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The aim of this study was to determine if differences exist in lumbar multifidus (LM) thickness at rest and during activation, between individuals with chronic low back pain (CLBP) and controls. Lumbar multifidus thickness was assessed via rehabilitative ultrasound imaging (RUSI), and was performed in prone and standing both at rest and during muscle activation i.e. with a contralateral arm lift (CAL). Twenty participants were assessed; ten CLBP participants and ten controls. Rehabilitative ultrasound imaging was used to measure LM thickness and percentage thickness change at L4/L5 and L5/S1 in four positions; prone at rest, prone during activation with a CAL, standing at rest, and standing during activation with a CAL. Independent and paired t -tests were used to calculate differences in LM thickness and percentage thickness change between groups, and also between sides in the CLBP group. There was a significant difference in LM percentage thickness change in standing during activation with a CAL; the CLBP demonstrated a greater percentage thickness increase at L5/S1 compared to the controls, ( p = 0.05). There were no differences between groups at the L4/L5 level for this position. There were no differences between the groups for LM thickness or percentage thickness change in prone or standing at rest, or during activation with a CAL in prone. Within the CLBP group, no significant between side differences were found. These results give preliminary insight into possible differences in LM contractile behaviour during functional movements in CLBP, however, larger scale research is warranted. [ABSTRACT FROM AUTHOR]

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Background context Transcutaneous neuromuscular electrical stimulation (NMES) can stimulate contractions in deep lumbar stabilizing muscles. An optimal protocol has not been devised for the activation of these muscles by NMES, and information is lacking regarding an optimal stimulation point on the abdominal wall. Purpose The goal was to determine a single optimized stimulation point on the abdominal wall for transcutaneous NMES for the activation of deep lumbar stabilizing muscles. Study design Ultrasound images of the spinal stabilizing muscles were captured during NMES at three sites on the lateral abdominal wall. After an optimal location for the placement of the electrodes was determined, changes in the thickness of the lumbar multifidus (LM) were measured during NMES. Methods Three stimulation points were investigated using 20 healthy physically active male volunteers. A reference point R, 1 cm superior to the iliac crest along the midaxillary line, was used. Three study points were used: stimulation point S1 was located 2 cm superior and 2 cm medial to the anterior superior iliac spine, stimulation point S3 was 2 cm below the lowest rib along the same sagittal plane as S1, and stimulation point S2 was midway between S1 and S3. Sessions were conducted stimulating at S1, S2, or S3 using R for reference. Real-time ultrasound imaging (RUSI) of the abdominal muscles was captured during each stimulation session. In addition, RUSI images were captured of the LM during stimulation at S1. Results Thickness, as measured by RUSI, of the transverse abdominis (TrA), obliquus internus, and obliquus externus was greater during NMES than at rest for all three study points (p<.05). Transverse abdominis was significantly stimulated more by NMES at S1 than at the other points (p<.05). The LM thickness was also significantly greater during NMES at S1 than at rest (p<.05). Conclusions Neuromuscular electrical stimulation at S1 optimally activated deep spinal stabilizing muscles, TrA and LM, as evidenced by RUSI. The authors recommend this optimal stimulation point be used for NMES in the course of lumbar spine stabilization training in patients having difficulty initiating contraction of these muscles. [ABSTRACT FROM AUTHOR]

Abstract: Although individual reports suggest that baseline morphometry or activity of transversus abdominis or lumbar multifidus predict clinical outcome of low back pain (LBP), a related systematic review is unavailable. Therefore, this review summarized evidence regarding the predictive value of these muscular characteristics. Candidate publications were identified from 6 electronic medical databases. After review, 5 cohort studies were included. Although this review intended to encompass studies using different muscle assessment methods, all included studies coincidentally used ultrasound imaging. No research investigated the relation between static morphometry and clinical outcomes. Evidence synthesis showed limited evidence supporting poor baseline transversus abdominis contraction thickness ratio as a treatment effect modifier favoring motor control exercise. Limited evidence supported that high baseline transversus abdominis lateral slide was associated with higher pain intensity after various exercise interventions at 1-year follow-up. However, there was limited evidence for the absence of relation between the contraction thickness ratio of transversus abdominis or anticipatory onset of lateral abdominal muscles at baseline and the short- or long-term LBP intensity after exercise interventions. There was conflicting evidence for a relation between baseline percent thickness change of lumbar multifidus during contraction and the clinical outcomes of patients after various conservative treatments. Given study heterogeneity, the small number of included studies and the inability of conventional greyscale B-mode ultrasound imaging to measure muscle activity, our findings should be interpreted with caution. Further large-scale prospective studies that use appropriate technology (ie, electromyography to assess muscle activity) should be conducted to investigate the predictive value of morphometry or activity of these muscles with respect to LBP-related outcomes measures. [Copyright &y& Elsevier]

Abstract: Study design: Reliability study. Objective: To investigate the inter-session reliability of measuring the thickness of deep (dMF) and superficial layer of lumbar multifidus (sMF) using ultrasonography for participants with and without low back pain (LBP). Background: The lumbar multifidus is an important muscle in maintaining spinal stability. The dMF is considered important in maintaining tonic contraction and joint stability. Motor control impairment is also discovered in patients with LBP. However, no study to date has investigated the method of observing both the sMF and dMF through ultrasound imaging (USI). Methods: Twenty subjects aged 18–35 years old with LBP (N =10) and without LBP (N =10) were recruited. Every subject extended the upper trunk in prone lying with maximal isometric contraction. Simultaneously, the examiner measured the thickness of the dMF and the sMF using ultrasonography after ensuring the muscle belly was located. The participants performed three trials of isometric trunk extension in each session, with 30min between each session. The reliability of measuring the change of thickness is represented by the intra-class correlation coefficient (ICC). Results: Through averaging three trials of measurement, the reliability of measuring the thickness of the dMF or the sMF in static or in the contracted condition, and the change of the thickness during contraction, is reliable (ICC=0.84–1.00). Conclusions: The intra-rater inter-session reliability of measurement of the dMF and the sMF with USI has been established. This method could be applied to the qualification of the activation level of the dMF and the sMF with specific tasks. [Copyright &y& Elsevier]

The article discusses a study that tested the reliability of rehabilitative ultrasound imaging (RUSI) using static images (static RUSI) and video clips (video RUSI) to quantify the lumbar multifidus (LM) muscle thickness at rest and while contracted. The study concluded that video RUSI is a suitable substitute for static RUSI for LM muscle measurements.

Introduction: Magnetic resonance imaging (MRI) is the standard to quantify size and structure of lumbar muscles. Three-dimensional volumetric measures are expected to be more closely related to muscle function than two-dimensional measures such as cross-sectional area. Reliability and agreement of a standardized method should be established to enable the use of MRI to assess lumbar muscle characteristics., Objectives: This study investigates the intra- and inter-processor reliability for the quantification of (1) muscle volume and (2) fat fraction based on chemical shift MRI images using axial 3D-volume measurements of the lumbar multifidus in patients with low back pain., Methods: Two processors manually segmented the lumbar multifidus on the MRI scans of 18 patients with low back pain using Mevislab software following a well-defined method. Fat fraction of the segmented volume was calculated. Reliability and agreement were determined using intra-class correlation coefficients (ICC), Bland-Altman plots and calculation of the standard error of measurement (SEM) and minimal detectable change (MDC)., Results: Excellent ICCs were found for both intra-processor and inter-processor analysis of lumbar multifidus volume measurement, with slightly better results for the intra-processor reliability. The SEMs for volume were lower than 4.1 cm³. Excellent reliability and agreement were also found for fat fraction measures, with ICCs of 0.985-0.998 and SEMs below 0.946%., Conclusion: The proposed method to quantify muscle volume and fat fraction of the lumbar multifidus on MRI was highly reliable, and can be used in further research on lumbar multifidus structure., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Abstract: Understanding the clinical characteristics of patients with low back pain (LBP) who display improved lumbar multifidus (LM) muscle function after spinal manipulative therapy (SMT) may provide insight into a potentially synergistic interaction between SMT and exercise. Therefore, the purpose of this study was to identify the baseline historical and physical examination factors associated with increased contracted LM muscle thickness one week after SMT. Eighty-one participants with LBP underwent a baseline physical examination and ultrasound imaging assessment of the LM muscle during submaximal contraction before and one week after SMT. The relationship between baseline examination variables and 1-week change in contracted LM thickness was assessed using correlation analysis and hierarchical multiple linear regression. Four variables best predicted the magnitude of increases in contracted LM muscle thickness after SMT. When combined, these variables suggest that patients with LBP, (1) that are fairly acute, (2) have at least a moderately good prognosis without focal and irritable symptoms, and (3) exhibit signs of spinal instability, may be the best candidates for a combined SMT and lumbar stabilization exercise (LSE) treatment approach. [Copyright &y& Elsevier]

Abstract: Objective: Evidence is currently lacking for guidance on ultrasound transducer configuration (shape) when imaging muscle to measure its size. This study compared measurements made of lumbar multifidus on images obtained using curvilinear and linear transducers. Method: Fifteen asymptomatic males (aged 21–32 years) had their right lumbar multifidus imaged at L3. Two transverse images were taken with two transducers (5 MHz curvilinear and 6 MHz linear), and linear and cross-sectional area (CSA) measurements were made off-line. Reliability of image interpretation was shown using intra-class correlation coefficients (0.78–0.99). Muscle measurements were compared between transducers using Bland and Altman plots and paired t-tests. Relationships between CSA and linear measurements were examined using Pearson''s Correlation Coefficients. Results: There were no significant differences (p > 0.05) in the measurements of the two transducers. Thickness and CSA measurements had small differences between transducers, with mean differences of 0.01 cm (SDdiff = 0.21 cm) and 0.03 cm2 (SDdiff = 0.58 cm2) respectively. Width measures had a mean difference of 0.14 cm, with the linear transducer giving larger measures. Significant correlations (p < 0.001) were found between all linear measures and CSA, with both transducers (r = 0.78–0.89). Conclusion: Measurements of multifidus at L3 were not influenced by the configuration of transducers of similar frequency. For the purposes of image interpretation, the curvilinear transducer produced better definition of the lateral muscle border, suggesting it as the preferable transducer for imaging lumbar multifidus. [Copyright &y& Elsevier]

[Purpose] The purpose of this study was to evaluate the intra-examiner reliability of rehabilitative ultrasound imaging (RUSI) in obtaining thickness measurements of the lumbar multifidus (LM) with intraclass correlation coefficients (ICC) and minimum detectable change (MDC). [Subjects] Ten healthy volunteers participated in the study. [Method] We measured thickness measurements of LM at 3 angles of pelvic tilt (moderate anterior-tilt, neutral position and moderate posterior-tilt) and different percentages of voluntary isometric contraction. The task was static muscle contraction of LM during pelvic anterior-tilt with nutation of the sacrum in a prone position on the edge of the bed and hanging subject's legs. Thickness measurements of left LM were obtained by using RUSI during 2 sessions, 1 to 4 weeks apart. ICC and measurement error by 95% confidence intervals of MDC (MDC95) were used to estimate reliability. [Result] Intra-examiner reliability estimates ranged from 0.73-0.96 for same-day comparisons and from 0.67-0.93 for between-day comparisons, except for maximum effort in the neutral pelvic position. MDC95 of thickness measurements were 0.8-2.7 mm for same-day and 1.5-3.0 mm for between-day measurements. [Conclusion] We suggest that RUSI thickness measurements of LM are highly reliable at the 3 angles of pelvic tilt and different percentages of voluntary isometric contraction. [ABSTRACT FROM AUTHOR]

[Purpose] The purpose of this study was to consider the best way of activating the lumbar multifidus. [Subjects] Ten healthy men participated in this study. [Methods] We measured low back muscles at moderate anterior tilt and moderate posterior tilt of pelvis in sitting under two conditions (rest and hollowing abdominals). Surface electromyography of the right lumbar erecter spinae and lumbar multifidus was recorded. [Results] The results demonstrated that moderate anterior tilt of the pelvis facilitated the lumbar multifidus without over-activation of lumbar erecter spinae under both conditions. [ABSTRACT FROM AUTHOR]

Abstract: Recurrent low back pain (LBP) is associated with altered motor coordination of the lumbar paraspinal muscles. Whether these changes can be modified with motor training remains unclear. Twenty volunteers with unilateral LBP were randomly assigned to cognitively activate the lumbar multifidus independently from other back muscles (skilled training) or to activate all paraspinal muscles with no attention to any specific muscles (extension training). Electromyographic (EMG) activity of deep (DM) and superficial multifidus (SM) muscles were recorded bilaterally using intramuscular fine-wire electrodes and that of superficial abdominal and back muscles using surface electrodes. Motor coordination was assessed before and immediately after training as onsets of trunk muscle EMG during rapid arm movements, and as EMG amplitude at the mid-point of slow trunk flexion-extension movements. Despite different intentions of the training tasks, the pattern of activity was similar for both. After both training tasks, activation of the DM and SM muscles was earlier during rapid arm movements. However, during slow trunk movements, DM and SM activity was increased, and EMG activity of the superficial trunk muscles was reduced only after skilled training. These findings show the potential to alter motor coordination with motor training of the lumbar paraspinal muscles in recurrent LBP. Perspectives: Changes in motor coordination differed between skilled and extension training during slows trunk movements. As identical patterns of muscle activity were observed between training protocols, the results suggest that training-induced changes in motor coordination are not simply related to the muscle activation, but appear to be related to the task. [Copyright &y& Elsevier]

The article discusses a study which compared the myosin heavy-chain isoform distribution in paraspinal muscles, and tested whether fiber-type gradients are a function of paraspinal muscle depth. The study was conducted on 15 patients requiring spine surgery. A description of the experiment's basis and methodology is provided. It was found that the fiber-type distribution was similar among the posterior paraspinal muscles and composed of relatively high percentage of type I compared to other types.

Abstract: The purpose of this study was to compare the passive mechanical properties and titin isoform sizes of the multifidus, longissimus, and iliocostalis muscles. Given our knowledge of each muscle''s architecture and the multifidus’ operating range, we hypothesized that multifidus would have higher elastic modulus with corresponding smaller titin isoforms compared to longissimus or iliocostalis muscles. Single-fiber and fiber-bundle material properties were derived from passive stress–strain tests of excised biopsies (n=47). Titin isoform sizes were quantified via sodium dodecyl sulfate-vertical agarose gel electrophoresis (SDS-VAGE) analysis. We found that, at the single-fiber level, all muscles had similar material properties and titin isoform sizes. At the fiber-bundle level, however, we observed significantly increased stiffness (∼45%) in multifidus compared to longissimus and iliocostalis muscles. These data demonstrate that each muscle may have a different scaling relationship between single-fiber and fiber-bundle levels, suggesting that the structures responsible for higher order passive mechanical properties may be muscle specific. Our results suggest that divergent passive material properties are observed at size scales larger than the single cell level, highlighting the importance of the extracellular matrix in these muscles. In addition to architectural data previously reported, these data further support the unique stabilizing function of the multifidus muscle. These data will provide key input variables for biomechanical modeling of normal and pathologic lumbar spine function and direct future work in biomechanical testing in these important muscles. [Copyright &y& Elsevier]

[Purpose] The purpose of this study was to investigate whether stabilization of the lumbar spinal column by training the lumbar multifidus helped to improve sitting balance. [Subjects] The subjects were 21 healthy individuals. [Methods] The subjects performed muscle function training 3 times a week for 4 weeks. The displacement width of pressure, which shows the control of movement of the lumbar in bending forward and backward, the center of pressure (COP) in sitting at rest and maximum lateral reaching, and %maximal voluntary contraction (%MVC) of trunk muscle while maintaining the sitting position were measured before and after the training. [Results] The displacement width of pressure after the training was significantly decreased as compared with before. With COP and %MVC, no significant differences were found between before and after the training. [Conclusion] The results indicate that bolstering the immobility of the centrum by improving lumbar multifidus function does not always influence sitting balance. [ABSTRACT FROM AUTHOR]

Background: The specific training of lumbar local stabilizing muscles is one of the recent focuses in management of patients with chronic LBP. Enhanced stability of the lumbar spine segments is the mechanism for pain relief with this specific exercise. Objective: The aim of this study was to compare the effect of motor control exercises with general exercises on the lumbar local stabilizing muscles thickness, activity limitation and pain in patients with chronic low back pain (LBP). Design: A double-blind, randomized controlled trial. Methods: Forty-nine patients with chronic LBP were randomly assigned to either a motor control (n = 25) or a general exercises group (n = 24). Before and after intervention, we assessed the lumbar multifidus (LM) and Transversus abdominis (TA) muscles thickness (mm) using a 7.5 MHz B-mode transducer ultrasound, pain through visual analog scale and activity limitation through Back Performance Scale (Ordinal). A 16 session's exercise program which lasted 8 weeks, twice per week, and 30 minutes per session was performed for both groups. Results: The mean TA thickness increased from 1.87 ± 0.63 mm to 2.39 ± 0.63 mm in the motor control group and from 1.93 ± 0.49 mm to 2.22 ± 0.47 mm in the general exercise group (P < 0.0001). The mean LM thickness increased from 8.63 ± 2.37 mm to 9.69 ± 2.49 mm in the motor control group and from 8.83 ± 1.53 mm to 9.26 ± 1.56 mm in the general exercise group (P < 0.0001). The mean activity limitation decreased from 8.83 ± 3.38 to 5.42 ± 2.43 in the motor control group and from 10.67 ± 2.81 to 7.25 ± 2.73 in the general exercise group (P < 0.0001). After treatment, there was no significant difference between two groups, with the exception of pain (P > 0.05). Conclusion: The motor control and general exercises decreased pain and increased TA and LM muscles thickness and lumbar mobility in patients with chronic LBP without any signs of spinal instability. Although, the motor control exercises were more effective than general exercises in pain decreasing. [ABSTRACT FROM AUTHOR]

Abstract: Rehabilitative ultrasound imaging (RUSI) is considered a valid method to measure muscle activation in key spinal muscles in asymptomatic subjects. Research measuring muscle activation with RUSI in painful subjects is limited. The aim of this study was to determine if changes in muscle activation from experimentally induced pain can be measured by RUSI. Six male subjects performed tasks known to activate the transverse abdominis (TrA) and lumbar multifidus (LM) while RUSI measurements of muscle thickness were obtained during control and hypertonic saline conditions. The abdominal draw-in maneuver was used to volitionally activate the TrA and a series of upper extremity lifting tasks were used to automatically activate the LM. Pain was induced by injecting 5% hypertonic saline into the longissimus muscle adjacent to the LM at the L4 level. The percent change in muscle thickness from rest to contraction represented muscle activation. Activation was significantly less (p<0.01) during the painful condition on 4 of the 5 tasks performed for the LM and on the task performed for the TrA. These results indicate that RUSI can be used to measure pain-related changes in deep trunk muscle activation. Future research should include a larger sample size and women. [Copyright &y& Elsevier]

The aim of this review was to evaluate the effects of specific spinal stabilisation exercises in patients with low back pain (LBP). PubMed and PEDro databases were searched. Ten relevant randomised controlled trials (RCTs) with a study population of patients with acute, sub-acute or chronic LBP were reviewed and quality assessed. The intervention method should have included specific spinal stabilisation exercises including co-contraction of multifidus muscles and transversus abdominis muscles. Seven RCTs were high quality and three were low quality. The results indicate moderate evidence of improved disability and/or pain level, increased multifidi cross-sectional area, and limited evidence for improved quality of life after treatment. The outcome measures used showed extensive heterogeneity. Larger, randomised, controlled trials of high quality, in different subgroups of LBP patients, with long-term follow-up are warranted. A standardisation of outcome measures would be beneficial in order to facilitate comparability among studies. [ABSTRACT FROM AUTHOR]

Abstract: The contribution of the trunk muscles to spinal stability is well established. There is convincing evidence for the role of multifidus in spinal stability. Recently, emphasis has shifted to the deep fibres of this muscle (DM) and five key clinical beliefs have arisen: (i) that DM stabilizes the lumbar spine whereas the superficial fibres of lumbar multifidus (SM) and the erector spinae (ES) extend and/or rotate the lumbar spine, (ii) that DM has a greater percentage of type I (slow twitch) muscle fibres than SM and ES, (iii) that DM is tonically active during movements of the trunk and gait, whereas SM and ES are phasically active, (iv) that DM and the transversus abdominis (TrA) co-contract during function, and (v) that changes in the lumbar paraspinal muscles associated with LBP affect DM more than SM or ES. This paper reviews the biomechanical, electromyographic, histochemical and morphological data that underpin these beliefs. Although there is support for the importance of the lumbar multifidus and the specific contribution of this muscle to intervertebral control, several of the clinical beliefs have little or no support and require further evaluation. These findings have implications for clinical practice. [Copyright &y& Elsevier]

Increasing documentation on the size and appearance of muscles in the lumbar spine of low back pain (LBP) patients is available in the literature. However, a comparative study between unoperated chronic low back pain (CLBP) patients and matched (age, gender, physical activity, height and weight) healthy controls with regard to muscle cross-sectional area (CSA) and the amount of fat deposits at different levels has never been undertaken. Moreover, since a recent focus in the physiotherapy management of patients with LBP has been the specific training of the stabilizing muscles, there is a need for quantifying and qualifying the multifidus. A comparative study between unoperated CLBP patients and matched control subjects was conducted. Twenty-three healthy volunteers and 32 patients were studied. The muscle and fat CSAs were derived from standard computed tomography (CT) images at three different levels, using computerized image analysis techniques. The muscles studied were: the total paraspinal muscle mass, the isolated multifidus and the psoas. The results showed that only the CSA of the multifidus and only at the lowest level (lower end-plate of L4) was found to be statistically smaller in LBP patients. As regards amount of fat, in none of the three studied muscles was a significant difference found between the two groups. An aetiological relationship between atrophy of the multifidus and the occurrence of LBP can not be ruled out as a possible explanation. Alternatively, atrophy may be the consequence of LBP: after the onset of pain and possible long-loop inhibition of the multifidus a combination of reflex inhibition and substitution patterns of the trunk muscles may work together and could cause a selective atrophy of the multifidus. Since this muscle is considered important for lumbar segmental stability, the phenomenon of atrophy may be a reason for the high recurrence rate of LBP. [ABSTRACT FROM AUTHOR]

Background: The pathophysiology of concussion is complex. Altered sensorimotor function post-concussion may contribute to the wide range of symptoms and impairments reported. There is currently limited evidence documenting changes in sensorimotor function during the recovery period. The aim of this study was to investigate the effect of concussion on the sensorimotor system in adolescents post-concussion using a multifaceted approach., Study Design: Prospective nested case-control study., Methods: A total of 285 male adolescent rugby players underwent assessment of sensorimotor function during preseason. Players who sustained a concussion during the season and control players, matched for age and playing position, were assessed in the subacute period (3-5 days) and after return-to-sport (3 weeks). Tests of sensorimotor function included balance, cervical spine and vestibulo-ocular function, and measurement of the size and contraction of lumbopelvic muscles (ultrasound imaging)., Results: Twenty-three players (8%) sustained a concussion. Of these, 20 players were assessed during the subacute period and 17 players following return-to-sport. The prevalence of vestibulo-ocular dysfunction increased from 38.9% to 72.2% during the subacute period and dysfunction was present in 83.3% of players after return-to-sport (p = 0.01). Changes in lumbar multifidus muscle size (p = 0.002) and thickness (p = 0.05) at the L5 vertebral level were observed. No statistically significant changes in balance, cervical spine proprioception, or contraction of lumbopelvic muscles were found (p > 0.05)., Conclusion: Changes in sensorimotor function were observed in the subacute period post-concussion, with some persisting after return-to-sport. Using symptom-based criteria for return-to-sport may not adequately reflect the sequelae of concussion on the sensorimotor system., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Since the contribution of the lumbar multifidus(LM) is not well understood in relation to non-specific low back pain(LBP), this may limit physiotherapists in choosing the most appropriate treatment strategy., Objectives: This study aims to compare clinical characteristics, in terms of LM function and morphology, between subacute and chronic LBP patients from a large clinical practice cohort compared to healthy controls., Design: Multicenter case control study., Method: Subacute and chronic LBP patients and healthy controls between 18 and 65 years of age were included. Several clinical tests were performed: primary outcomes were the LM thickness from ultrasound measurements, trunk range of motion(ROM) from 3D kinematic tests, and median frequency and root mean square values of LM by electromyography measurements. The secondary outcomes Numeric Rating Scale for Pain(NRS) and the Oswestry Disability Index(ODI) were administered. Comparisons between groups were made with ANOVA, p-values<0.05, with Tukey's HSD post-hoc test were considered significant., Results: A total of 161 participants were included, 50 healthy controls, 59 chronic LBP patients, and 52 subacute LBP patients. Trunk ROM and LM thickness were significantly larger in healthy controls compared to all LBP patients(p < 0.01). A lower LM thickness was found between subacute and chronic LBP patients although not significant(p = 0.11-0.97). All between-group comparisons showed no statistically significant differences in electromyography outcomes (p = 0.10-0.32). NRS showed no significant differences between LBP subgroups(p = 0.21). Chronic LBP patients showed a significant higher ODI score compared to subacute LBP patients(p = 0.03)., Conclusions: Trunk ROM and LM thickness show differences between LBP patients and healthy controls., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

New trends in ultrasound imaging are focused on exploration of morphology and muscle quality. The main goal of the study was to evaluate the first-order descriptor and echostructure of lumbar multifidus at the L4 vertebral level in athletes with and without chronic lumbopelvic pain (CLPP). A case-control study was performed in 15 semiprofessional athletes with CLPP and 15 without (healthy athletes). Lumbar multifidus echointensity and echovariation were measured for muscle quality assessment. Echostructure was used to evaluate lumbar multifidus cross-sectional area (CSA) at resting and during muscle contraction, respective differences during both phases (CSADif.), activation patterns, and thoracolumbar fasciae morphology and thickness. Significant differences with a large effect size were observed in quantitative data from CLPP and healthy athletes for left lumbar multifidus CSADif. and thoracolumbar fasciae morphology. Categorical data showed statistically significant differences with a small-to-moderate effect size for lumbar multifidus activation pattern and thoracolumbar fasciae morphology. Athletes with CLPP showed a reduced CSA difference between lumbar multifidus contraction and at resting and higher disorganization of thoracolumbar fasciae morphology compared to healthy athletes. These findings suggest the importance of dynamic exploration of the lumbar region and connective tissue in sports performance and injury prevention. [ABSTRACT FROM AUTHOR]

Lumbar multifidus muscle (LM) activation deficit has been proposed as a potential underlying mechanism responsible for recurrence episode of low back pain (LBP). The quantification of voluntary LM activation can provide a better understanding of the role of muscle activation deficit in LBP. The objective of this technical report is to propose a new approach using neuromuscular electrical stimulation (NMES) in combination with the ultrasound imaging technique (USI) to investigate the ability of individual to voluntarily activate the LM. We recruited ten participants with a recurrent LBP (rLBP) and twelve participants with no history of LBP (NoLBP). Theoretically, the superimposition of NMES on the LM during maximum voluntary isometric contraction (MVIC) should activate all motor units available in the LM. The percentage of LM activation (%LM) can be calculated by the changes of LM thickness during MVIC, divided by the changes of LM thickness during the combination of MVIC and NMES. This %LM was used to compare between groups. The individuals with rLBP had significantly lower %LM (p < 0.05) compared with the NoLBP counterpart (%LM = 72.4 and 92.9, respectively). Results demonstrate that this new approach can potentially differentiate %LM among individuals with rLBP and NoLBP. This new approach can be potentially used to 1) determine the extent of LM activation deficit, 2) identify the existence of muscle activation deficit in the LM, and 3) objectively measure the effect of the intervention designed to address the LM activation deficit., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Little is known about the activity of the abdominal internal oblique (IO) and lumbar multifidus (LM) muscles relative to kinetic chain exercises performed in a standing position., Hypothesis/purpose: The purpose of this study was to identify the activity of the IO and the LM muscles during weight-bearing exercises. The authors hypothesized that IO and LM muscle activity would vary with lower body positions during the kinetic chain exercises., Methods: Nineteen healthy, young, active subjects volunteered to participate. The electromyographic (EMG) activity (via surface EMG) of the abdominal external oblique (EO), IO, and LM muscles on both sides and the rectus femoris and semitendinosus muscles on the dominant side was determined during rhythmical lower body twisting exercise with three lower body positions: straight leg (SL), athletic position (AP), dynamic knee extension (DE) at two exercise speeds: 150 and 90 beats per min. These were reported as % maximum voluntary contraction. Mean EO, IO, and LM muscle activities were also compared with those of common core stability exercises., Results: IO EMG activity was significantly greater in SL than that of AP (p < 0.05). In contrast, LM EMG activity was significantly greater in the DE position than that of both SL and AP positions (p < 0.05)., Conclusion: IO muscle activity could be attenuated by the contraction of lower body extensor muscles during the standing position., Level of Evidence: Basic Laboratory Study, Level 3b., (© 2020 by the Sports Physical Therapy Section.)

Objective: The aim of this study was to investigate whether fat infiltration of the lumbar multifidus (LM) muscle affects revision surgery rates for adjacent-segment degeneration (ASD) after L4-5 transforaminal lumbar interbody fusion (TLIF) for degenerative spondylolisthesis., Methods: A total of 178 patients undergoing single-level L4-5 TLIF for spondylolisthesis (2006 to 2016) were retrospectively analyzed. Inclusion criteria were a minimum 2-year follow-up, preoperative MR images and radiographs, and single-level L4-5 TLIF for degenerative spondylolisthesis. Twenty-three patients underwent revision surgery for ASD during the follow-up. Another 23 patients without ASD were matched with the patients with ASD. Demographic data, Roussouly curvature type, and spinopelvic parameter data were collected. The fat infiltration of the LM muscle (L3, L4, and L5) was evaluated on preoperative MRI using the Goutallier classification system., Results: A total of 46 patients were evaluated. There were no differences in age, sex, BMI, or spinopelvic parameters with regard to patients with and those without ASD (p > 0.05). Fat infiltration of the LM was significantly greater in the patients with ASD than in those without ASD (p = 0.029). Fat infiltration was most significant at L3 in patients with ASD than in patients without ASD (p = 0.017). At L4 and L5, there was an increasing trend of fat infiltration in the patients with ASD than in those without ASD, but the difference was not statistically significant (p = 0.354 for L4 and p = 0.077 for L5)., Conclusions: Fat infiltration of the LM may be associated with ASD after L4-5 TLIF for spondylolisthesis. Fat infiltration at L3 may also be associated with ASD at L3-4 after L4-5 TLIF.