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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.

Adolescent↗

Low back pain, disability and back pain myths in a community sample: prevalence and interrelationships.

This study investigated the prevalence of back pain, disability, and, of most importance, the presence of misconceptions about low back pain (LBP), its diagnosis and treatment in a bicultural community sample (Belgium). Using the Graded Chronic Pain Scale [Pain 50 (1992) 133] persons were classified according to pain intensity and disability in five subgroups. The interrelationship between LBP beliefs and these five subgroups was also investigated. In our sample (n=1624) the 6-month prevalence of low back pain was 41.8%. Only in 8.2% back pain was disabling. Misconceptions about back pain were widespread, even in the group reporting no back pain. The least misconceptions were found to exist in participants with mild LBP without disability. It is suggested that recovery from an episode of acute low back pain is an active process that involves a correction of beliefs about harm, about the need to restrict physical activities and about medical diagnosis and cure. Finally, it is argued that community actions may be useful to correct LBP myths in order to prevent the development of long-term disability due to LBP.

Activities of Daily Living↗

Back belt use for prevention of occupational low back pain: a systematic review.

BACKGROUND: Back pain continues to be the leading overall cause of morbidity and lost productivity in the workplace. Recently, there has been a renewed interest in the use of back belts by industry to reduce occupational low back pain (LBP). OBJECTIVES: To examine the literature and evaluate the effectiveness of back belt use for the primary prevention of occupational LBP. METHODS: MEDLINE, CINAHL, EMBASE, and HEALTHSTAR were searched for relevant articles published up to July 2003. Studies were included if participants were material handlers, and outcomes included the incidence and/or duration of lost time of reported LBP among workers who wore back belts compared with those who did not. The quality of the evidence was scored independently by 2 reviewers using a double rating method, first according to research design followed by an internal validity rating. Final synthesis of the evidence was performed in which the evidence was classified as good, fair, conflicting, or insufficient. RESULTS: Ten epidemiologic studies meeting inclusion criteria were identified. Of 5 randomized controlled trials, 3 showed no positive results with back belt use; 2 cohort studies had conflicting results; and 2 nonrandomized controlled studies and 1 survey showed positive results. CONCLUSIONS: Currently, because of conflicting evidence and the absence of high-quality trials, there is no conclusive evidence to support back belt use to prevent or reduce lost time from occupational LBP.

Humans↗

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.

Adult↗

Fear-avoidance beliefs about back pain in patients with subacute low back pain.

The fear-avoidance beliefs of patients with subacute low back pain (LBP) considered at risk for chronic disabling LBP are not well known. The objectives of this cross-sectional descriptive survey, conducted in secondary care practice, were to assess fear-avoidance beliefs about back pain in patients with subacute LBP and to seek an association between physician or patient characteristics and level of fear-avoidance beliefs. A total of 286 rheumatologists completed a self-administered questionnaire assessing physicians' demographic, professional data, personal history of back pain, and back pain fear-avoidance beliefs (on the Fear-Avoidance Belief Questionnaire [FABQ]) and 443 patients with sLBP completed one on pain, perceived handicap and disability (Quebec Back Pain Disability Scale), anxiety and depression (Hospital Anxiety Depression questionnaire), and back pain beliefs (FABQ). Mean FABQ scores for rheumatologists for physical activities (FABQ Phys) and occupational activities (FABQ Work) were 9.2+/-4.4 (range 0-21) and 16.7+/-6.9 (range 2-37), respectively, and patient scores were 16.7+/-5.2 and 19.3+/-12.4, respectively. A total of 68% of patients and 10% of physicians had a high rating on the FABQ Phys (>14). Patients' fear-avoidance beliefs about physical activity were associated with low level of education (odds ratio [OR] 4.19; 95% confidence interval [CI] 1.83-9.57), patients' perceived disability (OR 1.05; CI 1.03-1.07), and physicians' high FABQ Phys score (OR 5.92; CI 1.31-26.32). Here we show that fear-avoidance beliefs about back pain were high in patients with subacute LBP and their rheumatologists.

Acute Disease↗

The impact of treatment confidence on pain and related disability among patients with low-back pain: results from the University of California, Los Angeles, low-back pain study.

BACKGROUND CONTEXT: Although many researchers and practitioners believe that patients' positive expectations of their treatment favorably influence clinical outcomes, there is little scientific evidence to support this belief. PURPOSE: To describe the level of patients' initial confidence in the success of their assigned treatment, by treatment group and other factors; and to estimate the effects of treatment confidence on subsequent changes in low-back pain and related disability. STUDY DESIGN AND PATIENT SAMPLE: Randomized clinical trial involving 681 patients treated for low-back pain in a managed-care facility in Southern California. OUTCOME MEASURES: Treatment confidence; and changes in three clinical measures of low-back pain: average pain, most severe pain and back-pain-related disability. METHODS: Patients were randomly assigned to one of four treatment groups: medical care with and without physical therapy, and chiropractic care with and without physical modalities. Information was collected by questionnaires at baseline, 2 weeks, 6 weeks and 6 months. Treatment confidence was measured just after randomization on a scale of 0 to 10. RESULTS: Treatment confidence was lowest, on average, for patients assigned to medical care only and highest for patients assigned to medical care plus physical therapy. Other predictors of high treatment confidence were having acute pain and being older, female and nonwhite. Although treatment confidence was only weakly associated with subsequent changes in low-back pain or disability in the total sample, high treatment confidence was associated with greater improvement among patients assigned to medical care plus physical therapy. CONCLUSIONS: Initial confidence in treatment for low-back pain varies by type of care and other factors. Higher confidence may have some beneficial effect on the course of low-back pain in certain patients, but this effect may depend on the type of interaction between client and provider.

Adult↗

[Non-operative treatment of chronic low back pain: specific back muscular strength training versus improvement of physical fitness].

AIM: A systematic review was performed to evaluate the clinical effects of specific back muscle and non-specific physical fitness training in chronic low back pain. METHOD: A computer-aided Medline research (19861999) of randomised clinical trials concerning both rehabilitation concepts was conducted. A rating system was used to assess the methodological score of each study. The results were analysed and a final statement for evidence according to three main parameters (back pain, physical capacity, and patients comfort) was postulated. RESULTS: Twelve randomised clinical trials were identified. Nine studies were determined as high-quality trials. For chronic low back pain specific back muscle exercises as well as non-specific fitness training were able to improve the patients' conditions sufficiently. In comparison with passive treatment or no treatment there is strong evidence for pain and physical capacity in both groups, but only a positive influence for patient' comfort in fitness groups. Nevertheless, a confrontation of both concepts in two studies did not reveal any notable differences in all three parameters. CONCLUSION: Principally, a specific strength training for back rnuscles as well as a non-specific fitness training are comparably effective to rehabilitate chronic low back pain.

Combined Modality Therapy↗

Classification of nonspecific low back pain. I. Psychological involvement in low back pain. A clinical, descriptive approach.

An unselected sample of outpatient subjects (n = 330) with localized nonspecific low back pain (LBP) was studied. Investigation consisted of clinical assessment, physical examination, and psychiatric interview based on the DSM-III classification. A psychiatric disorder, according to the DSM-III criteria (axis I) was found in 41% of the subjects. Multiple correspondence analysis and cluster analysis were used to objectively identify clinical subtypes without preconceived theoretical models. Correspondence analyses suggested the existence of a 'psychological pain' syndrome consisting of several of the following symptoms: diffuse back pain, impossibility to assess intensity of pain on a pain scale, aggravation of pain by changing climate, by domestic activities or by psychological factors and dysesthesias in the back. Cluster analysis provided support for a four-group classification of low back pain, which may be interpreted through the relationships between psychological disturbances and the LBP clinical features. The results call for further investigation of the complex relationship between psychological disturbances and back pain. However, clinicians must be aware of the interest of a minimal psychiatric assessment in low back pain patients: psychiatric disorders frequently appear in these patients and an appropriate treatment of the psychiatric syndrome may reduce back pain.

Adolescent↗

Estimating the prevalence of low back pain in the general population. Evidence from the South Manchester Back Pain Survey.

STUDY DESIGN: This report gives the results of a population-based cross-sectional mailed questionnaire, with prospective follow-up of survey responders and nonresponders. OBJECTIVE: To determine the 1-month period prevalence of low back pain in an adult population in the United Kingdom and to estimate the effect of nonresponse bias. SUMMARY OF BACKGROUND DATA: Previous United Kingdom population studies have reported a 1-year period prevalence of low back pain of 37%. However, the definitions of low back pain have varied, and the influence of nonresponse rarely has been reported. METHODS: The study population was made up of all 7669 adults (18 to 75 years old) registered with two family practices in a sociodemographically mixed suburban area. The questionnaire, including a pain drawing to identify the site of any pain, was mailed to the entire study population. Two repeat mailings were sent to nonresponders. Family practice consultations about low back pain by individuals from the study population were monitored over the following 12 months using computerized records of all surgery contacts. RESULTS: Of the study population, 4501 (59%) responded. The 1-month period prevalence of low back pain was 39% (35% in males, 42% in females). The age distribution was unimodal, with peak prevalence in those aged 45 to 59 years old. Responders to the first mailing had a small but nonsignificant increase in prevalence compared with those who responded to the second or third mailing. Nonresponders had a subsequent consultation rate for low back pain that was 22% lower than that for the survey responders. CONCLUSIONS: After considering potential differences in nonresponders, the estimated 1-month prevalence of low back pain was between 35% and 37%. Prevalence figures in survey responders may overestimate the true population prevalence by a modest amount.

Adolescent↗

The effectiveness of acupuncture in the management of acute and chronic low back pain. A systematic review within the framework of the Cochrane Collaboration Back Review Group.

STUDY DESIGN: A systematic review of randomized controlled trials. OBJECTIVES: To evaluate the efficacy and effectiveness of acupuncture for the management of nonspecific low back pain. SUMMARY OF BACKGROUND DATA: Acupuncture is one of the oldest forms of therapy, but little is known about the effectiveness of acupuncture for low back pain. METHODS: Randomized controlled trials were done to assess the effectiveness of all types of acupuncture treatment, which involves needling for subjects with nonspecific low back pain. Two reviewers blinded with respect to authors, institution, and journal independently assessed the methodologic quality of the studies. Because data were statistically and clinically too heterogeneous, a qualitative review was performed. The evidence was classified into four levels: strong, moderate, limited, or no evidence. RESULTS: Eleven randomized controlled trials were included. Overall, the methodologic quality was low. Only two studies met the preset "high quality" level for this review. No study clearly evaluated acupuncture for acute low back pain. The results indicate that there was no evidence showing acupuncture to be more effective than no treatment. There was moderate evidence indicating that acupuncture is not more effective than trigger-point injection or transcutaneous electrical nerve stimulation, and there was limited evidence that acupuncture is not more effective than placebo or sham acupuncture for the management of chronic low back pain. CONCLUSIONS: Because this systematic review did not clearly indicate that acupuncture is effective in the management of back pain, the authors would not recommend acupuncture as a regular treatment for patients with low back pain. There clearly is a need for more high-quality randomized controlled trials.

Acupuncture Analgesia↗

Nonsteroidal anti-inflammatory drugs for low back pain: a systematic review within the framework of the Cochrane Collaboration Back Review Group.

STUDY DESIGN: A systematic review of randomized and double-blind controlled trials was performed. SUMMARY OF BACKGROUND DATA: Nonsteroidal anti-inflammatory drugs are the most frequently prescribed medications worldwide and are widely used for patients with low back pain. OBJECTIVES: To assess the effects of nonsteroidal anti-inflammatory drugs in the treatment of nonspecific low back pain with or without radiation, and to assess which type of nonsteroidal anti-inflammatory drug is most effective. METHODS: For this study, the Cochrane Controlled Trials Register, Medline and Embase, and reference lists of articles were searched. Two reviewers blinded with respect to authors, institution, and journal independently extracted data and assessed the methodologic quality of the studies. If data were considered clinically homogeneous, a meta-analysis was performed. If data were considered clinically heterogeneous, a qualitative analysis was performed using a rating system with four levels of evidence: strong, moderate, limited, and no evidence. RESULTS: This review involved 51 trials and 6057 patients. Of these trials, 16 (31%) were of high quality. The pooled relative risk for global improvement after 1 week was 1.24 (95% confidence interval [CI] = 1.10-1.41), and for additional analgesic use was 1.29 (95% CI = 1.05-1.57), indicating a statistically significant but small effect in favor of nonsteroidal anti-inflammatory drugs as compared with a placebo. The results of the qualitative analysis showed that there is conflicting evidence (Level 3) that nonsteroidal anti-inflammatory drugs are more effective than paracetamol for acute low back pain, and that there is moderate evidence (Level 2) that nonsteroidal anti-inflammatory drugs are not more effective than other drugs for acute low back pain. There is strong evidence (Level 1) that various types of nonsteroidal anti-inflammatory drugs are equally effective for acute low back pain. CONCLUSIONS: The evidence from the 51 trials included in this review suggests that nonsteroidal anti-inflammatory drugs are effective for short-term symptomatic relief in patients with acute low back pain. Furthermore, there does not seem to be a specific type of nonsteroidal anti-inflammatory drug that is clearly more effective than others. Sufficient evidence on chronic low back pain still is lacking.

Adolescent↗

Surfing for back pain patients: the nature and quality of back pain information on the Internet.

STUDY DESIGN: A prospective, systematic review of web sites related to back pain. OBJECTIVE: To assess the nature and quality of back pain-related information on the World Wide Web during a 2-year period. SUMMARY OF BACKGROUND DATA: The Internet has become a rich source of medical information. Limited knowledge is available, however, about the quality of online resources. Although previous systematic reviews on medical-related web sites found problems in varying degrees with the credibility of information, no such review was conducted to assess the back pain-related sites. METHODS: A search of web sites was conducted in November 1996 using five search engines (AltaVista, Infoseek, Lycos, Yahoo, and Magellan) and two key terms ("back pain" and "back problems"). A sample of sites was evaluated by two independent reviewers. Each site was described by the type and nature of the sponsor, target audience, and content. Overall quality was assessed in terms of evidence-based information available. RESULTS: Seventy-four web sites were reviewed in 1996, and nine of them (12.2%) were identified as high-quality sites. Advertising was the focus of 80.8% of the sites. Eleven sites (14.9%) were found to be discontinued 1 year later, and 20 (27.0%) were not accessible by the reviewers at the 2-year follow-up evaluation. Of the remaining 54 sites, 44.4% were produced by for-profit companies, and most sites targeted people with back pain (63.0%). Only seven out of the nine high-quality sites held their ratings at the 2-year follow-up evaluation. CONCLUSION: Most back pain-related web sites can be classified as advertising. The quality varied considerably, resulting in difficulties for patients to find useful information in this field. The increasing number of people seeking medical information on the Web creates a need for more high quality sites. Further, systematic review of web sites should be encouraged to monitor the accuracy of Internet publication.

Bias↗

A randomized trial of medical care with and without physical therapy and chiropractic care with and without physical modalities for patients with low back pain: 6-month follow-up outcomes from the UCLA low back pain study.

STUDY DESIGN: A randomized clinical trial. OBJECTIVES: To compare the effectiveness of medical and chiropractic care for low back pain patients in managed care; to assess the effectiveness of physical therapy among medical patients; and to assess the effectiveness of physical modalities among chiropractic patients. SUMMARY OF BACKGROUND DATA: Despite the burden that low back pain places on patients, providers, and society, the relative effectiveness of common treatment strategies offered in managed care is unknown. METHODS: Low back pain patients presenting to a large managed care facility from October 30, 1995, through November 9, 1998, were randomly assigned in a balanced design to medical care with and without physical therapy and to chiropractic care with and without physical modalities. The primary outcome variables are average and most severe low back pain intensity in the past week, assessed with 0 to 10 numerical rating scales, and low back-related disability, assessed with the 24-item Roland-Morris Disability Questionnaire. RESULTS: Of 1,469 eligible patients, 681 were enrolled; 95.7% were followed through 6 months. The mean changes in low back pain intensity and disability of participants in the medical and chiropractic care-only groups were similar at each follow-up assessment (adjusted mean differences at 6 months for most severe pain, 0.27, 95% confidence interval, -0.32-0.86; average pain, 0.22, -0.25-0.69; and disability, 0.75, -0.29-1.79). Physical therapy yielded somewhat better 6-month disability outcomes than did medical care alone (1.26, 0.20-2.32). CONCLUSIONS: After 6 months of follow-up, chiropractic care and medical care for low back pain were comparable in their effectiveness. Physical therapy may be marginally more effective than medical care alone for reducing disability in some patients, but the possible benefit is small.

Analgesics↗

Low back pain in professional golfers: the role of associated hip and low back range-of-motion deficits.

BACKGROUND: Low back pain is fairly prevalent among golfers; however, its precise biomechanical mechanism is often debated. HYPOTHESIS: There is a positive correlation between decreased lead hip rotation and lumbar range of motion with a prior history of low back pain in professional golfers. STUDY DESIGN: A cross-sectional study. METHODS: Forty-two consecutive professional male golfers were categorized as group 1 (history of low back pain greater than 2 weeks affecting quality of play within past 1 year) and group 2 (no previous such history). All underwent measurements of hip and lumbar range of motion, FABERE's distance, and finger-to-floor distance. Differences in measurements were analyzed using the Wilcoxon signed rank test. RESULTS: 33% of golfers had previously experienced low back pain. A statistically significant correlation (P <.05) was observed between a history of low back pain with decreased lead hip internal rotation, FABERE's distance, and lumbar extension. No statistically significant difference was noted in nonlead hip range of motion or finger-to-floor distance with history of low back pain. CONCLUSIONS: Range-of-motion deficits in the lead hip rotation and lumbar spine extension correlated with a history of low back pain in golfers.

Adult↗

Electric behavior of low back muscles during lumbar pelvic rhythm in low back pain patients and healthy controls.

UNLABELLED: The functioning of low back muscles of back pain patients during flexion and reextension has not been properly investigated. In this study, we analyzed rectified, averaged electric activity (RMS EMG) and corresponding raw intramuscular (IM) EMG from lumbar paraspinal muscles to quantify the activity level during simple bending cycles in 87 back pain patients compared to 25 able-bodied controls. THE RESULTS: All functional phases seen in raw IM EMG were also shown in surface RMS EMG. Surface RMS EMG pattern seems to yield more information from activity level than IM EMG pattern. The RMS EMG patterns of back pain patients differed from those of controls as follows: (1) There was clearly noticeable activity during standing in back pain patients. (2) There was only a partial decrease of EMG activity after flexion in back pain patients with current pain. (3) The ratio of mean reached at maximal activity level during extension and flexion was less in patients (1.8, SD = 0.5, p less than .001) than able-bodied controls (3.2, SD = 0.8). (4) Segmental differences were observed in IM EMG activities in patients having hypermobility in bending x-ray. (5) Large peak potentials occurred during movements in patients having segmental hypermobility. THE RESULTS indicate that averaged surface recording is a valuable tool in the investigation of dynamic spine functions in back pain patients.

Adult↗

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.

Adult↗

Back muscle injury after posterior lumbar spine surgery. Topographic evaluation of intramuscular pressure and blood flow in the porcine back muscle during surgery.

STUDY DESIGN: Intramuscular pressure and blood flow of the back muscles were evaluated topographically during posterior lumbar spine surgery. The topographic damage of the back muscle after surgery was studied. OBJECTIVE: To investigate the relationship between intramuscular pressure or blood flow during posterior lumbar surgery and the back muscle injury after surgery. SUMMARY OF BACKGROUND DATA: Latrogenic back muscle injury in an animal and human model has been reported previously. Changes of intramuscular pressure and blood flow during surgery might be related to the muscle injury. No previous study on this issue has been published. METHODS: The contact pressure between the retractor blade and muscle tissue was monitored in 10 pigs during posterior surgery of the lumbar spine. On one side, intramuscular pressure at 5, 10, and 20 mm lateral to the retractor and on the other side blood flow of the back muscle at 5 and 20 mm during surgery were measured. Histologic changes of the back muscle at 5, 10, and 20 mm to the midline were evaluated 3 hours after surgery. RESULTS: The contact pressure decreased exponentially with time. Intramuscular pressure 5 mm lateral to the retractor was 114 +/- 31 mm Hg and was significantly higher than at 10 mm and 20 mm. Blood flow markedly decreased during surgery and recovered incompletely after releasing the retractor at 5 mm and 20 mm lateral to the retractor. Blood flow at 5 mm was significantly lower than at 20 mm throughout surgery. The muscle damage 3 hours after surgery was more severe near the retractor blade. CONCLUSIONS: The back muscles were exposed to pathophysiologic condition by a retractor during posterior lumbar spine surgery. External compression by a retractor increases intramuscular pressure to levels that impede local muscle blood flow. The muscle degeneration after surgery could be explained by direct mechanical damage and by the increased intramuscular pressure of muscle tissue by the retractor.

Animals↗

Back muscle strength and fatigue in healthy and chronic low back pain subjects: a comparative study of 3 assessment protocols.

OBJECTIVE: To compare the sensitivity of 3 different back test protocols in measuring differences in strength and fatigue between subjects with and without chronic low back pain (CLBP). DESIGN: Descriptive study using a repeated-measures design. SETTING: A research laboratory within a rehabilitation center. PARTICIPANTS: Eighteen healthy subjects and 13 subjects with CLBP were assessed in a single session to compare the 3 protocols. The protocols were an upright position test (UPP), a semicrouched lifting test (LIF), and the Sorensen fatigue test. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Moments of force and surface electromyography were recorded bilaterally from 4 homologous back muscles while the subjects performed static trunk extension efforts for each protocol. Fatigue was quantified by the slopes of the linear regression of electromyography time-series. RESULTS: The back muscle fatigue and strength scores did not differ significantly for the 2 subject groups for any of the 3 protocols. The electromyography fatigue indices revealed that the Sorensen fatigue test and UPP produced more fatigue in the back muscles than the LIF. CONCLUSIONS: It was impossible to specify which protocol is more sensitive to low back status because no between-group difference was observed for any of the 3 tests.

Adult↗