Timing and magnitude of lumbar spine contribution to trunk forward bending and backward return in patients with acute low back pain

Different Spatial Characteristic Changes in Lumbopelvic Kinematics Before and After Fatigue: Comparison Between People with and Without Low Back Pain

BACKGROUND

The lumbopelvic region plays a pivotal role in enabling various functional activities. This study quantified and compared the kinematic changes between healthy individuals and patients with recurrent low back pain (LBP) in both rested and fatigued states to gain insight into the kinematic adaptation and mechanisms underlying kinematic variations that occur in the presence of these factors.

METHODS

Participants were divided into two groups: the LBP (n = 23) and healthy control groups (n = 19). Dynamic lumbopelvic measurements were taken using a biplane radiography image system while the participants performed weight-bearing forward-backward bending before and after fatigue. All lumbopelvic kinematics were described as the three-dimensional motion of the vertebra relative to the pelvis and were measured at normalized time intervals from maximum extension to approximately 45° of flexion.

RESULTS

Repetitive lifting- and lowering-induced fatigue significantly affected lumbopelvic kinematics in the anterior/posterior translation (mm) and rotation around the z-axis in both healthy individuals and patients with LBP (p < 0.05). In healthy individuals, significant differences occurred in approximately 13-83% of the forward-backward bending cycle (0-100%), whereas, in patients with LBP, significant differences mainly occurred in 61-93% of the cycle (p < 0.01).

CONCLUSIONS

The lumbopelvic kinematic changes observed in both LBP patients and healthy individuals after fatigue may indicate protective compensation or vulnerability and could play a role in LBP dysfunction.

Kinematic patterns in performing trunk flexion tasks influenced by various mechanical optimization targets: A simulation study

BACKGROUND

Low back pain is the most prevalent and disabling condition worldwide, with a high recurrence rate in the general adult population.

METHODS

A set of open-sourced trunk musculoskeletal models was used to investigate trunk flexion kinematics under different motor control strategies, including minimizing shearing or compressive loads at the L4/L5 or L5/S1 level.

FINDINGS

A control strategy that minimizes the load on the lower lumbar intervertebral disc can result in two kinematic patterns-the "restricted lumbar spine" and the "overflexed lumbar spine"-in performing the trunk flexion task. The "restricted" pattern can reduce the overall load on the lower lumbar levels, whereas the "overflexed" pattern can reduce the shearing force only at the L4/L5 level and increase the compressive and shearing forces at the L5/S1 level and the compressive force at the L4/L5 level.

INTERPRETATION

This study investigated the relationships between specific trunk kinematics in patients with low back pain and lumbar intervertebral loading via musculoskeletal modelling and simulation. The results provide insight into individualized treatment for patients with low back pain.

Associations between pain-related fear and lumbar movement variability during activities of daily living in patients with chronic low back pain and healthy controls

Low back pain (LBP) is a global issue involving biological, psychological, and social factors. Pain-related fear has been shown to influence movement behavior, however, its association with some measures of movement behavior, such as spinal movement variability, remains inconclusive. To further investigate this, spinal kinematics during various activities of daily living (i.e., walking, running, lifting, and stair climbing) of 49 patients with chronic LBP and a group of 51 sex-, age-, and BMI-matched healthy controls were used to calculate lumbar spine movement variability which was quantified using different indices (i.e., coefficient of variation, coupling angle variability in vector coding, deviation phase of the continuous relative phase and an angle-angular velocity variability). General and task-specific pain-related fear was assessed using the Tampa Scale of Kinesiophobia and the Photograph Series of Daily Activities-Short Electronic Version, respectively. Linear regression analyses showed no significant association between movement variability and pain-related fear, however, the sample consisted of younger individuals with moderate disability and with low levels of pain and pain-related fear. In addition, the different variability indices were weakly correlated and varied greatly depending on the method used and the task performed. Therefore, comparisons between studies with different movement variability calculation methods or different activities should be treated with caution.

Altered Movement Coordination during Functional Reach Tasks in Patients with Chronic Low Back Pain and Its Relationship to Numerical Pain Rating Scores

Identifying the effects of pain catastrophizing on movement patterns in people with chronic low back pain (CLBP) has important clinical implications for treatment approaches. Prior research has shown people with CLBP have decreased lumbar-hip ratios during trunk flexion movements, indicating a decrease in the contribution of lumbar flexion relative to hip flexion during trunk flexion. In this study, we aim to explore the relationship between pain catastrophizing and movement patterns during trunk flexion in a CLBP population. Participants with CLBP (N = 98, male = 59, age = 39.1 ± 13.0) completed a virtual reality standardized reaching task that necessitated a progressively larger amount of trunk flexion. Specifically, participants reached for four virtual targets to elicit 15°, 30°, 45°, and 60° trunk flexion in the mid-sagittal plane. Lumbar flexion was derived from the motion data. Self-report measures of numerical pain ratings, kinesiophobia, and pain catastrophizing were obtained. Pain catastrophizing leads to decreased lumbar flexion angles during forward reaching. This effect is greater in females than males.

Spinal loads during dynamic full flexion and return to standing posture in different age and sex groups: A musculoskeletal model study

During forward flexion, spine motion varies due to age and sex differences. Previous studies showed that lumbar/pelvis range of flexion (RoF) and lumbo-pelvic ratio (L/P) are age/sex dependent. How variation of these parameters affects lumbar loading in a normal population requires further assessment. We aimed to estimate lumbar loads during dynamic flexion-return cycle and the differences in peak loads (compression) and corresponding trunk inclinations due to variation in lumbar/pelvis RoF and L/P. Based on in vivo L/P (0.11-3.44), temporal phases of flexion (early, middle, and later), the lumbar (45-55°) and hip (60-79°) RoF; full flexion-return cycles of six seconds were reconstructed for three age groups (20-35, 36-50 and 50+ yrs.) in both sexes. Six inverse dynamic analyses were performed with a 50th percentile model, and differences in peak loads and corresponding trunk inclinations were calculated. Peak loads at L4-L5 were 179 N higher in younger males versus females, but 228 N and 210 N lower in middle-aged and older males, respectively, compared to females. Females exhibited higher trunk inclinations (6°-20°) than males across all age groups. Age related differences in L4-L5 peak loads and corresponding trunk inclinations were found up to 415 N and 19° in males and 152 N and 13° in females. With aging, peak loads were reduced in males but were found non-monotonic in females, whereas trunk inclinations at peak loads were reduced in both sexes from young to middle/old age groups. In conclusion, lumbar loading and corresponding trunk inclinations varied notably due to age/sex differences. Such data may help distinguishing normal or pathological condition of the lumbar spine.

Lumbo-Pelvic Rhythm Monitoring Using Wearable Technology with Sensory Biofeedback: A Systematic Review

As an essential lower-back movement pattern, lumbo-pelvic rhythm (LPR) during forward trunk flexion and backward return has been investigated on a large scale. It has been suggested that abnormalities in lumbo-pelvic coordination are related to the risk of developing low back disorders. However, considerable differences in the approaches used to monitor LPR make it challenging to integrate findings from those investigations for future research. Therefore, the aim of this systematic review was to summarize the use of wearable technology for kinematic measurement with sensory biofeedback for LPR monitoring by assessing these technologies' specific capabilities and biofeedback capacities and exploring their practical viability based on sensor outcomes. The review was developed following the PRISMA guidelines, and the risk of bias was analyzed using the PREDro and STROBE scales. PubMed, Web of Science, Scopus, and IEEEXPLORE databases were searched for relevant studies, initially returning a total of 528 articles. Finally, we included eight articles featuring wearable devices with audio or vibration biofeedback. Differences in protocols and limitations were also observed. This novel study presents a review of wearable tracking devices for LPR motion-mediated biofeedback for the purpose of correcting lower back posture. More research is needed to determine the long-term effectiveness of these devices, as well as their most appropriate corresponding methodologies.

Not all movements are equal: Differences in the variability of trunk motor behavior between people with and without low back pain-A systematic review with descriptive synthesis

BACKGROUND

Differences in variability of trunk motor behavior between people with and without low back pain (LBP) have been reported in the literature. However, the direction and consistency of these differences remain unclear. Understanding variability of trunk motor behavior between individuals with LBP and those without is crucial to better understand the impact of LBP and potentially optimize treatment outcomes. Identifying such differences may help tailor therapeutic interventions.

OBJECTIVE

This systematic review aims to answer the question: Is variability of trunk motor behavior different between people with and without LBP and if so, do people with LBP show more or less variability? Furthermore, we addressed the question whether the results are dependent on characteristics of the patient group, the task performed and the type of variability measure.

METHODS

This study was registered in PROSPERO (CRD42020180003). A comprehensive systematic literature search was performed by searching PubMed, Embase, Cinahl, Cochrane Central Register of Controlled Trials, Web of Science and Sport Discus. Studies were eligible if they (1) included a LBP group and a control group, (2) included adults with non-specific low back pain of any duration and (3) measured kinematic variability, EMG variability and/or kinetic variability. Risk of Bias was evaluated and a descriptive synthesis was performed.

RESULTS

Thirty-nine studies were included, thirty-one of which were included in the descriptive synthesis. In most studies and experimental conditions, variability did not significantly differ between groups. When significant differences were found, less variability in patients with LBP was more frequently reported than more variability, especially in gait-related tasks.

CONCLUSIONS

Given the considerable risk of bias of the included studies and the clinical characteristics of the participants with low severity scores for pain, disability and psychological measures, there is insufficient evidence to draw firm conclusions.

The influence of sedentary behaviour on lumbar-pelvic kinematics during squatting and forward bending among physically active students

Prolonged sitting may involve several mechanisms that make it a risk factor for low back pain. The aim of this study was to investigate lumbar-pelvic kinematics and multifidus muscle (MF) activity during squatting and forward bending in relation to the sedentary behaviour of physically active students. Sixty-three students were divided into two groups according to the time spent in a sitting position during the day: 'high' (>7 h/day); 'low' (≤7 h/day). Lumbar-pelvic ratios, ranges of motion, angular velocities, and MF flexion-relaxation phenomenon were investigated. Data were obtained using the optical motion analysis system, and surface electromyography. The results indicated that lumbar-pelvic ratios during both tasks and velocity of lumbar spine during squatting were significantly greater in the 'high' than in the 'low' sitting group. Muscle activity showed no differences between groups. Prolonged sitting can be considered a factor that slightly, but statistically significantly influences the lumbar-pelvic kinematics in physically active people.Practitioner summary: Lumbar-pelvic kinematics can be altered by prolonged sitting in physically active students. Lumbar-pelvic ratios during squatting and forward bending and lumbar spine velocity during squatting were significantly greater in the 'high' than in the 'low' sitting group. Sedentary behaviour should be considered during an assessment of movement patterns.Abbreviations: BMI: body mass index; ERR: extension-relaxation ratio; FRP: flexion-relaxation phenomenon; FRR: flexion-relaxation ratio; IPAQ: International Physical Activity Questionnaire; LBP: low back pain; METs: metabolic equivalent of tasks; MF: multifidus muscle; PA: physical activity; ROM: range of motion; sEMG: surface electromyography.

Sensor-based intervention to enhance movement control of the spine in low back pain: Protocol for a quasi-randomized controlled trial

Introduction

Chronic low back pain is a common condition that imposes an enormous burden on individuals and society. Physical exercise with education is the most effective treatment, but generally results in small, albeit significant improvements. However, which type of exercise is most effective remains unknown. Core stability training is often used to improve muscle strength and spinal stability in these patients. The majority of the core stability exercises mentioned in intervention studies involve no spinal movements (static motor control exercises). It is questionable if these exercises would improve controlled movements of the spine. Sensor-based exergames controlled with spinal movements could help improve movement control of the spine. The primary aim of this study is to compare the effects of such sensor-based exergames to static motor control exercises on spinal movement control.

Methods and analysis

In this quasi-randomized controlled trial, 60 patients with chronic low back pain who are already enrolled in a multidisciplinary rehabilitation programme will be recruited. Patients will be randomly allocated into one of two groups: the Sensor-Based Movement Control group (n = 30) or the Static Motor Control group (n = 30). Both groups will receive 8 weeks of two supervised therapy sessions and four home exercises per week in addition to the rehabilitation programme. At baseline (week 1) and after the intervention (week 10), movement control of the spine will be assessed using a tracking task and clinical movement control test battery. Questionnaires on pain, disability, fear avoidance and quality of life will be taken at baseline, after intervention and at 6- and 12 months follow-up. Repeated measures ANOVAs will be used to evaluate if a significant Group x Time interaction effect exists for the movement control evaluations.

Discussion

Sensor-based spinal controlled exergames are a novel way to train spinal movement control using meaningful and engaging feedback. The results of this study will inform clinicians and researchers on the efficacy of movement control training for patients with low back pain.

Ethics and dissemination

Ethical approval for this study protocol was obtained from the METC Brabant (protocol number NL76811.028.21).

Trial registration

Open Science Framework Registries (https://osf.io/v3mw9/), registration number: 10.17605/OSF.IO/V3MW9, registered on 1 September 2021.

Machine Learning Identifies Chronic Low Back Pain Patients from an Instrumented Trunk Bending and Return Test

Nowadays, the better assessment of low back pain (LBP) is an important challenge, as it is the leading musculoskeletal condition worldwide in terms of years of disability. The objective of this study was to evaluate the relevance of various machine learning (ML) algorithms and Sample Entropy (SampEn), which assesses the complexity of motion variability in identifying the condition of low back pain. Twenty chronic low-back pain (CLBP) patients and 20 healthy non-LBP participants performed 1-min repetitive bending (flexion) and return (extension) trunk movements. Analysis was performed using the time series recorded by three inertial sensors attached to the participants. It was found that SampEn was significantly lower in CLBP patients, indicating a loss of movement complexity due to LBP. Gaussian Naive Bayes ML proved to be the best of the various tested algorithms, achieving 79% accuracy in identifying CLBP patients. Angular velocity of flexion movement was the most discriminative feature in the ML analysis. This study demonstrated that: supervised ML and a complexity assessment of trunk movement variability are useful in the identification of CLBP condition, and that simple kinematic indicators are sensitive to this condition. Therefore, ML could be progressively adopted by clinicians in the assessment of CLBP patients.

Patients with chronic non-specific low back pain have altered movement coordination during functional reaching tasks

BACKGROUND

Identifying altered motor control patterns during functional movements in patients with chronic non-specific low back pain (LBP) has important clinical implications for reducing the risk of recurrence. While prior research has shown that magnitudes of lumbar and hip motion are not altered in patients with chronic non-specific LBP, it is possible that outcomes which describe coordination could provide greater discriminatory information between pathological and healthy movement.

RESEARCH QUESTION

Determine the effect of biological sex and chronic non-specific LBP on coordination between hip and lumbar motion during cyclic and discrete reaching.

METHODS

Twenty participants with chronic non-specific LBP (11 male/9 female, 23.5 ± 4.9 years old) and 21 control participants (12 male/9 female, 22.9 ± 6.1 years old) completed discrete and cyclic reaching tasks to a target in the mid-sagittal plane, while whole-body kinematics were collected using a three-dimensional motion capture system. Movement time, lumbar motion, hip motion, and the ratio between lumbar and hip motion were compared between participants with and without chronic non-specific LBP and between men and women using two-way mixed ANOVAs.

RESULTS

Participants with chronic non-specific LBP had reduced lumbar-hip ratios relative to control participants during both the cyclic (F = 4.779, p = 0.035, η² = 0.114) and discrete tasks (F = 4.743, p = 0.036, η² = 0.119), however group differences were not observed for hip or lumbar excursion during either task (p > 0.05). Participants with chronic non-specific LBP had slower reaching times relative to controls during the discrete reaching task (F = 4.795, p = 0.035, η² = 0.115). No significant effects of sex, and no interactions between group and sex were observed for any outcome.

SIGNIFICANCE

Reduced lumbar-hip ratios during reaching likely reflect a compensatory movement strategy that could play an important role in the development and progression of LBP.

Recovery of the lumbopelvic movement and muscle recruitment patterns using motor control exercise program in people with chronic nonspecific low back pain: A prospective study

This study aims to investigate the dysfunction and recovery of the lumbopelvic movement and motor control of people with chronic nonspecific low back pain after a structured rehabilitation which emphasizes on re-education and training of movement and motor control. The lumbopelvic movement and motor control pattern of 30 adults (15 with chronic low back pain, 15 healthy controls) were assessed using 3D motion and electromyographic analysis during the repeated forward bending test, in additional to the clinical outcome measures. Regional kinematics and muscle recruitment pattern of the symptomatic group was analysed before and after the 6-week rehabilitation, and compared to healthy controls. Significant improvement in back pain, functional capacity and self-efficacy of the symptomatic group was found after the rehabilitation. Patients with chronic nonspecific low back pain were capable to recover to a comparable level of the healthy controls in terms of their lumbopelvic movement and motor control pattern upon completion of a 6-week rehabilitation program, despite their dysfunction displayed at baseline. Phase specific motor control reorganization in which more profound and positive changes shown during the flexion phase. Our findings indicate that the recovery of the movement and motor control pattern in patients with chronic low back pain achieved to a comparable level of the healthy able-bodies. The improvement of both the physical outcome measures suggest that specific rehabilitation program which emphasizes on optimizing motor control during movements would help promoting the functional recovery of this specific low back pain subgroup.

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.

Changes in Lumbo-Pelvic Coordination of Individuals With and Without Low Back Pain When Wearing a Hip Orthosis

Individuals with low back pain demonstrate an abnormal lumbo-pelvic coordination compared to back-healthy individuals. This abnormal coordination presents itself as a reduction in lumbar contributions and an increase in pelvic rotations during a trunk forward bending and backward return task. This study investigated the ability of a hip orthosis in correcting such an abnormal lumbo-pelvic coordination by restricting pelvic rotation and, hence increasing lumbar contributions. The effects of the hip orthosis on the lumbo-pelvic coordination were investigated in 20 low back pain patients and 20 asymptomatic controls. The orthosis reduced pelvic rotation by 12.7° and increased lumbar contributions by 11%. Contrary to our expectation, orthosis-induced changes in lumbo-pelvic coordination were smaller in patients; most likely because our relatively young patient group had smaller unrestricted pelvic rotations compared to asymptomatic individuals. Considering the observed capability of a hip orthosis in causing the expected changes in lumbo-pelvic coordination when there is a relatively large pelvic contribution to trunk motion, application of a hip orthosis may provide a promising method of correcting abnormal lumbo-pelvic coordination, particularly among patients who demonstrate larger pelvic rotation, that warrants further investigation.

Spinal Flexibility Is an Important Factor for Improvement in Spinal and Knee Alignment after Total Knee Arthroplasty: Evaluation Using a Whole Body EOS System

The purposes of this study were (1) to evaluate the relationship between lumbosacral flexibility and the effects of total knee arthroplasty (TKA) on whole-body alignment; and (2) to determine the prerequisites of the adjacent joints for successful TKA. A total of 116 patients (156 cases) who had whole-body X-ray and flexion-extension lumbar radiograph available were enrolled. For the sagittal alignment evaluation, hip-knee-ankle (HKA) angle, pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), thoracic kyphosis (TK), and C7 plumb line-sacrum distance (SVA) were evaluated on the whole-body radiographs. Lumbar flexibility (LF) was evaluated using the flexion-extension lumbar radiographs, and pelvic flexibility (PF) was evaluated using the pelvic incidence (PI). The disparities in the knee joint between postoperative passive motion and weight-bearing posture were assessed. LF was significantly correlated with ΔLL and ΔSVA (LL: p = 0.039, SVA: p = 0.040; Pearson correlation coefficient (PCC): -0.206 and 0.205, respectively). There were correlations between PF and ΔSS (p < 0.001, PCC: -0.362), and between the disparity and LF (p = 0.005, PCC = -0.275). Linear regression analysis demonstrated that LF was significantly associated with the presence of disparity (p = 0.005, β = -0.205). LF is an important factor for improved spinal and lower limb alignment after TKA. Additionally, reduced LF may result in knee joint disparity between passive extension and standing extension status. Therefore, surgeons should consider spinopelvic alignment, including lower limb alignment preoperatively, to be able to predict possible changes in whole-body alignment following TKA.

The relationship between indicators of lumbo-pelvic coordination and pain, disability, pain catastrophizing and depression in patients presenting with non-chronic low back pain

This study examined associations and changes overtime in low back kinematics and disability, pain, pain catastrophizing, and depression and assessed whether associations and changes overtime varied between individuals who meet the classification criteria for chronic low back pain at 6 months and those who do not. Findings suggested that those persons with a higher ratio of lumbar contribution to thorax motion and smaller pelvic tilt during forward bending had higher scores on measures of disability, pain and pain catastrophizing. This same association was found in those who met classification criteria for chronic low back pain at 6 months. Opposing associations were found in the group not meeting classification criteria for chronic low back pain, specifically, increased pelvic tilt was positively associated with higher pain catastrophizing scores. Practitioner summary This study examined associations and changes overtime in low back kinematics and psychosocial and clinical factors and whether associations and changes overtime varied between individuals who meet the classification criteria for chronic low back pain at 6 months and those who do not, Results suggest that associations exist between psychological factors and kinematic changes during the time between an acute low back pain episode to meeting classification for chronic low back pain at 6 months.

A prospective study of lumbo-pelvic coordination in patients with non-chronic low back pain

Despite the current knowledge about abnormalities in the lumbo-pelvic coordination of patients with non-specific low back pain (LBP), it is unclear how such abnormalities change with time. Timing and magnitude aspects of lumbo-pelvic coordination during a trunk forward bending and backward return task along with subjective measures of pain and disability were collected at three-time points over a six-month period from 29 patients who had non-chronic LBP at the time of enrollment in the study. To enable investigation of abnormalities in lumbo-pelvic coordination of patients, we also included lumbo-pelvic coordination data of age and gender-matched back healthy individuals from an earlier study of our group. Finally, differences in lumbo-pelvic coordination between patients with moderate-severe LBP (i.e., those whose level of pain was ≥ 4 (out of 10) at all three data collection sessions; n = 8) and patients with low-moderate LBP (n = 21) were investigated. There were clear distinctions in measures of lumbo-pelvic coordination between patients with low-moderate and moderate-severe LBP. Contrary to our expectation, however, the abnormalities in magnitude aspects of lumbo-pelvic coordination were larger (F > 4.84, P < 0.012) in patients with low-moderate LBP. These abnormalities in patients with low-moderate LBP, compared to controls, included larger (>12°) pelvic and thoracic rotations as well as smaller (>10°) lumbar flexion. The abnormal lumbo-pelvic coordination of patients with non-specific LBP, observed at baseline, persisted (F < 1.96, P > 0.156) or worsen (F > 3.48, P < 0.04) over the course of study period despite significant improvement in their pain (18% decrease; F = 12.10, P < 0.001) and disability (10% decrease; F = 4.39, P = 0.017). Distinct but lingering abnormalities in lumbo-pelvic coordination, observed in patients with low-moderate and moderate-severe LBP, might have a role in persistence and/or relapse of symptoms in patients with non-specific LBP. Such inferences, however, should further be studied in future via investigation of the relationship between abnormalities in lumbo-pelvic coordination and clinical presentation of LBP.

Inter-segmental coordination of the spine is altered during lifting in patients with ankylosing spondylitis: A cross-sectional study

The abnormal inter-segmental coordination of the spine during lifting could be used to monitor disease progression and rehabilitation efficacy in patients with ankylosing spondylitis (AS). This study aimed to compare the inter-segmental coordination patterns and variability of the spine during lifting between patients with AS (n = 9) and control (n = 15) groups.Continuous relative (CRP) and deviation (DP) phases between each segment of the spine (two lumbar and three thorax segments) and lumbosacral joint were calculated. The CRP and DP curves among participants were decomposed into few functional principal components (FPC) via functional principal component analysis (FPCA). The FPC score of CRP or DP of the two groups were compared, and its relationship with the indexes of spinal mobility was investigated.Compared with the control group, the AS patients showed more anti-phase coordination patterns in each relative upper spine segment and lumbosacral joint. In addition, either less or more variation was found in the coordination of each relative lower spine segment and lumbosacral joint during different time periods of lifting for these patients. Some cases were considerably related to spinal mobility.the inter-segmental coordination of the spine was altered during lifting in AS patients to enable movement, albeit inefficient and might cause spinal mobility impairment.

Low Back Pain: The Potential Contribution of Supraspinal Motor Control and Proprioception

Motor control, which relies on constant communication between motor and sensory systems, is crucial for spine posture, stability and movement. Adaptions of motor control occur in low back pain (LBP) while different motor adaption strategies exist across individuals, probably to reduce LBP and risk of injury. However, in some individuals with LBP, adapted motor control strategies might have long-term consequences, such as increased spinal loading that has been linked with degeneration of intervertebral discs and other tissues, potentially maintaining recurrent or chronic LBP. Factors contributing to motor control adaptations in LBP have been extensively studied on the motor output side, but less attention has been paid to changes in sensory input, specifically proprioception. Furthermore, motor cortex reorganization has been linked with chronic and recurrent LBP, but underlying factors are poorly understood. Here, we review current research on behavioral and neural effects of motor control adaptions in LBP. We conclude that back pain-induced disrupted or reduced proprioceptive signaling likely plays a pivotal role in driving long-term changes in the top-down control of the motor system via motor and sensory cortical reorganization. In the outlook of this review, we explore whether motor control adaptations are also important for other (musculoskeletal) pain conditions.

Discriminating spatiotemporal movement strategies during spine flexion-extension in healthy individuals

BACKGROUND CONTEXT

The spine is an anatomically complex system with numerous degrees of freedom. Due to this anatomical complexity, it is likely that multiple motor control options exist to complete a given task.

PURPOSE

To identify if distinct spine spatiotemporal movement strategies are utilized in a homogenous sample of young healthy participants.

STUDY DESIGN

Kinematic data were captured from a single cohort of male participants (N=51) during a simple, self-controlled spine flexion-extension task.

METHODS

Thoracic and lumbar flexion-extension data were analyzed to extract the continuous relative phase between each spine subsection. Continuous relative phase data were evaluated using a principal component analysis to identify major sources of variation in spine movement coordination. Unsupervised machine learning (k-means clustering) was used to identify distinct clusters present within the healthy participants sampled. Once distinguished, intersegmental spine kinematics were compared amongst clusters.

RESULTS

The findings of the current work suggest that there are distinct timing strategies that are utilized, within the participants sampled, to control spine flexion-extension movement. These strategies differentiate the sequencing of intersegmental movement and are not discriminable on the basis of simple participant demographic characteristics (ie, age, height, and body mass index), total movement time or range of motion.

CONCLUSIONS

Spatiotemporal spine flexion-extension patterns are not uniform across a population of young healthy individuals.

CLINICAL SIGNIFICANCE

Future work needs to identify whether the motor patterns characterized with this work are driven by distinct neuromuscular activation patterns, and if each given pattern has a varied risk for low back injury.

The effects of backpack type on lumbo-pelvic coordination during trunk bending and return tasks

Backpacks with ergonomic features are recommended to mitigate the risk of developing low back pain due to carrying a heavy school backpack. A repeated measure study was conducted on 40 college-age students to investigate the immediate changes in magnitude and timing aspects of lumbo-pelvic coordination when carrying an ergonomically modified vs. a normal backpack relative to no backpack condition during trunk forward bending and backward return tasks. We found a smaller reduction in the thoracic range of rotation, an increase vs. a decrease in pelvic range of rotation and a larger reduction in lumbar flexion for a modified vs. a normal backpack. Furthermore, during the forward bending, a less in-phase motion for the modified backpack was observed. Our results suggest that participants have likely experienced larger spinal loads with the modified backpack; a conclusion that should be investigated in future to determine whether ergonomic backpacks can reduce the risk of low back pain in children. Practitioner summary: Research participants performed trunk bending and return closer to their habitual way under modified versus normal school backpack. From an equilibrium point of view, therefore, individuals are likely experiencing larger spinal loads during activities of daily living with a modified backpack. However, such a conclusion may change when considering stability requirements.

Application of advanced biomechanical methods in studying low back pain - recent development in estimation of lower back loads and large-array surface electromyography and findings

Low back pain (LBP) is a major public health problem and the leading disabling musculoskeletal disorder globally. A number of biomechanical methods using kinematic, kinetic and/or neuromuscular approaches have been used to study LBP. In this narrative review, we report recent developments in two biomechanical methods: estimation of lower back loads and large-array surface electromyography (LA-SEMG) and the findings associated with LBP. The ability to estimate lower back loads is very important for the prevention and the management of work-related low back injuries based on the mechanical loading model as one category of LBP classification. The methods used for estimation of lower back loads vary from simple rigid link-segment models to sophisticated, optimization-based finite element models. In general, reviewed reports of differences in mechanical loads experienced in lower back tissues between patients with LBP and asymptomatic individuals are not consistent. Such lack of consistency is primarily due to differences in activities under which lower back mechanical loads were investigated as well as heterogeneity of patient populations. The ability to examine trunk neuromuscular behavior is particularly relevant to the motor control model, another category of LBP classification. LA-SEMG not only is noninvasive but also provides spatial resolution within and across muscle groups. Studies using LA-SEMG showed that healthy individuals exhibit highly organized, symmetric back muscle activity patterns, suggesting an orderly recruitment of muscle fibers. In contrast, back muscle activity patterns in LBP patients are asymmetric or multifocal, suggesting lack of orderly muscle recruitment. LA-SEMG was also shown capable of capturing unique back muscle response to manual therapy. In conclusion, estimation of low back load and LA-SEMG techniques demonstrated promising potentials for understanding LBP and treatment effects. Future studies are warranted to fully establish clinical validity of these two biomechanical methods.