Iliocostalis Research Articles

Different ways to balance the spine in sitting: Muscle activity in specific postures differs between individuals with and without a history of back pain in sitting

BackgroundPrevious research explored muscle activity in four distinct sitting postures with fine-wire electromyography, and found that lumbar multifidus muscle activity increased incrementally between sitting with flat thoracolumbar and lumbar regions, long thoracolumbar lordosis, or short lordosis confined to the lumbar region. This study used similar methods to explore whether people with a history of low back pain provoked by prolonged sitting used different patterns of trunk muscle activity in specific postures. MethodsFine-wire electromyography electrodes were inserted into the right lumbar multifidus (deep and superficial), iliocostalis (lateral and medial), longissimus thoracis and transversus abdominis muscles. Superficial abdominal muscle activity was recorded with surface or fine-wire electrodes. Electromyography amplitude was compared between postures for the back pain group and observations were contrasted with the changes previously reported for pain-free controls. For comparison between groups normalised and non-normalised electromyography amplitudes were compared. FindingsIndividuals with a history of back pain demonstrated greater activity of the longissimus thoracis muscle in the long lordosis compared with the flat posture [mean difference (95% CI): 46.6 (17.5–75.7)%, normalised to sitting posture peak activity], but pain-free participants did not [mean difference: 7.7 (minus 12–27.6)%]. Pain-free participants modulated lumbar multifidus activity with changes in lumbar curve, but people with a history of pain in prolonged sitting did not change multifidus activity between the long and short lordotic postures. InterpretationIn clinical ergonomic interventions that modify spinal curves and sagittal balance in sitting, the muscle activity used in those postures may differ between people with and without a history of back pain.

Fiber type composition of epaxial muscles is geared toward facilitating rapid spinal extension in the leaper Galago senegalensis.

We hypothesized that the vertical leaper Galago senegalensis will have epaxial extensor muscles with a fast fiber phenotype to facilitate rapid spinal extension during leaping in comparison to the slow-moving quadruped Nycticebus coucang. To test this, we determined the percentage of fiber cross-sectional area (%CSA) devoted to Type 2 fibers in epaxial muscles of G. senegalensis compared to those of N. coucang. Immunohistochemistry was used to identify Type 1, Type 2, and hybrid fibers in iliocostalis, longissimus, and multifidus muscles of G. senegalensis (n = 3) and N. coucang (n = 3). Serial muscle sections were used to estimate and compare proportions, cross-sectional areas (CSAs), and %CSAs of Type 1, Type 2, and hybrid fibers between species. Epaxial muscles of G. senegalensis were comprised predominantly of Type 2 fibers with large CSAs (%CSA range ≈ 83-94%; range of mean CSA = 1,218-1,586 μm2 ). N. coucang epaxial muscles were comprised predominantly Type 1 fibers with large CSAs (%CSA range ≈ 69-77%; range of mean CSA = 983-1,220 μm2 ). The predominance of Type 2 fibers in G. senegalensis epaxial muscles facilitates rapid muscle excursion and spinal extension during leaping, and is consistent with their relatively long muscle fibers. The predominance of Type 1 fibers in N. coucang epaxial muscles may aid in maintaining stable postures during bridging and cantilevering behaviors characteristic of slow-climbing. These histochemical characteristics highlight the major divergent locomotor repertoires of G. senegalensis and N. coucang.

Experimental Low Back Pain Decreased Trunk Muscle Activity in Currently Asymptomatic Recurrent Low Back Pain Patients During Step Tasks

Low back pain (LBP) patients show reorganized trunk muscle activity but if similar changes are manifest in recurrent LBP (R-LBP) patients during asymptomatic periods remains unknown. In 26 healthy and 27 currently asymptomatic R-LBP participants electromyographic activity (EMG) was recorded from trunk and gluteal muscles during series of stepping up and down on a step bench before and during experimentally intramuscular induced unilateral and bilateral LBP. Pain intensity was assessed using numeric rating scale (NRS) scores. Root mean square EMG (RMS-EMG) normalized to maximal voluntary contraction EMG and pain-evoked differences from baseline (ΔRMS-EMG) were analyzed. Step task duration was calculated from foot sensors. R-LBP compared with controls showed higher baseline RMS-EMG and NRS scores of experimental pain (P < .05). In both groups, bilateral compared with unilateral experimental NRS scores were higher (P < .001) and patients compared with controls reported higher NRS scores during both pain conditions (P < .04). In patients, unilateral pain decreased ΔRMS-EMG in the Iliocostalis muscle and bilateral pain decreased ΔRMS-EMG in all back and gluteal muscles during step tasks (P < .05) compared with controls. In controls, bilateral versus unilateral experimental pain induced increased step task duration and trunk RMS-EMG whereas both pain conditions decreased step task duration and trunk RMS-EMG in R-LBP patients compared with controls (P < .05). PerspectiveTask duration and trunk muscle activity increased in controls and decreased in R-LBP patients during experimental muscle LBP. These results indicate protective strategies in controls during acute pain whereas R-LBP patients showed higher pain intensity and altered strategies that may be caused by the higher pain intensity, but the long-term consequence remains unknown.

Application of blood oxygenation level dependent fMRI on lumbar dorsal extensor muscles before and after exercise in healthy young adults

Objective To investigate the value of blood oxygenation level dependent (BOLD) fMRI in assessing the functional changes of the lumbar dorsal extensor muscles before and after exercise in healthy young people. Methods The changes of the R2* value of lumbar dorsal extensor group in 30 healthy young volunteers (15 males and 15 females) before and after exercise was prospectively studied. BOLD-fMRI scans were performed on healthy young volunteers before and after exercise, the exercise mode was to perform the upper body flexion and extension movement with a simple Rome stool. The scanned images were processed and analyzed, the cross-sectional area and R2* value of the lumbar dorsal extensor muscles (including the multifidus, the longissimus and the iliocostalis) were measured at the upper margin of the L3 and L4 vertebral body before and after exercise. The paired t test was used to compare CSA and R2* values of muscles before and after loading. The CSA and R2* value of different muscles in different sides were compared by independent sample t test. Pearson correlation analysis was used to analyze the relevance between CSA and R2* in muscle before and after exercise. Results After exercise, the R2* values of multifidus, longissimus and iliocostalis at the upper margin of the L4 vertebral body were [(39.2±8.6),(38.9±7.7),(41.6±7.8)]Hz, significantly lower than before exercise [(46.1±6.9),(45.3±6.2),(46.0±6.7)]Hz (P 0.05).The R2* values of longissimus and iliocostalis at the upper margin of the L3 vertebral body were [(44.2±9.1), (46.6±9.3)]Hz, significantly lower than before exercise [(48.6±7.2),(49.7±6.8)]Hz(P 0.05);there was a significant difference in the changes of R2* value before and after the movement between the left and right side of iliocostalis(P<0.05).A significant negative correlation between CSA and R2* value was found in the iliocostalis on the right side at the upper margin of L3 vertebral body and in the multifidus on the left side at the upper margin of L4 vertebral body, and the correlation coefficients were (-0.697,-0.616). Conclusion BOLD-fMRI can be a new way to assess the functional changes of the lumbar dorsal extensor group before and after exercise. Key words: Psoas muscles; Magnetic resonance imaging; Oximetry

Influence of anterior load carriage on lumbar muscle activation while walking in stable and unstable shoes

Load carriage can be harmful for workers, and alternative interventions to reduce back pain while walking and carrying loads are necessary. Unstable shoes have been used to improve balance and reduce back pain, but it is unknown whether walking wearing unstable shoes while carrying loads anteriorly causes excessive trunk extensors muscle activation. The aim of this study was to investigate the effects of different shoe types and anterior load carriage on gait kinematics and lumbar electromyographic (EMG) activity. Fourteen adults that predominantly walk or stand during the work day were asked to walk with and without carrying 10% of body mass anteriorly while wearing regular walking shoes (REG) and unstable shoes (MBT). The effects of shoe type, load carriage, and shoe × load interactions on the longissimus thoracis (LT) and iliocostalis lumborum (IC) EMG, stride duration, and stride frequency were assessed. MBT shoes induced a significant increase in LT (44.4 ± 35%) and IC EMG (33.0 ± 32%, p < .005), while load carriage increased LT (58.5 ± 41%) and IC EMG (55.1 ± 32%, p < .001). No significant shoe × load interaction was found (p>.05). However, walking wearing MBT shoes while carrying loads induced a 46 ± 40% higher EMG activity compared to walking wearing MBT shoes without load carriage. No effects of shoes or load carriage were found on stride duration and stride frequency. It was concluded that walking wearing MBT shoes and carrying 10% of total body mass induced greater activation of trunk extensors muscle compared to these factors in isolation, such a combination may not influence gait patterns.

Trunk muscle activation pattern in parkinsonian camptocormia as revealed with surface electromyography

IntroductionCamptocormia is frequently seen in Parkinson's disease (PD) and multiple system atrophy. It is characterized by a pathological forward bending of the trunk during standing, often combined with a lateral trunk deviation. The etiology of camptocormia in PD is still unknown. Muscle MRI studies show abnormalities mainly of the erector spinae confirmed by muscle biopsies. Quantitative electromyographic examination of trunk muscle activity is missing. MethodsVentral (rectus and obliquus externus abdominis) and dorsal (iliocostalis lumborum, longissimus, multifidus) trunk muscles and the rectus femoris were recorded bilaterally with surface electromyography in standing PD patients with camptocormia (n = 10) and matched healthy controls (n = 10) who mimicked the patients' posture. EMG amplitudes were compared quantitatively. In controls, the relation between varying degrees of trunk flexion and EMG was established systematically. ResultsIncreasing forward trunk flexion was associated with increasing back muscle activity in controls, while abdominal muscle activity was negligible. During anterolateral trunk flexion, back muscle activity increased particularly on the contralateral side. The patients showed a similar pattern. However, normalized EMG activity of their trunk extensors was significantly higher than in controls, often reaching half-maximal amplitudes. Their rectus femoris and oblique abdominal muscles were overactive, but to a lesser extent. ConclusionsPD patients with camptocormia must use the functional reserve of their lumbar trunk muscles to counteract gravity. We interpret this as a weakness of the paravertebral muscles. Compared to the other examined muscles the paravertebral muscles are most affected. The increased EMG activity of the rectus femoris warrants further research.

Spinal loads and trunk muscles forces during level walking – A combined in vivo and in silico study on six subjects

During level walking, lumbar spine is subjected to cyclic movements and intricate loading of the spinal discs and trunk musculature. This study aimed to estimate the spinal loads (T12–S1) and trunk muscles forces during a complete gait cycle.Six men, 24–33years walk barefoot at self-selected speed (4–5km/h). 3D kinematics and ground reaction forces were recorded using a motion capturing system and two force plates, implemented in an inverse dynamic musculoskeletal model to predict the spinal loads and trunk muscles forces. Additionally, the sensitivity of the intra-abdominal pressure and lumbar segment rotational stiffness was investigated.Peak spinal loads and trunk muscle forces were between the gait instances of heel strike and toe off. In L4–L5 segment, sensitivity analysis showed that average peak compressive, antero-posterior and medio-lateral shear forces were 130–179%, 2–15% and 1–6%, with max standard deviation (±STD) of 40%, 6% and 3% of the body weight. Average peak global muscles forces were 24–55% (longissimus thoracis), 11–23% (iliocostalis thoracis), 12–16% (external oblique), 17–25% (internal oblique) and 0–8% (rectus abdominus) of body weight whereas, the average peak local muscles forces were 11–19% (longissimus lumborum), 14–31% (iliocostalis lumborum) and 12–17% (multifidus). Maximum±STD of the global and local muscles forces were 13% and 8% of the body weight.Large inter-individual differences were found in peak compressive and trunk muscles forces whereas the sensitivity analysis also showed a substantial variation.

Epaxial Musculature in Armadillos, Sloths, and Opossums: Functional Significance and Implications for the Evolution of Back Muscles in the Xenarthra

To investigate the evolution of xenarthran epaxial muscles, fresh specimens of the North American Common long-nosed armadillo Dasypus novemcinctus and of a marsupial, the Virginia opossum Didelphis virginiana, were dissected. Data from one fixed specimen of a two-toed sloth Choloepus didactylus were also used for comparison, because it is a xenarthran exhibiting a highly derived locomotor mode. The opossum was used to represent a more generalized mammalian condition. Each of the three mammalian epaxial muscle groups, the iliocostalis, longissimus dorsi, and transversospinalis, was removed and its mass was determined. All data were corrected for body mass and length. Unpaired, one-tailed t-tests showed the average mass of the iliocostalis and transversospinalis of Dasypus to be significantly larger than the mass of the same muscles in Didelphis, whereas the average mass of the longissimus dorsi was not statistically different between the two species. In agreement with pronounced lateral bending and de-emphasized dorso-ventral flexion and extension, Choloepus also had a relatively large iliocostalis and small longissimus. Our limited data suggest that this condition was inherited from non-arboreal and probably digging early xenarthrans. We believe the relatively larger iliocostalis and transversospinalis muscles in Dasypus can be attributed to the need to provide vertical stabilization of the trunk and resist lateral reaction forces generated by digging. Thus, for Xenarthra it represents a synapomorphy linked to adaptations for fossoriality.

Biomechanical and Anatomical correlations as a determiner for Qualitative exercises of Pull circular kick skill in Sanda – Kung Fu

This Biomechanical analytic research aims to know the time distribution, percentage, some momentary and general biomechanical variables (displacement, Velocity, acceleration, and angles), functional anatomical analysis of main articulations and muscles for the performance's stages - subject of research - of Pull circular kick skill (modernized skill) and some private qualitative exercises in Sanda, Kung Fu. And to know the values of Spearman correlation factors in such biomechanical and biological variables between the skill Biomechanical performance and its qualitative exercises and determining the perfect rate for these values as a main criterion to select the skill qualitative exercises. The researcher used the descriptive method through cinematography and 3D movement analysis. The Sample participants was selected purposively of one player ,who holds the world championship of Sanda – Kung Fu on (2013-2016) of (75) kg. He is the only who used the skill under research effictively in different championships. Observation was one of the most important methods for collecting data, The most important results were represented in that the time of performing pull circular kick skill was (0.44) sec and ranging in the qualitative exercises between (0.42-0.52) sec and The least value of time was in the exercise of drop ball and the highest value was in the exercise of elastic triangle. There was a correlation or a great similarity between basic movement variables for the technical performance of the skill under research and all its qualitative exercises range in most studied movement variables between (0.77 - 1.000) and it was the highest correlation in the exercises of punch bags, weights bands and drop ball and the minimum in the exercises of elastic triangle, lion jaws and steering pin . And muscles worked in the main articulation movements through Pull circular kick skill and its qualitative exercises in Sanda - subject of research - that became (32) skeletal muscles distributed on (13) main articulation movements, the top of them is the femur grasping that is Psoasmajor, Iliocostalis and Sartorius muscles. The lower of them is finger flexion in the grasp muscle of fingers.

Relationship between the distribution of spinal nerve posterior ramus and locations of acupoint in low back

To explore the relationship between the distributions of posterior ramus of spinal nerve (PRSN) and locations of acupoint in low back through anatomical observation. The regional anatomy was performed at five corpses to observe the distribution of erector spinae muscle and PRSN in areas of Jiaji points and back-shu points in low back. The T12, L1, L2, L3 and L4 PRSN distributed on both sides of the spine; the medial branches of PRSN travelled between spinalis thoracis muscle and longissimus thoracis muscle, while the lateral branches of PRSN travelled between longissimus thoracis muscle and iliocostalis lumborum muscle. Jiaji points and back-shu points in low back are closely associated with PRSN, particularly T12, L1, L2, L3 and L4.

Effects of external loading on lumbar extension moment during squat lifting.

The main objective of this study has been qualitative investigation of the effects of external loading on the lumbar extension moment during squat lifting. Findings of this study may allow to determine the factor with the most considerable effect on the lumbar extension moment and may help determine the lumbar spine risk factors at temporo-spatial coordination during squat lifting. Twelve healthy men volunteered to perform slow and fast squat lifting of a box of varied mass (4 kg, 8 kg and 12 kg). The eight-channel electromyography was applied to detect the activities of abdominal (rectus abdominis and external oblique) and lower back muscles (iliocostalis lumborum and multifidus). The lumbar extension moment was calculated using 3D linked segment model. Ground reaction forces and kinematic data were recorded using a Vicon system with 2 parallel Kistler force-plates. Significant increases (both p-values < 0.05) were detected for the peak lumbar extension moment with increases in the lift speed and box weight. Moreover, a significant interaction (p = 0) was detected between the lift speed and box weight. Furthermore, insignificant differences (all p-values > 0.05) were detected between the lumbar angles related to the lower trunk muscles peak activities and lumbar angle related to the peak lumbar extension moment in most of the lifts. According to the findings, the inertial force of the lifted box is the most important factor that affects the lumbar extension moment during squat lifting. Moreover, critical lumbar angles are seemingly those ones in which the lifted box reaches the peak acceleration. Int J Occup Med Environ Health 2017;30(4):665-679.

Estimating Neural Control from Concentric vs. Eccentric Surface Electromyographic Representations during Fatiguing, Cyclic Submaximal Back Extension Exercises.

Purpose: To investigate the differences in neural control of back muscles activated during the eccentric vs. the concentric portions of a cyclic, submaximal, fatiguing trunk extension exercise via the analysis of amplitude and time-frequency parameters derived from surface electromyographic (SEMG) data.Methods: Using back dynamometers, 87 healthy volunteers performed three maximum voluntary isometric trunk extensions (MVC's), an isometric trunk extension at 80% MVC, and 25 cyclic, dynamic trunk extensions at 50% MVC. Dynamic testing was performed with the trunk angular displacement ranging from 0° to 40° and the trunk angular velocity set at 20°/s. SEMG data was recorded bilaterally from the iliocostalis lumborum at L1, the longissimus dorsi at L2, and the multifidus muscles at L5. The initial value and slope of the root mean square (RMS-SEMG) and the instantaneous median frequency (IMDF-SEMG) estimates derived from the SEMG recorded during each exercise cycle were used to investigate the differences in MU control marking the eccentric vs. the concentric portions of the exercise.Results: During the concentric portions of the exercise, the initial RMS-SEMG values were almost twice those observed during the eccentric portions of the exercise. The RMS-SEMG values generally increased during the concentric portions of the exercise while they mostly remained unchanged during the eccentric portions of the exercise with significant differences between contraction types. Neither the initial IMDF-SEMG values nor the time-course of the IMDF-SEMG values significantly differed between the eccentric and the concentric portions of the exercise.Conclusions: The comparison of the investigated SEMG parameters revealed distinct neural control strategies during the eccentric vs. the concentric portions of the cyclic exercise. We explain these differences by relying upon the principles of orderly recruitment and common drive governing motor unit behavior.

Effects of Dry Needling on Spinal Mobility and Trigger Points in Patients with Fibromyalgia Syndrome

Background: The etiology of fibromyalgia syndrome (FMS) is inconclusive, but central mechanisms are well accepted for this pain condition. Myofascial pain syndrome (MPS) is one of the most common musculoskeletal pain diseases and is characterized by myofascial trigger points (MTrPs). It has been suggest that MTrPs have an important factor in the genesis of FMS. Objective: The purpose of the current randomized clinical trial was to compare the effectiveness of dry needling versus cross tape on spinal mobility and MTrPs in spinal muscles in patients with FMS. Study Design: A single-blind randomized controlled trial was conducted on patients with FMS. Setting: Clinical setting. Methods: Sixty-four patients with FMS were randomly assigned to an experimental group receiving dry needling therapy or to a control group for cross tape therapy in the MTrPs in the latissimus dorsi, iliocostalis, multifidus, and quadratus lumbourum muscles. Spinal mobility measures and MTrPs algometry were recorded at baseline and after 5 weeks of treatment. Results: The repeated measures analysis of variance (ANOVA) demonstrated that significant differences between groups were achieved for the MTrPs in latissimus dorsi muscle (right axillary portion: F = 9.80, P = 0.003); multifidus muscle (right L2 level: F = 11.80, P = 0.001); quadratus lumborum (right lateral superficial upper: F = 6.67, P = 0.012; and right lateral superficial lower: F = 5.38, P = 0.024). In addition, the ANOVA repeated measures test showed significant differences between groups for the segmental amplitude thoracic spine in the standing erect position (F = 7.33, P = 0.009), and segmental amplitude of lumbar spine (F = 11.60, P = 0.001) in the sitting erect position. Limitations: The outcomes were not collected from a long-term follow-up period. Dry needling therapy or cross tape were used alone when in reality physical therapists usually treat patients with FMS using a multi-modal approach. A non-treatment control group was not included. Conclusions: This study has demonstrated that dry needling therapy reduces myofacial trigger points algometry on thoracic and lumbar muscles. Dry needling and cross tape approaches reported a similar effect size for spinal mobility measures in patients with FMS. Key words: Fibromyalgia, trigger points, physical therapy modalities, musculoskeletal equilibrium, myofascial pain syndromes

Pisa syndrome in Parkinson's disease: electromyographic quantification of paraspinal and non-paraspinal muscle activity.

Patients with Parkinson's disease (PD) and Pisa syndrome (PS) may present tonic dystonic or compensatory (i.e. acting against gravity) hyperactivity in the paraspinal and non-paraspinal muscles. Electromyographic (EMG) activity was measured in nine patients with PD and PS, three with PD without PS, and five healthy controls. Fine-wire intramuscular electrodes were inserted bilaterally into the iliocostalis lumborum (ICL), iliocostalis thoracis (ICT), gluteus medius (GM), and external oblique (EO) muscles. The root mean square (RMS) of the EMG signal was calculated and normalized for each muscle. In stance condition, side-to-side muscle activity comparisons showed a higher RMS only for the contralateral ICL in PD patients with PS (p=0.028). Moreover, with increasing degrees of lateral flexion, the activity of the EO and the ICL muscles progressively increased and decreased, respectively. The present data suggest that contralateral paraspinal muscle activity plays a crucial compensatory role and can be dysfunctional in PD patients with PS.

Three-dimensional trajectories affect the epaxial muscle activity of arboreal snakes crossing gaps.

The need for long-axis support is widespread among non-aquatic vertebrates and may be particularly acute for arboreal snakes when many vertebrae span sizable gaps between branches with diverse orientations. Hence, we used brown tree snakes (Boiga irregularis) bridging gaps to test how three-dimensional trajectories affected muscle activity and whether these motor patterns differed from those for the locomotion of terrestrial snakes and movements of other vertebrates. We used five trajectories: pitch angles of 90, 0 and -90deg (downward) when yaw=0 deg, and 90deg yaw angles to the left and right when pitch=0deg. We recorded movement and electromyograms from the three largest epaxial muscles, which from dorsal to ventral are the semispinalis-spinalis (SSP), longissimus dorsi (LD) and iliocostalis (IL). Overall, the SSP had extensive bilateral activity, which resembled the motor pattern during the dorsiflexion of sidewinding snakes. Unlike any previously described terrestrial snake locomotion, bilateral activity of the LD and IL was also common during gap bridging. The largest amounts of muscle activity usually occurred for horizontal gaps, and muscle activity decreased markedly as soon as the snake's head touched the far edge of the gap. Snakes had the least amount of muscle activity for pitch=-90deg. While turning sideways, muscles on the convex side had less activity when turning compared with the concave side. Hence, the orientation relative to gravity profoundly affected muscle activity during gap bridging, and these complex three-dimensional movements involved several previously undescribed variants of axial motor pattern.

Neuromuscular control strategies of the trunk antagonist muscles during the Biering-Sorensen test in individuals with recurrent low back pain and healthy subjects

OBJECTIVES To compare the activation pattern of the trunk antagonistic muscles and also the myoelectric manifestations of muscle fatigue between subjects with and without recurrent non-specific low back pain, during the fatigue provocation of the erector spinae. METHODS The study involved 19 subjects with recurrent low back pain with a non-specific cause (seven men, 12 women, 38.53 ± 8.12 years, 68.35 ± 18.12 kg, 1.66 ± 0.09 m), and 19 healthy subjects (seven men, 12 women, 40.42 ± 8.63 years, 69.57 ± 12.76 kg, 1.64 ± 0.07 m). The electromyographic signal of the internal oblique, lumbar multifidus, rectus abdominis and lumbar iliocostalis muscles, bilateral, were collected during Biering-Sorensen test execution. RESULTS The group with low back pain showed a lower co-contraction rate of the internal oblique/lumbar multifidus (p = 0.006) and lower activation amplitude of the internal oblique (p = 0.019), both on the right side when compared to the group without low back pain. No differences were observed between the groups for muscle fatigue indicators (p > 0.05). CONCLUSION When the erector spine muscle fatigue occurs - even when the groups were similar as to the ability of extensors muscles to resist fatigue - differences were found between subjects with and without low back pain regarding the recruitment pattern of the task antagonist muscle, because subjects with low back pain showed lesser activation and co-contraction in relation to the healthy group.

Efeito agudo de exercícios do método Pilates na ativação dos músculos do tronco de pessoas com e sem dor lombar

Introdução: O método Pilates é indicado para reabilitação de pacientes com dor lombar inespecífica (DLI). Contudo, o efeito deste treinamento no padrão de recrutamento muscular é desconhecido. Objetivo: Analisar o efeito agudo do método Pilates na ativação dos músculos do tronco em indivíduos com e sem DLI. Métodos: Participaram do estudo 18 sujeitos, separados em dois grupos: grupo com DLI e sem DLI. No primeiro dia de coleta, foram obtidos: dados pessoais, medidas antropométricas e familiarização com os exercícios. No segundo dia, foram realizados: teste de elevação do braço, teste de Biering-Sorensen, os exercícios e reavaliação. Foram coletados os sinais eletromiográficos dos músculos: oblíquo interno, multífido lombar, iliocostal lombar e reto abdominal. Resultados: Após o treinamento, o grupo com DLI apresentou, no teste de Biering-Sorensen, maior ativação do iliocostal lombar (p=0,016) e menor ativação do oblíquo interno (p=0,031). Conclusão: Uma sessão do método Pilates foi capaz de alterar o padrão de recrutamento dos músculos do tronco em indivíduos com DLI.

The effects of task execution variables on the musculature activation strategy of the lower trunk during squat lifting

The main objective of this study was to investigate the innervation behavior of lower trunk musculature to determine the muscular activation strategy during free dynamic squat lifting. This may clarify how lower trunk musculature activation compliments task execution variables to control motion during labor and industrial lifting tasks. In total, 12 healthy men volunteered to perform symmetric squat lifting of boxes of various masses (4, 8 and 12 kg) at slow and fast speeds. Eight-channel electromyography was performed on two pairs of abdominal (rectus abdominis and external oblique) and lower back muscles (iliocostalis lumborum and multifidus). Movement patterns were extracted using a 3D-linked segment model and a Vicon system. The results indicated that there were significant increases (all p-values < 0.05) in the mean muscle activation of the right and left multifidus and iliocostalis lumborum with increases in the lift speed and box weight. Furthermore, the results indicated that there were significant decreases (all p-values < 0.05) in the time required for the peak activation of the right and left multifidus, iliocostalis lumborum and external oblique with increases in the lift speed and box weight. Finally, the lower trunk musculature activation strategy was revealed to be compatible with different task execution variables, controlling motion in a manner that compensated for the effects of task execution variables. The findings of this study may effectively be applied to ergonomics, particularly to symmetric squat lifting.

Magnitude of muscle activity of the lumbar multifidus using the Core-Noodle device with varied upper extremity postures.

Lumbar Multifidus (LM) exercise is a treatment in patients with low back pain. We designed a new exercise using device ``Core-Noodle'' (Copyright has been observed in Japan). The purpose of this study was to record the electromyographic (EMG) activity of the lumbar multifidus during a novel exercise. Twenty-one healthy young volunteers performed the LM exercise using Core-Noodle in three conditions: no-weight (NW), 1 kg weight (1W), 2 kg-weight (2W). This exercise was performed in supine with left shoulder abduct 90 degrees and right shoulder flexed 90 degrees. EMG activity was recorded from surface electrodes on the LM and the thoracic part of the iliocostalis lumborum (ICLT), and normalized to values derived from maximal isometric trials (%MVIC). In addition, the ratio of the LM to ICLT (L/G ratio) was calculated to compare selectivity of LM activity. One-way ANOVA and Bonferroni method were used to draw comparisons among the three conditions. Muscle activation of LM was gradually increased in proportion to the loading dose. L/G ratio increased by weight loading significantly, but slightly decreased at 2W. The results suggest that characteristic EMG patterns of LM ``selective contraction'' and ``adjustment of load'' are obtained concurrently.

Mechanical and neuromuscular changes with lateral trunk lean gait modifications

Lateral trunk lean (LTL) is a proposed intervention for knee osteoarthritis but increased muscular demands have not been considered. The objective was to compare lower extremity and trunk muscle activation and joint mechanics between normal and increased LTL gait in healthy adults. Participants (n=20, mean age 22 years) were examined under two gait conditions: normal and increased LTL. A motion capture system and force plates sampled at 100 and 2000Hz respectively were used to determine joint angles and external moments including LTL angle and external knee adduction moment (KAM). Surface electromyography, sampled at 2000Hz, measured activation of six trunk/hip muscles bilaterally. Peak LTL angle, peak KAM, gait speed, and mean values from electromyography waveforms were compared between normal and LTL conditions using paired t-tests or 2-way analysis of variance. There was a significant (p<0.05) increase in peak LTL angle, decrease in first but not second peak KAM, and decrease in gait speed during LTL gait. There were significant (p<0.01) increases in external oblique and iliocostalis muscle activation during LTL gait. There was no change in activation for internal oblique, rectus abdominis, longissimus, and gluteus medius. LTL gait decreased early/mid-stance KAM demonstrating its ability to decrease medial compartment knee loading. Increases in external oblique and iliocostalis activation were present but small to moderate in size and unlikely to lead to short term injury. Longitudinal studies should evaluate the effectiveness of increased LTL for knee osteoarthritis and if the increase in muscular demands leads to negative long term side effects.