Trunk muscle strength and back muscle endurance in construction workers with and without low back disorders.

The aim of this study was to test the hypothesis that male workers exposed to heavy work and with no lifetime history of a low back disorder (group A) have better trunk muscle strength and back muscle endurance compared to male workers with the same work exposure but with a probable (group B) or definite low back disorder (group C). Group A (n = 42) was clinically negative on physical examination. Group B (n = 75) was clinically negative or uncertain and group C (n = 86) was clinically positive, with current or previous low back disorders occurring in both groups. Group A had a significantly higher mean intraindividual extension/flexion ratio, namely 1.29 versus 1.19, in group C. The mean values for maximum isometric trunk extension and flexion strength did not differ between the groups. The isometric trunk extensor endurance was significantly lower in group C than in both group A and group B.     

Trunk muscle recruitment patterns in specific chronic low back pain populations

BACKGROUND: It is hypothesized that injury or degeneration of osteoligamentous spinal structures would require compensation by trunk musculature and alterations in motor control to maintain spine stability. While, biomechanical modeling has supported this hypothesis, studies of muscle recruitment patterns in chronic low back pain patients both with and without significant osteoligamentous damage have been limited. This study utilized a non-randomized case-control design to investigate trunk muscle recruitment patterns around the neutral spine position between subgroups of patients with chronic mechanical low back pain and asymptomatic controls. METHODS: Twenty subjects with chronic low back pain attributed to clinical lumbar instability were matched to 20 asymptomatic controls. In addition 12 patients with non-specific chronic low back pain were studied. Surface EMG from five trunk muscles was analyzed to determine activation levels and patterns of recruitment during a standing reach under two different loading conditions. FINDINGS: The chronic low back pain group with symptoms attributed to clinical instability demonstrated significantly higher activation levels of the external oblique and rectus abdominus muscles and lower abdominal synergist ratios than the control group. No significant differences were found between patient subgroups. INTERPRETATION: While these data demonstrate altered muscle recruitment patterns in patients with chronic low back pain, the changes are not consistent with Panjabi's theory suggesting that these alterations are driven by passive subsystem damage. However, the higher activation of global abdominal musculature and altered synergist patterns may represent a motor control pattern that has consequences for continued dysfunction and chronic pain.     

Trunk strength, back muscle endurance and low-back trouble

The strength and endurance of the trunk muscles was studied in relation to the extent of earlier low-back trouble (LBT) in a homogeneous, and occupationally active group. Twenty-four female and 53 male postmen with an occupational seniority of more than 2 years took part in the investigation. The cumulative lifetime prevalence, the one-year and the point prevalence of LBT were 67%, 62%, and 4% in females and 55%, 52%, and 0% in males. The rates are higher than in a representative Danish population 40 years old. Anthropometrical measurements and isometric strength (MVC) in trunk flexors and extensors were recorded. The flexibility of the spine, hip and knee joints, the fingertip-floor distance, and the restricted extension of the knee were evaluated. The isometric endurance in the trunk extensors was measured by two methods: 1) prone with the unsupported trunk in a horizontal position and the legs and hips fixated to a couch; and 2) standing, at 60% MVC. The participants were divided into three groups according to the extent of previous LBT, Group I: LBT to a degree that made work impossible, Group II: LBT experienced but not to such a degree that work was hindered, and Group III: LBT never experienced. The main findings were that the isometric endurance time of the trunk extensors was shorter in group I than in II and III, while the trunk muscle strength, anthropometrical measures and joint flexibility were independent of the persons' earlier low-back episodes. Differences in the distribution of ST and FT muscle fibres are suggested as an explanation of the endurance difference.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relationships between strength of low back muscle contraction and reported intensity of chronic low back pain

The electromyographic patterns produced by recording the left and right paraspinal muscles of subjects while in motion (bending and rising) and still (standing upright, sitting supported and unsupported, and prone) were contrasted for people with: 1) no history of back pain; 2) past episodes of low back pain but currently pain free; and 3) chronic low back pain with various diagnosed etiologies. Each of the 83 individuals recorded during episodes of low back pain produced a unique pattern of muscle contraction which was relatively stable between weekly recording sessions. In every case, at least one of the six positions showed elevated contraction levels significantly above that of the 15 subjects with no history of back pain and the 28 with no current back pain. For nine of the eleven subjects who reported changes in pain intensity between recording sessions, a clearly positive correlation occurred between the reported intensity of pain and the level of contraction in the one position most different from the reference group. No diagnostic subgroup of low back pain subjects produced a single unique pattern. Furthermore, no single aspect of the EMG signal, such as bilateral asymmetry, had predictive value for any individual subject. Our recordings did not differ with respect to diagnostic category so further research will have to be done to determine whether the diagnostic categories currently in use do not fit the physiological bases for the problems and/or whether prolonged abnormal levels of muscle contraction eventually produce problems such as disc displacement.     

肌力训练对下背痛患者胸腰椎生物力学的影响

目的 探讨肌力训练对下背痛患者胸腰椎生物力学的影响.方法 分为观察组与对照组2组,观察组为2008年9月～2010年8月间本院门诊的50例下背痛患者,其中男24例,女26例,年龄50～70岁,平均(59.7±5.7)岁.对照组为50～70岁的正常人群,其中男23例,女27例,平均(61.1±5.6)岁.观察组进行肌力训...     

Trunk muscle activity during holding two types of dynamic loads in subjects with nonspecific low back pain

BackgroundChronic low back pain due to manual lifting continues to be one of the significant common public health challenges in modern societies despite increased automation. While there are extensive studies on the biomechanics of lifting as associated with LBP, the role of unstable and time-varying dynamic loads, quite common in industrial lifting and daily life, remains elusive.ObjectivesThe present study aimed to investigate the response of trunk muscles in subjects with chronic non-specific low back pain (CNLBP) while holding unstable dynamic loads.MethodsTwelve male patients with CNLBP and twelve healthy controls participated in this cross-sectional study. The subjects held static and dynamic loads in neutral positions. Normalized EMG data of the trunk muscles were captured and analyzed by repeated-measures ANOVA test.ResultsThe low back pain group demonstrated significantly higher activation levels of the internal and external abdominal oblique muscles while holding dynamic loads (p < 0.05).ConclusionOur results suggest that the neuromusculoskeletal system in low back patients holding dynamic loads may invoke a motor control strategy that significantly increases muscle co-activation leading to higher joint stiffness at the expense of higher compressive loads on the lumbar spine. Importantly, the type of load plays a critical role in terms of external perturbations that may lead to spinal injury in CNLBP patients and must, therefore, be considered in the risk prevention and assessment of lifting and other manual material handling tasks.     

Isometric back strength of low back pain patients and healthy controls.

The primary objective of this study was to determine the back strength of low back pain patients and to compare their values with healthy control subjects. Using the back and leg dynamometer, we measured the isometric back strength of 21 patients (14 men and 7 women), with chronic low back pain and 21 (14 men and 7 women) healthy (control) subjects. Both groups are comparable (p greater than 0.05) in age, body weight, height and Quetelet index (weight/height2). The back strength of the low back pain patients is not significantly (p greater than 0.05) different from their sex, age and anthropometric matched healthy controls. However, the males in the study were stronger (p less than 0.01) than their female counterparts. Based on our findings, we conclude that weakness of the paraspinal extension muscles is not the likely primary cause of idiopathic low back pain.     

Paralumbar muscle activity in chronic low back pain

Muscle spasm is often considered to be a prominent feature operating in chronic low back spin syndrome (LBP). The present study compared levels of paralumbar muscle activity, determined by an electromyogram (EMG), for LBP patients and normal subjects during periods of rest and voluntary muscular contraction. The resting state EMG measure did not differ in the 2 groups. However, when attempting to relax the low back while contracting other muscle groups, LBP patients exhibited higher mean levels of low back muscle activity as compared to the non-pain group. These results would suggest that such "cocontraction relaxation" procedures may provide a viable behavioral technique for assessing and possibly treating functional backache thought to be symptomatic of muscle spasm. Previous studies employing feedback and progressive relaxation techniques have trained subjects to reduce muscle tension in the resting state. Results of the present study suggest that the acquisition of "resting level" relaxation may be of little benefit to patients who exhibit excessive muscular tension while performing daily tasks. Rather, to maximize the likelihood of beneficial results, training would be better directed at relaxation of the low back during activity of other muscle groups.     

腰痛患者腰活动度、肌力与生活质量的相关回归分析

目的：分析等长和等速运动对腰伸肌肌力的相关性,探讨影响腰痛患者生活质量的主要原因。方法：对20例腰痛患者进行髋关节和腰的活动性测量、腰伸肌等长、等速肌力测定和改良的Oswestry腰痛问卷评分,将结果进行相关和回归分析。结果：腰伸肌等长肌力峰值与慢速等速峰力矩和最大做功量显著性正相关,腰痛问卷得分与腰伸肌肌力、腰屈曲范围和双直腿抬高角度之差显著性负相关。腰痛问卷得分的69.0%可以用腰屈曲范围和腰伸肌肌力来预测。结论：腰伸肌等长肌力测定方法简单,可以作为评定腰痛患者肌力的方法。增加腰活动性和腰伸肌肌力的康复训练可以改善腰痛患者的生活质量。     

青年慢性非特异性腰痛患者腰部本体感觉及其与肌力的相关性

目的:对比青年慢性非特异性腰痛(CNLBP)患者和正常健康青年腰部本体感觉及肌力的差异,并分析腰部本体感觉与肌力的相关性。方法:选取25例青年CNLBP患者纳入腰痛组,25例正常健康青年纳入对照组。采用CON-TREX等速系统测试其腰部本体感觉及腰部屈肌、伸肌肌群在60°/s角速度下的等速向心肌力。以被动复位绝对误差角度(AE)作为个体本体感觉评价指标,以各肌群的峰值力矩(PT)、峰力矩体重比(PT/BW)及屈/伸肌峰值力矩比(F/E)作为等速向心肌力观察的主要指标。并分析CNLBP患者腰部本体感觉与腰部肌力的相关性。结果:(1)腰痛组患者腰部前屈、后伸的AE值均高于对照组,差异有显著性意义(P0.05);(2)腰痛组患者伸肌肌群的PT及PT/BW与对照组相比均有降低,差异有显著性意义(P0.05);腰痛组患者屈肌肌群的PT及PT/BW与对照组相比,差异无显著性意义(P0.05);同时腰痛组F/E与对照组相比,差异无显著性意义(P0.05);(3)腰痛组腰部AE值与PT、PT/BW及F/E之间均无相关性(P0.05)。结论:青年CNLBP患者的腰部本体感觉及腰部伸肌肌群肌力均较正常健康青年有所减弱,且青年CNLBP患者的腰部本体感觉与腰部肌力之间无相关性。     

青年下背痛患者躯干肌力及腰椎曲度的临床研究

目的 研究青年下背痛患者躯干肌力和腰椎曲度的变化以及二者之间的关系。方法 应用CYBEX-6000型等速测试训练系统测试下背痛组和正常组的躯干肌力指标,并在立位腰椎侧位X光片上测量腰椎曲度,两组间进行比较。结果 躯干屈肌:下背痛组PT/BW与正常组无差异(P>0.05),TAE低于正常组(P<0.05),ER大于正常组(P<0.05)。躯干伸肌:下背痛组PT/BW和TAE均低于正常组(P<0.05),ER与正常组无差异(P>0.05)。下背痛组的F/E大于正常组(P<0.05)。下背痛组腰椎曲度小于正常组(P<0.05)。结论 青年下背痛患者存在着明显的腰背肌肌力下降和腰椎生理曲度变直,以及由腰背肌肌力下降所致的躯干肌肌力失衡。     

慢性下腰痛患者腰椎曲度与躯干肌等长收缩肌力的关系

目的：观察慢性下腰痛患者腰椎曲度与躯干肌肌力的变化,为慢性下腰痛的康复和预防提供依据.方法：选择2004-08/12第二军医大学长海医院康复医学科门诊接诊慢性下腰痛患者36例,均为女性;平均（44.2&;#177;3.9）岁;平均体质量（61.9&;#177;7.7）kg;平均身高（160.3&;#177;5.6）cm.对36例患者分别进行躯干肌屈伸等长收缩肌力测试和腰椎曲度测量,并根据腰椎曲度测量结果分为曲度正常组19例和曲度异常组16例,评价两组间等长收缩肌力测试的屈伸峰力矩及屈、伸峰力矩之比.结果：两组屈、伸峰力矩和屈、伸峰力矩之比值的比较：两组躯干肌等长收缩肌力测试中前屈峰力矩无显著差别（t=0.525,P=0.603＞0.05）,曲度异常组后伸峰力矩值显著小于曲度正常组[（86.50&;#177;10.30）,（117.21&;#177;23.32）N&;#183;m,t=4.875,P=0.000＜0.05],曲度异常组前屈和后伸峰力矩之比值显著大于曲度正常组（0.359&;#177;0.050,0.286&;#177;0.009,t=2.699,P=0.011＜0.05）.结论：慢性下腰痛患者躯干肌后伸肌力的显著降低和腰椎曲度的降低可能存在着互为因果的密切关系,加强躯干肌后伸肌力训练和调整腰椎曲度的训练可能会促进慢性下腰痛的康复和预防慢性下腰痛的发生和发展.     

慢性下腰痛患者腰椎曲度与躯干肌等长收缩肌力的关系

目的:观察慢性下腰痛患者腰椎曲度与躯干肌肌力的变化,为慢性下腰痛的康复和预防提供依据。方法:选择2004-08/12第二军医大学长海医院康复医学科门诊接诊慢性下腰痛患者36例,均为女性;平均(44.2±3.9)岁;平均体质量(61.9±7.7)kg;平均身高(160.3±5.6)cm。对36例患者分别进行躯干肌屈伸等长收缩肌力测试和腰椎曲度测量,并根据腰椎曲度测量结果分为曲度正常组19例和曲度异常组16例,评价两组间等长收缩肌力测试的屈伸峰力矩及屈、伸峰力矩之比。结果:两组屈、伸峰力矩和屈、伸峰力矩之比值的比较:两组躯干肌等长收缩肌力测试中前屈峰力矩无显著差别(t=0.525,P=0.603>0.05),曲度异常组后伸峰力矩值显著小于曲度正常组[(86.50±10.30),(117.21±23.32)N·m,t=4.875,P=0.000<0.05],曲度异常组前屈和后伸峰力矩之比值显著大于曲度正常组(0.359±0.050,0.286±0.099,t=2.699,P=0.011<0.05)。结论:慢性下腰痛患者躯干肌后伸肌力的显著降低和腰椎曲度的降低可能存在着互为因果的密切关系,加强躯干肌后伸肌力训练和调整腰椎曲度的训练可能会促进慢性下腰痛的康复和预防慢性下腰痛的发生和发展。     

躯干肌肌力训练与牵伸对慢性腰痛的康复作用观察

目的探讨躯干肌肌力训练与牵伸对慢性腰痛患者的疗效和预防其复发的效果。方法46例慢性腰痛患者随机分为观察组和对照组,观察组采用超短波、躯干肌肌力训练与牵伸;对照组采用超短波、腰背部和下肢传统中医按摩。结果两组经过5个疗程治疗后,观察组总有效率为86.96％,对照组总有效率为65.21％,两组有显著性差异（P<0.05）。结论躯干肌肌力训练与牵伸对慢性腰痛患者的疗效明显并肥有效的防治其复发。     

Pregnancy and low back pain

Back pain is ubiquitous in today’s society and is particularly common during pregnancy. There are multiple factors contributing to these symptoms during pregnancy including pelvic changes as well as alterations to loading. Potential imaging modalities are limited during pregnancy due to the desire to limit ionizing radiation exposure to the fetus. Treatments are generally conservative, exercise-based interventions and alternative modalities may also be considered. Low back pain associated with pregnancy does generally resolve postpartum.     

Neck and low back pain

These cases represent a sample of conditions that impact the spine and paraspinous structures. Central to establishing a correct diagnosis and the cost-effective application of neurodiagnostic tests is a careful history and physical examination. The primary care physician is often the only physician to have a perception of the whole patient. The primary care physician is in an excellent position to initiate the evaluation of patients with spine symptoms and, where appropriate, monitor the treatment plans of consulting physicians.     

Chronic low back pain

Low back pain (LBP) is one of the most prevalent medical problems in society today. In addition to the profound effect LBP can have on patients, it has an exceedingly high societal cost. Although most acute episodes of back pain will ultimately resolve, this condition will become chronic for many. Those with chronic LBP are a challenge to treat. Nonetheless, with a better understanding of the underlying pathophysiology and treatment options, our management of these patients is gradually improving. Conservative therapy remains the mainstay treatment of chronic LBP. If this has failed, surgical options may be considered in the carefully selected patient. Fusion is the most established treatment option for this condition. Disc arthroplasty is being increasingly considered. Class I studies critically evaluating established and evolving technologies continue to help shape our understanding of the surgical options for this condition.     

Easing low back pain

Most of the time, low back pain does not have a serious cause. It may result from straining or “pulling” the muscles in your back or from the pressure of poor posture or overweight. Often, the pain is nearly gone in a week or so with only simple treatment methods.