Differences in end-range lumbar flexion during slumped sitting and forward bending between low back pain subgroups and genders

Patterns of lumbar posture and motion are associated with low back pain (LBP). Research suggests LBP subgroups demonstrate different patterns during common tasks. This study assessed differences in end-range lumbar flexion during two tasks between two LBP subgroups classified according to the Movement System Impairment model. Additionally, the impact of gender differences on subgroup differences was assessed. Kinematic data were collected. Subjects in the Rotation (Rot) and Rotation with Extension (RotExt) LBP subgroups were asked to sit slumped and bend forward from standing. Lumbar end-range flexion was calculated. Subjects reported symptom behaviour during each test. Compared to the RotExt subgroup, the Rot subgroup demonstrated greater end-range lumbar flexion during slumped sitting and a trend towards greater end-range lumbar flexion with forward bending. Compared to females, males demonstrated greater end-range lumbar flexion during slumped sitting and forward bending. A greater proportion of people in the Rot subgroup reported symptoms with each test compared to the RotExt subgroup. Males and females were equally likely to report symptoms with each test. Gender differences were not responsible for LBP subgroup differences. Subgrouping people with LBP provides insight into differences in lumbar motion within the LBP population. Results suggesting potential consistent differences across flexion-related tasks support the presence of stereotypical movement patterns that are related to LBP.     

Myoglobin and enzyme adaptations in erector spinae muscles in thoracal scoliosis

Summary. Bilateral biopsies from the erector spinae muscles were taken during surgery from 10 females and two males (mean age 14, range 13–17 years) with thoracal scoliosis for 6 years (range 2–11 years). The biopsies were analysed for myoglobin (MYO), citrate synthase (CS) and creatine kinase MB (CK-MB). The severity of scioliosis was estimavoted by Cobb's angle, the greater the angle the more severe the disease. The convex/concave side ratio (CVX/CCV) was for CS l·3±0·4 (P<0·01), CK 0·9 ± 01 (P<0·05), CK-MB 1·6±0·4 (P<0·01) and for MYO 1·1±0·2 (P>0·05). No significant correlations were found between the CVX/CCV for CS, CK or CK-MB on the one hand and the Cobb's angle on the other. The CVX/CCV for MYO was, however, directly related to the angle (r= 0·80, P<0·01). For the lower range of angles (≤59°) the CVX/CCV for MYO was below unity (0·88, P>0·05) and for the larger angles (>59°) above unity (1·23, P<0·05). In conclusion, a dissociation in the adaptive response of m. erector spinae in scoliosis between mitochondrial enzyme and myoglobin content was demonstrated.     

EMG activities of the quadratus lumborum and erector spinae muscles during flexion-relaxation and other motor tasks

OBJECTIVE: The aim of this study was to provide new information on the myoelectrical activation of the quadratus lumborum, the deep lateral and the superficial medial lumbar erector spinae, the psoas, and the iliacus muscles in various motor tasks. DESIGN: An intramuscular electromyographic study was performed. BACKGROUND: The contribution of individual deep trunk muscles to the stability of the lumbar spine is relatively unknown in different tasks, including the flexion-relaxation phenomenon. METHODS: Seven healthy subjects participated. Fine-wire electrodes were inserted with a needle guided by ultrasound. RESULTS: The highest activity observed for quadratus lumborum and deep lateral erector spinae occurred in ipsilateral trunk flexion in a side-lying position and for superficial medial erector spinae during bilateral leg lift in a prone position. Quadratus lumborum and deep lateral erector spinae were activated when the flexion-relaxation phenomenon was present for superficial medial erector spinae, i.e. when its activity ceased in the latter part of full forward flexion of the trunk, held relaxed and kyphotic. CONCLUSIONS: In general, the activation of the investigated muscles showed a high degree of task specificity, where activation of a certain muscle was not always predictable from its anatomical arrangement and mechanical advantage.     

The effects of repetitive motion on lumbar flexion and erector spinae muscle activity in rowers

OBJECTIVE: The purpose of this study was to investigate changes in lumbar flexion together with the pattern and level of muscle activity of selected erector spinae during a rowing trial.Design. Cross-sectional repeated measures design. BACKGROUND: Low back pain is a common problem in rowers. The amount of lumbar flexion occurring during rowing might influence the possibility of injury. METHODS: Sixteen young adult school rowers participated in the study. Changes in lumbar flexion and muscle activity were recorded across the drive phase, at three stages of an ergometer based rowing trial. Lumbar flexion was calculated by computerised motion analysis of surface markers attached to the spinous processes of L1 and S1. Surface electromyography techniques were used to examine the magnitude of activity from three erector spinae muscles. The median frequency of the electromyographic signal was examined to quantify fatigue in the erector spinae muscles during isometric maximal effort muscle activation prior to and after the rowing trial. RESULTS: Lumbar flexion increased significantly (P<0.05) during the rowing trial, as did the magnitude of electromyographic activity from sites over the lumbar multifidus, iliocostalis lumborum and longissimus thoracis muscles. The median frequency decreased significantly (P<0.05) in each muscle examined. CONCLUSIONS: The findings showed that rowers attain relatively high levels of lumbar flexion during the rowing stroke, and these levels are increased during the course of the rowing trial. Indirect evidence of muscle fatigue in erector spinae muscles was also apparent, and this observation may in part be responsible for the increased levels of lumbar flexion observed. RELEVANCE: Excessive lumbar flexion may influence the potential for injury to spinal structures. An awareness of increased lumbar flexion and muscle fatigue in the erector spinae muscles may be important for injury prevention programs for rowers.     

Relationship between the thickness and hemodynamics of the erector spinae muscles in various lumbar curvatures

BACKGROUND: There is little information about the relationship between the changes of hemodynamics and the morphologic changes of the erector spinae muscle. METHODS: Fifty healthy male volunteers participated. Ultrasonography was used to measure muscle thickness, and near-infrared spectroscopy was used to measure tissue blood volume and its oxygenation in the erector spinae muscle at L3 in six different relaxed trunk postures (flexed 20 degrees , flexed 40 degrees, flexed maximum, neutral posture, extended 20 degrees, and extended maximum of the lumbar spine). We also evaluated the reproducibility of the near-infrared spectroscopy measurements. FINDINGS: Near-infrared spectroscopy gave highly reproducible measurements. The thickness of the erector spinae muscle and the total and oxygenated hemoglobin were simultaneously increased during relaxed extension and decreased during relaxed flexion. Changes in the thickness of the erector spinae muscle with various lumbar curvature were similar in pattern to the changes in tissue blood volume and its oxygenation. INTERPRETATION: The erector spinae muscles' thickness, tissue blood volume, and its oxygenation are simultaneously increased during relaxed extension and decreased during relaxed flexion, as demonstrated by non-invasive near-infrared spectroscopy and ultrasonography. These findings might afford a better understanding of the pathomechanics of posture-related back symptoms. RELEVANCE: The erector spinae muscles' thickness, tissue blood volume, and its oxygenation are simultaneously increased during relaxed extension and decreased during relaxed flexion, as shown by non-invasive near-infrared spectroscopy and ultrasonography. Changes in hemodynamics and morphology of the erector spinae muscles in asymptomatic subjects are given for further research on the pathomechanism of back pain.     

Effect of the cervical flexion angle during smart phone use on muscle fatigue of the cervical erector spinae and upper trapezius

[Purpose] The purpose of this study was to examine the influence of the cervical flexion angle when using a smart phone on muscle fatigue of the cervical erector spinae (CES) and upper trapezius (UT). [Subjects] This study recruited 12 healthy adults. [Methods] Each subject sat on a chair, with his/her back against the wall and held a smart phone with both hands. Fatigue of the neck and shoulder muscles at different cervical flexion angles (0°, 30°, and 50°) was measured by electromyography. The following muscles were assessed: the right upper trapezius (RtUT), left upper trapezius (LtUT), right cervical erector spinae (RtCES), and left cervical erector spinae (LtCES). A cervical range of motion instrument was attached to the subjects’ heads to measure the cervical angle during the experiment. [Results] The RtUT and LtUT showed the highest muscle fatigue at a cervical flexion angle of 50° and the lowest fatigue at an angle of 30°. There was no significant difference in the muscle fatigue of the RtCES and LtCES at any of the cervical flexion angles. [Conclusion] UT muscle fatigue depends on the cervical flexion angle when using a smart phone.Key words: Smart phone, Muscle fatigue, Cervical flexion angle     

Effects of abdominal belts on intra-abdominal pressure, intra-muscular pressure in the erector spinae muscles and myoelectrical activities of trunk muscles

OBJECTIVE: To evaluate the effects of abdominal belts on lifting performance, muscle activation, intra-abdominal pressure and intra-muscular pressure of the erector spinae muscles. DESIGN: Simultaneous measurement of intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles was performed during the Valsalva maneuver and some isometric lift exertions. BACKGROUND: While several hypotheses have been suggested regarding the biomechanics of belts and performance has been found to increase when lifting with belts, very little is known about the modulating effects on trunk stiffness. At present, there is no reason to believe that spine tolerance to loads increases with belts. METHODS: An abdominal belt designed for weightlifting was used. Intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and myoelectric activities of trunk muscles (erector spinae, rectus abdominis and external oblique) were measured simultaneously during the Valsalva maneuver as well as three types of isometric lifting exertions (arm, leg and torso lift). A paired t-test was used to analyze for statistical differences between the two conditions (without-belt and with-belt) in intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and in the integrated EMG of the trunk muscles. RESULTS: Intra-muscular pressure of the erector spinae muscles increased significantly by wearing the abdominal belt during Valsalva maneuvers and during maximum isometric lifting exertions, while maximum isometric lifting capacity and peak intra-abdominal pressure were not affected. Integrated EMG of rectus abdominis increased significantly by wearing the abdominal belt during Valsalva maneuvers (after full inspiration) and during isometric leg lifting. CONCLUSIONS: Wearing abdominal belts raises intra-muscular pressure of the erector spinae muscles and appears to stiffen the trunk. Assuming that increased intra-muscular pressure of the erector spinae muscles stabilizes the lumbar spine, wearing abdominal belts may contribute to the stabilization during lifting exertions.     

Intramuscular hemodynamics in bilateral erector spinae muscles in symmetrical and asymmetrical postures with and without loading

BACKGROUND: Although attention has been paid to the relationship between the changes in blood circulation in erector spinae muscles and back pain, little is known about their hemodynamics in several various comparable postures with and without loading. Studies on hemodynamics of erector spinae muscles using near-infrared spectroscopy have been performed on subjects and patients mainly in forward flexion positions. METHODS: Two near-infrared spectroscopes were used to measure oxygenated hemoglobin, deoxygenated hemoglobin, and total hemoglobin in bilateral erector spinae muscles at L2-3 in subjects in 9 postures, and holding no load, 10 kg or 20 kg in maximum flexed and lateral bending. Those three values in each posture and loading condition were expressed as a percentage of their corresponding values obtained in the standing upright position, and designated and statistically analyzed as %Oxy-Hb, %Deoxy-Hb and %Total-Hb, respectively. FINDINGS: %Total-Hb and %Oxy-Hb in maximum flexion were the most decreased. In maximum lateral bending, %Oxy-Hb only in the contralateral erector spinae muscles was decreased. When the load was 20 kg, the decreases in %Oxy-Hb were the largest in maximum flexion and lateral bendings. INTERPRETATION: Using two near-infrared spectroscopes allowed us to measure simultaneously the hemodynamics of bilateral muscles. They demonstrated different responses in each side. Asymmetrical posture and loading were accompanied by asymmetrical changes of the bilateral erector spinae muscles. Stretched muscle had less blood volume and oxygenation, both of which decreased with increasing load. These results showed that these postures and conditions might lead to fatigue of the ES muscles.     

Effects of myofascial release on flexibility and electromyographic activity of the lumbar erector spinae muscles in healthy individuals

ObjectiveTo investigate the effects of myofascial release on the flexibility and electromyographic activity of the lumbar erector spinae muscle in healthy individuals.MethodsTen healthy subjects were recruited to an intervention protocol of myofascial release techniques: (1) superficial myofascial release; (2) deep myofascial release apply along 10 sessions, twice a week, with 40 min per sessions. The outcomes evaluated were flexibility (Toe-Touch Test) and electromyography activity (EMG) of the lumbar erector spinae muscle (Iliocostalis and Longissimus bilaterally) during the movement of extension-flexion of the trunk. Paired t-test was used to compare the electromyographic outcomes, while the Wilcoxon test was used to compare the flexibility outcomes.ResultsThe myofascial release techniques increased the flexibility (p = 0.005; r = 0.88) and have no influence over the electromyographic activity of the right iliocostalis (p = 0.179; r = 0.43), right longissimus (p = 0.877; r = 0.05), left iliocostalis (p = 0.386; r = 0.29) and left longissimus (p = 0.418; r = 0.27).ConclusionsThe application of myofascial release techniques increase flexibility and did not influence over the electromyographic activity of the lumbar erector spinae muscles in healthy individuals. Further studies should include a larger sample with a sham group and/or compare EMG activity of the lumbar erector spinae muscles with patients with low back pain during the movement of extension-flexion of the trunk.     

Comparison of the isolated contraction ratios of the hip extensors and erector spinae muscles of the lumbar region and thoracic muscles during different back extension exercises

[Purpose] This study compared the isolated contraction ratios of the hip extensors, erector spinae muscles of the lumbar region, and thoracic muscles during different back extension exercises. [Subjects] Twelve males participated in this study. [Methods] The subjects performed various back extension exercises. The activities of the T7 erector spinae muscles, L3 erector spinae muscles, and the gluteus maximus were measured, and the isolation contraction ratios were calculated. [Results] The isolated contraction ratio of the T7 erector spinae muscles significantly increased during exercise 2. The isolated contraction ratio of the gluteus maximus increased by a significant degree during exercise 1 compared with the other exercises. [Conclusion] This study demonstrated that the back extension exercises 1 and 2 can be applied to selectively exercise the hip extensors, thoracic muscles, and muscles of the lumbar region.Key words: Back extensor, Isolated contraction ratio, Selected exercise     

超声引导下竖脊肌平面阻滞在围术期镇痛中的研究进展

超声引导下竖脊肌平面阻滞(ESPB)是一种新型的躯干神经阻滞技术,其结合了超声可视化技术的优点,能实时显示针尖的穿刺路径,准确地将局麻药注射到竖脊肌深面,从而有效阻滞竖脊肌平面及周围神经,获得良好的镇痛效果.ESPB不仅可以减少围术期阿片类药物的用量,而且为开放性手术提供了良好的术后镇痛效果.本文对ESPB的解剖基础、...     

Age affects the latency of the erector spinae response to sudden loading

BACKGROUND: Aging and a past history of low back pain are risk factors for a future low back pain. Recent findings have demonstrated an impaired feed-forward control of paraspinal muscles during upper limb loading in low back pain patients as well as decreased feed-forward mechanism in elderly. The aims of the current study were to assess the age-related changes in paraspinal reflex latencies, flexion movement as well as flexion moment of the lumbar spine during sudden upper limb loading and the expectation effects via feed-forward mechanism on these postural responses. METHODS: The paraspinal reflex latencies for upper limb loading during unexpected and expected conditions were measured in erector spinae and multifidus muscles by surface electromyography from 23 young healthy subjects (aged 30 or younger) and 15 healthy elderly subjects (aged 60 or older). The kinematic and kinetic data were obtained simultaneously from a magnetic motion measurement system and a force plate, which were used to calculate flexion moments. FINDINGS: The age was found to have a significant effect for delaying the paraspinal reflex latencies. Expectation shortened the reflex latencies, as well as decreasing the flexion movement and the flexion moment of the lumbar spine. The expectation effects on theses postural responses were reduced by subject's age. INTERPRETATION: These findings suggest that aging process is associated with a decreased motor control of the spine, particularly via reduced feed-forward control of paraspinal muscles. These findings may contribute to decreased ability to stabilize the spine and development of low back injury in elderly.     

Isokinetic knee flexion and extension torque in the upright sitting and semireclined sitting positions

We undertook this study to determine whether the isokinetic knee extension and flexion torque generated by 14 young healthy women was greater in the upright sitting test position or in the semireclined sitting test position. Testing was performed at 60 degrees/sec. Knee extension torque did not differ significantly between the two test positions. The subjects, however, did produce significantly greater knee flexion torque when upright compared with when semireclined (p less than .001). Therapists should recognize that the results of testing isokinetic knee extension in the two positions may be similar, but that the results of testing isokinetic knee flexion may be significantly different.     

Abdominal and erector spinae muscle activity during gait: the use of cluster analysis to identify patterns of activity

OBJECTIVE: To describe patterns of muscle activation during gait in selected abdominal and lumbar muscles using cluster analysis. PARTICIPANTS: A sample of convenience of 38 healthy adult volunteers.Outcome measures. Electromyographic activity from the right internal and external obliques, rectus abdominis and lumbar erector spinae were recorded, and the root mean square values for each muscle were calculated throughout the stride in 5% epochs. These values were normalised to maximum effort isometric muscle contractions. Cluster analysis was used to identify groups of subjects with similar patterns of activity and activation levels. RESULTS: Cluster analysis identified two patterns of activity for the internal oblique, external oblique and rectus abdominis muscles. In the lumbar erector spinae, three patterns of activity were observed. In most instances, the patterns observed for each muscle differed in the magnitude of the activation levels. In rectus abdominis and external oblique muscles, the majority of subjects had low levels of activity (<5.0% of a maximum voluntary contraction) that were relatively constant throughout the stride cycle. In the internal oblique and the erector spinae muscles, more distinct bursts of activity were observed, most often close to foot-strike. The different algorithms used for the cluster analysis yielded similar results and a discriminant function analysis provided further evidence to support the patterns observed. CONCLUSIONS: Cluster analysis was useful in grouping subjects who had similar patterns of muscle activity. It provided evidence that there were subgroups that might otherwise not be observed if a group ensemble was presented as the "norm" for any particular muscle's role during gait. RELEVANCE: The identification of common variations in muscle activity may prove valuable in identifying individuals with electromyographic patterns that might influence their chances of sustaining injury. Alternatively, clusters may provide important information related to muscle activity in those that do well or otherwise after a particular injury.