pain and to explore the patterns of disagreement in classification errors., Background: Although the interrater reliability of individual test items in the TBC system is moderate to good, some error persists in classification decision making. Understanding which classification errors are common could direct further refinement of the TBC system., Methods: Using previously recorded patient data (n = 24), 12 novice raters classified patients according to the TBC schema. These classification results were combined with those of 7 other raters, allowing examination of the overall agreement using the kappa statistic, as well as agreement/disagreement among pairwise comparisons in classification assignments. A chi-square test examined differences in percent agreement between the novice and more experienced raters and differences in classification distributions between these 2 groups of raters., Results: Among 12 novice raters, there was 80.9% agreement in the pairs of classification (κ = 0.62; 95% confidence interval: 0.59, 0.65) and an overall 75.5% agreement (κ = 0.57; 95% confidence interval: 0.55, 0.69) for the combined data set. Raters were least likely to agree on a classification of stabilization (77.5% agreement). The overall percentage of pairwise classification judgments that disagreed was 24.5%, with the most common disagreement being between manipulation and stabilization (11.0%), followed by a mismatch between stabilization and specific exercise (8.2%)., Conclusion: Additional refinement is needed to reduce rater disagreement that persists in the TBC decision-making algorithm, particularly in the stabilization category. J Orthop Sports Phys Ther 2012;42(9):797-805, Epub 7 June 2012. doi:10.2519/jospt.2012.4078.

There is increasing evidence that individuals with non-specific low back pain (LBP) have altered movement coordination. However, the relationship of this neuromotor impairment to recurrent pain episodes is unknown. To assess coordination while minimizing the confounding influences of pain we characterized automatic postural responses to multi-directional support surface translations in individuals with a history of LBP who were not in an active episode of their pain. Twenty subjects with and 21 subjects without non-specific LBP stood on a platform that was translated unexpectedly in 12 directions. Net joint torques of the ankles, knees, hips, and trunk in the frontal and sagittal planes as well as surface electromyographs of 12 lower leg and trunk muscles were compared across perturbation directions to determine if individuals with LBP responded using a trunk stiffening strategy. Individuals with LBP demonstrated reduced peak trunk torques, and enhanced activation of the trunk and ankle muscle responses following perturbations. These results suggest that individuals with LBP use a strategy of trunk stiffening achieved through co-activation of trunk musculature, aided by enhanced distal responses, to respond to unexpected support surface perturbations. Notably, these neuromotor alterations persisted between active pain periods and could represent either movement patterns that have developed in response to pain or could reflect underlying impairments that may contribute to recurrent episodes of LBP., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

People with a history of low back pain (LBP) exhibit altered responses to postural perturbations, and the central neural control underlying these changes in postural responses remains unclear. To characterize more thoroughly the change in muscle activation patterns of people with LBP in response to a perturbation of standing balance, and to gain insight into the influence of early- vs. late-phase postural responses (differentiated by estimates of voluntary reaction times), this study evaluated the intermuscular patterns of electromyographic (EMG) activations from 24 people with and 21 people without a history of chronic, recurrent LBP in response to 12 directions of support surface translations. Two-factor general linear models examined differences between the 2 subject groups and 12 recorded muscles of the trunk and lower leg in the percentage of trials with bursts of EMG activation as well as the amplitudes of integrated EMG activation for each perturbation direction. The subjects with LBP exhibited 1) higher baseline EMG amplitudes of the erector spinae muscles before perturbation onset, 2) fewer early-phase activations at the internal oblique and gastrocnemius muscles, 3) fewer late-phase activations at the erector spinae, internal and external oblique, rectus abdominae, and tibialis anterior muscles, and 4) higher EMG amplitudes of the gastrocnemius muscle following the perturbation. The results indicate that a history of LBP associates with higher baseline muscle activation and that EMG responses are modulated from this activated state, rather than exhibiting acute burst activity from a quiescent state, perhaps to circumvent trunk displacements.

Background: Low back pain is associated with abnormal movement strategies due to changes in neuromuscular control. A plausible contributing factor to low back pain is poor control of trunk muscles, thus understanding motor control alterations in this population can guide rehabilitation. Quantification of postural responses following support surface translations is one way to examine motor control impairments in people with low back pain., Methods: Twenty-four healthy subjects [mean 33 (SD 11) years] who had no low back pain and 26 subjects [mean 39 (SD 13) years] with chronic, recurrent low back pain were instructed to stand with feet placed on separate force plates, which were mounted on a moveable platform. The platform was translated unexpectedly in one of 12 directions for a total of 72 trials. For both the sagittal and frontal planes, the net center of pressure displacement was derived and the total body center of mass was calculated by combining kinematic and anthropometric data., Findings: For sagittal plane responses, subjects with low back pain had reduced and delayed sagittal plane center of pressure responses (P<0.01) compared to the subjects without low back pain. In contrast, the sagittal plane center of mass responses were larger in magnitude (P=0.03) yet similarly delayed in onset (P=0.04) for the low back pain group. Frontal plane responses did not differ between groups., Interpretation: Subjects with low back pain have altered automatic postural coordination, both in terms of magnitude and timing of responses, indicating alterations in neuromuscular control.