A hypothesis of chronic back pain: ligament subfailure injuries lead to muscle control dysfunction

Frequency of breaks, amount of muscular rest, and sustained muscle activity related to neck pain in a pooled dataset

BACKGROUND

Neck pain remains a persistent challenge in modern society and is frequently encountered across a wide range of occupations, particularly those involving repetitive and monotonous tasks. It might be expected that patterns of trapezius muscle activity at work, characterized by few breaks and prolonged periods of sustained muscle activity, are linked to neck pain. However, previous cross-sectional studies have generally failed to establish a definitive association. While some longitudinal studies have suggested that extended periods of heightened muscle activity could be a risk factor for neck pain, these findings often relied on limited participant numbers or specific professional groups. This study aimed to investigate the relationship between trapezius muscle activity and neck pain by pooling data from seven Scandinavian research institutes encompassing a diverse range of occupational backgrounds.

METHODS

Electromyographic (EMG) data for the upper trapezius muscle, collected during working hours, were coupled with questionnaire responses pertaining to neck pain, individual characteristics, and potential confounding variables for a total of 731 subjects. Additionally, longitudinal data from 258 subjects were available. The various EMG datasets were consolidated into a standardized format, and efforts were made to harmonize inquiries about neck pain. Regression analyses, adjusting for sex and height, were conducted to explore the associations between muscle activity variables and neck pain. An exposure index was devised to quantify the cumulative neck load experienced during working hours and to differentiate between various occupational categories.

RESULTS

The cross-sectional data displayed a distinct pattern characterized by positive associations for brief periods of sustained muscle activity (SUMA) and negative associations for prolonged SUMA-periods and neck pain. The longitudinal data exhibited a contrasting trend, although it was not as pronounced as the cross-sectional findings. When employing the exposure index, notable differences in cumulative muscle load emerged among occupational groups, and positive associations with longitudinal neck pain were identified.

DISCUSSION

The results suggest that individuals with neck pain experience higher cumulative workloads and extended periods of muscle activity over the long term. In the short term, they appear to compensate by taking frequent short breaks, resulting in a lower cumulative workload. Regardless of their occupation, it is crucial to distribute work breaks throughout the workday to ensure that the cumulative load remains manageable.

Cortical Mechanisms Underlying Effects of Repetitive Peripheral Magnetic Stimulation on Dynamic and Static Postural Control in Patients with Chronic Non-Specific Low Back Pain: A Double-Blind Randomized Clinical Trial

INTRODUCTION

Patients with chronic non-specific low back pain (CNLBP) often experience impaired postural control, contributing to pain recurrence. Although repetitive peripheral magnetic stimulation (rPMS) combined with core muscle training (CMT) could improve postural control, its neural mechanism remains unclear. This study aims to investigate the postural control-related cortical mechanism of the effect of rPMS on patients with CNLBP.

METHODS

This unicentric, prospective, randomized, double-blind, controlled trial was conducted in a public hospital from May to December 2023. A total of 40 patients (27 females and 13 males, mean age 29.38 ± 7.72) with CNLBP were randomly assigned to either the rPMS group (real rPMS with CMT) or the sham-rPMS group (sham-rPMS with CMT) for 12 sessions over 4 weeks. The rPMS was applied to the lumbar paravertebral multifidus muscle on the painful side. Pain and disability were quantified using the visual analog scale (VAS) and Oswestry dysfunction index (ODI) pre- and post-intervention. Furthermore, the sway area and velocity of the center of pressure (COP) were measured using a force platform. The cortical activities in 6 regions of interest during 4 tasks (standing with eyes open/closed on a stable/unstable plane) were recorded by functional near-infrared spectroscopy (fNIRS) pre- and post-intervention. The repeated measure ANOVA was applied for statistical analysis. Spearman's correlation was used to determine the relationships between variables.

RESULTS

After the intervention, the rPMS group showed decreased pain intensity (p = 0.001) and sway area (unstable eyes-closed task) (p = 0.046) compared to the sham-rPMS group. Additionally, the rPMS group exhibited increased activation in left primary motor cortex (M1) (p = 0.042) and reduced in left supplementary motor area (SMA) (p = 0.045), whereas the sham-rPMS group showed no significant changes. The increased activation of left M1 was negatively correlated to the reduction of pain intensity (r = - 0.537, p = 0.018) and sway area (r = - 0.500, p = 0.029) under the static balancing task. Furthermore, there was a positive correlation between sway velocity and VAS (r = 0.451, p = 0.046) post-rPMS intervention.

CONCLUSION

Repetitive peripheral magnetic stimulation combined with core muscle training demonstrated better analgesic effects and postural control improvements, compared to sham-stimulation. This may be attributed to the increased activation of the left primary motor cortex.

CLINICAL TRIAL REGISTRATION

The trial was registered on ClinicalTrials.gov (ChiCTR2300070943).

Passive intervertebral restraint is different in patients with treatment-resistant chronic nonspecific low back pain: a retrospective cohort study and control comparison

PURPOSE

In vivo studies of continuous lumbar sagittal plane motion have found passive intervertebral motion to be more uneven in patients with chronic nonspecific low back pain (CNSLBP) than healthy controls, but the mechanisms are unclear. This study aimed to compare patients with CNSLBP with a matched group of pain-free controls for intervertebral restraint during passive recumbent bending.

METHODS

Seventeen patients with CNSLBP and minimal disc degeneration who had quantitative fluoroscopy investigations were matched to 17 healthy controls from a database acquired using the same imaging protocol. The entire database (n = 136) was examined for clustering of peaking times, magnitudes and ROM of the first derivatives of the intervertebral angle/motion curves (PTFD, PMFD and ROM) during flexion and return that might introduce confounding. The groups were then compared for differences in these variables.

RESULTS

There were significant segmental ROM differences among clusters in the database when PMFD and ROM were used as clustering variables, indicating heterogeneity. However, in the patient-control study, it was PTFD (velocity) that differentiated the groups. At L5-S1, this was at 10.82% of the motion path compared with 25.06% in the controls (p = 0.0002). For L4-5, PTFD was at 23.42% of the motion path in patients and 16.33% in controls (p = 0.0694) suggesting a reduced initial bending moment there. There were no significant differences for PMFD or ROM.

CONCLUSION

Peaking time of passive intervertebral velocity occurs early at L5-S1 in patients with CNSLBP; however, these findings should be treated with caution pending their replication. Future studies should explore relationships with altered disc pressures and biochemistry. Usefulness for monitoring regenerative disc therapies should be considered.

Poor lumbar spine coordination in acute low back pain predicts persistent long-term pain and disability

PURPOSE

Sitting balance on an unstable surface requires coordinated out-of-phase lumbar spine and provides sufficient challenge to expose quality of spine control. We investigated whether the quality of spine coordination to maintain balance in acute low back pain (LBP) predicts recovery at 6 months.

METHODS

Participants in an acute LBP episode (n = 94) underwent assessment of sitting balance on an unstable surface. Seat, hip and spine (lower lumbar, lumbar, upper lumbar, thoracic) angular motion and force plate data were recorded. Coordination between the seat and hip/spine segments to maintain balance was quantified in the frequency domain to evaluate coordination (coherence) and relative timing (phase angle: in-phase [segments move together]; out-of-phase [segments move opposite]). Center of pressure (CoP) and upper thorax motion assessed overall balance performance. Hip and spine coordination with the seat were compared between those who did not recover (increased/unchanged pain/disability), partially recovered (reduced pain/disability) or recovered (no pain and disability) at 6 months.

RESULTS

In both planes, coherence between the seat and lower lumbar spine was lower (and in-phase-unhelpful for balance) at baseline in those who did not recover than those who recovered. Coherence between the seat and hip was higher in partially recovered in both planes, suggesting compensation by the hip. LBP groups had equal overall balance performance (CoP, upper thorax motion), but non-recovery groups used a less optimal strategy that might have consequences for long-term spine health.

CONCLUSION

These longitudinal data revealed that individuals with compromised contribution of the lumbar spine to the balance during unstable sitting during acute LBP are less likely to recover.

Development of Quasi-Passive Back-Support Exoskeleton with Compact Variable Gravity Compensation Module and Bio-Inspired Hip Joint Mechanism

The back support exoskeletons have garnered significant attention to alleviate musculoskeletal injuries, prevalent in industrial settings. In this paper, we propose AeBS, a quasi-passive back-support exoskeleton developed to provide variable assistive torque across the entire range of hip joint motion, for tasks with frequent load changes. AeBS can adjust the assistive torque levels while minimizing energy for the torque variation without constraining the range of motion of the hip joint. To match the requisite assistance levels for back support, a compact variable gravity compensation module with reinforced elastic elements is applied to AeBS. Additionally, we devised a bio-inspired hip joint mechanism that mimics the configuration of the human hip axis to ensure the free body motion of the wearer, significantly affecting assistive torque transmission and wearing comfort. Benchtop testing showed that AeBS has a variable assistive torque range of 5.81 Nm (ranging from 1.23 to 7.04 Nm) across a targeted hip flexion range of 135°. Furthermore, a questionnaire survey revealed that the bio-inspired hip joint mechanism effectively facilitates the transmission of the intended assistive torque while enhancing wearer comfort.

Comparisons of postural control, proprioception, muscle strength, pain and disability between individuals with acute, subacute and chronic low back pain

PURPOSE/AIM

Postural control, proprioception and lower extremity muscle strength are affected in individuals with low back pain (LBP). However, it is yet unknown whether these variables differentiate between acute, subacute and chronic stages of LBP. The aim was to investigate if there were any differences in postural control, proprioception, lower extremity muscle strength, pain intensity and disability between individuals in the different stages of LBP.

MATERIALS AND METHODS

In this cross-sectional study, 124 individuals with LBP were grouped as acute LBP (ALBP) (n = 38), subacute LBP (SLBP) (n = 30) and chronic LBP (CLBP) (n = 56) groups. Postural control was assessed via computerised technology. Lumbar proprioception, lower extremity muscle strength, pain intensity and disability were assessed using Joint Repositioning Error Test, hand-held dynamometer, Numeric Rating Scale and Oswestry Disability Index (ODI), respectively. Kruskal-Wallis Tests, ANCOVA and post hoc Mann-Whitney U-Test with Bonferroni correction were performed.

RESULTS

While there were no significant differences in terms of postural control, proprioception and pain intensity (p > 0.05), significant differences were found in terms of lower extremity muscle strength and ODI scores between groups when adjusted for age (p < 0.05). Individuals with CLBP demonstrated poorer lower extremity muscle strength than those with ALBP and SLBP, and higher disability than those with ALBP (p < 0.017).

CONCLUSIONS

Although postural control, proprioception and pain intensity were similar between individuals with acute, subacute and chronic LBP, muscle strength and disability seem to worsen stepwise as the pain becomes chronic. Muscle strength and disability should be taken into account while evaluating and/or managing individuals with acute and subacute stages of LBP.

The Impact of Spine Pathology on Posterior Ligamentous Complex Structure and Function

PURPOSE OF REVIEW

Spinal ligament is an important component of the spinal column in mitigating biomechanical stress. Particularly the posterior ligamentous complex, which is composed of the ligamentum flavum, interspinous, and supraspinous ligaments. However, research characterizing the biomechanics and role of ligament health in spinal pathology and clinical context are scarce. This article provides a comprehensive review of the implications of spinal pathology on the structure, function, and biomechanical properties of the posterior ligamentous complex.

RECENT FINDINGS

Current research characterizing biomechanical properties of the posterior ligamentous complex is primarily composed of cadaveric studies and finite element modeling, and more recently incorporating patient-specific anatomy into finite element models. The ultimate goal of current research is to understand the relative contributions of these ligamentous structures in healthy and pathological spine, and whether preserving ligaments may play an important role in spinal surgical techniques. At baseline, posterior ligamentous complex structures account for 30-40% of spinal stability, which is highly dependent on the intrinsic biomechanical properties of each ligament. Biomechanics vary widely with pathology and following rigid surgical fixation techniques and are generally maladaptive. Often secondary to morphological changes in the setting of spinal pathology, but morphological changes in ligament may also serve as a primary pathology. Biomechanical maladaptations of the spinal ligament adversely influence overall spinal column integrity and ultimately predispose to increased risk for surgical failure and poor clinical outcomes. Future research is needed, particularly in living subjects, to better characterize adaptations in ligaments that can provide targets for improved treatment of spinal pathology.

Trunk muscle dysfunction in patients with myotonic dystrophy type 2 and its contribution to chronic low back pain

Introduction

Myotonic dystrophy type 2 (MD2) presents with a varied manifestation. Even though the myopathy in these patients is more widespread, axial musculature involvement is one of the most prominent conditions. MD2 patients also often report chronic low back pain (CLBP). The purpose of this study was to evaluate trunk muscle function, including respiratory muscles, in patients with MD2 and to compare it with healthy controls, to determine the occurrence of CLBP in patients with MD2, and to assess whether trunk muscle dysfunction increases the risk of CLBP in these patients.

Methods

We enrolled 40 MD2 patients (age range 23 to 76 years, 26 women). A comprehensive battery of tests was used to evaluate trunk muscle function. The tests consisted of quantitative muscle strength testing of low back extensor muscles and respiratory muscles and the assessment of trunk muscle endurance. A neurological evaluation contained procedures assessing the distribution of muscle weakness, myotonia, and pain, and used questionnaires focused on these items and on disability, depression, and physical activity.

Results

The results of this study suggest that patients with MD2 show significant dysfunction of the trunk muscles, including the respiratory muscles, expressed by decreased muscle strength and endurance. The prevalence of CLBP in patients with MD2 was 52.5%. Based on our analysis, the only independent significant risk factor for CLBP in these patients was maximal isometric lower back extensor strength in a prone position ≤ 15.8 kg (OR = 37.3). Other possible risk factors were severity of myotonia and reduced physical activity.

Conclusion

Outcomes of this study highlighted the presence of axial muscle dysfunction, respiratory muscle weakness, and frequent occurrence of CLBP together with its risk factors in patients with MD2. We believe that the findings of this study may help in management and prevention programs for patients with MD2.

Muscle-driven forward dynamic active hybrid model of the lumbosacral spine: combined FEM and multibody simulation

Most spine models belong to either the musculoskeletal multibody (MB) or finite element (FE) method. Recently, coupling of MB and FE models has increasingly been used to combine advantages of both methods. Active hybrid FE-MB models, still rarely used in spine research, avoid the interface and convergence problems associated with model coupling. They provide the inherent ability to account for the full interplay of passive and active mechanisms for spinal stability. In this paper, we developed and validated a novel muscle-driven forward dynamic active hybrid FE-MB model of the lumbosacral spine (LSS) in ArtiSynth to simultaneously calculate muscle activation patterns, vertebral movements, and internal mechanical loads. The model consisted of the rigid vertebrae L1-S1 interconnected with hyperelastic fiber-reinforced FE intervertebral discs, ligaments, facet joints, and force actuators representing the muscles. Morphological muscle data were implemented via a semi-automated registration procedure. Four auxiliary bodies were utilized to describe non-linear muscle paths by wrapping and attaching the anterior abdominal muscles. This included an abdominal plate whose kinematics was optimized using motion capture data from upper body movements. Intra-abdominal pressure was calculated from the forces of the abdominal muscles compressing the abdominal cavity. For the muscle-driven approach, forward dynamics assisted data tracking was used to predict muscle activation patterns that generate spinal postures and balance the spine without prescribing accurate spinal kinematics. During calibration, the maximum specific muscle tension and spinal rhythms resulting from the model dynamics were evaluated. To validate the model, load cases were simulated from -10° extension to +30° flexion with weights up to 20 kg in both hands. The biomechanical model responses were compared with in vivo literature data of intradiscal pressures, intra-abdominal pressures, and muscle activities. The results demonstrated high agreement with this data and highlight the advantages of active hybrid modeling for the LSS. Overall, this new self-contained tool provides a robust and efficient estimation of LSS biomechanical responses under in vivo similar loads, for example, to improve pain treatment by spinal stabilization therapies.

Test-retest reliability and construct validity of trunk extensor muscle force modulation accuracy

Low back pain is associated with changes in trunk muscle structure and function and motor control impairments. Voluntary force modulation (FM) of trunk muscles is a unique and under-investigated motor control characteristic. One of the reasons for this paucity of evidence is the lack of exploration and publication on the reliability and validity of trunk FM protocols. The purpose of this study was to determine the within- and between-day test-retest reliability and construct validity for trunk extensor muscle FM. Twenty-nine healthy participants were tested under three FM conditions with different modulation rates. Testing was performed on a custom-built apparatus designed for trunk isometric force testing. FM accuracy relative to a fluctuating target force (20-50%MVF) was quantified using the root mean square error of the participant's generated force relative to the target force. Reliability and precision of measurement were assessed using the Intraclass Correlation Coefficient (ICC), standard error of measurement (SEM), minimal detectable difference (MDD95), and Bland-Altman plots. In a subset of participants, we collected surface electromyography of trunk and hip muscles. We used non-negative matrix factorization (NNMF) to identify the underlying motor control strategies. Within- and between-day test-retest reliability was excellent for FM accuracy across the three conditions (ICC range: 0.865 to 0.979). SEM values ranged 0.9-1.8 Newtons(N) and MDD95 ranged from 2.4-4.9N. Conditions with faster rates of FM had higher ICCs. NNMF analysis revealed two muscle synergies that were consistent across participants and conditions. These synergies demonstrate that the muscles primarily involved in this FM task were indeed the trunk extensor muscles. This protocol can consistently measure FM accuracy within and between testing sessions. Trunk extensor FM, as measured by this protocol, is not specific to any trunk muscle group but is the result of modulation by all the trunk extensor muscles.

Biomechanical Phenotyping of Chronic Low Back Pain: Protocol for BACPAC

OBJECTIVE

Biomechanics represents the common final output through which all biopsychosocial constructs of back pain must pass, making it a rich target for phenotyping. To exploit this feature, several sites within the NIH Back Pain Consortium (BACPAC) have developed biomechanics measurement and phenotyping tools. The overall aims of this article were to: 1) provide a narrative review of biomechanics as a phenotyping tool; 2) describe the diverse array of tools and outcome measures that exist within BACPAC; and 3) highlight how leveraging these technologies with the other data collected within BACPAC could elucidate the relationship between biomechanics and other metrics used to characterize low back pain (LBP).

METHODS

The narrative review highlights how biomechanical outcomes can discriminate between those with and without LBP, as well as among levels of severity of LBP. It also addresses how biomechanical outcomes track with functional improvements in LBP. Additionally, we present the clinical use case for biomechanical outcome measures that can be met via emerging technologies.

RESULTS

To answer the need for measuring biomechanical performance, our "Results" section describes the spectrum of technologies that have been developed and are being used within BACPAC.

CONCLUSION AND FUTURE DIRECTIONS

The outcome measures collected by these technologies will be an integral part of longitudinal and cross-sectional studies conducted in BACPAC. Linking these measures with other biopsychosocial data collected within BACPAC increases our potential to use biomechanics as a tool for understanding the mechanisms of LBP, phenotyping unique LBP subgroups, and matching these individuals with an appropriate treatment paradigm.

The effect of dual-task conditions on postural control in adults with low back pain: a systematic review and meta-analysis

BACKGROUND

Dual-task conditions, which involve performing two tasks simultaneously, may exacerbate pain and further impair daily functioning in individuals with low back pain (LBP). Understanding the effects of dual-task conditions on postural control in patients with LBP is crucial for the development of effective rehabilitation programs. Our objective was to investigate the impact of dual-task conditions on postural control in individuals with LBP compared to those without LBP.

METHODS

We conducted a comprehensive search of Medline via PubMed, Scopus, the Cochrane Central Register of Controlled Trials, Web of Science, and EMBASE databases, with no language restrictions, from inception to January 1, 2023. The primary outcome measures of the study were velocity, area, amplitude, phase plane portrait, and path/sway length of the center of pressure (CoP). Standardized mean difference (SMD) effect sizes were calculated, and the quality of the studies was assessed using the Newcastle-Ottawa Scale (NOS).

RESULTS

From 196 studies, five involving 242 adults (≥ 18 years) met the inclusion criteria. Three studies were rated as high quality, while two were deemed moderate. In the included studies, 140 participants had non-specific LBP, while 102 participants did not report any symptoms, with mean ages of 36.68 (± 14.21) and 36.35 (± 15.39) years, respectively. Three studies had both genders, one exclusively included females, and one did not specify gender. Meta-analyses of primary outcomes revealed no significant differences in postural control between patients with LBP and pain-free controls during both easy and difficult postural tasks and cognitive load for velocity (easy: SMD - 0.09, 95% CI - 0.91 to 0.74; difficult: SMD 0.12, 95% CI - 0.67 to 0.91), area (easy: SMD 0.82, 95% CI - 2.99 to 4.62; difficult: SMD 0.14, 95% CI - 2.62 to 2.89), phase plane (easy: SMD - 0.59, 95% CI - 1.19 to 0.02; difficult: SMD - 0.18, 95% CI - 0.77 to 0.42), path/sway length (easy: SMD - 0.18, 95% CI - 0.77 to 0.42; difficult: SMD - 0.14, 95% CI - 0.84 to 0.55), and amplitude (easy: SMD 0.89, 95% CI - 1.62 to 3.39; difficult: SMD 1.31, 95% CI - 1.48 to 4.10).

CONCLUSIONS

The current evidence suggests that there are no significant differences in postural control parameters during dual-task conditions between individuals with non-specific LBP and pain-free subjects. However, due to the limited number of available studies, significant publication bias, and considerable statistical heterogeneity, definitive conclusions cannot be drawn. Therefore, further research comprising high-quality studies with larger sample sizes is necessary to obtain conclusive results. Trial registration PROSPERO CRD42022359263.

Levels of ACL-straining activities increased in the six months prior to non-contact ACL injury in a retrospective survey: evidence consistent with ACL fatigue failure

Introduction: Recent evidence has emerged suggesting that a non-contact anterior cruciate ligament (ACL) tear can result from repetitive submaximal loading of the ligament. In other words, when the intensity of ACL-straining athletic activities is increased too rapidly, microdamage can accumulate in the ligament beyond the rate at which it can be repaired, thereby leading to material fatigue in the ligament and its eventual failure. The objective of this survey-based exploratory study was to retrospectively determine whether the levels of various athletic activities performed by ACL-injured patients significantly changed during the 6 months before injury. Methods: Forty-eight ACL-injured patients completed a survey to characterize their participation in various activities (weightlifting, sport-specific drills, running, jumping, cutting, pivoting/twisting, and decelerating) at three timepoints (1 week, 3 months, 6 months) prior to ACL injury. Activity scores, which summarized the frequency and intensity of each activity, were calculated for each patient at each time interval. A series of linear mixed-effects regression models was used to test whether there was a significant change in levels of the various activities in the 6-month period leading up to ACL injury. Results: Patients who sustained a non-contact ACL injury markedly increased their sport-specific drills activity levels in the time leading up to injury (p = 0.098), while those patients who sustained a contact ACL injury exhibited no change in this activity during the same time period (p = 0.829). Levels of running, jumping, cutting, pivoting/twisting, and decelerating increased for non-contact ACL-injured patients but decreased for contact ACL-injured patients, though not significantly (p values > 0.10). Weightlifting activity significantly decreased leading up to injury among contact ACL-injured patients (p = 0.002). Discussion: We conclude that levels of ACL-straining athletic activities or maneuvers in non-contact ACL-injured patients markedly increased in the 6 months leading up to their injury, providing evidence that changing levels of certain activities or maneuvers may play a role in ACL injury risk. This warrants further investigation of the hypothesis that too rapid an increase in activities or maneuvers known to place large loads on the ACL can cause microdamage to accumulate in the ligament, thereby leading to failure.

Dancers with non-specific low back pain have less lumbar movement smoothness than healthy dancers

BACKGROUND

Ballet is a highly technical and physically demanding dance form involving extensive end-range lumbar movements and emphasizing movement smoothness and gracefulness. A high prevalence of non-specific low back pain (LBP) is found in ballet dancers, which may lead to poor controlled movement and possible pain occurrence and reoccurrence. The power spectral entropy of time-series acceleration is a useful indicator of random uncertainty information, and a lower value indicates a greater smoothness or regularity. The current study thus applied a power spectral entropy method to analyze the movement smoothness in lumbar flexion and extension in healthy dancers and dancers with LBP, respectively.

METHOD

A total of 40 female ballet dancers (23 in the LBP group and 17 in the control group) were recruited in the study. Repetitive end-range lumbar flexion and extension tasks were performed and the kinematic data were collected using a motion capture system. The power spectral entropy of the time-series acceleration of the lumbar movements was calculated in the anterior-posterior (AP), medial-lateral (ML), vertical (VT), and three-directional (3D) vectors. The entropy data were then used to conduct receiver operating characteristic curve analyses to evaluate the overall distinguishing performance and thus cutoff value, sensitivity, specificity, and area under the curve (AUC) were calculated.

RESULTS

The power spectral entropy was significantly higher in the LBP group than the control group in the 3D vector in both lumbar flexion and lumber extension (flexion: p = 0.005; extension: p < 0.001). In lumbar extension, the AUC in the 3D vector was 0.807. In other words, the entropy provides an 80.7% probability of distinguishing between the two groups (i.e., LBP and control) correctly. The optimal cutoff entropy value was 0.5806 and yielded a sensitivity of 75% and specificity of 73.3%. In lumbar flexion, the AUC in the 3D vector was 0.777, and hence the entropy provided a probability of 77.7% of distinguishing between the two groups correctly. The optimal cutoff value was 0.5649 and yielded a sensitivity of 90% and a specificity of 73.3%.

CONCLUSIONS

The LBP group showed significantly lower lumbar movement smoothness than the control group. The lumbar movement smoothness in the 3D vector had a high AUC and thus provided a high differentiating capacity between the two groups. It may therefore be potentially applied in clinical contexts to screen dancers with a high risk of LBP.

A Comparative Electromyographic Analysis of Flying Squirrel and 3-Point Quadripod Exercise for Lumbar Multifidus Muscle Activations among Healthy Female Subjects

Physical therapists employ several exercises to alleviate low back pain (LBP). Electromyography (EMG) examination of exercises can monitor muscle activation to help clinicians determine the exercise’s effect on stabilisation, endurance, or strength. This study evaluated surface EMG activity comparison for Flying Squirrel Exercise (FSE) and the novel 3-Point Quadripod Exercise (3-PQE) to find the most effective exercise for stimulating the lumbar multifidus (LM) muscle. The study recruited 64 healthy young females (19–24 years). Raw data were normalized and are expressed as the percentage of maximum voluntary isometric contraction (%MVIC). The test–retest reliability of the EMG recordings was estimated using intraclass correlation coefficient (ICC3,1). One-way ANOVA was used to statistically analyse and compare the EMG amplitudes during the two exercises. The ICCs for 3-PQE and FSE were 0.94 (SEM, 21.7% MVIC) and 0.87 (SEM, 19.05% MVIC), respectively. The 3-PQE (69 ± 26% MVIC) demonstrated significantly higher activity than did FSE (30 ± 18% MVIC) (F = 15.573, p = 0.001). Thus, 3-PQE might be a feasible strategy for the prevention and rehabilitation of LBP in females.

EMG Amplitude-Force Relationship of Lumbar Back Muscles during Isometric Submaximal Tasks in Healthy Inactive, Endurance and Strength-Trained Subjects

Previous data suggest a correlation between the cross-sectional area of Type II muscle fibers and the degree of non-linearity of the EMG amplitude-force relationship (AFR). In this study we investigated whether the AFR of back muscles could be altered systematically by using different training modalities. We investigated 38 healthy male subjects (aged 19-31 years) who regularly performed either strength or endurance training (ST and ET, n = 13 each) or were physically inactive (controls (C), n = 12). Graded submaximal forces on the back were applied by defined forward tilts in a full-body training device. Surface EMG was measured utilizing a monopolar 4 × 4 quadratic electrode scheme in the lower back area. The polynomial AFR slopes were determined. Between-group tests revealed significant differences for ET vs. ST and C vs. ST comparisons at the medial and caudal electrode positions, but not for ET vs. C. Further, systematic main effects of the "electrode position" could be proven for ET and C groups with decreasing x² coefficients from cranial to caudal and lateral to medial. For ST, there was no systematic main effect of the "electrode position". The results point towards training-related changes to the fiber-type composition of muscles in the strength-trained participants, particularly for their paravertebral region.

Effectiveness of Spinal Stabilization Exercises on Dynamic Balance in Adults with Chronic Low Back Pain

Background

Dynamic balance is a vital aspect of everyday life. It is important to incorporate an exercise program that is useful for maintaining and improving balance in patients with chronic low back pain (CLBP). However, there is a lack of evidence supporting the effectiveness of spinal stabilization exercises (SSEs) on improving dynamic balance.

Purpose

To determine the effectiveness of SSEs on dynamic balance in adults with CLBP.

Study Design

A double-blind randomized clinical trial.

Methods

Forty participants with CLBP were assigned randomly into either an SSE group or a general exercise (GE) group, which consisted of flexibility and range-of-motion exercises. Participants attended a total of four to eight supervised physical therapy (PT) sessions and performed their assigned exercises at home in the first four weeks of the eight-week intervention. In the last four weeks, the participants performed their exercises at home with no supervised PT sessions. Participants' dynamic balance was measured using the Y-Balance Test (YBT) and the normalized composite scores, Numeric Pain Rating Scale and Modified Oswestry Low Back Pain Disability Questionnaire scores were collected at baseline, two weeks, four weeks, and eight weeks.

Results

A significant difference between groups from two weeks to four weeks (p = 0.002) was found, with the SSE group demonstrating higher YBT composite scores than the GE group. However, there were no significant between-group differences from baseline to two weeks (p =0.098), and from four weeks to eight weeks (p = 0.413).

Conclusions

Supervised SSEs were superior to GEs in improving dynamic balance for the first four weeks after initiating intervention in adults with CLBP. However, GEs appeared to have an effect equivalent to that of SSEs after 8-week intervention.

Levels of Evidence

1b.

Adherence and Effect of Home-Based Rehabilitation with Telemonitoring Support in Patients with Chronic Non-Specific Low Back Pain: A Pilot Study

Home-based exercises have been on the rise recently. This pilot study aimed to assess the adherence and effect of a home-based rehabilitation programme using telemonitoring in patients with chronic non-specific low back pain (CNLBP). Twenty-seven patients with CNLBP were enrolled in the study, each of whom underwent a neurological assessment, including patient-oriented measures and a functional assessment-a battery of tests that comprehensively evaluated trunk muscle function. The rehabilitation programme lasted 18 weeks and included daily home-based exercises. A mobile application or an exercise diary was used to monitor compliance. Adherence to the programme was excellent for both the diary and mobile application groups, with 82.3% in the diary group exercising at least once a day and 72.9% twice a day, and 94.8% in the mobile application group exercising at least once a day and 86.6% twice a day. Both patient-oriented and functional outcomes improved significantly; however, the relative changes of the parameters in these two groups did not correlate, which supports the idea that trunk muscle function does not directly relate to patient complaints and that CNLBP is a multifactorial issue. This model of rehabilitation programme should be used in clinical practice, as its adherence and effectiveness seem noticeable.

Comparison of transversus abdominis activation characteristics between healthy and chronic low back pain population during upright functional movement

BACKGROUND

Previous literature suggests that transversus abdominis (TrA) activation is diminished in chronic low back pain (cLBP) subjects compared to healthy subjects in less-functional positions. However, few studies have investigated the effects of upright functional movement on TrA activation in cLBP individuals.

OBJECTIVE

This pilot study aimed to compare TrA activation characteristics in healthy and cLBP subjects during the movement of double leg standing (DLS) to single leg standing (SLS) and to a 30∘ single leg quarter squat (QSLS).

METHODS

TrA activation was determined by the percentage change in TrA thickness from DLS to SLS and DLS to QSLS. TrA thickness was measured in 14 healthy and 14 cLBP participants using ultrasound imaging with a probe holder at 20 mm and 30 mm from the fascia conjunction point.

RESULTS

At both measurement points (20 and 30 mm), there were no significant main effects of body sides, lower limb movements and the interactions between them on TrA activations between the healthy and cLBP participants even after covariates were adjusted for (all p> 0.05).

CONCLUSIONS

Results from this study suggest the evaluation of TrA activation during upright functional movements as part of an assessment for cLBP management may not be suggested.

Mechanisms behind the Development of Chronic Low Back Pain and Its Neurodegenerative Features

Chronic back pain is complex and there is no guarantee that treating its potential causes will cause the pain to go away. Therefore, rather than attempting to "cure" chronic pain, many clinicians, caregivers and researchers aim to help educate patients about their pain and try to help them live a better quality of life despite their condition. A systematic review has demonstrated that patient education has a large effect on pain and pain related disability when done in conjunction with treatments. Therefore, understanding and updating our current state of knowledge of the pathophysiology of back pain is important in educating patients as well as guiding the development of novel therapeutics. Growing evidence suggests that back pain causes morphological changes in the central nervous system and that these changes have significant overlap with those seen in common neurodegenerative disorders. These similarities in mechanisms may explain the associations between chronic low back pain and cognitive decline and brain fog. The neurodegenerative underpinnings of chronic low back pain demonstrate a new layer of understanding for this condition, which may help inspire new strategies in pain education and management, as well as potentially improve current treatment.

ACL microtrauma: healing through nutrition, modified sports training, and increased recovery time

PURPOSE

Sports injuries among youth and adolescent athletes are a growing concern, particularly at the knee. Based on our current understanding of microtrauma and anterior cruciate ligament (ACL) healing characteristics, this clinical commentary describes a comprehensive plan to better manage ACL microtrauma and mitigate the likelihood of progression to a non-contact macrotraumatic ACL rupture.

METHODS

Medical literature related to non-contact ACL injuries among youth and adolescent athletes, collagen and ACL extracellular matrix metabolism, ACL microtrauma and sudden failure, and concerns related to current sports training were reviewed and synthesized into a comprehensive intervention plan.

RESULTS

With consideration for biopsychosocial model health factors, proper nutrition and modified sports training with increased recovery time, a comprehensive primary ACL injury prevention plan is described for the purpose of better managing ACL microtrauma, thereby reducing the incidence of non-contact macrotraumatic ACL rupture among youth and adolescent athletes.

CONCLUSION

Preventing non-contact ACL injuries may require greater consideration for reducing accumulated ACL microtrauma. Proper nutrition including glycine-rich collagen peptides, or gelatin-vitamin C supplementation in combination with healthy sleep, and adjusted sports training periodization with increased recovery time may improve ACL extracellular matrix collagen deposition homeostasis, decreasing sudden non-contact ACL rupture incidence likelihood in youth and adolescent athletes. Successful implementation will require compliance from athletes, parents, coaches, the sports medicine healthcare team, and event organizers. Studies are needed to confirm the efficacy of these concepts.

LEVEL OF EVIDENCE

V.

The effect of treadmill walk with abdominal bracing versus usual care on functional limitation and fear-avoidance behaviours in the management of non-specific low back pain—a randomized control study

Background

The use of a combined abdominal bracing technique concurrently with treadmill walking exercise seems not to have been widely investigated, The use of either abdominal bracing and treadmill walk as a single individual method of treatment has proven to be of immense benefit in athletic training and amelioration of pain and functional limitation among different age groups suffering from chronic low back pain. Thus, the need to investigate whether the combination of abdominal bracing and treadmill walking would produce greater benefits than when the exercises are carried out in isolation in the management of chronic low back pain patients.

Study design

The study was a randomized control.

Participants

Thirty-three participants who met the inclusion criteria with age from 18 to 65 participated in the study.

Aim

This study aimed to compare the effects of treadmill walk with and without abdominal bracing versus usual care on pain, functional limitation and fear-avoidance behaviours among patients with non-specific chronic low back pain.

Methods

Thirty-three non-specific chronic low back pain (NSCLBP) patients were randomized into three groups treadmill walk without abdominal bracing (TWW), treadmill walk with abdominal bracing (TWAB) and usual care (UC). Interventions were carried out for 6 weeks.

Outcome measure

Pre and post-intervention scores of pain intensity, functional limitation, and fear-avoidance belief were assessed with box numerical pain rating scales, Oswestry disability index and Fear-Avoidance Belief Questionnaire, respectively.

Results

Pre-intervention scores of pain intensity functional disability and fear-avoidance belief did not show significant differences among the groups (P >0.05). Within-group analysis with paired t-test showed that pain intensity and functional limitation were significantly reduced after 6 weeks of intervention among the 3 groups. Fear-avoidance belief recorded statistical reduction among the 2 treadmill procedures (TWAB and TWW) groups (P<0.05) but not in the usual care groups (P>0.05). Participants in the TWW group showed greater improvement than those in TWAB in terms of reduction in pain intensity (24.17±16.49), functional limitation (7.00±5.97, P = 0.001) and fear- avoidance (30.83±17.90, P = 0.003)

Conclusion

Treadmill walk with and without abdominal bracing as well as usual care could be effective in reducing pain. However, treadmill walk without abdominal bracing was more effective in improving back function in terms of reduction in pain intensity, functional limitation (as reported by the Oswestry scale) and reducing fear-avoidance behaviour (as reported by fear-avoidance belief scores).

Trial registration

PACTR, PACTR201910691645076. Registered on 22 October 2019.

Five Times Sit-to-Stand Test in people with non-specific chronic low back pain—a cross-sectional test–retest reliability study

PURPOSE/AIM

The Five Times Sit-to-Stand Test (FTSST) is a method that evaluates lower extremity muscle strength and balance level. The aim of this study is to test the validity and reliability of the FTSST in patients with non-specific chronic low back pain (NSCLBP) whose lower extremity muscle strength and balance levels are adversely affected.

METHODS

The first outcome measure of the study was the FTSST, which was conducted by two different researchers. Secondary outcome measures are Biodex Balance System (BBS), Quadriceps Muscle Strength Test, Oswestry Disability Index (ODI), and Visual Analogue Scale (VAS). Intraclass Correlation Coefficient (ICC) was used for the validity and reliability of the FTSST, which was made by two different researchers, and Pearson's Correlation Analysis was used to determine its relationship with other measurements.

RESULTS

Inter-rater and test-retest reliability for the FTSST were excellent (Intraclass Correlation Coefficient = 0.99). A statistically significant correlation was found between all secondary outcome measures (BBS, quadriceps muscle strength, ODI, VAS) and FTSST (p < 0.05).

CONCLUSION

In line with the findings of our study, we think that FTSST is a simple, easy, and reproducible method for evaluating lower extremity muscle strength, balance level, functional status, and pain in patients with NSCLBP.

Associations between Deformation of the Thoracolumbar Fascia and Activation of the Erector Spinae and Multifidus Muscle in Patients with Acute Low Back Pain and Healthy Controls: A Matched Pair Case-Control Study

Background: The thoracolumbar fascia (TLF) is thought to play a role in the development of LBP, but it is not yet clear which factor of TLF changes is a cause and which is an effect. Therefore, some studies used the cross-correlation function (CCR) to reveal time-dependent relationships between biomechanical and neuromotor factors. Methods: Ten patients with acute low back pain (aLBP) were matched to healthy controls. Simultaneous recording of surface electromyography (sEMG) of the erector spinae and multifidus muscle (ESM) and dynamic ultrasound (US) images of TLF deformation were performed during trunk extension. CCR functions and Granger causality (GC) were used to describe the relationship between the two measures. Results: CCR time lags were significant higher in the aLBP group (p = 0.04). GC showed a direct effect of TLF deformation on ESM activation only in the aLBP group (p < 0.03). Conclusions: The results suggest that in aLBP, ESM activity is significantly affected by TLF, whereas this relationship is completely random in healthy subjects studied with CCR and GC comparisons of dynamic US imaging and sEMG data signals. Fascia-related disturbances in neuromotor control, particularly due to altered muscle spindle functions, are suspected as a possible mechanism behind this.

Correlation between diminished vagal tone and somatic dysfunction severity in very and extremely low birth weight preterm infants assessed with frequency spectrum heart rate variability and salivary cortisol

Osteopathic manipulative treatment (OMT) is evolving in the neonatal intensive care unit (NICU) setting. Studies showed its efficacy in length of stay and hospitalization costs reduction. Moreover, it was suggested that OMT has a modulatory effect on the preterm infants' autonomic nervous system (ANS), influencing saturation and heart rate. Even if OMT is based on the palpatory examination of the somatic dysfunctions (SD), there are controversies about its identification and clinical relevance. The objective of this study was to evaluate the inter-rater reliability, clinical characteristics, and functional correlation of the SD Grade score with the heart rate variability (HRV) and the salivary cortisol (sCor) using a multivariate linear model approach. To evaluate those features, we implemented an ad hoc SD examination for preterm infants that was performed by 2 trained osteopaths. It was based on the new variability model of SD that includes an SD Grade assessment procedure. The ANS features were assessed by frequency parameters of HRV studying high frequency (HF), low frequency (LF), and HF/LF, whereas sCor was tested with a radioimmunoassay. The ANS assessment was standardized and performed before SD testing. Sixty-nine premature infants were eligible. SD Grade showed excellent concordance between the blinded raters. Using SD Grade as a grouping variable, the infants presented differences in GA, Apgar, pathological findings, length of stay, and ventilatory assistance. In our multivariate model, HF, LF, and LF/HF resulted linearly correlated with SD Grade. Instead, sCor presented a linear correlation with 5' Apgar and respiratory distress syndrome but not with SD Grade. SD Grade was in line with the natural history of the underdevelopment due to prematurity. Our models indicate that the cardiac vagal tone is linearly related with SD Grade. This finding may improve the multidisciplinary decision making inside NICU and the management of modifiable factors, like SD, for cardiac vagal tone regulation.

Practical Measurement of Changes in Leg Length Discrepancy After a Myofascial Release on the Thoracolumbar Fascia in Patients With Acute Low Back Pain: A Pilot Study

Background

Recent work has examined an association between leg length discrepancy (LLD) and low back pain (LBP). Myofascial release (MFR) techniques are thought to be frequently applied in the treatment of chronic and acute LBP. The purpose of this study was to evaluate a practical measure of LLD and the feasibility of an MFR technique in a randomised controlled trial (RCT).

Methods

In 12 subjects (seven women and five men) with acute LBP and LLD greater than 3 mm, an MFR technique was performed on the thoracolumbar fascia. At the baseline, after the intervention, and at follow-up, LLD was measured using a cross-line laser and finger-to-floor distance, and the pain was measured with a visual analogue scale (VAS). Patients completed a questionnaire after follow-up to assess the acceptability of the study procedure. The therapist evaluated the methods in terms of their feasibility.

Results

LLD measurement and MFR treatment required little time and few resources. Participants agreed to the study procedure with moderate to high acceptance. The LLD decreased by 5 mm after treatment and by 4 mm at follow-up. The VAS showed a reduction in pain of 17.50 mm at follow-up but not immediately after treatment.

Conclusion

The measurement of LLD is applicable in daily osteopathic practice, but it cannot be assumed to be a valid method for an RCT. Validated methods such as video raster stereography are, therefore, recommended. Comprehensive RCTs to study the effects of MFR intervention on leg length are feasible.

Chiropractic Care and Quality of Life Among Office Workers With Nonspecific Pain: A Cross-Sectional Study

Objective

The aim of this study was to evaluate the quality of life by a self-administered World Health Organization Quality of Life short version survey (WHOQoL-BREF) among office workers with nonspecific pain receiving chiropractic care in Istanbul, Turkey.

Methods

This cross-sectional study included 77 office workers (age interval, 18-65) with nonspecific neck, thoracic, back and/or extremity pain who underwent chiropractic care. Two weeks later, the quality of life was evaluated by a self-administered WHOQoL-BREF. The Numeric Pain Scale to evaluate the perceived pain was administered to all of the participants in the beginning and at the end of the study. Group-level changes on WHOQoL-BREF total score and subdimensions were compared according to descriptive data of office workers. The significance level was set at P ≤ .05.

Results

WHOQoL-BREF scale scores after chiropractic care (mean ± standard deviation) were 71.21% ± 7.91% (total score), 81.49% ± 14.43% (general health), 80.38% ± 10.49% (physical health), 73.16% ± 11.68% (psychological), 70.41% ± 12.43% (social), and 65.58% ± 10.91% (environment). Numeric Pain Scale scores decreased in a statistically significant way when compared with baseline (P ≤ .05). The descriptive statistical analysis of WHOQoL-BREF dimensions revealed that women had significantly higher scores than men, the 18-to-35 age group had higher scores compared with the 50-to-65 age group, and those married had significantly higher scores than those who were not married (P ≤ .05).

Conclusion

The findings of our study suggest that chiropractic care had positive effects on the quality of life of office workers.

Effects of exercise on balance in patients with non-specific low back pain: a systematic review and meta-analysis

INTRODUCTION

Non-specific low back pain (NS-LBP) is one of the most common musculoskeletal conditions related to medical expenses and disability. Evidence suggests that changes in motion patterns could induce trunk instability and impaired postural control. Therefore, this systematic review investigated the effects of exercise on balance in patients with NS-LBP.

EVIDENCE ACQUISITION

A systematic review and meta-analysis were conducted. Findings were reported following the 2020 PRISMA statement and the main databases were searched for RCTs. Studies were independently screened through a standardized form and their internal validity assessed by using the Cochrane risk of bias (RoB) tool. Pooled effects were calculated at post-treatment and quality of evidence was assessed through the GRADE framework.

EVIDENCE SYNTHESIS

Twelve articles were included in the review, eight in the meta-analysis. None of the studies were judged at low RoB. There is very low-quality evidence that exercise is effective in reducing Centre of Pressure (CoP) displacement (-16.99 [-27.29, -6.68]; P=0.001) and in improving single-leg stance test performance (-28.7 [-48.84, -8.67]; P=0.005) and dynamic balance (-4.74 [-8.02, -1.46]; P=0.005). Conversely, no significant results were observed in "ellipse area" and in "limits of stability" indexes. Other results were summarized in a qualitative synthesis.

CONCLUSIONS

Exercise could be effective in improving both static and dynamic balance in patients with NS-LBP over a short-term period. However, quality of evidence was estimated as very low, hence further double-blinded, high-quality RCTs are needed to address clinical practice and research.

Balance control in unstable sitting in individuals with an acute episode of low back pain

BACKGROUND

Low back pain (LBP) is associated with altered postural control, mostly observed at later stages in the LBP trajectory. It is unclear whether postural control differs in the acute phase of LBP.

RESEARCH QUESTION

Is postural control different in the acute phase of LBP (<2 weeks) and do differences depend on pain intensity, psychological features and/or availability of vision to control posture?

METHODS

Cross-sectional study design. An unstable sitting paradigm (to reduce the contribution of the legs) assessed postural control of participants with acute LBP (n = 133) and pain-free controls (n = 74). Centre of pressure (CoP) reflected seat movements. Participants balanced with eyes closed, open, or with visual feedback of the anteroposterior CoP position. Balance performance was expressed by CoP displacement and velocity, and stabilogram diffusion analysis. Generalised estimating equations (GEEs) including body mass index, sex, and safety bar touch, tested differences between groups and between balance conditions. Separate GEEs were used to model performance measures and bar touch (yes/no) including pain intensity, disability and psychological features.

RESULTS

CoP displacement and critical point coordinates (time and distance where CoP diffusion rate or spread slows) were larger in LBP than pain-free controls independent of balance condition. Long-term diffusion rate was greater in LBP than controls with eyes closed. CoP velocity measures (RMS, short term diffusion rate) were not different between groups. Pain intensity and psychological features were not linearly related to balance performance in participants with acute LBP. Higher pain catastrophizing was associated with touching the safety bar.

SIGNIFICANCE

Postural control differs in acute LBP than pain-free controls. Findings might be explained by altered sensory processing, lesser ability to reweight proprioceptive information and/or less accurate trunk muscle control. Although not linearly related to pain-intensity or psychological features in the acute stage, reduced balance performance could potentially have impact on LBP recovery.

Electromyography of the Multifidus Muscle in Horses Trotting During Therapeutic Exercises

Thoracolumbar pain has been identified in both human and equine patients. Rehabilitation and conditioning programs have focused specifically on improving trunk and abdominal muscle function (1–5). Equine exercise programs routinely incorporate ground poles and training devices for the similar goals of increasing spinal and core stability and strength (6–8). The multifidus muscle has been an area of focus due to atrophy associated with disease (9). To date, there have been no reports on the activity of the multifidus muscle in horses in relation to therapeutic exercises. Our objectives were to use electromyography to determine the average work performed and peak muscle activity of the multifidus in horses trotting, trotting over ground poles, trotting while wearing a resistance band-based training device and trotting while wearing the training device over ground poles. We hypothesized that ground poles and the training device would each increase average work performed and peak multifidus muscle activity. Right and left cranial thoracic locations showed significant increased muscle work and peak activation when horses were trotted over ground poles versus without. The peak activation was significantly greater in horses trotting over poles in both lumbar regions, but there was no significant change in peak activation in either location due to the training device. When the influence of the training device was investigated without ground poles, left caudal thoracic muscle work and peak activity, and right lumbar muscle work were significantly lower when using the training device, as compared to without. When the training device was combined with trotting over ground poles, both left and right caudal thoracic regions showed significantly lower muscle work and peak activity when the device was used. There was no significant difference between with and without the device in either left or right lumbar muscle work. In conclusion, implementing ground poles can be an effective strategy to increase the activation of the multifidus muscle, however, caution should be taken when incorporating the use of a resistance band training device as muscle work and peak activation were significantly reduced in most locations. Further study should be performed in regards to the training device to determine its effects on epaxial musculature.

Muscle spindles of the multifidus muscle undergo structural change after intervertebral disc degeneration

Purpose

Proprioceptive deficits are common in low back pain. The multifidus muscle undergoes substantial structural change after back injury, but whether muscle spindles are affected is unclear. This study investigated whether muscle spindles of the multifidus muscle are changed by intervertebral disc (IVD) degeneration in a large animal model.

Methods

IVD degeneration was induced by partial thickness annulus fibrosus lesion to the L3-4 IVD in nine sheep. Multifidus muscle tissue at L4 was harvested at six months after lesion, and from six age-/sex-matched naïve control animals. Muscle spindles were identified in Van Gieson’s-stained sections by morphology. The number, location and cross-sectional area (CSA) of spindles, the number, type and CSA of intrafusal fibers, and thickness of the spindle capsule were measured. Immunofluorescence assays examined Collagen I and III expression.

Results

Multifidus muscle spindles were located centrally in the muscle and generally near connective tissue. There were no differences in the number or location of muscle spindles after IVD degeneration and only changes in the CSA of nuclear chain fibers. The thickness of connective tissue surrounding the muscle spindle was increased as was the expression of Collagen I and III.

Conclusion

Changes to the connective tissue and collagen expression of the muscle spindle capsule are likely to impact their mechanical properties. Changes in capsule stiffness may impact the transmission of length change to muscle spindles and thus transduction of sensory information. This change in muscle spindle structure may explain some of the proprioceptive deficits identified with low back pain.

In-vitro Biomechanics of the Cervical Spine: a Systematic Review

In-vitro testing has been conducted to provide a comprehensive understanding of the biomechanics of the cervical spine. This has allowed a characterization of the stability of the spine as influenced by the intrinsic properties of its tissue constituents and the severity of degeneration or injury. This also enables the pre-clinical estimation of spinal implant functionality and the success of operative procedures. The purpose of this review paper was to compile methodologies and results from various studies addressing spinal kinematics in pre- and post-operative conditions so that they could be compared. The reviewed literature was evaluated to provide suggestions for a better approach for future studies, to reduce the uncertainties and facilitate comparisons among various results. The overview is presented in a way to inform various disciplines, such as experimental testing, design development, and clinical treatment. The biomechanical characteristics of the cervical spine, mainly the segmental range of motion (ROM), intradiscal pressure (IDP), and facet joint load (FJL), have been assessed by testing functional spinal units (FSUs). The relative effects of pathologies including disc degeneration, muscle dysfunction, and ligamentous transection have been studied by imposing on the specimen complex load scenarios imitating physiological conditions. The biomechanical response is strongly influenced by specimen type, test condition, and the different types of implants utilized in the different experimental groups.

Validity and reliability of balance Y-MED application in chronic mechanical low back pain patients

Background

Low back pain patients suffer from balance disturbance. Balance allows a person to interact with the surrounding environment and to do his daily activities. As recent technology has facilitated patient monitoring and enhanced our ability to monitor patients remotely, smartphone apps have been developed to achieve this goal. There are various balance assessment instruments used nowadays. It may be subjective or objective assessments. This study was applied to verify if the measurements of balance Y-MED smartphone applications are valid and reliable compared to the HUMAC balance board in order to offer easy, fast, cost-effective, and time-effective valid and reliable balance assessment that can be used in a clinical setting.

Methods

Fifty-four patients (12 males and 42 females) with chronic mechanical low back pain for more than 3 months was volunteered to participate in the current study with an age range of 25–60 years and BMI range of 18–34 kg/m2. Compared with the HUMAC balance board, the validity of the balance Y-MED smartphone application is evaluated, and the test-retest reliability of the balance Y-MED smartphone application is obtained by the same examiner 3 times.

Results

For concurrent validity, the correlations between balance measurements by Y-MED smartphone application and HUMAC balance board were not significant in both eyes open (r = − 0.12, p = 0.38) and eyes closed (r = 0.26, p = 0.054). The smartphone application showed poor test-retest reliability measurement of balance with eyes open; (ICC was 0.279, with 95% CI − 0.117–0.554) and with eyes closed (ICC was − 0.159, with 95% CI − 0.814–0.287).

Conclusions

According to the evaluation scheme selected in this study, the researchers were unable to confirm the validity of the balance Y-MED smartphone application in the balance assessment of patients with mechanical chronic low back pain. More than that, the balance Y-MED smartphone application has been shown poor score reliability. This makes it inaccurate for use in assessment balance.

Strain Response in the Facet Joint Capsule During Physiological Joint Rotation and Translation Following a Simulated Impact Exposure: an in Vitro Porcine Model

Low back pain (LBP) is frequently reported following rear impact collisions. Knowledge of how the facet joint capsule (FJC) mechanically behaves before and after rear impact collisions may help explain LBP development despite negative radiographic evidence of gross tissue failure. This study quantified the Green strain tensor in the facet joint capsule during rotation and translation range-of-motion tests completed before and following an in vitro simulation of a rear impact collision. Eight FSUs (4 C3-C4, 4 C5-C6) were tested. Following a preload test, FSUs were flexed and extended at 0.5 degrees/second until an ±8 Nm moment was achieved. Anterior and posterior joint translation was then applied at 0.2 mm/s until a target ±400 N shear load was imposed. Markers were drawn on the facet capsule surface and their coordinates were tracked during pre- and post-impact range-of-motion tests. Strain was defined as the change in point configuration relative to the determined neutral joint posture. There were no significant differences (p > 0.05) observed in all calculated FJC strain components in rotation and translation before and after the simulated impact. Our results suggest that LBP development resulting from the initiation of strain-induced mechanoreceptors and nociceptors with the facet joint capsule is unlikely following a severe rear impact collision within the boundaries of physiological joint motion.

Effects of core stabilization exercise and strengthening exercise on proprioception, balance, muscle thickness and pain related outcomes in patients with subacute nonspecific low back pain: a randomized controlled trial

Background

Therapeutic exercises are used in clinical practice for patients with low back pain (LBP). Core stabilization exercises can retrain the important function of local trunk muscles and increase the accuracy of the sensory integration process for stability of the spine in individuals with LBP. The aim of this study was to compare the effects of two different exercise regimes, Core stabilization exercises (CSE) and Strengthening exercise (STE), on proprioception, balance, muscle thickness and pain-related outcomes in patients with subacute non-specific low back pain (NSLBP).

Methods

Thirty-six subacute NSLBP patients, [mean age, 34.78 ± 9.07 years; BMI, 24.03 ± 3.20 Kg/m²; and duration of current pain, 8.22 ± 1.61 weeks], were included in this study. They were randomly allocated into either CSE (n = 18) or STE groups (n = 18). Exercise training was given for 30 min, three times per week, for up to 4 weeks. Proprioception, standing balance, muscle thickness of transversus abdominis (TrA) and lumbar multifidus (LM), and pain-related outcomes, comprising pain, functional disability and fear of movement, were assessed at baseline and after 4 weeks of intervention.

Results

The CSE group demonstrated significantly more improvement than the STE group after 4 weeks of intervention. Improvements were in: proprioception [mean difference (95% CI): − 0.295 (− 0.37 to − 0.2), effect size: 1.38, (p <  0.001)], balance: single leg standing with eyes open and eyes closed on both stable and unstable surfaces (p <  0.05), and percentage change of muscle thickness of TrA and LM (p <  0.01). Although both exercise groups gained relief from pain, the CSE group demonstrated greater reduction of functional disability [effect size: 0.61, (p <  0.05)] and fear of movement [effect size: 0.80, (p < 0.01)]. There were no significant adverse effects in either type of exercise program.

Conclusion

Despite both core stabilization and strengthening exercises reducing pain, core stabilization exercise is superior to strengthening exercise. It is effective in improving proprioception, balance, and percentage change of muscle thickness of TrA and LM, and reducing functional disability and fear of movement in patients with subacute NSLBP.

Trial registration

Thai Clinical Trial Registry (TCTR20180822001; August 21, 2018).

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04858-6.

Analysis of the Effect of Wearing Extensible and Non-Extensible Lumbar Belts on Biomechanical Factors of the Sit-to-Stand Movement and Pain-Related Psychological Factors Affecting Office Workers with Low Back Pain

This study aimed to investigate the effects of wearing extensible and non-extensible lumbar belt (LB) on biomechanical factors of the sit-to-stand (STD) movement and pain-related psychological factors affecting office workers with low back pain. Among 30 office workers, 15 with low back pain (LBP) were assigned to the experimental group and 15 healthy adults were assigned to the control group. The participants performed STD movement in random order of three different conditions: without LB (Condition 1), with extensible LB (Condition 2), and with non-extensible LB (Condition 3). Biomechanical variables of STD movement in each condition were measured using a three-dimensional motion analysis system and force plate. Pain-related psychological factors were measured only in the experimental group. Among the biomechanical factors of STD movement, an interaction effect was found in the maximum anterior pelvic tilt angle and total-phase range of motion of the trunk (p < 0.05). Pain intensity, pain-related anxiety, and pain catastrophizing were decreased in the conditions with lumbar belts (Conditions 2 and 3) compared to the condition without LB (Condition 1) (p < 0.05). Extensible and non-extensible lumbar belts engender biomechanically beneficial effects during STD movement in both office workers with LBP and healthy office workers. Further, pain intensity, pain-related anxiety, and pain catastrophizing were decreased in office workers with LBP. Therefore, both types of extensible lumbar belts may be helpful in the daily life of patients with LBP and office workers.

Impairment of Proprioception in Young Adult Nonradicular Patients with Lumbar Derangement Syndrome

Maintaining body balance is a complex function based on the information deriving from the vestibular, visual, and proprioceptive systems. The aim of the study was to evaluate quiet single stance stability in young adults with lumbar derangement syndrome (LDS) and in the control group of the healthy subjects. The second aim of this study was to determine whether pain intensity, degree of disability, and the level of physical activity can influence postural control in patients with LDS. It is important to underline that selecting a homogeneous group of LBP patients using, for example, mechanical diagnosis and therapy method and Quebec Task Force Classification, can result in an increased sensitivity of the study. The study included 126 subjects: 70 patients with LDS (37 women, 33 men) and the control group 56 healthy volunteers (36 women, 20 men). In case of multiple group comparisons for variables with normal distribution, ANOVA post hoc test was used or, as the nonparametric equivalent, Kruskal-Wallis test. In all these calculations, the statistical significance level was set to p < 0.05. The stability index eyes open for the study group was 88.34 and for the control group 89.86. There was no significant difference in the level of postural control between the study and control groups (p > 0.05). The level of stability index eyes closed (SI EC) for the study group was 71.44 and for the control group 77.1. SI EC results showed significant differences in proprioceptive control during single leg stance between the study and control groups (p < 0.05). The level of pain intensity, the degree of disability, and physical activity level did not influence postural control in the study group with LDS. In summary, patients with LDS showed significantly worse proprioceptive control.

Analysis of Muscle Activity Following the Application of Myofascial Release Techniques for Low-Back Pain-A Randomized-Controlled Trial

Introduction. Lumbosacral dysfunctions and the resulting pain syndromes, such as low-back pain (LBP), are one of the most common musculoskeletal problems being faced by society around the world. So far, a contributory role of thoracolumbar fascia (TLF) dysfunction in some cases of LBP has been suggested. Research also confirms that muscle resting activity level in the TLF area is increased in people with LBP. Myofascial release (MFR) is a therapeutic option offered to patients with chronic low-back pain (CLBP). The therapy aims to improve flexibility and sliding between layers of soft tissue, and thus decrease muscle activity, reduce pain intensity, and improve functional performance. Objective. This study aims to assess changes in resting activity of selected muscles within the TLF in a group of patients with CLBP immediately after a single MFR treatment and one month after the intervention. Methods. A total of 113 patients with CLBP completed the study. Simple randomization was applied to assign subjects to study groups. The experimental group (n = 59) underwent a single session of MFR therapy. No therapeutic intervention was applied to the control group (n = 54). Surface electromyography was used to evaluate positive treatment effects in patients immediately after receiving the therapy (experimental group) and after one month (experimental and control group). Results. A statistically reliable decrease in the activity of erector spinae (ES) and multifidus muscles (MF) was observed after a single session of MFR therapy. Effects of the treatment were present immediately after receiving the therapy and one month after the intervention. Conclusions. A single MFR treatment in patients with CLBP immediately reduces the resting activity levels of ES and MF. Results of measurements carried out one month after the treatment confirm that the therapeutic effects were maintained.

The association of reactive balance control and spinal curvature under lumbar muscle fatigue

Background

Although low back fatigue is an important intervening factor for physical functioning among sedentary people, little is known about its possible significance in relation to the spinal posture and compensatory postural responses to unpredictable stimuli. This study investigates the effect of lumbar muscle fatigue on spinal curvature and reactive balance control in response to externally induced perturbations.

Methods

A group of 38 young sedentary individuals underwent a perturbation-based balance test by applying a 2 kg load release. Sagittal spinal curvature and pelvic tilt was measured in both a normal and Matthiass standing posture both with and without a hand-held 2 kg load, and before and after the Sørensen fatigue test.

Results

Both the peak anterior and peak posterior center of pressure (CoP) displacements and the corresponding time to peak anterior and peak posterior CoP displacements significantly increased after the Sørensen fatigue test (all at p < 0.001). A lumbar muscle fatigue led to a decrease of the lumbar lordosis in the Matthiass posture while holding a 2 kg load in front of the body when compared to pre-fatigue conditions both without a load (p = 0.011, d = 0.35) and with a 2 kg load (p = 0.000, d = 0.51). Also the sacral inclination in the Matthiass posture with a 2 kg additional load significantly decreased under fatigue when compared to all postures in pre-fatigue conditions (p = 0.01, d = 0.48). Contrary to pre-fatigue conditions, variables of the perturbation-based balance test were closely associated with those of lumbar curvature while standing in the Matthiass posture with a 2 kg additional load after the Sørensen fatigue test (r values in range from −0.520 to −0.631, all at p < 0.05).

Conclusion

These findings indicate that lumbar muscle fatigue causes changes in the lumbar spinal curvature and this is functionally relevant in explaining the impaired ability to maintain balance after externally induced perturbations. This emphasizes the importance for assessing both spinal posture and reactive balance control under fatigue in order to reveal their interrelations in young sedentary adults and predict any significant deterioration in later years.

The relationship between muscle size, obesity, body fat ratio, pain and disability in individuals with and without nonspecific low back pain

Patients with nonspecific low back pain (NSLBP) may face motor control problems and health disability barriers during various tasks. However, studies investigating the extent of these disadvantages, and possible associated factors are quite limited in patients with NSLBP. To compare motor control performances and physical assessment domains between patients with NSLBP and asymptomatic controls. Twenty-seven patients with NSBLP and 27 age- and sex-matched asymptomatic controls participated in this cross-sectional study. Ultrasonographic imaging was used to determine abdominal and multifidus muscles thicknesses and adipose tissue rate. Visual analog scale was used to assess LBP severity. Body mass index (BMI) and Oswestry Disability Index (ODI) scores of the participants were physical assessment domains of LBP. BMI values were greater in the NSLBP group compared to the asymptomatic participants. ANCOVA revealed a significant interaction effect regarding external abdominal oblique and multifidus lumborum muscles thickness, and abdominal adipose tissue (p = 0.015; p = 0.001; p = 0.006), respectively in terms of two groups. The thicknesses of these muscles were lesser in the NSLBP group compared with the control group. Similarly, abdominal adipose tissue was higher in the NSLBP group. The stepwise multiple regression analysis demonstrated that the Oswestry Disability Index and abdominal adipose tissue rate were significant and independent factors of the low back pain severity with 73.5% of the variance. The study results indicate that increased disability and fat infiltration are possible determinants influencing pain severity, although further research is required. Examining musculoskeletal properties of lumbar region could provide information about the limitation in patients with NSBLP.

Trunk muscle activation patterns during active hip abduction test during remission from recurrent low back pain: an observational study

Background

The active hip abduction test (AHAbd) is widely used to evaluate lumbopelvic stability, but the onset of trunk muscle activation during the test in individuals with recurrent low back pain (rLBP) has not been investigated so far. It is important to investigate the pattern of trunk muscle activation during the AHAbd test to provide insight into the interpretation of observation-based assessment results; this may help to create exercise therapy interventions, from a movement control perspective, for people seeking treatment for rLBP. The purpose of this study was to compare the timing of trunk muscle activation between individuals with and without rLBP and to assess potential differences.

Methods

Seventeen subjects in remission from rLBP and 17 subjects without rLBP were recruited. We performed surface electromyography of the transversus abdominis/internal abdominal oblique, external oblique, erector spinae, and gluteus medius muscles during the AHAbd test on both sides. The onset of trunk muscle activation was calculated relative to the prime mover gluteus medius. The independent-samples t- and Mann-Whitney U tests were used to compare the onset of trunk muscle activation between the two groups.

Results

The onset of transversus abdominis/internal abdominal oblique activation on the ipsilateral (right AHAbd: −3.0 ± 16.2 vs. 36.3 ± 20.0 msec, left AHAbd: −7.2 ± 18.6 vs. 29.6 ± 44.3 ms) and contralateral sides (right AHAbd: −11.5 ± 13.9 vs. 24.4 ± 32.3 ms, left AHAbd: −10.1 ± 12.5 vs. 23.3 ± 17.2 ms) and erector spinae on the contralateral side (right AHAbd: 76.1 ± 84.9 vs. 183.9 ± 114.6 ms, left AHAbd: 60.7 ± 70.5 vs. 133.9 ± 98.6 ms) occurred significantly later in individuals with rLBP than in individuals without rLBP (p < 0.01). During the left AHAbd test, the ipsilateral erector spinae was also activated significantly later in individuals with rLBP than in individuals without rLBP (71.1 ± 80.1 vs. 163.8 ± 120.1 ms, p < 0.05). No significant difference was observed in the onset of the external oblique activation on the right and left AHAbd tests (p > 0.05).

Conclusions

Our results suggest that individuals with rLBP possess a trunk muscle activation pattern that is different from that of individuals without rLBP. These findings provide an insight into the underlying muscle activation patterns during the AHAbd test for people with rLBP and may support aggressive early intervention for neuromuscular control.

Spinal movement variability associated with low back pain: A scoping review

Objective

To identify suggestions for future research on spinal movement variability (SMV) in individuals with low back pain (LBP) by investigating (1) the methodologies and statistical tools used to assess SMV; (2) characteristics that influence the direction of change in SMV; (3) the methodological quality and potential biases in the published studies; and (4) strategies for optimizing SMV in LBP patients.

Methods

We searched literature databases (CENTRAL, Medline, PubMed, Embase, and CINAHL) and comprehensively reviewed the relevant papers up to 5 May 2020. Eligibility criteria included studies investigating SMV in LBP subjects by measuring trunk angle using motion capture devices during voluntary repeated trunk movements in any plane. The Newcastle-Ottawa risk of bias tool was used for data quality assessment. Results were reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews.

Results

Eighteen studies were included: 14 cross-sectional and 4 prospective studies. Seven linear and non-linear statistical tools were used. Common movement tasks included trunk forward bending and backward return, and object lifting. Study results on SMV changes associated with LBP were inconsistent. Two of the three interventional studies reported changes in SMV, one of which was a randomized controlled trial (RCT) involving neuromuscular exercise interventions. Many studies did not account for the potential risk of selection bias in the LBP population.

Conclusion

Designers of future studies should recognize that each of the two types of statistical tools assesses functionally different aspects of SMV. Future studies should also consider dividing participants into subgroups according to LBP characteristics, as three potential subgroups with different SMV characteristics were proposed in our study. Different task demands also produced different effects. We found preliminary evidence in a RCT that neuromuscular exercises could modify SMV, suggesting a rationale for well-designed RCTs involving neuromuscular exercise interventions in future studies.

Calibration and validation of a novel hybrid model of the lumbosacral spine in ArtiSynth-The passive structures

In computational biomechanics, two separate types of models have been used predominantly to enhance the understanding of the mechanisms of action of the lumbosacral spine (LSS): Finite element (FE) and musculoskeletal multibody (MB) models. To combine advantages of both models, hybrid FE-MB models are an increasingly used alternative. The aim of this paper is to develop, calibrate, and validate a novel passive hybrid FE-MB open-access simulation model of a ligamentous LSS using ArtiSynth. Based on anatomical data from the Male Visible Human Project, the LSS model is constructed from the L1-S1 rigid vertebrae interconnected with hyperelastic fiber-reinforced FE intervertebral discs, ligaments, and facet joints. A mesh convergence study, sensitivity analyses, and systematic calibration were conducted with the hybrid functional spinal unit (FSU) L4/5. The predicted mechanical responses of the FSU L4/5, the lumbar spine (L1-L5), and the LSS were validated against literature data from in vivo and in vitro measurements and in silico models. Spinal mechanical responses considered when loaded with pure moments and combined loading modes were total and intervertebral range of motions, instantaneous axes and centers of rotation, facet joint contact forces, intradiscal pressures, disc bulges, and stiffnesses. Undesirable correlations with the FE mesh were minimized, the number of crisscrossed collagen fiber rings was reduced to five, and the individual influences of specific anatomical structures were adjusted to in vitro range of motions. Including intervertebral motion couplings for axial rotation and nonlinear stiffening under increasing axial compression, the predicted kinematic and structural mechanics responses were consistent with the comparative data. The results demonstrate that the hybrid simulation model is robust and efficient in reproducing valid mechanical responses to provide a starting point for upcoming optimizations and extensions, such as with active skeletal muscles.

Slacklining as therapy to address non-specific low back pain in the presence of multifidus arthrogenic muscle inhibition

Low back pain (LBP) represents the most prevalent, problematic and painful of musculoskeletal conditions that affects both the individual and society with health and economic concerns. LBP is a heterogeneous condition with multiple diagnoses and causes. In the absence of consensus definitions, partly because of terminology inconsistency, it is further referred to as non-specific LBP (NSLBP). In NSLBP patients, the lumbar multifidus (MF), a key stabilizing muscle, has a depleted role due to recognized myocellular lipid infiltration and wasting, with the potential primary cause hypothesized as arthrogenic muscle inhibition (AMI). This link between AMI and NSLBP continues to gain increasing recognition. To date there is no 'gold standard' or consensus treatment to alleviate symptoms and disability due to NSLBP, though the advocated interventions are numerous, with marked variations in costs and levels of supportive evidence. However, there is consensus that NSLBP management be cost-effective, self-administered, educational, exercise-based, and use multi-modal and multi-disciplinary approaches. An adjuvant therapy fulfilling these consensus criteria is 'slacklining', within an overall rehabilitation program. Slacklining, the neuromechanical action of balance retention on a tightened band, induces strategic indirect-involuntary therapeutic muscle activation exercise incorporating spinal motor control. Though several models have been proposed, understanding slacklining's neuro-motor mechanism of action remains incomplete. Slacklining has demonstrated clinical effects to overcome AMI in peripheral joints, particularly the knee, and is reported in clinical case-studies as showing promising results in reducing NSLBP related to MF deficiency induced through AMI (MF-AMI). Therefore, this paper aims to: rationalize why and how adjuvant, slacklining therapeutic exercise may positively affect patients with NSLBP, due to MF-AMI induced depletion of spinal stabilization; considers current understandings and interventions for NSLBP, including the contributing role of MF-AMI; and details the reasons why slacklining could be considered as a potential adjuvant intervention for NSLBP through its indirect-involuntary action. This action is hypothesized to occur through an over-ride or inhibition of central down-regulatory induced muscle insufficiency, present due to AMI. This subsequently allows neuroplasticity, normal neuro-motor sequencing and muscle re-activation, which facilitates innate advantageous spinal stabilization. This in-turn addresses and reduces NSLBP, its concurrent symptoms and functional disability. This process is hypothesized to occur through four neuro-physiological processing pathways: finite neural delay; movement-control phenotypes; inhibition of action and the innate primordial imperative; and accentuated corticospinal drive. Further research is recommended to investigate these hypotheses and the effect of slacklining as an adjuvant therapy in cohort and control studies of NSLBP populations.

Immediate effects of myofascial release on neuromechanical characteristics in female and male patients with low back pain and healthy controls as assessed by tensiomyography. A controlled matched-pair study

BACKGROUND

Low back pain (LBP) is a major health issue in most industrialised countries. Lumbodorsal fascia has been advocated as a potential source of pain in the lumbopelvic region. Myofascial release constitutes a manual therapeutic approach focussing on the restoration of altered soft tissue function. No previous study has focused on quantifying neuromechanical effects of myofascial release on LBP patients through tensiomyography. The purpose of this study was to quantify immediate neuromechanical alterations of myofascial release on patients with LBP and healthy controls through tensiomyography parameters.

METHODS

The participants' (n = 30) bilateral lumbar erector spinae muscles were assessed via tensiomyography before and after a 6-min myofascial release treatment of the lumbodorsal fascia to evaluate the muscles' mechanical characteristics. Subjects with LBP (n = 15) were eligible to partake if they reported having had LBP for most days in the past 12 weeks. Muscle displacement (Dm [mm]), velocity of contraction (Vc [mm/s]), and lateral symmetry (Ls [%]) were assessed through tensiomyography testing.

FINDINGS

Statistical analyses revealed a significant increase for velocity of contraction in the right (p = .021) and left (p = .041) lumbar erector spinae for the subjects with LBP but not for the healthy controls (both p > .14).

INTERPRETATION

We suggested that myofascial release alters neuromechanical characteristics in subjects with LBP. Tensiomyography may be implemented in clinical settings to monitor intervention effects of the myofascial system, especially the tensiomyography parameter velocity of contraction.

Comparison of the reliance of the postural control system on the visual, vestibular and proprioceptive inputs in chronic low back pain patients and asymptomatic participants

BACKGROUND

Although proprioception deficits have been documented in chronic low back pain (CLBP) patients, little is known about adaptive strategies to provide postural control in these patients. Substitution of unreliable proprioceptive information with other afferents might be considered plausible.

RESEARCH QUESTION

Is the response of the postural control system dependent on the source of sensory afferents being manipulated in persons with and without CLBP?

METHODS

Sixty persons with and without CLBP participated in this cross-sectional study. Center of pressure (COP) displacement range, velocity, path length and area were calculated under four sensory conditions: 1) normal upright standing; 2) upright standing on a foam with eyes open and head in neutral position; 3) upright standing with eyes open and 60° cervical extension and 4) upright standing with eyes closed and 60° cervical extension. A two-way repeated measures analysis of variance was used to compare COP masseurs under different conditions and between the groups.

RESULTS

CLBP patients demonstrated fewer alterations to manipulation of both visual and vestibular afferents in terms of number of COP variables significantly altered. ML range and velocity in both groups and path length in the CLBP group were significantly different between conditions 2 and 4. In both groups, all COP variables except AP range increased significantly in condition 2 compared to conditions 1and 3 (p < 0.001). AP velocity was the only variable to be different between conditions 1 and 3 in both CLBP (p = 0.025) and control (p < 0.001) groups. Between group differences were significant on AP velocity (p = 0.019).

SIGNIFICANCE

No overweighting was observed in the vestibular or visual afferents in CLBP patients. Compensatory strategies seem to lie within proprioceptive system by reweighting afferents from different body segments. The postural control system behaved more robustly in CLBP patients while AP COP velocity was found as the most sensitive and discriminating parameter.

The morphological and microscopical characteristics of posterior layer of human thoracolumbar fascia; A potential source of low back pain

BACKGROUND

Posterior layer of thoracolumbar fascia (PTLF) is the deep fascia of back of the trunk, which connects the trunk, upper limb and lower limb muscles. Very few cadaveric studies of posterior layer of thoracolumbar fascia (PTLF) are found in the literature, which mention the presence of nerve receptors in it but, quantification of the nerve receptors where not found. Providing the morphological and morphometrical data of PTLF may help the exercise physiologists, sports physicians, occupational health assistants and, physiotherapists to modify or invent new protocol of treatment to help the society.

METHODS

In this study, twenty formalin embalmed human cadavers were used and we have documented the orientation of the PTLF and quantified the number of peripheral nerve endings at the different vertebral levels.

RESULTS

Mean distance of PTLF from vertebral spines to the musculofascial junction was at thoracic region 3.38cm and 3.34cm; at lumbar region, it was 7.4cm and 7.36cm and at sacral region it was 2.98cm and 2.96cm on right and left side, respectively. The angulation of PTLF varies from 18-110 degrees at different vertebral levels. The microscopic data shows the thickness of PTLF and number of nerve endings in the sacral level is increased compared to that of thoracic vertebral levels.

CONCLUSIONS

We have contributed the novel morphological and microscopical details to the limited existing data on PTLF. We also have provided the quantitative data of nerve fibers, which are possible nociceptors of PTLF.