The relationship beween posture and back muscle endurance in industrial workers with flexion-related low back pain

This preliminary cross-sectional study was undertaken to determine if there were measurable relationships between posture, back muscle endurance and low back pain (LBP) in industrial workers with a reported history of flexion strain injury and flexion pain provocation. Clinical reports state that subjects with flexion pain disorders of the lumbar spine commonly adopt passive flexed postures such as slump sitting and present with associated dysfunction of the spinal postural stabilising musculature. However, to date there is little empirical evidence to support that patients with back pain, posture their spines differently than pain-free subjects. Subjects included 21 healthy industrial workers and 24 industrial workers with flexion-provoked LBP. Lifestyle information, lumbo-pelvic posture in sitting, standing and lifting, and back muscle endurance were measured. LBP subjects had significantly reduced back muscle endurance (P < 0.01). LBP subjects sat with less hip flexion, (P = 0.05), suggesting increased posterior pelvic tilt in sitting. LBP subjects postured their spines significantly closer to their end of range lumbar flexion in 'usual' sitting than the healthy controls (P < 0.05). Correlations between increased time spent sitting, physical inactivity and poorer back muscle endurance were also identified. There were no significant differences found between the groups for the standing and lifting posture measures. These preliminary results support that a relationship may exist between flexed spinal postures, reduced back muscle endurance, physical inactivity and LBP in subjects with a history of flexion injury and pain.     

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.     

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.     

Back pain and isometric back muscle strength of workers in a Danish factory.

105 factory workers (38 females and 67 males) have been questioned about their frequency of back pain. 60% of the females and 61% of the males have previously experienced episodes of back pain. 21% of the females and 37% of the males have been absent from work due to back pain. The incidence of back pain is not related to age, height, sort of work, or isometric muscle strength of the back (IS). For the males the incidence rises with increasing weight, i.e. combination of height and obesity, but is not related to any two single factors. For the females there is no correlation between the incidence of pain and weight. IS is correlated to height and age in the males but not in the females. Standards for IS are presented and suggested as a guide to evaluation of the working capabilities of individual subjects with back pain.     

Biopsychosocial factors are associated with low back pain in female nursing students: A cross-sectional study

Background

Occupational low back pain is a significant problem among nurses. Recent literature suggests current occupational preventative strategies for nurses have not been effective. Given low back pain is already prevalent before commencing employment, nursing students should be the target of preventative interventions. Modifiable personal factors which contribute to low back pain have proven difficult to identify, but are thought to play an important role in the biopsychosocial nature of low back pain.

Objectives

To evaluate the contribution of personal biopsychosocial factors to low back pain in nursing students.

Design

Cross-sectional study comprising physical testing and questionnaires.

Settings

Two university undergraduate nursing schools in Western Australia.

Participants

170 female undergraduate nursing students.

Methods

Low back pain and control subjects were compared across social, lifestyle (physical activity), psychological (stress, anxiety, depression, back pain beliefs, coping strategies and catastrophising) and physical (spinal postures and spinal kinematics in functional tasks, leg and back muscle endurance, spinal repositioning error and cardiovascular fitness) characteristics. Low back pain was considered as either “minor” or “significant” depending upon pain severity, duration, impact and level of disability.

Results

Over 30% of all subjects (mean age 22.5 ± 4.5 years) reported “significant” low back pain in the preceding 12 months. Univariate analysis: social measures did not distinguish between groups. Subjects with “significant” low back pain were more physically active (p = 0.04), had higher stress scores (p = 0.01) and used passive coping strategies (p < 0.001) more than other subjects. “Significant” low back pain subjects held their lower lumbar spine in a more extended posture during transfers at bed height than other subjects. No differences between groups were found for sagittal spinal mobility, static spinal posture, muscle endurance, spinal repositioning error, cardiovascular fitness or other psychological measures. Multivariate analysis: regression analysis revealed stress, coping, physical activity, spinal kinematics, and age all contributed independently to the presence of low back pain, representing a significant 23% of variance.

Conclusions

Modifiable lifestyle, psychological and physical factors were independently associated with low back pain in nursing students. Targeting personal factors associated with low back pain in nursing students, rather than occupational factors in working nurses may help improve the impact of low back pain in nurses. Prospective studies are required to confirm the relevance of these findings for risk of future low back pain in nurses.     

The role of exercise and posture in preventing low back injury

Low back injury is a serious problem for U.S. industries, accounting for as much as one third of all workers' compensation payments. The number of low back injuries can be reduced effectively through the stressing of proper posture and the use of back care exercises. Body posture that maintains the spine's three natural curves decreases intradiscal stress. Back care exercises decrease the likelihood of low back injury by strengthening and adding flexibility to the spine's supportive structures.     

Web-based touch-screen computer assessment of chronic low back pain: a pilot study

The objective of this study was to evaluate the acceptability and feasibility of a Web-based touch-screen computer questionnaire as a data collection method for patients experiencing chronic low back pain in a tertiary spine clinic. Participants completed the Oswestry Low Back Pain Disability Index, SF-36, and Beck Depression Inventory using a touch-screen computer. The time taken to complete the questionnaire was recorded electronically (M = 27.4 minutes; SD = 13.8). Prior computer experience and perceptions of computer use were also assessed. Low back pain was evaluated before and after completing the touch-screen computer questionnaire. Observations of sitting and standing tolerances were made. Participants completed a nine-item paper-and-pencil satisfaction survey after completing the computer questionnaire. Overall satisfaction level with this mode of data collection was high, supporting a larger study using touch-screen technology in patients with chronic low back pain. Important factors influencing satisfaction were the computer environment, ease of use, security, and the ability to interrupt the questionnaire process to allow for changes in sitting or standing posture.     

体力活动对慢性非特异性腰痛患者疼痛和姿势控制的影响

摘要 目的：探索体力活动对慢性非特异性腰痛（chronic non-specific low back pain, CNSLBP）患者的疼痛和姿势控制能力的影响。 方法：根据是否符合世界卫生组织建议的体力活动标准,受试者被分为体力活动达标组和体力活动不达标组,每组分别纳入31例CNSLBP患者。采集患者的基本信息,评估患者的腰痛程度和姿势控制能力（包括腰部屈伸活动度、闭眼单腿站和下肢Y平衡测试）。 结果：与缺乏体力活动的CNSLBP患者相比,体力活动达标的患者疼痛症状较轻,姿势控制功能更佳,包括过去一周最严重疼痛评分（P<0.01）、过去一周平均疼痛评分（P<0.01）、腰部屈伸活动范围（P<0.05）、静态平衡（P<0.05）和大部分的Y平衡测试。 结论：常参加体力活动的CNSLBP患者疼痛强度较缺乏体力活动者轻,姿势控制功能也优于缺乏体力活动者。     

Physical activity and low back pain: A critical narrative review

BackgroundNon-specific low back pain (LBP) is the leading cause of years lived with disability worldwide. Physical activity is an integral part of LBP treatment.ObjectiveTo critically review available evidence regarding the efficacy of physical activity for people with LBP.MethodsUp to date critical narrative review of the efficacy of physical activity for the managment LBP. The process of article selection was unsystematic; articles were selected based on authors’ expertise, self-knowledge and reflective practice.ResultsTherapeutic physical activity for LBP includes a wide range of non-specific and specific activities. The efficacy of physical activity on pain and activity limitations has been widely assessed. In acute and subacute LBP, exercise did not reduce pain compared to no exercise. In chronic low back pain (CLBP), exercise reduced pain at the earliest follow-up compared with no exercise. In a recent systematic review, exercise improved function both at the end of treatment and in the long-term compared with usual care. Exercice also reduced work disability in the long-term. We were unable to establish a clear hierarchy between different exercise modalities. Multidisciplinary functional programs consistently improved pain and function in the short- and long-term compared with usual care and physiotherapy and improved the long-term likelihood of returning to work compared to non-multidisciplinary programs.ConclusionPhysical activity of all types is an effective treatment for CLBP.     

Trunk muscle strength and low back pain

The strength of the trunk muscles was measured in a group of young males with low back insufficiency (n=7) and in an age matched (19-21 yrs) healthy control group (n=8). A recently designed new application of the isokinetic technique was used to record maximal torque produced by the trunk muscles during flexion, extension and lateral flexion. Trunk muscle strength was measured during isometric contractions in different trunk positions and during slow isokinetic contractions in the whole range of motion. No significant differences between the groups were observed for trunk extension, lateral flexion or flexion with the centre of rotation at L2-L3 level. However, in the initial part of isokinetic trunk flexion with the pivot point at the hip joint the strength values for the back patients were significantly lower than for the controls. The present results demonstrate the importance of a comprehensive approach to the assessment of trunk muscle strength, including different movement velocities, body positions and pivot points. Further studies are needed to evaluate the significance of the specific weakness observed in dynamic trunk flexion strength in the back patients.     

Effect of postural angle on back muscle activities in aging female workers performing computer tasks

[Purpose] This study investigated the effects of postural angle on back muscle activity during a computer task in aging women. [Subjects] Seventeen women ≥50 years old participated. [Methods] The participants were instructed to perform computer-related tasks for 20 minutes on a workstation that simulated typical office working conditions. Back posture was measured from the measured trunk and pelvic angles. Electromyography activities were recorded simultaneously from the cervical erector spinae, longissimus, and multifidus muscles. [Results] The lowest mean percentages of maximum voluntary contraction for the cervical erector spinae and longissimus muscles were obtained when the upper trunk and pelvic angles were between 0° to −5° from the sagittal plane. The back muscle activities increased as the upper trunk and pelvic angles exceeded 0°. Statistical analysis showed significant correlations between upper trunk angle and cervical erector spinae and longissimus muscle activities. Similarly, pelvic angle was significantly correlated with cervical erector spinae and multifidus muscle activities. [Conclusion] A neutral back posture minimizes muscle activities in aging women performing computer tasks.Key words: Postural angle, Muscle activity, Aging     

Association of low back pain with muscle stiffness and muscle mass of the lumbar back muscles,and sagittal spinal alignment in young and middle-aged medical workers

BackgroundMuscle stiffness of the lumbar back muscles in low back pain (LBP) patients has not been clearly elucidated because quantitative assessment of the stiffness of individual muscles was conventionally difficult. This study aimed to examine the association of LBP with muscle stiffness assessed using ultrasonic shear wave elastography (SWE) and muscle mass of the lumbar back muscle, and spinal alignment in young and middle-aged medical workers.MethodsThe study comprised 23 asymptomatic medical workers [control (CTR) group] and 9 medical workers with LBP (LBP group). Muscle stiffness and mass of the lumbar back muscles (lumbar erector spinae, multifidus, and quadratus lumborum) in the prone position were measured using ultrasonic SWE. Sagittal spinal alignment in the standing and prone positions was measured using a Spinal Mouse. The association with LBP was investigated by multiple logistic regression analysis with a forward selection method. The analysis was conducted using the shear elastic modulus and muscle thickness of the lumbar back muscles, and spinal alignment, age, body height, body weight, and sex as independent variables.FindingsMultiple logistic regression analysis showed that muscle stiffness of the lumbar multifidus muscle and body height were significant and independent determinants of LBP, but that muscle mass and spinal alignment were not. Muscle stiffness of the lumbar multifidus muscle in the LBP group was significantly higher than that in the CTR group.InterpretationThe results of this study suggest that LBP is associated with muscle stiffness of the lumbar multifidus muscle in young and middle-aged medical workers.     

Reduced task-induced variations in the distribution of activity across back muscle regions in individuals with low back pain

This study investigated change in the distribution of lumbar erector spinae muscle activity and pressure pain sensitivity across the low back in individuals with low back pain (LBP) and healthy controls. Surface electromyographic (EMG) signals were recorded from multiple locations over the lumbar erector spinae muscle with a 13 × 5 grid of electrodes from 19 people with chronic nonspecific LBP and 17 control subjects as they performed a repetitive lifting task. The EMG root mean square (RMS) was computed for each location of the grid to form a map of the EMG amplitude distribution. Pressure pain thresholds (PPT) were recorded before and after the lifting task over a similar area of the back. For the control subjects, the EMG RMS progressively increased more in the caudal region of the lumbar erector spinae during the repetitive task, resulting in a shift in the distribution of muscle activity. In contrast, the distribution of muscle activity remained unaltered in the LBP group despite an overall increase in EMG amplitude. PPT was lower in the LBP group after completion of the repetitive task compared to baseline (average across all locations: pre: 268.0 ± 165.9 kPa; post: 242.0 ± 166.7 kPa), whereas no change in PPT over time was observed for the control group (320.1 ± 162.1 kPa; post: 322.0 ± 179.5 kPa). The results demonstrate that LBP alters the normal adaptation of lumbar erector spinae muscle activity to exercise, which occurs in the presence of exercise-induced hyperalgesia. Reduced variability of muscle activity may have important implications for the provocation and recurrence of LBP due to repetitive tasks.     

The effect of the Swedish Back School in chronic idiopathic low back pain. A prospective controlled study

A prospective controlled study of the effect of the Swedish Back School in chronic idiopathic Low Back Pain was conducted. Forty-eight patients entered the study. There were no significant pre-treatment differences between the experimental group members who attended the four lessons of the Back School, and the control group who received four detuned shortwave applications to the low back. Forty-three patients (21 in the experimental and 22 in the control group) completed the study. Subjects were repeatedly tested for one year. The following assessments were made: 1) subjective scores of pain and functional capacity, and 2) objective measurements of spinal mobility. After one year, no statistically significant differences between the two groups were observed. Given the proven efficacy of the Back School in (sub)acute Low Back Pain, it should be administered when it is most beneficial, i.e. in the early phase of Low Back Pain.     

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。     

A qualitative study: Clinical decision making in low back pain

Classification systems are available to subgroup patients with acute/nonspecific low back pain (LBP) to determine interventions. The use of classification systems by physical therapists (PT) has little published evidence. The aims of this study were to understand the process PTs use when assessing and determining interventions for patients with acute/nonspecific LBP in outpatient settings and what classification systems, if any, are used in clinical practice. Qualitative methods were used to investigate the decision-making process PTs use when managing patients with LBP. Semi-structured interviews focused on the decision-making process of examination and intervention selection for patients with LBP. Findings were verified through member checking, triangulation, and audit trail. Thirteen PTs were included in the study. Four decision-making preferences emerged from the data: (1) identifying the root cause, (2) eclectic approach, (3) experience-based management, and (4) evidence-based management. Experience, education, and other aspects of the PTs' backgrounds influenced their preferred decision-making style, and use of resources, such as classification systems, varied broadly.     

Precision control of an upright trunk posture in low back pain patients

Background

Low back pain appears to be associated with impaired trunk postural control, which could be caused by proprioceptive deficits. We assessed control of trunk posture in conditions requiring high and low precision, with and without disturbance of proprioception by lumbar muscle vibration.

Methods

Twenty a-specific low back pain patients and 13 healthy controls maintained a self-chosen upright trunk posture. Initial frontal and sagittal plane angles of an opto-electronic marker on the 12th thoracic spinous process defined the center of a target area on a monitor. Subjects were instructed to stay within that target and visual feedback was provided when they left the target. The precision demand was manipulated by changing target size. The standard deviation of trunk angle quantified precision and mean Euclidian distance to target center quantified accuracy. Ratios of antagonistic co-activation were calculated from trunk muscle electromyography recordings.

Findings

With the small target, visual feedback was present intermittently and patients controlled their trunk as accurately and precisely as healthy controls. For the large target, subjects mostly stayed within the target, and patients were on average 0.18° (31%) less accurate than healthy controls (P = 0.025), due to a larger postural drift. Lumbar muscle vibration deteriorated control over trunk posture in both groups and ratios of antagonistic co-activation did not differ between groups or conditions.

Interpretation

These results indicate that the weighting of proprioceptive feedback from lumbar muscle spindles did not differ between groups and that low back pain patients were less able to detect low frequency drift in posture.     

Changes in muscle activity and stature recovery after active rehabilitation for chronic low back pain

Patients with low back pain often demonstrate elevated paraspinal muscle activity compared to asymptomatic controls. This hyperactivity has been associated with a delayed rate of stature recovery following spinal loading tasks. The aim of this study was to investigate the changes in muscle activity and stature recovery in patients with chronic low back pain following an active rehabilitation programme. The body height recovery over a 40-min unloading period was assessed via stadiometry and surface electromyograms were recorded from the paraspinal muscles during standing. The measurements were repeated after patients had attended the rehabilitation programme and again at a six-month follow-up. Analysis was based on 17 patients who completed the post-treatment analysis and 12 of these who also participated in the follow-up. By the end of the six months, patients recovered significantly more height during the unloading session than at their initial visit (ES = 1.18; P < 0.01). Greater stature recovery immediately following the programme was associated with decreased pain (r = −0.55; P = 0.01). The increased height gain after six months suggests that delayed rates of recovery are not primarily caused by disc degeneration. Muscle activity did not decrease after treatment, perhaps reflecting a period of adaptation or altered patterns of motor control.