Article

Trunk Muscle Recruitment Patterns in Patients With Low Back Pain Enhance the Stability of the Lumbar Spine

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Abstract

A comparative study of trunk muscle recruitment patterns in healthy control subjects and patients with chronic low back pain was conducted. To assess trunk muscle recruitment in patients with low back pain. Conflicting evidence has been reported on the level and pattern of trunk muscle recruitment in patients with low back pain. The disparities can be explained partly by methodologic differences. It was hypothesized that trunk muscle recruitment patterns may be altered in patients with low back pain to compensate for reduced spinal stability. For this study, 16 patients with low back pain and 16 matched control subjects performed slow trunk motions about the neutral posture and isometric ramp contractions while seated upright. Ratios of electromyographic amplitudes and estimated moment contributions of antagonist over agonist muscles and of segmentally inserting muscles over muscles inserting on the thorax and pelvis only were calculated. In addition, model simulations were performed to assess the effect of changes in muscle recruitment on spinal stability. The ratios of antagonist over agonist, and of lumbar over thoracic erector spinae electromyographic amplitude and estimated moment contributions were greater in the patients than in the control subjects. The simulation model predicted that these changes would effectively increase spinal stability. Trunk muscle recruitment patterns in patients with low back pain are different from those in healthy control subjects. The differences are likely to be functional with respect to enhancement of spinal stability in the patients.

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... MVCs are also difficult even for healthy workers as they need to be well motivated (Jung & Hallbeck, 2004) and ideally trained (Larivière et al., 2014;Sale et al., 1983) to perform "real" MVCs. To circumvent such MVC concerns, submaximal voluntary contractions (SVCs) have been proposed (Cholewicki et al., 2011;Dufour et al., 2013;Van Dieën et al., 2003), which can be integrated within an EMG-assisted optimization framework (Ghezelbash et al., 2022). ...
... The ratio variables are hypothesized to be useful model outcomes to study trunk muscle coordination strategies in patients with LBP (Van Dieën et al., 2003. Abdominal to back muscle ratio was different between all models (Fig. 4) but further pairwise comparisons between GAIN and MVC models showed that the effect sizes were small in all four experimental conditions (η 2 G ≤ 0.102). ...
... Van Dieën et al., 2003; and (3) Highly aggregated outcomes: (i) L4/L5 Intradiscal Pressure (IDP) ...
Article
Background Multijoint EMG-assisted optimization models are reliable tools to predict muscle forces as they account for inter- and intra-individual variations in activation. However, the conventional method of normalizing EMG signals using maximum voluntary contractions (MVCs) is problematic and introduces major limitations. The sub-maximal voluntary contraction (SVC) approaches have been proposed as a remedy, but their performance against the MVC approach needs further validation particularly during dynamic tasks. Methods To compare model outcomes between MVC and SVC approaches, nineteen healthy subjects performed a dynamic lifting task with two loading conditions. Results Results demonstrated that these two approaches produced highly correlated results with relatively small absolute and relative differences (<10%) when considering highly-aggregated model outcomes (e.g. compression forces, stability indices). Larger differences were, however, observed in estimated muscle forces. Although some model outcomes, e.g. force of abdominal muscles, were statistically different, their effect sizes remained mostly small (ηG2 ≤ .13) and in a few cases moderate (ηG2 ≤ .165). Conclusion The findings highlight that the MVC calibration approach can reliably be replaced by the SVC approach when the true MVC exertion is not accessible due to pain, kinesiophobia and/or the lack of proper training.
... 24 Also, a study analyzed the relative L/G ratio of the lumbar to thoracic ES muscular activity during isometric contractions in activities like flexion, extension, and lateral flexion from a semiseated position in an apparatus and estimated moment contributions were greater in the patients than in the control subjects. 38 In addition to the L/G ratio, previous researchers advocated for a gluteal-to-TFL muscle activation (GTA) index, where higher values indicate greater activation of GMax and GMed relative to TFL. 32 This index determines which exercises target gluteal activation while minimizing TFL activation to prevent abnormal hip kinematics (excessive abduction and internal rotation). 32 They recommended the clam, side step, the unilateral bridge, and quadruped hip extension exercises could be used to preferentially activate the gluteal muscles over TFL. ...
... The lumbar stabilization exercises mainly target the local muscles 35 ; however, there is some evidence that the high-load lumbar stabilization exercises, such as bridge exercises, could recruit both local and global muscles. 9,22 MF as the local muscle controls and ensures the spine curvature in sagittal and lateral stiffness to maintain mechanical stability of the lumbar spine 38 while ES as the global muscle produces torque to maintain overall trunk alignment. 38 The muscles of the hip transfer the loads of the tasks via the sacroiliac joint to the trunk and vice versa. ...
... 9,22 MF as the local muscle controls and ensures the spine curvature in sagittal and lateral stiffness to maintain mechanical stability of the lumbar spine 38 while ES as the global muscle produces torque to maintain overall trunk alignment. 38 The muscles of the hip transfer the loads of the tasks via the sacroiliac joint to the trunk and vice versa. 42 If the difficulty of the tasks and the magnitude of their loads are excessively beyond the tolerance of the hip muscles and joints, they can result in pressure on the lumbar joints, sacroiliac joint, pubic symphysis, and consequently functional failure of the sacroiliac joint and low back pain. ...
Article
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Background: There is some evidence that high-load lumbar stabilization exercises, such as back bridge, can recruit both local and global muscles. Hypothesis: Therapeutic exercises would optimize gluteus maximus (GMax), gluteus medius (GMed), multifidus (MF), and transversus abdominis (TrA) activation, while minimizing the activation of the tensor fascia latae (TFL) and erector spinae (ES) muscles in healthy individuals. Design: Cross-sectional study. Setting: Research laboratory. Level of Evidence: Level 4. Methods: In this cross-sectional study, surface electromyography (EMG) of GMax, GMed, TFL, TrA, MF, and ES was used to quantify the gluteal-to-TFL muscle activation (GTA) index and a ratio of local to global (L/G) lumbar muscles during (1) the elbow-toe exercise in the prone position, (2) the elbow-toe with right left lifted, (3) the hand-knee with left arm and right leg lifted, (4) the back bridge, (5) the back bridge with right leg lifted, (6) the back bridge with left leg lifted, (7) the side bridge with left leg lifted, (8) the side bridge with right leg lifted, and (9) the elbow-toe with right leg horizontally lifted exercises in healthy individuals (20 men, 20 women; age, 25 ± 4 years). Results: The back bridge exercise with left leg lift generated the highest L/G muscles activity ratio (L/G = 3.35) while the hand-knee exercise yielded the lowest L/G muscles activity ratio (L/G = 1.21). The side bridge exercise with left elbow and foot and lifting the right leg (GTA = 63.78), hand-knee exercise (GTA = 49.62), back bridge (GTA = 28.05), and elbow-toe exercise with left leg horizontally lifted (GTA = 23.02) generated the highest GTA indices, respectively. Meanwhile, the normalized EMG amplitude for GMax was significantly less than the TFL, for elbow-toe exercise (P < 0.001), back bridge with left leg lift (P = 0.001), side bridge exercise with the right elbow and foot and lifting the left leg (P = 0.002), and elbow-toe exercise with right leg horizontally lifted (P < 0.001). Conclusion: The highest GTA indexes were observed during (1) the side bridge lifting the dominant leg and (2) the hand-knee horizontally lifting dominant leg, respectively. The L/G ratio was highest during (1) the back bridge lifting nondominant leg, (2) back bridge, and (3) back bridge lifting dominant leg, respectively. This study supports the use of back bridge exercises to strengthen the MF and side bridges to improve gluteal muscle activation. Clinical Relevance: The highest GTA index was observed in the side bridge lifting the right leg. Highest L/G ratio was in the back bridge with nondominant leg lifted. This study supports the use of back bridge exercises to strengthen the MF. This study supports the use of side bridges to improve gluteal muscle activation. Keywords gluteal-to-tensor fascia latae activation (GTA) index, local/global (L/G) ratio, core stabilization exercise, healthy individual
... It has been claimed that LBP leads alterations in muscle activity around the location of pain [10]. So pattern of trunk muscle activation in patients with mechanical LBP (which the pain arises from structures of the spine including bones, ligaments, discs, joints, nerves and meninges [11]) is different from healthy population [12,13]. Most authors think that the changes in muscle activity in patients with LBP should be regarded as functional adaptations to a reduced spinal stabilization [13]. ...
... So pattern of trunk muscle activation in patients with mechanical LBP (which the pain arises from structures of the spine including bones, ligaments, discs, joints, nerves and meninges [11]) is different from healthy population [12,13]. Most authors think that the changes in muscle activity in patients with LBP should be regarded as functional adaptations to a reduced spinal stabilization [13]. Panjabi [14] first proposed that instability of the spine is likely due to any dysfunction of either spinal passive (non contractile) or active (trunk muscles) structures or from reduced neural control over these two parts and the instability could lead to LBP. ...
... Panjabi believed that to compensate a loss of passive stabilization, trunk muscles should be actively contracted. It has been shown, that co-contraction of muscles increases the stability of trunk [13]. In addition, healthy subjects when confronted with conditions that threaten spinal stability, increase co-contraction of their muscles [15]. ...
Article
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Background: Low back pain causes changes in muscle activation patterns. Knowing how different exercises may improve altered muscle activation is useful in the treatment of patients. The aim of the study was to investigate whether there was a difference in the pattern of muscle activation in chronic nonspecific low back pain sufferers following core stability exercise (CSE) and general exercise (GE). Methods: Fifty-six non-specific chronic LBP subjects were randomly assigned to either groups (28 participants in CSE and 28 in GE group). Both groups performed 16 sessions of an exercise program for about 5 weeks. Pain, disability and trunk muscle activation patterns (using surface electromyography) were measured at baseline and post-training. Results: After the intervention period, antagonist coactivation ratio did not change in either groups. Though all compensated imbalance ratios (residual unequal muscular activity after cancellation of directionality) decreased towards negative (imbalance to left side) only this change for total muscles ratio in GE was significant (mean difference in GE group, 0.15; 95% CI: 0.02 to 0.28; p-value of paired t-test: 0.022); (mean difference in CSE, 0.02; 95% CI: - 0.07 to 0.11; p-value of paired t-test: 0.614).. No overall significantly decrease in uncompensated imbalance ratio (absolute imbalance values without cancellation directionality) was observed. Pain and disability decreased significantly in both groups. However, there was no difference between two groups in either of the variables after the intervention. Conclusions: Both exercise programs reduced pain and disability and made or kept trunk muscle activation imbalance to the left side. The effects of two exercises on pain, disability and antagonist coactivation or imbalance ratios were not different. Trial registration: This study was registered in the Iranian Clinical Trial Center with the code IRCT201111098035N1, Registered Jan 21, 2013.
... Low back pain (LBP) is associated with postural control changes, some of which are considered to protect the painful area from further pain, injury or re-injury [1,2]. These postural characteristics have been typically observed during the later stages of LBP [2][3][4], and are thought to be detrimental if maintained beyond the initial acute/repair phase as they can increase spinal loads and reduce movement [5,6]. ...
... Compromised balance performance has also been argued to result from stiffening of the trunk [1,2], either to protect the back from real or perceived threat of further pain/injury [5], or to reduced reliance on proprioception which is necessary to fine tune coordinated muscle activation [29]. Elevated co-activation of trunk muscles would provide quicker responses to disturbances but might negatively impact balance control [15]. ...
Article
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. Generalized 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.
... Their adaptive strategy could be used to prevent possible fall injuries. The co-contraction of the lower limb muscles could be explained as longer delays to the mechanical disturbance, which may cause a smaller angular deviation of the trunk [22,23]. As lower limb function involves postural stability, our study utilized the preferential side to better discriminate the behavior on limb preference [24]. ...
... We also expected a trunk stiffening strategy might occur because of reduced trunk motion (possibly due to pain). These patterns are likely to be functional to enhance postural stability in the LBP group [23]. However, the somatosensory integration for the control of the preferred foot placement in subsequent trials was based on swing and step times in the initial trial in order to enhance gait stability. ...
Article
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A compensatory stepping strategy following repeated perturbations may compromise dynamic balance and postural stability. However, there is a lack of study on preferred limb reaction, swing, and step time adjustments. The purpose of this study was to investigate limb reaction, swing, and recovery step times following repeated trip perturbations in individuals with and without non-specific chronic low back pain (LBP). There were 30 subjects with LBP and 50 control subjects who participated in the study. The limb reaction, swing, and recovery step times (s) were measured following treadmill-induced random repeated perturbations (0.12 m/s velocity for 62.5 cm displacement), which caused subjects to move forward for 4.90 s. Both groups demonstrated a significant interaction of repetitions and times (F = 4.39, p = 0.03). Specifically, the recovery step time was significantly shorter in the LBP group during the first trip (t = 2.23, p = 0.03). There was a significant interaction on repetitions and times (F = 6.03, p = 0.02) in the LBP group, and the times were significantly different (F = 45.04, p = 0.001). The initial limb reaction time of the LBP group was significantly correlated with three repeated swing times to avoid falls. The novelty of the first trip tends to enhance a protective strategy implemented by the LBP group. Although limb preference did not demonstrate a significant difference between groups, the LBP group demonstrated shorter recovery step times on their preferred limb initially in order to implement an adaptive strategy to avoid fall injuries following repeated perturbations.
... Teniendo en cuenta que tanto la plancha frontal como la extensión isométrica de tronco que se considerarían ejercicios simétricos (con una supuesta demanda equitativa en ambos hemicuerpos), y el comportamiento observado en este caso, podríamos pensar, pero no concluir, que estaríamos ante un caso que refleja una conducta adaptativa, una compensación funcional a algún factor extra que no ha sido tenido en cuenta en este análisis. Observamos similitud de resultados con estudios realizados con pacientes con dolor lumbar crónico, en donde se reportan aumentos en la actividad eléctrica, particularmente del oblicuo mayor, y un patrón de reclutamiento alterado, coincidentes, a priori, con nuestro caso (Calatayud, 2019;Kim, 2013;Shamsi, 2020;Silfies, 2005, van Dieën, 2003. Asimismo, existe la posibilidad de que la causa de estos valores observados en el análisis electromiográfico pueda darse debido a una estrategia de control postural como consecuencia de una escoliosis, ya que se encontró en la literatura evidencia que sujetos con esta patología presentaban patrones anormales de activación ante demandas simétricas, comparados con Kuo, 2011). ...
... Ambos músculos presentan mucha más actividad que sus contralaterales sin importar el ejercicio o el rol que se les demandan, sin embargo, estos resultados no son concluyentes puesto que fueron obtenidos en un solo sujeto del cual se desconoce la existencia de alguna variable capaz de explicar el comportamiento observado, que probablemente podría estar relacionado a una respuesta adaptativa a algún factor no conocido. La evidencia nos sugiere que cambios en los patrones de reclutamiento son una adaptación a la inestabilidad espinal resultante de la laxitud o daño osteoligamentoso, disfunción muscular o control neuromuscular reducido (Silfies, 2005), como así también del dolor, la fatiga muscular (Enoka, 2008;Tsuboi, 1994), o una anomalía escoliótica. Sin embargo, no se puede atribuir a ninguno de estos factores los resultados obtenidos debido a que no han sido tenidos en cuenta en este estudio. ...
Article
Full-text available
Core stability has gained importance due to its role in movement and its relationship with low back pain, in this sense, various models have been proposed to explain its performance, without a clear consensus yet. The aim of this study was to quantitatively analyze the activation and participation of the trunk musculature in isometric exercises related to central stability. A 23-year-old student from the Facultad de Educación Física (UNT) was evaluated. Through surface electromyography, the activity of the external oblique, internal oblique, multifidus and gluteus maximus was bilaterally examined in four isometric exercises, prone plank, isometric trunk extension and right and left side plank. The results obtained indicate that the prone plank and the side plank mainly involve the oblique muscles, contrary to the isometric extension of the trunk that involves the multifidus. However, the results show a discrepancy with previous studies, an exacerbated activation was observed in all exercises of the right internal oblique and the left external oblique, a crossed pattern of synchronous activation that would reflect an adaptive behavior. For being a case report, this results are not conclusive, more research is needed in this regard.
... changes in muscle activity, kinematics, muscle properties, sensorimotor control, and performance) have been extensively examined in people with spinal pain as changes in these features may contribute to pain persistence or recurrence [6][7][8]. For example, adaptations in muscle activity, spine kinematics, and sensorimotor control have been reported in symptomatic people [9][10][11][12] and some studies suggest that these changes extend beyond the duration of a painful episode and could lead to potential long-term consequences, such as pain recurrence [13][14][15]. In support of this, current theories on pain and movement suggest that the new motor strategies which are adopted in the presence of pain could lead to suboptimal loading of the spine thereby contributing to persistent or recurrent symptoms [6][7][8]. ...
... Although affected by a very low quality of evidence, our findings are in accordance with those for people with chronic LBP [9,16], and with contemporary theories of motor adaptation to pain [10,14,15]. Motor behaviour changes are heterogenous across individuals but appear to have the common goal of protection in the short term [10,14,15]. ...
Article
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A plethora of evidence supports the existence of neuromuscular changes in people with chronic spinal pain (neck and low back pain), yet it is unclear whether neuromuscular adaptations persist for people with recurrent spinal pain when in a period of remission. This systematic review aimed to synthesise the evidence on neuromuscular adaptations in people with recurrent spinal pain during a period of remission. Electronic databases, grey literature, and key journals were searched from inception up to the 4 th of September 2020. Eligibility criteria included observational studies investigating muscle activity, spine kinematics, muscle properties, sensorimotor control, and neuromuscular performance in adults (≥ 18 years) with recurrent spinal pain during a period of remission. Screening, data extraction, and quality assessment (Newcastle-Ottawa Scale) were conducted independently by two reviewers. Data synthesis was conducted per outcome domain. A meta-analysis with a random-effects model was performed where possible. The overall strength of evidence was rated using the Grading of Recommendations, Assessment, Development and Evaluation guidelines (GRADE). From 8292 records, 27 and five studies were included in a qualitative and quantitative synthesis, respectively. Very low level of evidence supports muscle activity changes in people with recurrent low back pain, especially greater co-contraction, redistribution of muscle activity, and delayed postural control of deeper trunk muscles. Reduced range of motion of the lumbar spine was also found. Meaningful conclusions regarding other outcome domains or people with recurrent neck pain could not be drawn. In conclusion, people with recurrent low back pain during a period of remission show muscle activity and spine kinematics adaptations. Future research should investigate the long-term impact of these changes, as well as adaptations in people with recurrent neck pain.
... Altered postural muscle control was described in CLPB participants as a mechanism to minimize trunk motion and maintain protective stiffness to avoid pain or successive injuries 43,45,46 . Moreover, the fear of falling, typically present in elderly people, may alter muscle control in a protective manner 32 . ...
... Moreover, the fear of falling, typically present in elderly people, may alter muscle control in a protective manner 32 . An altered timing of muscle activation and increased co-contraction in the axial muscles during body perturbation has been reported in individuals with CLBP 25,34,37,45 . This increases spinal stiffness and reduces spinal movement [47][48][49] . ...
Article
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Abstract Chronic low back pain (CLBP) is associated with postural control impairments and is highly prevalent in elderly people. The objective of this study is to verify whether anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs) are affected by CLBP in elderly people by assessing their postural control during a self-initiated perturbation paradigm induced by rapid upper arm movement when pointing to a target. The participants’ lower limb muscle onset and center of pressure (COP) displacements were assessed prior to perturbation and throughout the entire movement. T0 moment (i.e., the beginning of the movement) was defined as the anterior deltoid (DEL) onset, and all parameters were calculated with respect to it. The rectus femoris (RT), semitendinosus (ST), and soleous (SOL) showed delayed onset in the CLBP group compared with the control group: RF (control: − 0.094 ± 0.017 s; CLBP: − 0.026 ± 0.012 s, t = 12, p
... However, they suggested that LBP patients tend to avoid lumbar flexion due to pain, which reduces the contribution of LS to the overall movement and angular velocity during the STS performance of subjects [13]. In addition, van Dieën reported that in patients with LBP, discoordination of the LS and hip joints was induced when performing sit to stand due to changes in muscle activation [14]. ...
... Most patients with LBP have paravertebral muscle spasms [14,25]; vibration has been reported to relax muscles and relieve musculoskeletal pain caused by high muscle tone [26]. Studies on vibration exercise in LBP patients reported significant improvements in proprioception, following the stimulation of a proprioceptor such as the golgi tendon organ (GTO) [27]. ...
Article
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There are many adolescent patients complaining of low back pain, but research on it is lacking. The purpose of this study was to investigate the effects of trunk stabilization exercise combined with vibration on the pain, proprioception, and kinematics of the lumbar spine (LS) during sit to stand (STS) in adolescent patients with nonspecific low back pain (LBP). Fifty LBP patients were recruited and were randomly divided into two groups: Vibration group (n = 25) and placebo group (n = 25). All participants underwent 36-sessions of training consisting of six exercises. The Vibration group provided vibration stimulation during exercise, but the placebo group did not. The Numeric Pain Rating Scale (NPRS) and digital dual inclinometer were used to measure pain intensity and proprioception. The kinematics of the lumbar spine during STS were measured by motion capture system. After training, the pain and proprioception in the vibration group improved significantly greater than the placebo group (p < 0.05). The mobility of LS (maximum range of motion, angular velocity, lumbar to hip movement ratios) and lumbar-hip coordination during STS in the vibration group were significantly improved compared to the placebo group (p < 0.05). Thus, trunk stabilization exercise combined with vibration may be used to improve the pain, proprioception, and kinematic of the lumbar spine during sit to stand in adolescent patients with LBP.
... night pain, unexplained weight loss) [17]. The control group consisted of 15 participants who had never experienced back pain with a duration longer than 3 consecutive days [31]. They were matched with the LBP group for gender, age and body mass index. ...
Article
Background For people above 65 years old, low-back pain (LBP) is associated with balance problems and falls. Down-weighting of proprioception due to ageing and LBP may cause such balance problems. While lumbar proprioceptive deficits have been shown in LBP and indications for more generalized deficits have been found, ankle proprioception, which is crucial for balance control, has not been studied in people with LBP. Research question Is there any difference in ankle proprioceptive acuity between community-dwelling older adults with and without LBP? We hypothesized that ankle proprioception was impaired in community-dwelling older adults with LBP compared to those without LBP. Methods Thirty participants over 65 years old volunteered. Fifteen had LBP (M/F = 2/13, age = 72.0 (4.6) years), fifteen were healthy controls without back pain (control group) (M/F = 2/13, age = 72.1 (4.8) years). Ankle proprioception was measured in normal weight-bearing conditions, using the Active Movement Extent Discrimination Apparatus (AMEDA). Accuracy on the ankle proprioceptive test was expressed as absolute error (AE), constant error (CE) and variable error (VE). Results AE was significantly larger (P = 0.029, 95% CI = [0.00, 0.90]) in the LBP group, CE was also significantly larger (P = 0.046, 95% CI = [-0.91, -0.01]), indicating an underestimation of ankle inversion in participants with LBP compared to controls. VE was not different between the two groups (P = 0.520, 95% CI = [-0.20, 0.59]). No significant correlation was found between pain intensity and AE, CE or VE (P > 0.05). Conclusion Ankle proprioception decreased in older people with LBP compared to healthy peers, suggesting impaired central proprioceptive processing. Older people with LBP underestimate the extent of ankle inversion, which may increase fall risk. Thus, evaluation and training of ankle proprioception may be useful in older people with LBP.
... The basic premise of this landmark theoretical hypothesis is that the neural element is a regulating step in this stabilizing system [1,[4][5][6]. The neural reflex of peripheral sensory system, represented by vestibular system and muscle-tendon proprioceptors, does attempt to control muscles dynamics during head-neck movements [7][8][9][10][11]. The sensory information from the vestibular system is responsible for providing the brain with motion, head position, and spatial orientation, it is also involved with motor functions that keep balance, stabilize head-neck during movement, and maintain posture [12,13]. ...
Article
Background and objective Neural reflex is hypothesized as a regulating step in spine stabilizing system. However, neural reflex control is still in its infancy to consider in the previous finite element analysis of head-neck system for various applications. The purpose of this study is to investigate the influences of neural reflex control on neck biomechanical responses, then provide a new way to achieve an accurate biomechanical analysis for head-neck system with a finite element model. Methods A new FE head-neck model with detailed active muscles and spinal cord modeling was established and globally validated at multi-levels. Then, it was coupled with our previously developed neuromuscular head-neck model to analyze the effects of vestibular and proprioceptive reflexes on biomechanical responses of head-neck system in a typical spinal injury loading condition (whiplash). The obtained effects were further analyzed by comparing a review of epidemiologic data on cervical spine injury situations. Result The results showed that the active model (AM) with neural reflex control obviously presented both rational head-neck kinematics and tissue injury risk referring to the previous experimental and epidemiologic studies, when compared with the passive model (PM) without it. Tissue load concentration locations as well as stress/strain levels were both changed due to the muscle activation forces caused by neural reflex control during the whole loading process. For the bony structures, the AM showed a peak stress level accounting for only about 25% of the PM. For the discs, the stress concentrated location was transferred from C2-C6 in the PM to C4-C6 in the AM. For the spinal cord, the strain concentrated locations were transferred from C1 segment to around C4 segment when the effects of neural reflex control were implemented, while the grey matter and white matter peak strains were reduced to 1/3 and 1/2 of the PM, respectively. All these were well correlated with epidemiological studies on clinical cervical spine injuries. Conclusion In summary, the present work demonstrated necessity of considering neural reflex in FE analysis of a head-neck system as well as our model biofidelity. Overall results also verified the previous hypothesis and further quantitatively indicated that the muscle activation caused by neural reflex is providing a protection for the neck in impact loading by decreasing the strain level and changing the possible injury to lower spinal cord level to reduce injury severity.
... The seven muscles examined were: left and right rectus abdominus (RA), internal oblique (IO), tensor fascia latae (TFL), lumbar erector spinae (LES), lumbar multifidus (MUL), gluteus maximus (Gmax) and biceps femoris (BF). These muscles were chosen to be studied because of their functional roles as the prime movers and/or stabilisers of the lumbopelvic region during flexion (standing to end of bending) and extension (end of bending to standing) phases of the task [33,34]. Standardized skin preparation was applied to achieve the skin impedance <10 kO for EMG electrode placement [35]. ...
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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.
... Aktivnost mišića je neophodna da bi se zadržao položaj pasivne stabilnosti. Mišići centralnog dijela trupa kroz procese ko-kontrakcije najviše doprinose procesu aktivnog održavanja stabilnosti cijelog tijela (van Dieën, Cholewicki, & Radebold, 2003). Proces ko-kontrakcija se kod odraslih osoba dešava kada se detektuje pokret koji može da izazove povredu kičmenog stuba putem mehanoreceptora i receptora boli. ...
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Abstract Aim of the study was to experimentally validate and determine the effects of 8 - week additional motor control exercise (MCE) based like exercise program on body composition, body posture and some motor abilities. Sample was randomized from football in experimental group 1 (Ex1, n=12; mean (SD): 10.5 (0.5) yrs; 148 (5.4) cm; 39.6 (5.4) kg i 18.04 (1.9) kg/m2) and control group 1 (Kon1, n=11; 10.36 (0.5) yrs; 144 (6.2) cm; 37.9 (5.6) kg i 18.27 (2.1) kg/m2), from karate to experimental group 2 (Ex2, n=11; 12.2 (1.4) yrs; 158.1 (6.2) cm; 46.6 (7.15) kg and 18.63 (2.65) kg/m2) and control group 2 (Kon2, n=10; 11.8 (1.5) yrs; 155.4 (8.97) cm; 48.23 (13.5) kg i 19.6 (3.6) kg/m2) and from athletics to experimental group 3 (Ex3, n=13; 12.15 (1.2) yrs; 145 (6.17) cm; 41.54 (5.02) kg i 19.7 (2.2) kg/m2) and control group 3 (Kon3, n=10; 12.2 (0.9) yrs; 145.5 (6.0) cm; 44.25 (6.54) kg i 21.14 (2.26) kg/m2). Program with average attendance frequency of 2-3 times/week with duration of 20-30 minutes had large effect on Ex1 for overall stability index (OSI, (ES=-0.84; -26%,)), anterior – posterior stability (APSI, (ES=-0.73; -22%)) and flamingo test (ES=1.00; +105%) along with moderate effect on medial – lateral stability (MLSI, (ES=-0.73, -21%)). Ex2 significantly improved OSI (Large effect, ES=-1.22; -27%), and agility (T-test (Large effect, ES=-1.28; -3%)), along with moderate effect on APSI (ES=-0.63; -9%) and MLSI (ES=-0.60 -21%). Small effect was observed for flamingo test (ES=0.21; +28%) and 20 meters sprint (T20m, ES=-0.37; -1%). Ex3 significantly reduced percentage of relative body fat (Small effect, ES=-0.27; 0.2%). No significant changes were observed for the control groups. Results suggested that strength training of core muscles, based on motor control learning to induce changes in contraction intensity, can improve dynamic and static stability in young athletes. Adaptation on the exercise program indirectly improved stability and balance by reducing the latent time to muscle contraction by improving intramuscular coordination of the deep trunk muscles which improved maintaining of optimal body position during stability tasks. Programs with exercises intended to strengthen trunk and spine stabilization muscles, when additionally performed, can improve stability and prevent injuries. Exercise program did not significantly affect nor improved body composition, body posture, flexibility (sit and reach), sprinting performance (T20m), agility (T-test) and power (CMJ). Keywords: Body composition, motor control, postural control, stability
... Besides the role of psychosocial aspects in persistent pain [3,4], clinical evidence has revealed extensive changes in neuromuscular control in people with pain, during both acute and chronic stages [5][6][7][8][9]. Current theories suggest a strong relationship between pain and movement, implicating changes in response to pain at multiple levels of the neuromuscular system [1,10,11]. ...
Article
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Background Numerous studies report changes in neuromuscular control in people with low back pain (LBP). However, the relationship between pain and altered neuromuscular control is challenging to unravel given the heterogeneity that exists in clinical populations. One approach commonly adopted to overcome this issue is the use of experimental pain models, but it is currently unclear if the effects of experimental pain are consistent between studies. Therefore, this planned study will systematically evaluate and summarise the effect of experimentally induced pain in the lumbar region on neuromuscular control at sites both locally and remote to the low back. Methods This protocol has been developed following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P). MEDLINE, EMBASE, CINAHL, ZETOC, Web of Science, and grey literature will be searched up to August 31, 2021. Screening processes (title/abstract and full-text), data extraction, and risk of bias assessment will be conducted by two independent reviewers. Studies investigating the effects of exogenous pain models delivered to the low back region on neuromuscular control in healthy individuals will be included. Muscle activity and body kinematics will be the outcomes of interest. The comparisons of interest will be between baseline or control conditions and the experimental pain condition, as well as between the experimental pain and post-pain conditions. Randomised crossover and non-randomised studies of interventions will be included and their risk of bias will be evaluated with the Cochrane Risk-of-Bias tool or with the Risk Of Bias In Non-randomised Studies of Interventions tool, respectively. A random-effect meta-analysis will be conducted for quantitative synthesis when clinical and methodological consistency is ensured. Quality of evidence will be evaluated using the Grading of Recommendations, Assessment, Development and Evaluation guidelines. Discussion The current review will provide new insights to understand if and what neuromuscular adaptations are caused by pain experimentally induced in the lumbar region. Our findings will reveal which experimental pain model is able to better reproduce adaptations similar to those identified in people with low back pain, possibly contributing to improving our understanding of motor adaptation to low back pain in the long term. Systematic review registration PROSPERO CRD42020220130
... Since Panjabi rstly suggested the stabilizing system of spine: instability hypothesis of low back pain [5], people focus on studying the function of trunk muscle of the patients. Lumbar paraspinal muscle (LPM) such as erector spinae muscle, lumbar multi dus and transversus abdominis were found to be important for core stabilization [6]. ...
Preprint
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Background Non-specific chronic low back pain (NSCLBP) is a multifactor disorder with high prevalence rate of people all around the world. Lumbar paraspinal muscle (LPM) plays an important role of spine stabilization. However, the electrical properties of LPM in the patients were unclear. Aim to explore the electrical properties of bilateral LPM between patients with NSCLBP and healthy controls (HC), the study was designed to applied electrical impedance myography (EIM) technique to measure the LPM.MethodsA total of thirty participates (15 in NSCLBP group, 15 in HC group) were instructed to have each side of LPM measured at the rest state and the maximum volunteer contraction (MVC) state. Then measured the EIM parameters of LPM at L4/5 level by a multi-frequency device. Each measurement repeated three times. The EIM parameters at 50 kHz, 100 kHz, 200 kHz current frequencies were enrolled into the statistical analysis.ResultsAt the three current frequencies, parameters in the right side of LPM had not significantly difference from the left ( P >0.05, respectively). Resistance (R) of LPM in NSCLBP group was larger than that in HC group ( P <0.05, respectively), phase angle (PA) in NSCLBP group was smaller than that in HC group ( P <0.05, respectively) and there was no difference of the reactance value between the two groups ( P >0.05, respectively). At 50 kHz, relationships between the EIM parameters and geometric parameters of LPM were not significant in NSCLBP group or HC group ( P >0.05, respectively).Conclusion The electrical properties of bilateral LPM in young adults with NSCLBP were different from those of healthy individuals regardless of any current frequency. The ultrasound parameters of LPM, however, showed no significant difference between young patients with NSCLBP and healthy participants. EIM measurement might be more sensitive than rehabilitative ultrasound for NSCLBP in young adults.Trial registrationThe Chinese Clinical trial registration number: ChiCTR2100043113.
... Patients with LBP have been reported to display changed neuromuscular activity such as delayed local muscle activation and greater co-contraction of the abdominal and back muscles [4][5][6][7]. Some studies suggest that these changes extend beyond the duration of a painful episode and could lead to long-term consequences [8,9], as the pain may recur due to the increased loading of the spine [10,11]. ...
Article
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Abstract 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
... Sufficient LMM function is essential to maintain the stability of the kinetic chain and generate forces to the lower and upper limbs [4]. Magnetic resonance imaging (MRI) and ultrasound imaging studies of athletes and non-athletes with LBP have reported morphological changes and functional deficits of the LMM, such as LMM atrophy [5][6][7][8][9], LMM cross-sectional area (CSA) asymmetry [5,7,[10][11][12], increased fatty infiltration [13][14][15][16], and increased or decreased muscle activity [17][18][19]. Magnetic resonance imaging (MRI) remains the gold standard technique for muscle imaging, since the high resolution allows accurate assessment of muscle size and composition. However, ultrasound imaging is a more accessible and less expensive imaging technique that provides valuable information about muscle function [20][21][22]. ...
Article
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Background and Objectives: Ultrasound echo intensity (EI) of the lumbar multifidus muscle (LMM) could offer valuable insights regarding muscle quality in people with low back pain (LBP). However, whether the rater’s experience noticeably influences the reliability and precision of LMM EI measurements has not been established. The aims of this study were to investigate the intra-rater and inter-rater reliability of LMM EI measurements, and to compare the reliability and SEM between a novice and an experienced rater. Materials and Methods: Twenty athletes (10 females, 10 males) with a history of LBP were included in this study. Transverse ultrasound images of LMM were taken at L5 in prone. LMM EI measurements were obtained bilaterally by tracing the maximum ROI representing the LMM cross-sectional area (CSA), avoiding the inclusion of bone or surrounding fascia. All measurements were performed by two novice raters and an experienced researcher. Each measurement was acquired by each rater three times for each side on three different images, and the average was used in the analyses. Raters were blinded to each other’s measurements and the participant’s clinical information. Intra-class correlation coefficients (ICCs) were obtained to assess the intra-rater and inter-rater reliability. Results: The intra-rater ICC values for the LMM measurements for the experienced rater were excellent (ICC all > 0.997). The inter-rater reliability ICC values showed moderate to excellent reliability (0.614 to 0.994) and agreement between the novice raters and the experienced rater, except for Novice 1 for the right LMM, which revealed lower ICCs and a wider 95% CI. Intra-rater and inter-rater reliability results were similar when separately looking at the right and left side of the muscle and participant gender. Conclusions: Our findings support the clinical use of ultrasound imaging for the assessment of LMM EI in individuals with LBP.
... Because of the similar function, this pair of muscles acts similarly to the erector spinae (longissimus) and the rectus abdominis, with higher CoI during the explosive ascending phase. These results provide more information on the joint activation of muscles that act as both agonist and antagonist during trunk effort, with and without counting the additional resistance moment that must be overcome due to the joint activation of the muscles [17,18]. ...
Article
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The purpose of this study was to determine the muscle activation and co-activation of selected muscles during the kettlebell single arm swing exercise. To the best of our knowledge, this is the first study investigating the muscle co-activation of a kettlebell single arm swing exercise. Nine volunteers participated in the present study (age: 22.6 ± 3.8 years; body mass: 80.4 ± 9.2 kg; height: 175.6 ± 7.5 cm). The electrical muscle activity of eight right agonist/antagonist muscles (AD/PD, ESL/RA, ESI/EO, and GM/RF) were recorded using a surface EMG system (Myon m320RX; Myon, Switzerland) and processed using the integrated EMG to calculate a co-activation index (CoI) for the ascending and descending phases. A significant effect of the ascending and descending phases on the muscles’ CoI was observed. Post hoc analyses showed that the co-activation was significantly higher in the descending phase compared to that in the ascending phase of AD/PD CoI (34.25 ± 18.03% and 24.75 ± 13.03%, p < 0.001), ESL/RA CoI (34.97 ± 17.86% and 24.19 ± 10.32%, p < 0.001), ESI/EO CoI (41.14 ± 10.72% and 30.87 ± 11.26%, p < 0.001), and GM/RF CoI (27.49 ± 12.97% and 34.98 ± 14.97%, p < 0.001). In conclusion, the co-activation of the shoulder muscles varies within the kettlebell single arm swing. The highest level of co-activation was observed in the descending phase of AD/PD and GM/RF CoI, and the lowest level of co-activation was observed during the descending phase, ESL/RA and ESI/EO CoI. In addition, the highest level of co-activation was observed in the ascending phase of ESL/RA and ESI/EO CoI, and the lowest level of co-activation was observed during the ascending phase, AD/PD and GM/RF CoI. The co-activation index could be a useful method for the interpretation of the shoulder and core muscles’ co-activity during a kettlebell single arm swing.
... Altered muscle activation patterns and responses could also be any of the causes of non-specific LBP [45][46][47]. Van Dieën et al. have attributed altered muscle activation patterns to compensatory mechanisms that emerge to increase the stability of the spine [48]. It was also proposed that proprioception deficits in lumbar part of the spine are a major cause for poorer lumbar postural control [44]. ...
Article
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An abundance of literature has investigated the association between low back pain (LBP) and physical ability or function. It has been shown that LBP patients display reduced range of motion , decreased balance ability, impaired proprioception, and lower strength compared to asymptomatic persons. The aim of this study was to investigate the differences between LBP patients and healthy controls in terms of several physical abilities. Based on the premised that different biomechanical and physiological causes and consequences could be related to different types of LBP, a secondary exploratory attempt of the study was to examine the differences between LBP subgroups based on the pain location (local or referred) or type of pathology (discogenic or degenerative) on the level of impairment of function and ability. Participants performed range of motion tests, trunk maximal voluntary contraction force tests, a sitting balance assessment, the timed up-and-go test, the chair rise test, and the trunk reposition error test. Compared to the control group, symptomatic patients on average showed 45.7% lower trunk extension (p < 0.001, η 2 = 0.33) and 27.7 % lower trunk flexion force (p < 0.001, η 2 = 0.37) during maximal voluntary contraction. LBP patients exhibited decreased sitting balance ability and lower scores in mobility tests (all p < 0.001). There were no differences between groups in Schober's test and trunk repositioning error (p > 0.05). No differences were observed among the LBP subgroups. The exploratory analyses are limited by the sample size and uncertain validity of the diagnostic procedures within this study. Further studies with appropriate diagnostic procedures and perhaps a different subgrouping of the LBP patients are needed to elucidate if different types of LBP are related to altered biomechanics, physiology, and function.
... It is based on a large body of evidence suggesting that individuals with LBP have impaired control and coordination of the trunk muscles, including the deep trunk muscles (eg, transversus abdominis and multifidus). [35][36][37][38][39][40][41][42] The underlying premise is that for many with chronic LBP, ongoing nociceptive input from the periphery secondary to suboptimal tissue loading contributes to the ongoing pain. 43 The primary goal of motor control exercises is to retrain optimal control and coordination of the spine and limbs. ...
Article
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Introduction Exercise therapy is the most recommended treatment for chronic low back pain (LBP). Effect sizes for exercises are usually small to moderate and could be due to the heterogeneity of people presenting with LBP. Thus, if patients could be better matched to exercise based on individual factors, then the effects of treatment could be greater. A recently published study provided evidence of better outcomes when patients are matched to the appropriate exercise type. The study demonstrated that a 15-item questionnaire, the Lumbar Spine Instability Questionnaire (LSIQ), could identify patients who responded best to one of the two exercise approaches for LBP (motor control and graded activity). The primary aim of the current study isill be to evaluate whether preidentified baseline characteristics, including the LSIQ, can modify the response to two of the most common exercise therapies for non-specific LBP. Secondary aims include an economic evaluations with a cost-effectiveness analysis. Methods and analysis Participants (n=414) will be recruited by primary care professionals and randomised (1:1) to receive motor control exercises or graded activity. Participants will undergo 12 sessions of exercise therapy over an 8-week period. The primary outcome will be physical function at 2 months using the Oswestry Disability Index. Secondary outcomes will be pain intensity, function and quality of life measured at 2, 6 and 12 months. Potential effect modifiers will be the LSIQ, self-efficacy, coping strategies, kinesiophobia and measures of nociceptive pain and central sensitisation. We will construct linear mixed models with terms for participants (fixed), treatment group, predictor (potential effect modifier), treatment group×predictor (potential effect modifier), physiotherapists, treatment group×physiotherapists and baseline score for the dependent variable. Ethics and dissemination This study received ethics approval from the Hamilton Integrate Research Ethics Board. Results will be submitted for publication in peer-reviewed journals. Trial registration number NCT04283409 .
... The global stabilization system includes the larger superficial muscles-such as external oblique (EO), rectus abdominis (RA) and erector spinae-which provide torque across multiple segments for transferring the load directly between the thoracic cage-upper limbs and the pelvis-lower limbs [4,28]. It has been reported that increased vertebral stiffness by synergistic coactivation of both muscle systems is a central question improving the stabilization of the trunk [23,29,30]. ...
Article
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This cross-sectional study of repeated measures investigated whether integrating the abdominal hollowing maneuver (AHM) into the prone plank performance is an effective strategy for increasing both the activation of the deep and superficial core musculature. Electromyographical (EMG) responses of rectus abdominis (RA), external oblique (EO), internal oblique (IO), and lumbar erector spinae (LES), and ratings of perceived exertion (RPE) of 20 participants (13 male, 7 female; mean ± standard deviation (SD) age: 24.25 ± 3.54 years; body mass: 66.42 ± 8.40 kg; height: 1.70 ± 9.51 m) were compared across two experimental conditions: the traditional prone plank (STANDARD); and a variation including the AHM (HOLLOWING). Regarding Total Intensity, HOLLOWING resulted in significantly greater EMG response than STANDARD (p < 0.001; Effect size (ES) = 3.01). Specifically, RA showed no significant differences between STANDARD and HOLLOWING (p = 0.056; ES = 0.285). However, for the remaining analyzed muscles, HOLLOWING significantly provided higher EMG activation compared to STANDARD (LES: p = 0.004; ES = 0.619; left EO: p < 0.001; ES = 1.031; right EO: p < 0.001; ES = 1.419; left IO: p < 0.001; ES = 2.021; right IO: p < 0.001; ES = 2.269). Regarding RPE, HOLLOWING reported values significantly greater than STANDARD (p < 0.001; ES = 2.94). In conclusion, integrating the AHM into the prone plank exercise enhances overall abdominal activity, particularly in both obliques. These findings provide updated guidelines for lumbar stabilization and core strengthening in health-related physical fitness programs.
... (2)(3)(4)(5) This abnormal activity of superficial and deep muscles in LBP may lead to further pain and limitations in function. (6) Lumbar mobilization and thrust manipulation are manual therapy interventions that are recommended in the clinical guidelines for managing LBP. (7) There are few differences between lumbar mobilization and thrust manipulation. ...
Article
Background: Lumbar mobilization is a standard intervention for lower back pain (LBP). However, its effect on the activity of back muscles is not well known. Objectives: To investigate the effects of lumbar mobilization on the activity/contraction of erector spinae (ES) and lumbar multifidus (LM) muscles in people with LBP. Design: Randomized controlled study. Methods: 21 subjects with LBP received either grade III central lumbar mobilization or placebo (light touch) intervention on lumbar segment level 4 (L4). Surface electromyography (EMG) signals of ES and ultrasound (US) images of LM were captured before and after the intervention. The contraction of LM was calculated from US images at L4 level. The normalized amplitude of EMG signals (nEMG) and activity onset of ES were calculated from the EMG signals at both L1 and L4 levels. Results: Significant differences were found between the mobilization and placebo groups in LM contraction (p=0.03), nEMG of ES at L1 (p=0.01) and L4 (p=0.05), and activity onset of ES at L1 (p=0.02). Conclusion: Lumbar mobilization decreased both the activity amplitude and the activity onset of ES in people with LBP. However, the significant difference in LM contraction was small and may not have clinical significance.
... [12][13][14][15] More specifically, in people with spinal pain a number of common neuromuscular changes have been observed which have the potential to contribute to repeated episodes of pain. These include reduced muscle strength, endurance, 16-19 range of motion, 20 21 increased muscle co-activation, 22 23 poorer control of the deeper muscles, 24 25 poorer proprioception and changes in the quality and variability of movement. [26][27][28][29] Although these changes have been contextualised to be protective in nature 30 31 and occur early following the onset of pain, 32-34 they appear to be sustained beyond the acute phase 13 35 36 and have the potential to contribute to chronicity and repeated painful episodes. ...
Article
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Introduction The course of spinal pain (neck or low back pain) is often described as episodic and intermittent, with more than one-third of people continuing to experience episodic symptoms 1 year after first onset. Although ongoing neuromuscular adaptations could contribute to recurrent episodes of pain, no systematic review has synthesised evidence of ongoing neuromuscular changes in people with recurrent spinal pain during a period of symptom remission. Methods and analysis This protocol is developed and reported following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses-P, the Update of the Cochrane Back and Neck Group guidelines and the Methodological Expectations of Cochrane Intervention Reviews. PubMed, Web of Science, MEDLINE, EMBASE, CINAHL, ZETOC, Google Scholar, grey literature sources and key journals will be searched up to September 2019. Observational studies investigating neuromuscular changes in people with recurrent spinal pain during a period of remission will be included. Neuromuscular function will be considered under five outcome domains of muscle activity, spine kinematics, muscle properties, sensorimotor control and neuromuscular performance. Two independent reviewers will search, screen studies, extract data and assess risk of bias (Newcastle-Ottawa Scale). Data will be synthesised per outcome domain. Where clinical and methodological homogeneity across studies exists, a random-effects meta-analysis will be conducted. Otherwise, results will be synthesised narratively. The overall quality of evidence will be assessed using the Grading of Recommendations, Assessment, Development and Evaluation guidelines. Ethics and dissemination Findings of this review may aid the identification of factors that could contribute to spinal pain recurrence and aid the development of interventions for secondary prevention aimed at the restoration of optimal neuromuscular function. The results will be submitted for publication in a peer-reviewed journal and presented at conferences. No ethical approval was required. PROSPERO registration number CRD42019141527.
... Indicators of this dysfunction include decreased contraction of the transversus abdominis and multifidus muscles 1) coincident with reduced thickness of the transversus at rest and during contraction 2) , reduced cross-sectional area of the multifidus 3) and fat infiltration 4) . An association with altered muscle recruitment patterns 5) and transversus abdominis activation delay 6) was also found, as well as increased back muscle fatigue 7) and altered kinematic patterns in the hips and lumbar area 8) . ...
Article
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[Purpose] To determine if pressure biofeedback unit readings are related to abdominal muscle activation and centre of pressure displacement as well as to test the effects of using it as a biofeedback tool to control lumbopelvic motion. [Participants and Methods] Eighteen volunteers with chronic nonspecific low back pain (21.28 ± 1.41 years old) who performed an active straight leg raising (dynamic postural challenge) with and without pressure biofeedback. Changes in the pressure biofeedback unit and on centre of pressure displacement were assessed, as well as bilateral electromyographic abdominal muscle activity. Participants were not allowed to use a Valsalva manoeuvre. [Results] Pressure variation was not significantly correlated with abdominal muscle activity or with mediolateral centre of pressure displacement. When used as a biofeedback instrument, there was a significant increase in almost all abdominal muscles activity as well as a significant decrease in pressure variation and in mediolateral centre of pressure displacement while performing an active straight leg raising with a normal breathing pattern. [Conclusion] Despite not being an indicator of abdominal muscle activity or mediolateral load transfer in the supine position, the pressure biofeedback unit could have great relevance when used in the clinic for biofeedback purposes in individuals with low back pain.
... However, consequences of chronically modified muscle activity has unfavorable effects, typically resulting in increased loading of spinal structures. Several sensory-motor changes have been reported in patients with LBP: (i) decreased strength and endurance of trunk and/or hip muscles [8], (ii) increased level of co-contraction [9], (iii) changes in trunk muscle recruitment pattern [10], (iv) delays in APAs [11] and (v) in PRRs [12], (vi) impaired kinesthetic sense of the trunk [13] etc. Whether those changes are a cause or a consequence of LBP is not fully understood. Many clinicians and researches believe that micro damages of viscoelastic spinal tissues (ligaments, capsules and fascia) are a source of non-specific LBP. ...
Conference Paper
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Low back pain is a common symptom among office workers. Several mechanisms, through which prolonged sitting can contribute to the development of back pain, have been identified. The aim of this study was to test acute effects of an eight-hour office work on sensory-motor functions underlying spine stability. 17 healthy office workers participated in the study. Kinesthetic sense of the trunk, anticipatory postural adaptations and postural reflex reactions were tested before and after an eight-hour office work in real life environment. There was a tendency toward impaired kinesthetic sense (p = .079) and changes in postural trunk functions (p < .05) after an eight-hour office work. The detected (tendency of) changes in postural trunk functions suggest impairment in elements responsible for stability of the spine. Office workers should be informed about postural recommendations during sitting, benefits of active breaks and should avoid demanding exertions immediately after prolonged periods of sitting.
... However, most of the studies evaluating core muscle activity during different exercises have been conducted with healthy people and thus exercise selection in rehabilitative programs has been usually based in these data [12]. This limits proper design of therapeutic programs, because patients with NSCLBP have shown altered core activity patterns compared to healthy peers [13,14]. ...
Article
Full-text available
Most of the studies evaluating core muscle activity during exercises have been conducted with healthy participants. The objective of this study was to compare core muscle activity and tolerability of a variety of dynamic and isometric exercises in patients with non-specific low back pain (NSLBP). 13 outpatients (average age 52 years; all with standing or walking work in their current or latest job) performed 3 consecutive repetitions at 15-repetition maximum during different exercises in random order. Surface electromyography was recorded for the rectus abdominis; external oblique and lumbar erector spinae. Patients rated tolerability of each exercise on a 5-point scale. The front plank with brace; front plank and modified curl-up can be considered the most effective exercises in activating the rectus abdominis; with a median normalized EMG (nEMG) value of 48% (34–61%), 46% (26–61%) and 50% (28–65%), respectively. The front plank with brace can be considered the most effective exercise in activating the external oblique; with a nEMG of 77% (60–97%). The squat and bird-dog exercises are especially effective in activing the lumbar erector spinae; with nEMG of 40% (24–87%) and 29% (27–46%), respectively. All the exercises were well tolerated; except for the lateral plank that was mostly non-tolerated. In conclusion; the present study provides a variety of dynamic and isometric exercises; where muscle activity values and tolerability can be used as guide to design evidence-based exercise programs for outpatients with NSCLBP.
... Specifically, decreased performance, indicated as increased center-of-pressure (COP) displacements, is observed among individuals with LBP [10,11,13]. van Dieën [13] noted that individuals with a current episode of LBP exhibit lower COP frequencies, consistent with previous work that suggested individuals with LBP adopt a rigid, or "guarding", postural control strategy [14]. Individuals with LBP also demonstrate preferential recruitment of global movers (i.e., longissimus) vs. spinal stabilizers (i.e., iliocostalis) and larger trunk movements during an unstable sitting task. ...
Article
Background: Persons with unilateral lower-limb loss are at increased risk for developing chronic low back pain. Aberrant trunk and pelvis motor behavior secondary to lower-limb loss potentially alters trunk postural control and increases demands on the trunk musculature for stability. However, it is unclear whether trunk postural control is associated with the presence or chronicity of low back pain within this population. Research question: Is there a potential role of impaired trunk postural control among persons with lower limb loss and chronic low back pain? Methods: Two groups of males with unilateral lower-limb loss (n = 18 with chronic low back pain; n = 13 without pain) performed an unstable sitting task. Trunk postural control was characterized using traditional and non-linear measures derived from center-of-pressure time series, as well as trunk kinematics and the ratio of lumbar to thoracic erector spinae muscle activations. Results: Traditional and non-linear center-of-pressure measures and trunk muscle activation ratios were similar between groups, while participants with chronic low back pain demonstrated greater trunk motion and reduced local dynamic stability. Significance: Our results suggest that persons with both lower-limb loss and chronic low back pain exhibit impaired trunk postural control compared to those with limb loss but without pain. Aberrant trunk motor behavior may be a response to altered functional requirements of walking with a prosthesis. An inability to adequately control the trunk could lead to spinal instability and pain in the presence of repetitive exposure to aberrant motor behavior of these proximal structures during everyday activities.
Article
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Purpose To establish intra- and inter-session reliability of high-density surface electromyography (HDEMG)-derived parameters from the thoracic erector spinae (ES) during static and dynamic goal-directed voluntary movements of the trunk, and during functional reaching tasks. Methods Twenty participants performed: 1) static trunk extension, 2) dynamic trunk forward and lateral flexion, and 3) multidirectional functional reaching tasks on two occasions separated by 7.5 ± 1.2 days. Muscle activity was recorded bilaterally from the thoracic ES. Root mean square (RMS), coordinates of the barycentre, mean frequency (MNF), and entropy were derived from the HDEMG signals. Reliability was determined with intraclass correlation coefficient (ICC), coefficient of variation, and standard error of measurement. Results Good-to-excellent intra-session reliability was found for all parameters and tasks (ICC: .79-.99), whereas inter-session reliability varied across tasks. Static tasks demonstrated higher reliability in most parameters compared to functional and dynamic tasks. Absolute RMS and MNF showed the highest overall reliability across tasks (ICC: .66-.98), while reliability of the barycentre was influenced by the direction of the movements. Conclusion RMS and MNF derived from HDEMG show consistent inter-session reliability in goal-directed voluntary movements of the trunk and reaching tasks, whereas the measures of the barycentre and entropy demonstrate task-dependent reliability.
Article
Persons with lower limb amputation (LLA) are at high risk for developing chronic low back pain (LBP), often with biomechanical factors considered as likely contributors. Here, trunk and pelvis kinematics, muscle forces, and resultant spinal loads were characterized in persons with LLA, with and without chronic LBP. Thirty-five persons with unilateral LLA – 19 with chronic LBP (“LLA-cLBP”), 16 without LBP (“LLA-nLBP”) – and 15 (uninjured) persons without LBP (“CTR-nLBP”) walked overground (1.3 m/s) while thorax and pelvis kinematics were tracked (and ranges of motion [ROM] computed), and used as inputs for a non-linear finite element model of the spine to estimate global and local muscle forces, and resultant spinal loads. In the frontal and transverse planes, thorax ROM were up to 66.6% smaller in LLA-nLBP versus LLA-cLBP (P < 0.001) and CTR-nLBP (P < 0.001). In the sagittal plane, pelvis ROM was 50.4% smaller in LLA-nLBP versus LLA-cLBP (P = 0.014). LLA-cLBP exhibited 45.5% and 34.2% greater peak local and global muscle forces, respectively, versus CTR-nLBP (P < 0.011). Up to 48.1% greater spinal loads were observed in LLA-cLBP versus CTR-nLBP (P < 0.013); peak compression and local muscle forces were respectively 20.2% and 41.0% larger in LLA-nLBP versus CTR-nLBP (P < 0.005). Despite differences in trunk and pelvis kinematics between LLA-cLBP and LLA-nLBP, trunk muscle forces and spinal loads were similar (P > 0.101) between these groups. Similar loading parameters regardless of LBP presence, while highly dependent on trunk muscle activation strategies, may mitigate further accumulation of mechanical fatigue. It remains important to understand the temporality of loading with respect to LBP onset following LLA.
Article
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.
Article
Introduction: Low back pain is one of the most common disorders in modern society. Disturbed properioception can be a possible cause of low back pain and can cause recurrence of low back pain. Previous studies have shown that low back pain reduces proprioception due to instability in the low back. Since the degenerative process of disc herniation is one of the important factors in exacerbating the known low back pain process, it is not clear whether the degeneration of the lumbar disc exacerbates the deficits of proprioception or the proprioception reduction is resulted from the low back pain itself. The aim of this study was to dertimine whether disk degeneration is the cause of proprioception reduction or not? Materials and Methods: This observation study was performed on 70 patients with low back pain (35 people with chronic non-specific low back pain and 35 people with discopathic low back pain). Remarkably, the repositioning error of the forward bending angles at 30% and 60% of the total lumbar flexion angle and the neutral angle was measured by a digital electrogoniometer. Results: Based on the measurements of absolute error in 30% of the total range of motion (1.97±2.02 in patients with chronic nonspecific low back pain versus 1.92±1.04 in discopathic individuals, P=0.892) and 60% of the total range of motion (2.30±1.96 vs. 2.01±1.09, P=0.450) and neutral angle (1.74±1.36 vs. 1.44±1.41, P=0.370), there was no significant difference between these two groups. Conclusion: Patients with low back pain may have altered proprioception, but due to the lack of significant differences in proprioception between chronic nonspecific low back pain patients and discopathic patients, other factors appear to be involved in the exacerbation of low back pain disorder.
Article
Various interpretations and parameters have been proposed to assess spinal stability such as antagonist muscle coactivity, trunk stiffness and spinal buckling load; however, the correlation between these parameters remains unknown. We evaluated spinal stability during different tasks while changing the external moment and load height and investigated likely relationships between different EMG- and model-based parameters (e.g., EMG coactivity ratio, trunk stiffness, force coactivity ratio) and stability margins. EMG and kinematics of 40 young healthy subjects were recorded during various quasi-static tasks. Muscle forces, trunk stiffness and stability margins were calculated by a nonlinear subject-specific EMG-assisted-optimization musculoskeletal model of the trunk. The load elevation and external moment increased muscle activities and trunk stiffness while all stability margins (i.e., buckling loads) decreased. The force coactivity ratio was strongly correlated with the hand-load stability margin (i.e., additional weight in hands to initiate instability; R² = 0.54) demonstrating the stabilizing role of abdominal muscles. The total trunk stiffness (Pearson’s r = 0.96) and the sum of EMGs of back muscles (Pearson’s r = 0.65) contributed the most to the T1 stability margin (i.e., additional required load at T1 for instability/buckling). Force coactivity ratio and trunk stiffness can be used as alternative spinal stability metrics.
Article
Introduction Patients with chronic non-specific low back pain (CNSLBP) were found with impaired postural control in previous studies. Since the trunk muscle take important efforts on core stability, the study aimed to examine the relationships of postural control during stance tasks and the contractility of trunk muscle in young adults with CNSLBP and without. Methods Healthy individuals (n=25) and individuals with CNSLBP (n=30) were included. The thickness of the bilateral transversus abdominis (TrA) and lumbar multifidus (MF) was measured during rest and maximal voluntary contraction, and the change percentages (TrA%, MF%) were calculated. Regarding postural control, COP path length and sway area during the stance tasks were measured thrice in each group. Results The bilateral TrA% of the CNSLBP group was less than that of the HC group (p<0.05). The bilateral TrA% of the CNSLBP group was less than that of the HC group (p<0.05). The bilateral MF% showed no significantly different(p>0.05) between the two groups. Compared with healthy controls, CNSLBP patients resulted larger path length and sway area of COP during most of static stance tasks. During the EO task in the CNSLBP group, TrA% was found correlate to COP path length (p<0.05); the right MF% was correlated with COP sway area (p<0.05). No significant correlations appeared in the healthy controls (p>0.05). Conclusions Compared with healthy individuals, impaired postural control during static stance with eyes open in patients with CNSLBP was likely to be related to the poor contraction ability of bilateral transversus abdominis and correlated to the normal contraction ability of right lumbar multifidus.
Article
Background: The function of trunk muscles in chronic nonspecific low back pain (CNLBP) is controversially discussed, and trunk muscle function in sedentary occupation workers is poorly understood. Objective: To investigate whether muscle function differs between sedentary occupation workers with and without CNLBP and to determine the association between functional limitations and muscle function. Methods: This study included 32 sedentary occupation workers (16 workers with CNLBP and 16 age- and sex-matched workers without CNLBP). Group differences in isokinetic trunk flexion-extension strength, muscle cocontraction, endurance time (Biering-Sorensen test) and electromyographic muscle fatigue were assessed. The association of these parameters and Oswestry Disability Index (ODI) score were examined in the CNLBP group. Results: Participants with CNLBP had lower trunk extensor (-20%) and flexor (-18%) strength and less cocontraction (-22%) than participants without CNLBP, but due to large variability in both groups these differences were not statistically significant. Trunk muscle endurance and fatigue were comparable between groups. Variance in endurance time explained 28% of variance in the ODI-score in the CNLBP group (R2= 0.277). Conclusions: In patients with CNLBP, greater functional disability was associated with lower endurance. Further evidence is necessary to elucidate whether specifically training endurance performance may be beneficial for sedentary occupation workers.
Article
Study design: Numerical in-silico human spine stability finite element analysis. Objective: The purpose of this study was to investigate the contribution of major torso tissues toward static spine stability, mainly the thoracolumbar fascia (TLF), abdominal wall with its intra-abdominal pressure (IAP), and spinal muscles inclusive of their intramuscular pressure. Summary of background data: Given the numerous redundancies involved in the spine, current methodologies for assessing static spinal stability are limited to specific tissues and could lead to inconclusive results. A three-dimensional finite element model of the spine, with structured analysis of major torso tissues, allows for objective investigation of static spine stability. Methods: A novel previously fully validated spine model was employed. Major torso tissues, mainly the muscles, TLF, and IAP were individually, and in combinations, activated under a 350N external spine perturbation. The stability contribution exerted by these tissues, or their ability to restore the spine to the unperturbed position, was assessed in different case-scenarios. Results: Individual activations recorded significantly different stability contributions, with the highest being the TLF at 71%. Combined or synergistic activations showed an increase of up to 93% stability contribution when all tissues were simultaneously activated with a corresponding decrease in the tensile load exerted by the tissues themselves. Conclusion: This investigation demonstrated torso tissues exhibiting different roles toward static spine stability. The TLF appeared able to dissipate and absorb excessive loads, the muscles acted as antagonistic to external perturbations, and the IAP played a role limiting movement. Furthermore, the different combinations explored suggested an optimized engagement and coordination between different tissues to achieve a specific task, while minimizing individual work.Level of Evidence: N/A.
Article
Background: New motor adaptation to pain theory suggests that patients with low back pain (LBP) use the lumbopelvic stiffening strategy by redistribution of within and between muscle activities to protect painful structure. This could result in an altered postural control of the lumbopelvic region during active prone hip rotation (PHR). Objective: To investigate coordination and timing of lumbopelvic and hip movements, and smoothness of the lumbopelvic control during PHR between participants with and without LBP. Methods: Eight participants with LBP and eight participants without LBP were recruited. The electromagnetic tracking system was used to record kinematic data during PHR. Cross-correlation between hip rotation and lumbopelvic movement in the transverse plane was calculated. Correlation at zero time-lag, time-lag, correlation at time-lag, and maximal lumbopelvic motion were derived. Frequency of movement disruption was identified. An independent t-test was used in conjunction with the effect size and 95% minimal detectable difference (MDD95) to determine the difference in kinematic parameters. Results: Participants with LBP demonstrated a significant delay (exceeding MDD95) in lumbopelvic motion while nonsignificant frequency of disrupted motion on the painful side PHR demonstrated a trend with a large effect size that exceeded MDD95. There were trends with moderate to large effect sizes and differences exceeding MDD95 in delay of lumbopelvic motion with greater movement disruption on the nonpainful side in participants with LBP. Conclusion: Participants with LBP used a lumbopelvic stiffening strategy for postural control to protect painful structures; however, the stiffening might complicate efforts to smoothly control lumbopelvic movement.
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The prevalence of spondylolysis amongst adolescent athletes presenting with low back pain has been reported as high as 47-55%. Youth athletes participating in sports involving movements combining compression, extension and rotation appear most susceptible. As such, young golfers are a high-risk group, particularly given the high shear and compressive forces associated with the golf swing action. This is compounded by a culture which encourages very high practice volumes, typically poorly monitored. Although non-operative interventions are deemed the gold-standard management for this condition, surgery is indicated for more severe presentations and cases of 'failed' conservative management. The case presented herein outlines an inter-disciplinary, non-operative management of a 17-year old elite golfer with a moderate to severe presentation. A 4-stage model of reconditioning is outlined, which may be of use to practitioners given the paucity of rehabilitation guidelines for this condition. The report highlights the benefits of a graded program of exercise-based rehabilitation over the typically prescribed "12 weeks rest" prior to a return to the provocative activity. It also supports existing evidence that passive therapeutic approaches should only be used as an adjunct to exercise, if at all in the management of spondylolysis. Finally, and crucially, it also underlines that to deem non-surgical rehabilitation 'unsuccessful' or 'failed', clinicians should ensure that (long-term) exercise was included in the conservative approach. Level of evidence: 4-Case Report.
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Mechanical low back pain is the main common reason for referral to physiotherapy clinic, and a chief reason for people complains, and both men and women are equally reported to be affected by this condition. It is found that core stabilization exercises have got significant improvement when compared to conventional back care exercises in improving the function and in relieving pain. To see the effectiveness of core muscles activation over conventional exercises along with Interferential Therapy (IFT) in each group for the reduction of pain and to increase the range of motion and improve the disability in subjects with mechanical low back pain. This is an experimental study where pre and post design were used with 40 subjects with mechanical low back pain were taken considering the selection criteria and divided into two groups. 20 subjects in Group-A received Core muscles activation exercises and IFT with pre and post test analysis and 20 subjects in Group-B received Conventional exercises and IFT with pre and post test analysis. Visual Analogue Scale (VAS) for pain intensity, Revised Oswestry Disability Index (R-ODI) for the disability improvement and Goniometry for range of motion. Statistical analysis was done by using paired ‘t’ tests which showed significant improvement in reducing pain, improving the quality of life and increasing the ROM in Group-A as compared to Group-B but as p > 0.05 so it was non significant. It is concluded that subjects in Group-A who received Core muscles activation exercises are more effective as compared to Group-B who received Conventional exercises and it is found that IFT with core activation exercises is very effective in reducing pain, increasing the ROM and improving the disability.
Article
Introduction Decrease in cross-sectional thickness of lumbar multifidus (MF) muscles during prolonged low back pain episodes commonly occurs. Restoration of the MF muscle size can be an effective way of treating chronic low back pain (CLBP) patients. Traditionally, clinicians apply muscle stabilization exercises for these patients. Recent studies support the need for active strengthening exercises for treatment of the CLBP patients. Objective The MF muscles provide lumbar stability, and therefore we hypothesized that strengthening of these muscles can be more effective than the MF muscle stabilization exercises in restoration of the muscle size. Design Study design was a randomized allocation control trial with two groups of adult female CLBP patients (n = 12 each; age range of 20-45). Patients in the control group underwent stabilization exercises and the patients in the intervention group underwent the hip abductor strengthening exercises. Setting For all subjects of each group, the trials continued in 24 sessions distributed over 8 weeks and the MF muscles were measured in the beginning of the first session and one week after completion of the last session. Main Outcome Measures Statistical significance (p-value) of the change in the average MF muscle thickness, pain, and disability scores along with for each group were estimated. Results Both regimens of exercises can significantly decrease the pain and disability: average pain and disability reductions of 46% (p-value of 0.001) and 33% (p-value of 0.02) via stabilization versus average pain and disability reductions of 65% (p-value of 0.001) and 59% (p-value of 0.001) via hip abductor strengthening. However, the hip abductor strengthening is the sole statistically significant exercise regimen (p-value of 0.014 vs 0.94) for increasing the MF muscle size. Conclusion Replacement of the traditional stabilization exercises with the hip abductor strengthening exercises for effective treatment of female adults with CLBP is recommended.
Article
Zusammenfassung Ziel Ziel dieser Literaturübersicht ist es das fasziale Netzwerk im Zusammenhang mit der Entstehung von Rückenschmerzen zu betrachten, mögliche Einflussfaktoren zu analysieren und diagnostische Möglichkeiten aufzuzeigen, mit denen Veränderungen in faszialen Strukturen bei Rückenschmerzpatienten verdeutlicht werden können. Methode Es wurde eine Literaturrecherche mit den Schlagworten Faszien, Sensomotorik, unspezifischer Rückenschmerz, creep, Schmerz und Diagnostik durchgeführt. Von etwa 400 Artikeln wurden die Abstracts gesichtet, etwa 150 wurden gelesen und ausgewertet. Am Ende flossen 86 Artikel in die Erstellung dieses narrativen Reviews ein. Ergebnis Faszien können sich aufgrund der enthaltenen Fasern gut an eine Zugbelastung anpassen. Ab einer Dehnung der Fasern zwischen 3–8% kommt es zu ersten irreversiblen Gewebeveränderungen, die einen Beitrag zu unspezifischen Rückenschmerzen leisten können (creep-Effekt). Durch Mikroverletzungen können die in den Faszien enthaltenen Fibroblasten aktiviert werden und die Steifigkeit der Faszien erhöhen, was den möglichen Bewegungsradius einschränken kann und die Faszienvorspannung erhöht. Somit sinkt die Toleranz auf eine angelegte Zugspannung. Durch die Ultraschallelastografie ist die reduzierte Beweglichkeit in den Faserschichten der Faszien zu erkennen. Außerdem spielen Faszien durch ihre starke Innervation bei der Propriozeption, Exterozeption, Interozeption und Nozizeption eine maßgebliche Rolle. Schlussfolgerung Ob das fasziale Netzwerk mit der Entstehung von unspezifischen Rückenschmerzen in Verbindung steht, kann aufgrund der derzeit immer noch lückenhaften Erkenntnisse über die funktionellen Zusammenhänge noch nicht geklärt werden. Außerdem stehen noch keine diagnostischen Mittel zur Verfügung, die die Funktionalität der Faszien sicher bewerten können. Dennoch sollten die Faszien als sensomotorisches Netzwerk verstanden werden, das in seiner Komplexität mit allen Strukturen des menschlichen Körpers wechselwirkt und somit einen Einfluss auf Rückenschmerzen haben kann.
Article
Elastische Bandagen sind umstritten. Während Befürworter davon ausgehen, dass sie die natürliche Selbstheilung bei unspezifischen Rückenbeschwerden beschleunigen, wenden Gegner ein, dass die passive Unterstützung womöglich einen dekonditionierenden Effekt auf die Rumpfmuskeln haben könnte.
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Movement adaptations to low back pain (LBP) are believed to protect the painful area. Increased trunk stiffness and decreased trunk damping have been shown in people with recurrent LBP. However, no study has examined these properties using external force perturbations to the trunk during acute LBP when protective adaptations might be expected to have most relevance. Adaptations to an acute painful stimulus via unilateral injection of hypertonic saline into the right longissimus muscle were assessed using a trunk force perturbation paradigm and a mass-spring-damper model to describe effective trunk dynamical properties. Equal weights (15% body weight) were connected to the front and back of the trunk via a cable. Either one was dropped at random to perturb the trunk. Effective trunk dynamical properties were estimated in fourteen males (mean (standard deviation) age 25 (6) years) assuming that trunk movement can be modelled as a second order linear system. Effective trunk dynamical properties were compared before, during and after the experimentally induced painful period. Estimates of effective trunk stiffness (K) decreased and damping (B) increased during pain compared to both before ([mean contrast, 95% CI] K: −403 [−651 to −155] Nm⁻¹, B: 28 [9–50] Nms⁻¹) and after (K: −324 [−58 to −591] Nm⁻¹, B: 20 [4–33] Nms⁻¹) the experimentally induced painful period. We interpret our results to show that, when challenged by a step force perturbation, a healthy system adapts to noxious input by controlling trunk velocity rather than trunk displacement, in contrast to observations during remission from recurrent clinical LBP.
Article
Introduction Exercise with the Functional Re-adaptive Exercise Device (FRED) has previously been shown to activate the lumbar multifidus (LM) and transversus abdominis (TrA) muscles in non-symptomatic volunteers. This study aimed to determine the effects of a six-week FRED exercise intervention on pain intensity, patient-reported function and LM cross sectional area (CSA) in people with chronic non-specific low back pain (LBP). Methods Thirteen participants undertook six weeks of FRED exercise for up to 15 min, three times per week. At six weeks pre-, immediately pre-, immediately post-, and six and 15 weeks post-intervention, participants completed the Numeric Pain Rating Scale, Patient-Specific Functional Scale, and ultrasound imaging was used to assess the size of the LM muscles at L5 level. Changes in outcomes were assessed using effect size, confidence intervals and minimum clinically important difference (MCID). Results There was no improvement in pain intensity following the intervention. Patient-reported function improved by at least twice the MCID for all follow-up assessments compared to immediately pre-intervention (d = 4.20–6.58). Lumbar multifidus CSA showed a large effect size increase from immediately pre-intervention to immediately post-intervention (d = 0.8–1.1); this was maintained at six weeks post-intervention (not measured at 15 weeks post-intervention). Conclusion Six weeks of FRED exercise improved physical function in all 13 participants with chronic non-specific LBP who took part in this study and most participants' lumbar multifidus muscle CSA. On this basis, it may be an effective intervention for people with chronic LBP and should now be tested in a randomised controlled trial.
Article
Faster trunk motions could be a strategy to prevent loss of balance and fall injuries due to unexpected perturbations. However, it is unclear how trunk sway velocities can be compensated during stepping in subjects with low back pain (LBP). The purpose of this study was to investigate lower limb reaction, swing, and step times, as well as trunk sway velocities at heel strike and toe-off, following repeated step perturbations between subjects with and without LBP. There were 30 subjects with LBP and 42 control subjects who were exposed to treadmill-induced perturbations at a velocity of 0.12 m/sec for 0.62 m. The treadmill-induced steps caused subjects to walk forward for 4.90 sec after the perturbation. The groups demonstrated significant interactions on the lower limb reaction times and on the number of repeated perturbations (F = 4.83, p = 0.03) due to a decreased step time at the first perturbation (t = 2.52, p = 0.01) in the LBP group. For the trunk sway velocities, the repeated perturbations demonstrated a significant interaction between groups (F = 4.65, p = 0.03). This adaptive trunk strategy for gait stability increased step times with repeated perturbations in the LBP group. The group interactions on the trunk sway velocities also indicated a possible somatosensory integration for step time adjustments to avoid potential fall hazards. This adaptive response with repeated step perturbations could result in compensatory trunk sway for gait stability.
Article
Objectives: The effects of different physiotherapy protocols on patients suffering from grade-I spondylolisthesis have been thus far examined in a limited number of clinical trials. Therefore, the main purpose of this study was to compare the effects of lumbar segmental stabilization and general exercises on clinical and radiologic criteria in grade-I spondylolisthesis patients. Methods: This study was a double-blind randomized controlled trial (RCT) with a test-retest design and parallel groups. A total of 26 patients with grade-I spondylolisthesis were thus randomly assigned to experimental group (13 patients, lumbar segmental stabilization exercises) and control group (13 patients, general exercises). Subsequently, pain, functional disability, kinesiophobia, translational motion, angular motion and slip percentage of the vertebra were investigated. Results: Of the 120 people recruited in this study, only 26 patients were eligible. According to pre/post-intervention comparison, a statistically significant decrease was observed in the experimental group in terms of pain (p = 0.000), functional disability (p = 0.004), kinesiophobia (p = 0.002), translational motion (p = 0.043) and angular motion (p = 0.011), but not for slip percentage (p = 0.122). Considering the control group, a statistically significant decline was reported for pain (p = 0.043) and functional disability (p = 0.002). However, no significant differences were found for other variables in the control group. With regard to inter-group comparison, there was no statistically significant difference between the two groups regarding the given variables except for kinesiophobia (p = 0.040). Conclusion: Both lumbar segmental stabilization and general exercises led to reduction in pain and functional disability of patients with grade-I spondylolisthesis. Therefore, lumbar segmental stabilization exercises seemed to be better than general ones with reference to improving kinesiophobia and intervertebral movements.
Article
Low back pain is one of most common musculoskeletal disorders around the world. One major problem clinicians face is the lack of objective assessment modalities. Computed tomography and magnetic resonance imaging are commonly utilized but are unable to clearly distinguish patients with low back pain from healthy patients with respect to abnormalities. The reason may be the anisotropic nature of muscles, which is altered in function, and the scans provide only structural assessment. In view of this, ultrasound may be helpful in understanding the disease as it is performed in real-time and comprises different modes that measure thickness, blood flow and stiffness. By the use of ultrasound, patients with low back pain have been found to differ from healthy patients with respect to the thickness and stiffness of the transversus abdominis, thoracolumbar fascia and multifidus. The study results are currently still not conclusive, and further study is necessary to validate. Future work should focus on quantitative assessment of these tissues to provide textural, structural, hemodynamic and mechanical studies of low back pain. This review highlights the current understanding of how medical ultrasound has been used for diagnosis and study of low back pain and discusses potential new applications.
Article
LEVEL OF EVIDENCE: 3 SUMMARY Purpose. The aim of this study was to compare the effects of stabilization and general exercises on pain, disability and postural stability variables in patients with spondylolisthesis. Methods. 24 patients randomly assigned into the stabilization (n=12) and general exercise (n=12) groups. Both groups performed the exercises 2 times a week for a period of 2 months. Visual analogue scale (VAS) and Quebec back pain disability questionnaire were used to assess the pain and functional disability, respectively. Postural stability has been evaluated using a force platform with eyes opened and closed while standing on firm and foam base of support. The parameters were the mean total velocity (M-V) and the SD of velocity in sagittal (SD-Vy) and frontal (SD-Vx) plan. Results. There was a significant decrease in VAS and Quebec in both stabilization and general exercise groups (P= 0.001, P< 0.001 for VAS and P= 0.001, P= 0.001 for Quebec respectively). From postural stability parameters only SD-Vx has increases significantly in general exercise group (P= 0.008). More increase was observed in M-V variable in the stabilization group (P <0.001). Conclusions. Pain and disability were improved in both stabilization and general exercise groups but postural stability variables was not changed in different directions in stabilization group.
Article
Objective: The purpose of this review was to identify different kinematic characteristics between the movements of sit-to-stand-to-sit, sit-to-stand, or stand-to-sit of individuals with and without low back pain (LBP). Methods: A systematic search was conducted on scientific databases. The analyzed kinematic variables were duration of the movement, reproduction of the movement, ranges of motion, velocity, and acceleration. The studies were appraised for methodological quality using the Downs & Black scale and for the level of evidence using the Grading of Recommendations Assessment, Development, and Evaluation approach. Results: After all screening stages, this systematic review comprised 8 cross-sectional studies. When comparing the patients with LBP vs controls, patients with LBP take longer to perform the sit-to-stand-to-sit, sit-to-stand, and stand-to sit movements (eg, 9.33 ± 1.49 seconds vs 8.29 ± 1.23 seconds in the sit-to-stand-to-sit movement), show decreased mobility of the lumbar spine (eg, 26.21° ± 8.76° vs 32.07° ± 6.77° in the sit-to-stand-to-sit movement) and the hip (eg, 51.0° vs 77.25° in the sit-to-stand movement), present decreased velocity of the trunk (eg, 95.31° ± 25.13°/s vs 138.23° ± 23.42°/s in the sit-to-stand-to-sit movement) and the hip (eg, 46° ± 13°/s vs 69° ± 13°/s in the sit-to-stand movement), and decreased overall acceleration of the trunk (eg, 280.19° ± 113.08°/s2 vs 460.16° ± 101.49°/s2 in the sit-to-stand-to-sit movement), besides presenting greater variability of the trunk (eg, 5.53° ± 0.48° vs 4.32° ± 0.46° in the sit-to-stand movement). Conclusion: There are kinematic alterations in the lumbar spine, the hip, and the trunk of patients with LBP. However, information about pelvic and overall trunk mobility, velocity, and acceleration of the lumbar spine; and mobility, speed, and acceleration of hip and pelvis remain incipient in individuals with LBP. Based on the Grading of Recommendations Assessment, Development, and Evaluation criteria, the results of this review indicate that there is low scientific evidence on the characteristics of the kinematic variables (duration of the movement, reproduction of the movement, range of motion, velocity, and acceleration) of the trunk, lumbar spine, pelvis, and hip in patients with LBP.
Article
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The neutral zone is a region of intervertebral motion around the neutral posture where little resistance is offered by the passive spinal column. Several studies--in vitro cadaveric, in vivo animal, and mathematical simulations--have shown that the neutral zone is a parameter that correlates well with other parameters indicative of instability of the spinal system. It has been found to increase with injury, and possibly with degeneration, to decrease with muscle force increase across the spanned level, and also to decrease with instrumented spinal fixation. In most of these studies, the change in the neutral zone was found to be more sensitive than the change in the corresponding range of motion. The neutral zone appears to be a clinically important measure of spinal stability function. It may increase with injury to the spinal column or with weakness of the muscles, which in turn may result in spinal instability or a low-back problem. It may decrease, and may be brought within the physiological limits, by osteophyte formation, surgical fixation/fusion, and muscle strengthening. The spinal stabilizing system adjusts so that the neutral zone remains within certain physiological thresholds to avoid clinical instability.
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Presented here is the conceptual basis for the assertion that the spinal stabilizing system consists of three subsystems. The vertebrae, discs, and ligaments constitute the passive subsystem. All muscles and tendons surrounding the spinal column that can apply forces to the spinal column constitute the active subsystem. The nerves and central nervous system comprise the neural subsystem, which determines the requirements for spinal stability by monitoring the various transducer signals, and directs the active subsystem to provide the needed stability. A dysfunction of a component of any one of the subsystems may lead to one or more of the following three possibilities: (a) an immediate response from other subsystems to successfully compensate, (b) a long-term adaptation response of one or more subsystems, and (c) an injury to one or more components of any subsystem. It is conceptualized that the first response results in normal function, the second results in normal function but with an altered spinal stabilizing system, and the third leads to overall system dysfunction, producing, for example, low back pain. In situations where additional loads or complex postures are anticipated, the neural control unit may alter the muscle recruitment strategy, with the temporary goal of enhancing the spine stability beyond the normal requirements.
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Articles describing motor function in five chronic musculoskeletal pain conditions (temporomandibular disorders, muscle tension headache, fibromyalgia, chronic lower back pain, and postexercise muscle soreness) were reviewed. It was concluded that the data do not support the commonly held view that the pain of these conditions is maintained by some form of tonic muscular hyperactivity. Instead, it seems clear that in these conditions the activity of agonist muscles is often reduced by pain, even when this does not arise from the muscle itself. On the other hand, pain causes small increases in the level of activity of the antagonist. As a consequence of these changes, force production and the range and velocity of movement of the affected body part are often reduced. To explain how such changes in the behaviour come about, we propose a neurophysiological model based on the phasic modulation of excitatory and inhibitory interneurons supplied by high-threshold sensory afferents. We suggest that the "dysfunction" that is characteristic of several types of chronic musculoskeletal pain is a normal protective adaptation and is not a cause of pain.
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Although often suggested as a control measure to alleviate musculoskeletal stresses, the use of mechanical assistance devices (i.e. manipulators) in load transfers has not been extensively studied. Without data describing the biomechanical effects of such devices, justification for decisions regarding implementation of such tools is difficult. An experimental study of two types of mechanical manipulators (articulated arm and overhead hoist) was conducted to determine whether biomechanical stresses, and hence injury risk, would be alleviated. Short distance transfers of loads with moderate mass were performed both manually and with manipulator assistance under a variety of task conditions. Using analysis and output from new dynamic torso models, strength demands at the shoulders and low back, lumbar spine forces, and lumbar muscle antagonism were determined. Strength requirements decreased significantly at both the shoulders and low back when using either manipulator in comparison with similar transfers performed manually. Peak spine compression and anterior-posterior (a-p) shear forces were reduced by about 40% on average, and these reductions were shown to be primarily caused by decreases in hand forces and resultant spinal moments. Two metrics of muscular antagonism were defined, and analysis showed that torso muscle antagonism was largest overall when using the hoist. The results overall suggest that hoist-assisted transfers, although better in reducing spine compression forces, may impose relatively higher demands on coordination and/or stability at extreme heights or with torso twisting motions. The relatively higher strength requirements and spine compression associated with the articulated arm may be a result of the high inertia of the system. Potential benefits of practice and training are discussed, and conclusions regarding implementation of mechanical manipulators are given.
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The intersegmental and multisegmental musculature of the lumbar spine was studied in a biomechanical model to compare their lateral stabilizing potential. By approximating the active and passive behavior of the stretch reflex as a variable stiffness spring whose stiffness was proportional to activation, the critical muscle stiffness required for mechanical stability was calculated. The model demonstrated that the intersegmental muscles were the least efficient at laterally stabilizing the spine. At any given load, multisegmental muscles were more efficient, and their efficiency increased with the number of segments spanned. The most efficient muscles were those that originated from the pelvis, spanning the maximum number of segments. The muscular model was unstable, regardless of the muscular stiffness, when any vertebral segment was devoid of muscle. Moreover, when the load on the spine is increased, buckling can be prevented most efficiently with the pelvic muscles and least efficiently with the intersegmental muscles.
Estimates of peak spinal compression in manual materials handling were compared between a state-of-the-art laboratory technique and a method applicable at the worksite. Nine experienced masons performed seven simulated tasks in a mock-up in the laboratory and nine matched masons were studied during actual performance of the same tasks at the worksite. From kinematic and kinetic data obtained in the laboratory, compression forces on the L5S1 joint were calculated. In addition, compression forces were estimated from the horizontal and vertical position of the blocks handled relative to the subject measured at the worksite. Comparison of group-averaged values showed that the worksite method underestimated peak compression by about 20%. Rank ordering of tasks for back load was, however, consistent between methods, supporting validity of the worksite method to compare different tasks or to determine the effects of ergonomic interventions with regard to mechanical back load. Statement of Relevance: This study validated a method that can be used by ergonomists to determine the effects of (characteristics of) manual materials handling tasks on back load at the worksite.
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The existence of a pain-spasm-pain cycle in musculoskeletal disorders has been debated for over 40 years. This paper reviews critically the evidence for such a cycle in patients with back pain. Clinical studies indicate that a substantial proportion of patients with back pain have muscle spasm. Patients with acute back pain have increased muscular activity on electromyography (EMG). EMG studies of patients with chronic back pain show, on the whole, an increase in activity in static postures, and a reduction of muscle activity during movement. Experimental evidence shows that pain may cause muscle spasm and that muscular activity can be painful. Further evidence for the existence of a pain-spasm-pain cycle comes from studies which show that analgesics can reduce muscle spasm, and that a variety of muscle relaxant techniques can reduce pain. There are substantial methodological problems in many of the studies cited, but the evidence reviewed provides general support for the existence of a pain-spasm-pain cycle. However further work is required to determine the nature of spasm and to evaluate methods for its detection, particularly in acute back pain syndromes. The value of therapeutic intervention may then be assessed.
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Scaling of postural ankle-muscle responses was compared for transient (forward and backward acceleration pulses) and continuous (pseudorandom acceleration) platform-translation perturbations. The two types of perturbation were designed to be unpredictable, to have similar frequency content, and to represent similar levels of challenge to stability. A repeated measures experimental design was used to test 12 healthy young (20–45 years) males. Each type of perturbation was administered at three acceleration levels, in random order, and the tests were repeated under eyes-open and blindfolded conditions, while controlling for order of testing. Individual ankle-muscle responses were quantified and, in addition, used to estimate a net response measure (proportional to net ankle torque) and measures of antagonist activation and relative co-contraction level. The results failed to show strong evidence of differences between transient and continuous postural control with regard to the influence of vision, as both types of response were largely unaffected by vision deprivation; however, the results did demonstrate some substantial perturbation-dependent differences in the scaling of the responses to perturbations of differing magnitude. The most pronounced differences, seen in tibialis anterior, appeared to be related to a tendency to lean slightly further forward during continuous perturbations. Substantial co-contraction of antagonistic muscles was frequently observed, for both types of perturbation, and antagonist activation tended to increase at larger perturbation magnitudes. The observed differences in the scaling of the transient and continuous responses raise some concerns about the generalizability of posture control models derived from continuous-perturbation tests.
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When a patient presents himself with the common complaint of pain in the shoulder region and arm, with or without limitation of motion and unrelated to severe trauma, the physician usually thinks of the joints, bursae, tendons or nerves rather than of the shoulder girdle muscles as the primary source of pain. Thus the customary diagnosis in this type of patient is either arthritis, subacromial bursitis, brachial neuritis or radiculitis. The well known chronicity of these symptoms and the variety of therapeutic procedures employed suggest either that the customary methods of treatment are unsatisfactory or that the underlying cause is often overlooked. It is our purpose in this report to discuss the diagnosis of a type of pain in the shoulder and arm which has its origin in the muscles of the back or shoulder girdle and to present the results of an effective method of therapy, namely intramuscular infiltration
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Chronic low back pain (CLBP) is a major clinical problem with a substantial socio-economical impact. Today, diagnosis and therapy are insufficient, and knowledge concerning interaction between musculoskeletal pain and motor performance is lacking. Most studies in this field have been performed under static conditions which may not represent CLBP patients' daily-life routines. A standardized way to study the sensory-motor interaction under controlled motor performance is to induce experimental muscle pain by i.m. injection of hypertonic saline. The aim of the present controlled study was to analyze and compare electromyographic (EMG) activity of and coordination between lumbar muscles (8 paraspinal recordings) during gait in 10 patients with CLBP and in 10 volunteers exposed to experimental back muscle pain induced by bolus injection of 5% hypertonic saline. When the results are compared to sex- and age-matched controls, the CLBP patients showed significantly increased EMG activity in the swing phase; a phase where the lumbar muscles are normally silent. These changes correlated significantly to the intensity of the back pain. Similar EMG patterns were found in the experimental study together with a reduced peak EMG activity in the period during double stance where the back muscles are normally active. Generally, these changes were localized ipsilaterally to the site of pain induction. The clinical and experimental findings indicate that musculoskeletal pain modulates motor performance during gait probably via reflex pathways. Initially, these EMG changes may be interpreted as a functional adaptation to muscle pain, but the consequences of chronic altered muscle performance are not known. New possibilities to monitor and investigate altered motor performance may help to develop more rational therapies for CLBP patients.
Article
Surface electromyographic (EMG) activity recordings of bilateral paraspinal muscle tension were measured twice on 20 non-pain controls and on 46 low back pain subjects (21 individuals with intervertebral disk disorders and 25 subjects with unspecified musculoskeletal backache) during 6 positions: standing, bending from the waist, rising, sitting with back unsupported, sitting with back supported, and prone. Back pain subjects were measured during both low pain and high pain states. Results revealed a non-significant trend for all subjects, regardless of diagnosis, to have higher paraspinal muscle tension levels on the second (or high pain) assessment. A significant diagnosis by position interaction was observed which was similar to the interaction in our previous study which employed only a single measurement session. Analysis of simple main effects revealed this to be due to control subjects during the standing position having lower EMG levels than the back pain groups, and intervertebral disk disorder subjects having higher EMG levels than the other groups during the supported sitting position. As in our previous study, diagnosis was found to be a clinically significant factor, in that controls had much fewer clinically abnormal readings than back pain patients. The lack of a significant effect for pain state is congruent with findings in the headache literature. The importance of clearly defined diagnostic categories in low back pain research and the utility of measuring subjects in various positions is discussed, as are possible explanations for lack of significant pain state findings.
Article
Unlabelled: The functioning of low back muscles of back pain patients during flexion and reextension has not been properly investigated. In this study, we analyzed rectified, averaged electric activity (RMS EMG) and corresponding raw intramuscular (IM) EMG from lumbar paraspinal muscles to quantify the activity level during simple bending cycles in 87 back pain patients compared to 25 able-bodied controls. The results: All functional phases seen in raw IM EMG were also shown in surface RMS EMG. Surface RMS EMG pattern seems to yield more information from activity level than IM EMG pattern. The RMS EMG patterns of back pain patients differed from those of controls as follows: (1) There was clearly noticeable activity during standing in back pain patients. (2) There was only a partial decrease of EMG activity after flexion in back pain patients with current pain. (3) The ratio of mean reached at maximal activity level during extension and flexion was less in patients (1.8, SD = 0.5, p less than .001) than able-bodied controls (3.2, SD = 0.8). (4) Segmental differences were observed in IM EMG activities in patients having hypermobility in bending x-ray. (5) Large peak potentials occurred during movements in patients having segmental hypermobility. THE RESULTS indicate that averaged surface recording is a valuable tool in the investigation of dynamic spine functions in back pain patients.
Article
The intersegmental and multisegmental musculature of the lumbar spine was studied in a biomechanical model to compare their lateral stabilizing potential. By approximating the active and passive behavior of the stretch reflex as a variable stiffness spring whose stiffness was proportional to activation, the critical muscle stiffness required for mechanical stability was calculated. The model demonstrated that the intersegmental muscles were the least efficient at laterally stabilizing the spine. At any given load, multisegmental muscles were more efficient, and their efficiency increased with the number of segments spanned. The most efficient muscles were those that originated from the pelvis, spanning the maximum number of segments. The muscular model was unstable, regardless of the muscular stiffness, when any vertebral segment was devoid of muscle. Moreover, when the load on the spine is increased, buckling can be prevented most efficiently with the pelvic muscles and least efficiently with the intersegmental muscles.
Article
The attachments and orientation of every fascicle of the lumbar erector spinae were determined in five cadavers and recorded radiographically. Little variation was found in the sites of muscle attachment, which enabled the construction of maps whereby these sites could be plotted on clinical radiographs or models of the lumbar spine. When all fascicles were plotted on 21 clinical radiographs using the maps previously developed, no significant difference in the orientation of fascicles was found compared with that observed in cadavers. This result vindicates the technique used to plot the location of individual fascicles of the lumbar back muscles.
Article
Surface EMG recordings of bilateral paraspinal muscle tension were measured on 207 subjects (29 non-back pain controls, 20 individuals with spondyloarthritis, 52 with intervertebral disk disorders, 66 with unspecified musculoskeletal backache, 17 with some combination of the above 3 groups and 23 subjects with other types of back pain, including unknown, scoliosis and psychogenic) in 6 positions: standing, bending from the waist, rising, sitting with back unsupported, sitting with back supported and prone. Results of both individual and group analyses revealed a significant main effect of diagnosis. Post hoc analyses (Duncan's) revealed controls to have significantly lower overall EMG levels than the intervertebral disk disorders and unspecified musculoskeletal backache groups. A significant diagnosis by position interaction was observed. Analysis of simple main effects revealed this to be due primarily to control subjects during the standing position having lower EMG levels than all other groups, and intervertebral disk disorder subjects having higher EMG levels than all other groups during the supported sitting position. The importance of clearly defined diagnostic categories in low back pain research and the utility of measuring subjects in various positions are discussed.
Article
The myoelectric activity of selected trunk muscles at the L3 level was studied during the development of a controlled isometric axial torque. Muscle activity was recorded with surface electrodes bilaterally over the erector spinae muscles, the rectus abdominus, the obliques externus, and the obliques internus. Subjects applied graded isometric axial torque efforts with the addition of a Valsalva. The largest myoelectric activities were recorded over the obliques externus and internus. The side of the muscle developing the torque did show the greatest myoelectric activity, but considerable antagonistic activity was also present. Neither the rectus abdominus nor the internal oblique muscles showed any difference from side to side. The calculated forces in the rectus abdominus and the erectores spinae were high, suggesting that a considerable amount of the muscle contraction was used to control the posture. A Valsalva did not decrease myoelectric activity, but did increase the torque developed.
Article
It has been suggested that the muscles of the anterolateral abdominal wall increase the stability of the lumbar region of the vertebral column by tensing the thoracolumbar fascia and by raising intra-abdominal pressure. In this report these new mechanisms are reviewed and their contribution to vertebral stability assessed. The thoracolumbar fascia consists of two principal layers of dense fibrous tissue that attach the abdominal muscles to the vertebral column. Each of these layers was dissected in fresh and fixed material and samples chosen for light and scanning electron microscopy to study the arrangement of the component fibers. Computed axial tomography in volunteers showed the changes in spatial organization that occur during flexion of the back and during the Valsalva maneuver. The fascia was then tensed experimentally in isolated unfixed motion segments. The results suggested that the stabilizing action of the thoracolumbar fascia is less than had been thought previously but was consistent with calculations based on the more accurate structural and mechanical information that had been derived from the current study. Abdominal muscle contraction was simulated in whole cadavers in both the flexed and lateral bending positions to compare the stabilizing effect of the thoracolumbar fascia and intra-abdominal pressure mechanisms. These definitive experiments showed that the resistance to bending in the sagittal plane offered by the abdominal muscles acting through fascial tension was of a similar magnitude to that offered by a raised intra-abdominal pressure, both being relatively small in the fully flexed position. The stabilizing influence of the middle layer of the thoracolumbar fascia in lateral bending was clearly demonstrated and warrants further study in vivo.
Article
A study was undertaken to examine relations among some objective and subjective measures of low-back-related disability in a group of 41 low-back pain patients and in seven pain-free control subjects. Subjective measures of disability were obtained by Oswestry patient questionnaires. Oswestry disability score related significantly (P less than 0.001) to presence or absence of relaxation in back muscles during flexion. Mean trunk strength ratios were inversely related to disability score (P less than .05), and trunk mobility was meaningfully reduced (P less than .01). Despite loss of motion, a large enough excursion was observed to predict presence of back muscle relaxation. These findings imply that myoelectric signal levels, trunk strength ratios, and ranges of trunk motion may be used as objective indicators of low-back pain disability.
Article
Bilateral paraspinal electromyogram (EMG) at levels L1-L2 and L4-L5, and abdominal EMG of a group of 20 low-back pain patients were compared to those of a group of 20 pain-free controls during flexion, extension, lateral bending to right and left, and rotation to right and left. The results showed no significant left-right differences in paraspinal EMG levels between low-back pain patients and pain-free controls during any of the movements. However, patterns of paraspinal and abdominal EMG were found to be different for low-back pain patients compared to pain-free controls during flexion only.
Article
According to myogenic models that relate abnormal EMG patterns to the experience of pain, lumbar paravertebral muscle activity has been considered to play an important role in chronic low back pain. In the present study, 40 chronic low back pain patients and 40 matched non-patient controls were compared on lumbar paravertebral EMG during mechanically stabilized static and dynamic postures. Differences between groups in lumbar curvature and spinal range of motion were determined using a dual goniometer technique. Although the two groups did not differ on absolute levels of EMG during quiet standing, significant differences were found for EMG patterns during dynamic postures. In addition, most patients did not show the flexion-relaxation response or the expected pattern of EMG responses during trunk rotation, most likely because of restricted range of motion and/or compensatory posturing. These findings provide support for the biomechanical model of chronic pain and indicate the need for further research pertaining to pain behavior and movement-related lumbar muscle activity.
Article
This is the second part of an extended review of the etiology and treatment of chronic back pain (CBP). The first paper dealt with somatic factors and interventions, this paper will examine psychological theories on the etiology of CBP and psychological treatments for CBP. Finally common problems of both the somatic and the psychological approaches will be discussed and suggestions for treatment and research will be made.
Article
This is the first part of an extended review of the etiology and treatment of chronic back pain (CBP). This paper will address the pathophysiology of CBP, the somatic conceptualizations that have been developed, and the treatment modalities that have been employed to alleviate the symptoms. The adequacy of the different models and treatments will be critically examined. The second paper in this set will examine psychological models and interventions. Common problems to both somatic and psychological approaches will be discussed at the close of the second paper.
Article
A three-dimensional muscle model with complex geometry is described and tested against experimental data. Using this model, several muscles were constructed. These muscles have equal optimum length but differ in architecture. The force exerted by the constructed muscles, in relation to their actual length and velocity of shortening, is discussed. Generally speaking, the constructed muscles with considerable pennation have great fiber angles, a great physiological cross section, a narrow active and steep passive length-force relation, and a low maximal velocity of shortening. The maximal power (force times velocity) delivered by the constructed muscles is shown to be almost independent of the architecture of the muscles. The steepness of the passive length-force relation is determined mainly by the shortest fibers within the group of constructed muscles, whereas maximal velocity of shortening and the width of the active length-force relation are determined mainly by the longest fibers. The validity of the three-dimensional muscle model with respect to some morphological and functional characteristics is tested. Length-force relations of constructed muscles are compared with the actual length-force relations of mm. gastrocnemii mediales and mm. semimembranosi of male Wistar rats. Moreover, actual fiber angle, fiber length, and muscle thickness of three mm. gastrocnemii mediales are compared with values found for constructed muscles. It is concluded that the three-dimensional muscle model closely approximates the actual muscle form and function.
Article
The purpose of this study was to determine whether the same estimates of individual muscle and L4/L5 lumbar joint compressive forces result from an optimization (OPT) compared to an electromyography (EMG) assisted approach for solving the inderminate moment equilibrium equations in the same anatomical model. Four male subjects performed near maximum, isometric, ramp efforts in trunk flexion, extension and lateral bending in a testing apparatus. The EMG approach was sensitive to subject and trial differences in the magnitudes of individual muscle forces needed to produce the same reaction moment. In contrast, the OPT method converged on a similar estimate of muscle forces for all subjects and trials producing the same moment. The OPT method predicted lower L4/L5 joint compression values, on average, by 32, 43 and 23% in trunk extension, flexion and lateral bending, respectively, because, unlike the EMG method, it could not predict co-contraction of anatomically antagonistic muscles. We incorporated the OPT method's advantage of forcing an equilibrium in the reaction moments into the EMG method in a new approach we have called 'EMG assisted optimization' (EMGAO). Muscle force estimates from the EMG and EMGAO methods differed from those from the OPT method, on average, by 123% (RMS) for flexion and extension and by 218% for lateral bends. Data from the two approaches result in different conclusions about spine mechanics. We have more confidence in the EMG assisted methods because they respond to variation in muscle synergy and co-contraction patterns commonly observed in different trials and subjects for the same reaction moments.
Article
The transmission of load through the lumbar spine was analyzed in a model of the five lumbar vertebrae, the sacrum/pelvis and the thorax, and 66 symmetric pairs of multijoint muscles. The model was used to test the hypotheses that (1) the need to maintain equilibrium simultaneously at all vertebral levels precludes simultaneous maximum activation of synergistic muscles and (2) that the maximum loads which could be carried by the spine and the degree of muscle activation increases with increasing motion segment stiffness. Maximum moments applied to T12 were calculated for moments in three principal directions, subject to equilibrium at all six joints and to constraints on the maximum muscle stress and intervertebral displacements. A model with realistic motion segment stiffness predicted maximum efforts between 1.4 and 3.3 times greater than a model with 'ball-and-socket' joints, and in better agreement with published results from maximum effort experiments. The differences in maximal effort were greater than the moments transmitted through the joints. While muscle activation levels were greater, many synergistic muscles were still submaximally activated. Antagonistic muscles were recruited to maintain multijoint equilibrium. We concluded that (1) muscle activations permitted in single anatomic level analyses are generally not compatible with equilibrium at other levels; (2) the effect of moment transmission in the joints gives a more realistic representation of the lumbar spine.
Article
This work investigated the passive bending properties of the intact human torso about its three principal axes of flexion: extension, lateral bending, and axial rotation. Additionally, the effects of wearing an abdominal belt and holding the breath (full inhalation) on trunk stiffness was investigated. The torsos of 22 males and 15 females were subjected to bending moments while "floating" in a frictionless jig with isolated torso bending measured with a magnetic device. Belts and breath holding appear to stiffen the torso about the lateral bending and axial rotation axes but not in flexion or extension. Torsos are stiffer in lateral bending and capable of storing greater elastic energy. Regression equations were formulated to define stiffness and energy stored for input to biomechanical models that examine low back function and for bioengineers designing hardware for stabilization and bracing or investigation of traumatic events such as automobile collision.