The effectiveness of EMG biofeedback training in low back pain.

Eighteen patients with chronic low back pain (lbp) of muscle tension origin were given an EMG biofeedback training. Compared to seven controls they showed a significant decrease during training in muscle tension and subsequently in pain. However, at follow-up EMG levels dropped to the initial (high) level. Pain scores of patients with high pain decrements during training showed further improvement during follow-up, which was not the case with patients showing less substantial improvement. The importance of cognitions was discussed.     

Comments on the reliability of muscle activity comparisons in EMG biofeedback research with back pain patients

The underlying assumption in comparing muscle activity levels in back pain research is the reliability of the documented biological record. Surface-recorded EMG data are often used as "objective" indicators in treatment outcome studies. The present paper questions the reliability of this somatic measure. Three sources of error variance that interfere with the reliability of the recorded biological signal are discussed: movement of the body, replacement of electrodes, and electronic equipment instability. It is argued that surface-recorded EMG activities of the back are unreliable and unsuited for comparing the efficacy of a back pain treatment program.     

Postural taping applied to the low back influences kinematics and EMG activity during patient transfer in physical therapists with chronic low back pain

We examined the influence of the application of postural taping on the kinematics of the lumbo–pelvic–hip complex, electromyographic (EMG) activity of back extensor muscles, and the rating of perceived exertion (RPE) in the low back during patient transfer. In total, 19 male physical therapists with chronic low back pain performed patient transfers with and without the application of postural taping on the low back. The kinematics of the lumbo–pelvic–hip complex and EMG activity of the erector spinae were recorded using a synchronized 3-D motion capture system and surface EMG. RPE was measured using Borg’s CR-10 scale. Differences in kinematic data, EMG activity, and RPE between the two conditions were analyzed using a paired t-test. Peak angle and range of motion (ROM) of lumbar flexion, EMG activity of the erector spinae, and RPE decreased significantly, while peak angle and ROM of pelvic anterior tilt and hip flexion increased significantly during patient transfer under the postural taping condition versus no taping (p < 0.05). These findings suggest that postural taping can change back extensor muscle activity and RPE as well as the kinematics of the lumbo–pelvic–hip complex in physical therapists with chronic low back pain during patient transfer.     

A time series analysis of the relationship between ambulatory EMG,pain, and stress in chronic low back pain

Twenty-one subjects with chronic back pain (CBP) participated in an ambulatory electromyography (EMG) monitoring study to ascertain the relationships between muscle activity, physical activity, psychosocial stress, and pain. A time-series analysis approach was adopted to investigate both immediate and lagged associations between these variables in an attempt to determine potential causal relationships. Results for group relationships showed a significant relationship between physical activity and pain, self-report of stress and pain, but no relationship between EMG activity and pain. A lagged relationship between physical activity and pain was found, suggesting a causal relationship between physical activity and pain. However, no time lag was observed between stress and pain, hence no causal relationship can be elucidated. Analysis at the individual level indicated stronger relationships between several combinations of these variables, highlighting the need to consider the heterogeneity of the CBP population and etiology of CBP. The use of ambulatory monitoring of pain, stress, and EMG is suggested as one avenue to further explore the population's heterogeneity.     

The utilization of EMG biofeedback for the treatment of periorbital facial muscle tension

A case is presented of EMG feedback for reduction of tension in the orbicularis oculi muscle of both eyes. Feedback was provided for reduced firing of the upper and lower segments of the muscle. Within 25 sessions for the left eye and 20 sessions for the right, muscle output was markedly reduced from baseline and the patient reported no longer experiencing discomforting sensations of tightness. Follow-up of the patient 3 months posttreatment revealed that the initial problem of muscle tension no longer existed.The author is indebted to Charles H. Fitzpatrick, D.O., for his consultative services, to Augusta Alba, M.D., for her valuable critique and suggestions, and to John Mirone for his statistical services.     

Physical inactivity is associated with narrower lumbar intervertebral discs,high fat content of paraspinal muscles and low back pain and disability

IntroductionAlthough physical inactivity has been associated with numerous chronic musculoskeletal complaints, few studies have examined its associations with spinal structures. Moreover, previously reported associations between physical activity and low back pain are conflicting. This study examined the associations between physical inactivity and intervertebral disc height, paraspinal fat content and low back pain and disability.MethodsSeventy-two community-based volunteers not selected for low back pain underwent magnetic resonance imaging (MRI) of their lumbosacral spine (L1 to S1) between 2011 and 2012. Physical activity was assessed between 2005 and 2008 by questionnaire, while low back pain and disability were assessed by the Chronic Pain Grade Scale at the time of MRI. Intervertebral disc height and cross-sectional area and fat content of multifidus and erector spinae were assessed from MRI.ResultsLower physical activity levels were associated with a more narrow average intervertebral disc height (β −0.63 mm, 95% confidence interval (CI) −1.17 mm to −0.08 mm, P = 0.026) after adjusting for age, gender and body mass index (BMI). There were no significant associations between physical activity levels and the cross-sectional area of multifidus or erector spinae. Lower levels of physical activity were associated with an increased risk of high fat content in multifidus (odds ratio (OR) 2.7, 95% CI 1.1 to 6.7, P = 0.04) and high-intensity pain/disability (OR = 5.0, 95% CI 1.5 to 16.4, P = 0.008) after adjustment for age, gender and BMI.ConclusionsPhysical inactivity is associated with narrower intervertebral discs, high fat content of the multifidus and high-intensity low back pain and disability in a dose-dependent manner among community-based adults. Longitudinal studies will help to determine the cause and effect nature of these associations.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0629-y) contains supplementary material, which is available to authorized users.     

Assessment of low back muscle fatigue by surface EMG signal analysis: methodological aspects.

This paper focuses on methodological issues related to surface electromyographic (EMG) signal detection from the low back muscles. In particular, we analysed (1) the characteristics (in terms of propagating components) of the signals detected from these muscles; (2) the effect of electrode location on the variables extracted from surface EMG; (3) the effect of the inter-electrode distance (IED) on the same variables; (4) the possibility of assessing fatigue during high and very low force level contractions. To address these issues, we detected single differential surface EMG signals by arrays of eight electrodes from six locations on the two sides of the spine, at the levels of the first (L1), the second (L2), and the fifth (L5) lumbar vertebra. In total, 42 surface EMG channels were acquired at the same time during both high and low force, short and long duration contractions. The main results were: (1) signal quality is poor with predominance of non-travelling components; (2) as a consequence of point (1), in the majority of the cases it is not possible to reliably estimate muscle fiber conduction velocity; (3) despite the poor signal quality, it was possible to distinguish the fatigue properties of the investigated muscles and the fatigability at different contraction levels; (4) IED affects the sensitivity of surface EMG variables to electrode location and large IEDs are suggested when spectral and amplitude analysis is performed; (5) the sensitivity of surface EMG variables to changes in electrode location is on average larger than for other muscles with less complex architecture; (6) IED influences amplitude initial values and slopes, and spectral variable initial values; (7) normalized slopes for both amplitude and spectral variables are not affected by IED and, thus, are suggested for fatigue analysis at different postures or during movement, when IED may change in different conditions (in case of separated electrodes); (8) the surface EMG technique at the global level of amplitude and spectral analysis cannot be used to characterize fatigue properties of low back muscles during very low level, long duration contractions since in these cases the non-stable MU pool has a major influence on the EMG variables. These considerations clarify issues only partially investigated in past studies. The limitations indicated above are important and should be carefully discussed when presenting surface EMG results as a means for low back muscle assessment in clinical practice.     

Muscle functional magnetic resonance imaging and acute low back pain: a pilot study to characterize lumbar muscle activity asymmetries and examine the effects of osteopathic manipulative treatment

Background

Muscle functional magnetic resonance imaging (mfMRI) measures transverse relaxation time (T2), and allows for determination of the spatial pattern of muscle activation. The purposes of this pilot study were to examine whether MRI-derived T2 or side-to-side differences in T2 (asymmetries) differ in low back muscles between subjects with acute low back pain (LBP) compared to asymptomatic controls, and to determine if a single osteopathic manipulative treatment (OMT) session alters these T2 properties immediately and 48-hours after treatment.

Methods

Subjects with non-specific acute LBP (mean score on 1-10 visual analog score = 3.02 ± 2.81) and asymptomatic controls (n = 9/group) underwent an MRI, and subsequently the LBP subjects received OMT and then underwent another MRI. The LBP subjects reported back for an additional MRI 48-hours following their initial visit. T2 and T2 asymmetry were calculated from regions of interest for the psoas, quadratus lumborum (QL), multifidus, and iliocostalis lumborum/longissimus thoracis (IL/LT) muscles.

Results

No differences were observed between the groups when T2 was averaged for the left and right side muscles. However, the QL displayed a significantly greater T2 asymmetry in LBP subjects when compared to controls (29.1 ± 4.3 vs. 15.9 ± 4.1%; p = 0.05). The psoas muscle also displayed a relatively large, albeit non-significant, mean difference (22.7 ± 6.9 vs. 9.5 ± 2.8%; p = 0.11). In the subjects with LBP, psoas T2 asymmetry was significantly reduced immediately following OMT (25.3 ± 6.9 to 6.1 ± 1.8%, p = 0.05), and the change in LBP immediately following OMT was correlated with the change in psoas T2 asymmetry (r = 0.75, p = 0.02).

Conclusion

Collectively, this pilot work demonstrates the feasibility of mfMRI for quantification and localization of muscle abnormalities in patients with acute low back pain. Additionally, this pilot work provides insight into the mechanistic actions of OMT during acute LBP, as it suggests that it may attenuate muscle activity asymmetries of some of the intrinsic low back muscles.     

Biochemical adaptations to training: implications for resisting muscle fatigue

Skeletal muscle activity is invariably associated with a decline in force-generating capacity (fatigue). The build-up of metabolic by-products such as intracellular H+ and inorganic phosphate (Pi) has been shown to be one of the potential mechanisms of muscle fatigue. The use of phosphorus magnetic resonance spectroscopy is a repeatable and useful tool to study the effect of pH and Pi on force development. When maximal exercise is preceded by submaximal exercise to reduce the starting muscle pH and increase Pi, the degree of muscle fatigue correlates more strongly with H2PO4- than pH or Pi alone. However, other studies in humans have found that H2PO4- does not always correlate well with fatigue. The use of ramp exercise protocols allow repeatable and sensitive measurement of changes in muscle metabolism in response to endurance training. Chronic electrical stimulation in dogs and endurance training in humans results in reduced pH and Pi changes at the same exercise intensities. This means that the effect of pH and Pi in depressing force development is reduced, which could partially explain the increased fatigue resistance seen following endurance training.     

Association between history and physical examination factors and change in lumbar multifidus muscle thickness after spinal manipulation in patients with low back pain

Understanding the clinical characteristics of patients with low back pain (LBP) who display improved lumbar multifidus (LM) muscle function after spinal manipulative therapy (SMT) may provide insight into a potentially synergistic interaction between SMT and exercise. Therefore, the purpose of this study was to identify the baseline historical and physical examination factors associated with increased contracted LM muscle thickness one week after SMT. Eighty-one participants with LBP underwent a baseline physical examination and ultrasound imaging assessment of the LM muscle during submaximal contraction before and one week after SMT. The relationship between baseline examination variables and 1-week change in contracted LM thickness was assessed using correlation analysis and hierarchical multiple linear regression. Four variables best predicted the magnitude of increases in contracted LM muscle thickness after SMT. When combined, these variables suggest that patients with LBP, (1) that are fairly acute, (2) have at least a moderately good prognosis without focal and irritable symptoms, and (3) exhibit signs of spinal instability, may be the best candidates for a combined SMT and lumbar stabilization exercise (LSE) treatment approach.     

Controlled trial of mobilisation and manipulation for low back pain: hospital patients.

Ninety-four patients with non-specific lumbar pain referred to hospital rheumatology and orthopaedic clinics participated in a double-blind controlled trial comparing mobilisation and manipulation with placebo physiotherapy. Results were assessed immediately after the tratment course, two months later, and at one year. Many patients showed improvement, but in contrast to a study on general-practitioner patients with nonspecific back pain no definite advantage could be associated with mobilisation and manipulation. The benefits of mobilisation and manipulation for low back pain are probably restricted to hastening recovery in patients likely rapidly to improve spontaneously. Hence patients whose severity and duration of symptoms warrant specialist referral are less likely to benefit from the technique.     

The eccentric,concentric strength relationship of the hamstring muscles in chronic low back pain

ObjectiveThe objective of this study was to measure hamstring muscle eccentric and concentric strength in individuals with and without low back pain (LBP). Two composite scores for the relative balance of eccentric to concentric strength at the different movement velocities were calculated (the DEC and SEC), to determine whether or not self perceived pain, disability, or fear avoidance measures were associated with hamstring strength characteristics.DesignCross-sectional repeated measures design.SettingUniversity laboratory.ParticipantsFifteen individuals with chronic LBP and 15 matched controls.Main outcome measuresIsokinetic eccentric and concentric strength at 30° s^?1 and 120° s^?1_. Composite scores (DEC and SEC) based on peak torque were calculated to evaluate the relationship between the different muscle actions across the test velocities. Self report measures included the Oswestry disability index, general health and well being, fear avoidance, and pain.ResultsEccentric/concentric strength ratio at 30° s^?1 was higher for the LBP group (F(1,58) = 4.81, p = 0.032). The SEC was also higher for the LBP (F(1,58) = 5.97, p = 0.018). Fear avoidance beliefs and mental well-being were significantly associated with the SEC only in the LBP group (adjusted r² = 0.26, (F(2,27) = 5.8, p = .008). For the control group both the DEC and SEC were associated with self report measures. Matched differences between groups’ for the SEC were best explained by fear avoidance beliefs about work (adjusted r² = 0.12, F(1,28) = 5.1, p = 0.03).ConclusionReduced concentric relative to eccentric strength is best identified by the SEC. The SEC was significantly associated with impaired self report measures of fear avoidance and mental well being in individuals with LBP. Differences between groups for the SEC were best explained by fear avoidance beliefs about work.     

The impact of wool in the patients with chronic non-specific low back pain

The aim was to assess the effect of wool underwear use in patients with chronic non specific low back pain. The study employed two-group, experimental design. A total of 48 patients with chronic non specific low back pain were selected for the study. They were distributed into two groups: a control group and a treatment group. The 24 patients in each group were randomly selected and the compositions of the two groups. The patients in the treatment group wore woolen underwear during the experimental period of 2 month. All patients were assessed at the beginning the trial (pre-test) and the end of 8th (post-test) week. Data were collected using the visual analogue pain scale, Oswestry Disability Index and Schober test measurements. Patients in the treatment group reported significant improvements in their conditions including a reduction in pain levels and Oswestry Disability Index, and Schober test measurements increased (p<0.001). Patients with chronic non-specific low back pain who wore wool underwear experienced significant improvements in pain intensity, disability, and lower back flexibility.     

Applying psychological theories to evidence-based clinical practice: identifying factors predictive of lumbar spine x-ray for low back pain in UK primary care practice

Background

Effectiveness of combined physician and patient-level interventions for blood pressure (BP) control in low-income, hypertensive African Americans with multiple co-morbid conditions remains largely untested in community-based primary care practices. Demographic, clinical, psychosocial, and behavioral characteristics of participants in the Counseling African American to Control Hypertension (CAATCH) Trial are described. CAATCH evaluates the effectiveness of a multi-level, multi-component, evidence-based intervention compared with usual care (UC) in improving BP control among poorly controlled hypertensive African Americans who receive primary care in Community Health Centers (CHCs).

Methods

Participants included 1,039 hypertensive African Americans receiving care in 30 CHCs in the New York Metropolitan area. Baseline data on participant demographic, clinical (e.g., BP, anti-hypertensive medications), psychosocial (e.g., depression, medication adherence, self-efficacy), and behavioral (e.g., exercise, diet) characteristics were gathered through direct observation, chart review, and interview.

Results

The sample was primarily female (71.6%), middle-aged (mean age = 56.9 ± 12.1 years), high school educated (62.4%), low-income (72.4% reporting less than $20,000/year income), and received Medicaid (35.9%) or Medicare (12.6%). Mean systolic and diastolic BP were 150.7 ± 16.7 mm Hg and 91.0 ± 10.6 mm Hg, respectively. Participants were prescribed an average of 2.5 ± 1.9 antihypertensive medications; 54.8% were on a diuretic; 33.8% were on a beta blocker; 41.9% were on calcium channel blockers; 64.8% were on angiotensin converting enzyme (ACE) inhibitors/angiotensin receptor blockers (ARBs). One-quarter (25.6%) of the sample had resistant hypertension; one-half (55.7%) reported medication non-adherence. Most (79.7%) reported one or more co-morbid medical conditions. The majority of the patients had a Charlson Co-morbidity score ≥ 2. Diabetes mellitus was common (35.8%), and moderate/severe depression was present in 16% of participants. Participants were sedentary (835.3 ± 1,644.2 Kcal burned per week), obese (59.7%), and had poor global physical health, poor eating habits, high health literacy, and good overall mental health.

Conclusions

A majority of patients in the CAATCH trial exhibited adverse lifestyle behaviors, and had significant medical and psychosocial barriers to adequate BP control. Trial outcomes will shed light on the effectiveness of evidence-based interventions for BP control when implemented in real-world medical settings that serve high numbers of low-income hypertensive African-Americans with multiple co-morbidity and significant barriers to behavior change.     

Randomised controlled trial to compare surgical stabilisation of the lumbar spine with an intensive rehabilitation programme for patients with chronic low back pain: the MRC spine stabilisation trial

Objectives To assess the clinical effectiveness of surgical stabilisation (spinal fusion) compared with intensive rehabilitation for patients with chronic low back pain.Design Multicentre randomised controlled trial.Setting 15 secondary care orthopaedic and rehabilitation centres across the United Kingdom.Participants 349 participants aged 18-55 with chronic low back pain of at least one year''s duration who were considered candidates for spinal fusion.Intervention Lumbar spine fusion or an intensive rehabilitation programme based on principles of cognitive behaviour therapy.Main outcome measure The primary outcomes were the Oswestry disability index and the shuttle walking test measured at baseline and two years after randomisation. The SF-36 instrument was used as a secondary outcome measure.Results 176 participants were assigned to surgery and 173 to rehabilitation. 284 (81%) provided follow-up data at 24 months. The mean Oswestry disability index changed favourably from 46.5 (SD 14.6) to 34.0 (SD 21.1) in the surgery group and from 44.8 (SD14.8) to 36.1 (SD 20.6) in the rehabilitation group. The estimated mean difference between the groups was –4.1 (95% confidence interval –8.1 to –0.1, P = 0.045) in favour of surgery. No significant differences between the treatment groups were observed in the shuttle walking test or any of the other outcome measures.Conclusions Both groups reported reductions in disability during two years of follow-up, possibly unrelated to the interventions. The statistical difference between treatment groups in one of the two primary outcome measures was marginal and only just reached the predefined minimal clinical difference, and the potential risk and additional cost of surgery also need to be considered. No clear evidence emerged that primary spinal fusion surgery was any more beneficial than intensive rehabilitation.     

The use of EMG biofeedback for learning of selective activation of intra-muscular parts within the serratus anterior muscle: A novel approach for rehabilitation of scapular muscle imbalance

Motor control and learning possibilities of scapular muscles are of clinical interest for restoring scapular muscle balance in patients with neck and shoulder disorders. The aim of the study was to investigate whether selective voluntary activation of intra-muscular parts within the serratus anterior can be learned with electromyographical (EMG) biofeedback, and whether the lower serratus anterior and the lower trapezius muscle comprise the lower scapula rotation force couple by synergistic activation. Nine healthy males practiced selective activation of intra-muscular parts within the serratus anterior with visual EMG biofeedback, while the activity of four parts of the serratus anterior and four parts of the trapezius muscle was recorded. One subject was able to selectively activate both the upper and the lower serratus anterior respectively. Moreover, three subjects managed to selectively activate the lower serratus anterior, and two subjects learned to selectively activate the upper serratus anterior. During selective activation of the lower serratus anterior, the activity of this muscle part was 14.4 ± 10.3 times higher than the upper serratus anterior activity (P < 0.05). The corresponding ratio for selective upper serratus vs. lower serratus anterior activity was 6.4 ± 1.7 (P < 0.05). Moreover, selective activation of the lower parts of the serratus anterior evoked 7.7 ± 8.5 times higher synergistic activity of the lower trapezius compared with the upper trapezius (P < 0.05). The learning of complete selective activation of both the lower and the upper serratus anterior of one subject, and selective activation of either the upper or lower serratus anterior by five subjects designates the promising clinical application of EMG biofeedback for restoring scapular muscle balance. The synergistic activation between the lower serratus anterior and the lower trapezius muscle was observed in only a few subjects, and future studies including more subjects are required before conclusions of a lower scapula rotation couple can be drawn.     

Randomised controlled trial for evaluation of fitness programme for patients with chronic low back pain.

OBJECTIVE--To evaluate a progressive fitness programme for patients with chronic low back pain. DESIGN--Single blind randomised controlled trial. Assessments were carried out before and after treatment by an observer blinded to the study and included a battery of validated measures. All patients were followed up by postal questionnaire six months after treatment. SETTING--Physiotherapy department of orthopaedic hospital. SUBJECTS--81 patients with chronic low back pain referred from orthopaedic consultants for physiotherapy. The patients were randomly allocated to a fitness programme or control group. INTERVENTION--Both groups were taught specific exercises to carry out at home and referred to a back-school for education in back care. Patients allocated to the fitness class attended eight exercise classes over four weeks in addition to the home programme and backschool. RESULTS--Significant differences between the groups were shown in the changes before and after treatment in scores on the Oswestry low back pain disability index (P < 0.005), pain reports (sensory P < 0.05 and affective P < 0.005), self efficacy reports (P < 0.05), and walking distance (P < 0.005). No significant differences between the groups were found by the general health questionnaire or questionnaire on pain locus of control. A benefit of about 6 percentage points on the disability index was maintained by patients in the fitness group at six months. CONCLUSION--There is a role for supervised fitness programmes in the management of moderately disabled patients with chronic low back pain. Further clinical trials, however, need to be established in other centres to confirm these findings.