vendex and Low-Back-Pain

The purpose of this systematic review was to: (I) determine the quality of evidence from studies assessing trunk isokinetic strength in subjects with acute low back pain (ALBP) compared to healthy subjects and (II) establish reference values of isokinetic trunk strength in subjects with ALBP.. Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) statements were followed using keywords associated with trunk, strength and low back pain. Four databases were used: PubMed, Web of Science, Scopus and SPORTDiscus. Methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS).. A total of 1604 articles were retrieved, four included in this review. All were evaluated as high risk of bias (Rob). Due to the high Rob and the diversity of protocols, instruments and variables used, it was not possible to determine reference values for subjects with ALBP, we can only establish a range of flexion peak torque (PT) between 175.1 and 89.7 Nm at 60°/s and between 185 and 81.5 Nm at 120°/s, and for extension PT between 240.0 and 91.5 Nm at 60°/s and between 217.5 and 69.2 Nm at 120°/s in subjects with ALBP.. Due to the low quality of the evidence and the diversity of protocols used when measuring trunk isokinetic strength, it is necessary to carry out new high-quality research to establish reference values of trunk strength in subjects with ALBP.

Topics: Healthy Volunteers; Humans; Low Back Pain; Muscle, Skeletal; Torque; Torso

KT is an elastic taping that has been widely used as an adjunct to conventional physiotherapy. The purpose of this study was to evaluate the effects of Kinesio Taping on peak torque, muscle fatigue index and muscle activity of erector spinae in women with low back pain presenting fears and beliefs related to physical activity.. This is a pilot controlled clinical trial. The subjects were divided into two groups according to the Fear Beliefs Avoidance Questionnaire (FABQ): Group A (Patients with no fears and/or beliefs related to physical activity) and Group B (Patients with fears and/or beliefs related to physical activity). The Kinesio Taping was applied in "I" in order to facilitate erector spinae. An isokinetic dynamometer and a surface electromyography were used to evaluate the outcomes. The evaluations were performed without and with the KT.. Sample of 16 women equally divided into two groups with similar characteristics regarding age, weight, height, body mass index, functional capacity and pain levels in the evaluations without and with Kinesio Taping. There were within-groups and between-groups differences in the peak torque (p ≤ .05), with better results in the Group B. No differences were found on muscle fatigue index and muscle activity in both groups (p > .05).. It was concluded that Kinesio Taping had immediate effects in the peak torque of the erector spinae of women with nonspecific chronic low back pain presenting fears and beliefs related to physical activity. It is suggested that such results occurred by placebo effect. NCT: RBR-5xh3ch.

Topics: Athletic Tape; Exercise; Fear; Female; Humans; Low Back Pain; Paraspinal Muscles; Torque

Controlled laboratory study, cross-sectional.. To compare lumbar extensor muscle fatigability, lumbar stabilizing muscle activation, and lower-limb strength between male and female runners with chronic low back pain (LBP) and healthy runners.. Little is known about muscle performance in runners with chronic LBP.. Eighteen recreational runners with chronic LBP (9 men, 9 women; mean age, 27.8 years) and 18 healthy recreational runners (9 men, 9 women; mean age, 24.6 years) were recruited. The median frequency slopes for bilateral iliocostalis and longissimus were calculated from electromyographic signals captured during a 2-minute Sorensen test. The thickness changes of the transversus abdominis and lumbar multifidus between resting and contraction were measured using an ultrasound scanner. Peak concentric torques of the bilateral hip extensors, hip abductors, and knee extensors were measured using an isokinetic dynamometer at 60°/s. The average values for both sides were used for statistical analysis.. When averaged across sexes, peak knee extensor torque was 12.2% lower in the LBP group compared to the healthy group (mean difference, 0.29 Nm/kg; 95% confidence interval: 0.06, 0.53; P = .016). Male runners with chronic LBP exhibited smaller lumbar multifidus thickness changes compared to healthy male runners (mean difference, 0.13 cm; 95% confidence interval: 0.01, 0.25; P = .033). No other group differences were observed.. Runners with chronic LBP exhibited diminished knee extensor strength compared to healthy runners. Male runners with chronic LBP demonstrated additional deficits in lumbar multifidus activation.

Topics: Adult; Back Muscles; Chronic Disease; Cross-Sectional Studies; Electromyography; Female; Humans; Low Back Pain; Lower Extremity; Male; Muscle Fatigue; Muscle Strength; Muscle, Skeletal; Torque; Young Adult

Previously, we demonstrated that people in the Rotation with Extension low back pain subgroup display greater asymmetry of passive tissue characteristics during trunk lateral bending than people without low back pain. The purpose of this secondary analysis is to examine factors that explain the group differences.. Twenty-two people in the Rotation with Extension subgroup, and 19 people without low back pain were examined. Torque, lumbar region kinematics, and trunk muscle activity were measured during passive and isometric resisted trunk lateral bending. The dependent variables were lumbar region passive elastic energy to each side; the independent variables included group, gender, anthropometrics, trunk muscle characteristics, and an interaction factor of group and trunk muscle characteristics. Multiple linear regression was used for the analysis.. Anthropometrics explained passive measures to the left (P=.03). Anthropometrics (P<.01), trunk muscle characteristics (P<.01), and the interaction of group and trunk muscle characteristics (P=.01) explained passive measures to the right. After accounting for gender and anthropometrics, 43.7% of the variance in passive measures to the right was uniquely accounted for by trunk muscle characteristics for the Rotation with Extension subgroup, compared to 0.5% for the group without low back pain.. Anthropometrics explained passive measures with trunk lateral bending to both sides, in both groups. For people in the Rotation with Extension subgroup, there was a direct relationship between trunk muscle performance and passive measures to the right. Muscle is an important contributing factor to asymmetry in this subgroup and should be considered in treatment.

Topics: Adult; Anthropometry; Area Under Curve; Back Muscles; Beckwith-Wiedemann Syndrome; Biomechanical Phenomena; Female; Humans; Linear Models; Low Back Pain; Lumbosacral Region; Male; Movement; Posture; Rotation; Torque; Torso

To consider the efficacy of 10 weeks of Romanian deadlift (DL) training in increasing lumbar extension strength compared to isolated lumbar extension (LUMX) training.. Comparison of pre- and post-test data for Romanian deadlift 1RM, and lumbar extension torque between and within groups.. Male trained subjects (n = 36; (x¯±SD) 24.9 ± 6.5 years; 178.5 ± 5.2 cm; 81.6 ± 10.0 kg).. Pre- and post-testing included a Romanian deadlift 1RM and isometric strength tests every 12° through full range of motion on the MedX lumbar extension machine (MedX, Ocala, FL).. Repeated measures analysis of variance (ANOVA) with Bonferroni adjustments revealed that 1RM Romanian deadlift significantly increased from pre- to post-test in the DL group (p < 0.008; 143.3 ± 23.4 kg to 166.3 ± 21.9 kg) and the LUMX group (p < 0.008; 135.8 ± 23.1 kg to 146.0 ± 25.5 kg). In contrast, tested functional torque (TFT) significantly increased at 6 out of 7 joint angles (p < 0.008) for the LUMX group only. The control group showed no significant differences pre- to post-test.. These data suggest that the Romanian deadlift does not enhance lumbar extension torque. However, performing specific isolated lumbar extension training appears to improve both lumbar extension torque and Romanian deadlift 1RM.

Topics: Exercise Therapy; Humans; Low Back Pain; Male; Muscle Strength; Range of Motion, Articular; Torque; Treatment Outcome; Weight Lifting; Young Adult

Most empirical studies concerning rehabilitation yield numerous multidimensional signals (dozens of time variables are obtained for dozens of empirical situations). The purpose of this paper is to suggest a statistical analysis procedure based on: 1) space-time fuzzy windowing; 2) signal behavior characterization within the windows using membership value averages (MVA); and 3) MVA analysis using the multiple correspondence analysis (MCA). A load lifting study provided an example of 78 multidimensional signals including 89 time variables (forces, energy indicators, linear and angular positions, speeds, and accelerations). The main goal of MCA was to compare and contrast biomechanical signals from two lifting modes: "free" and "isokinetic." In the first mode, three loads were tested--light, medium, and heavy. In the second, three speeds were tested--slow, medium, and fast. Thirteen male individuals without disabilities participated in this study. The MCA showed that most of the free load-lifting strategies cannot be used in isokinetic lifting because the constraints of the subject and the environment are different. In addition, as the level of difficulty increases, free lifting became more economical while isokinetic lifting became less economical. These results would appear to indicate that movement strategies used for free lifting cannot be learned using an isokinetic machine during rehabilitation sessions for chronic low back pain. MCA was also suggested as a tool for comparing patients with control individuals. To achieve this aim, the notion of "supplementary data" was introduced.

Topics: Adult; Algorithms; Humans; Low Back Pain; Male; Models, Biological; Models, Statistical; Movement; Reproducibility of Results; Sensitivity and Specificity; Signal Processing, Computer-Assisted; Statistics as Topic; Torque; Weight-Bearing

A randomized controlled trial with a 6-month follow-up period was conducted.. To compare lumbar extension exercise and whole-body vibration exercise for chronic lower back pain.. Chronic lower back pain involves muscular as well as connective and neural systems. Different types of physiotherapy are applied for its treatment. Industrial vibration is regarded as a risk factor. Recently, vibration exercise has been developed as a new type of physiotherapy. It is thought to activate muscles via reflexes.. In this study, 60 patients with chronic lower back pain devoid of "specific" spine diseases, who had a mean age of 51.7 years and a pain history of 13.1 years, practiced either isodynamic lumbar extension or vibration exercise for 3 months. Outcome measures were lumbar extension torque, pain sensation (visual analog scale), and pain-related disability (pain disability index).. A significant and comparable reduction in pain sensation and pain-related disability was observed in both groups. Lumbar extension torque increased significantly in the vibration exercise group (30.1 Nm/kg), but significantly more in the lumbar extension group (+59.2 Nm/kg; SEM 10.2; P < 0.05). No correlation was found between gain in lumbar torque and pain relief or pain-related disability (P > 0.2).. The current data indicate that poor lumbar muscle force probably is not the exclusive cause of chronic lower back pain. Different types of exercise therapy tend to yield comparable results. Interestingly, well-controlled vibration may be the cure rather than the cause of lower back pain.

Topics: Chronic Disease; Depression; Disability Evaluation; Exercise Therapy; Female; Follow-Up Studies; Humans; Low Back Pain; Male; Manipulation, Spinal; Middle Aged; Muscle, Skeletal; Pain Measurement; Psychological Tests; Range of Motion, Articular; Torque; Treatment Outcome; Vibration; Weight-Bearing

To find the optimal height for sagittal motion axis for trunk strength test in chronic low back trouble.. Cross-sectional study.. The strength of trunk muscles of low back pain patients is decreased. The measured strength depends on the height of the sagittal motion axis but the differences between patients and controls are not known.. 114 (67 female) patients with chronic low back trouble are classified according to Quebec Task Force, 50 (31 female) patients with rheumatic disorder, but without low back trouble, and 33 (22 female) healthy controls, no appreciable physical differences but clear differences in Oswestry score. Isometric trunk extension-flexion test with different heights for the pelvic fulcrum.. Force decreased in extension, increased in flexion, and torque increased both in flexion and extension in every group (P<0.001) as the fulcrum was moved caudally. The male controls were stronger than patients with low back trouble (P<0.01). The female controls were stronger only if the fulcrum was set at the hip joint level (P<0.05). There were no differences between patients with rheumatic disorder and low back trouble, except in extension if the fulcrum was at the hip joint level (P<0.02).. The rotation axis in trunk extension-flexion strength test should be set at the level of the hip joint.. Trunk muscle weakness is a common sign of different rheumatic disorders. Proper setting of sagittal motion axis and concomitant measurement of trunk and hip extensor or flexor muscles increases the specificity of the strength test for low back trouble.

Topics: Abdominal Muscles; Adult; Chronic Disease; Cross-Sectional Studies; Female; Hip Joint; Humans; Isometric Contraction; Low Back Pain; Lumbar Vertebrae; Male; Middle Aged; Pectoralis Muscles; Range of Motion, Articular; Rheumatic Diseases; Rotation; Sensitivity and Specificity; Sex Factors; Torque

Bed rest is usually considered an efficient treatment for acute low back pain. However, the optimal duration of bed rest is still being discussed. The recommended periods vary from 2 days to 2 weeks. The duration of optimum length is an important topic given the economical and physiological drawbacks of prolonged inactivity. The purpose of this work is to measure objectively the efficacy of two different durations of bed rest through a dynamometric measure of trunk function. Some 51 male patients, students or self-employed, being treated for acute low back pain were randomized into two groups. Group I was prescribed a bed rest period of 3 days and group II, a period of 7 days. We used a multi-axis isoinertial trunk testing dynamometric device (Isostation B200, Isotechnologies, USA). Patients were all assessed on day 1 and also on day 5 for group I or on day 9 for group II. The variables measured in the sagittal plane were isometric torques in flexion and extension, unresisted range of motion, average dynamic torques and average velocities. Patients were also asked to fill in a visual analogue pain scale on both assessment days. The improvement of all performance measures were important and highly significant (P < 0.001) in both groups. The results of the functional testing and the visual analogue pain scale showed no significant differences between the groups. In these relatively young and motivated patients, a duration of bed rest of 3 days resulted in the same objective functional improvement of trunk function and pain rating as a period of 7 days. This shorter duration should be considered as preferable, given the same objective results but important physiological and economical advantages.

Topics: Activities of Daily Living; Acute Disease; Adolescent; Adult; Bed Rest; Humans; Low Back Pain; Male; Middle Aged; Movement; Outcome Assessment, Health Care; Pain Measurement; Range of Motion, Articular; Time Factors; Tomography, X-Ray Computed; Torque; Young Adult

Topics: Equipment Design; Humans; Low Back Pain; Motor Vehicles; Muscles; Occupational Exposure; Torque

Imbalance between flexor and extensor muscles of the trunk could negatively influence spinal stability.. Investigate the strength balance between flexor and extensor muscles of the trunk in military firefighters with non-specific chronic low back pain (NSCLBP).. One hundred and two male firefighters were assessed in an isokinetic dynamometer at 120°/s and 60°/s to investigate the balance ratio between flexor and extensor (F/E) muscles.. An F/E ratio of 0.72 (SD: 0.22; 95% CI: 0.67-0.76; SEM: 0.02) was observed at 60°/s and 0.94 (SD: 0.41; 95% CI: 0.85-1.03; SEM: 0.04) at 120°/s. The mean peak torque of the extensor muscles was 343.1 N.m/Kg (SD: 94.87; 95% CI: 322.8-363.5; SEM: 10.23) at 60°/s and 270.5 N.m/Kg (SD: 113; 95% CI 246.3-294.8; SEM: 12.18) at 120°/s. The mean peak torque of the flexor muscles was 232.4 N.m/Kg (SD: 53.86; 95% CI 220.8-243.9; SEM: 5.81) at 60°/s and 223.8 N.m/Kg (SD: 66.34; 95% CI 209.6-238.1; SEM: 7.15) at 120°/s. All torques generated by the extensor muscles were higher than the flexor muscles (p < 0.05).. Firefighters with NSCLBP presented a normal F/E balance ratio and higher strength of extensor muscles of the trunk.

Topics: Brazil; Cross-Sectional Studies; Firefighters; Humans; Low Back Pain; Male; Muscle Strength; Muscle, Skeletal; Torque

We quantified the relationship between spatial oscillations in surface electromyographic (sEMG) activity and trunk-extension torque in individuals with and without chronic low back pain (CLBP), during two submaximal isometric lumbar extension tasks at 20% and 50% of their maximal voluntary torque. High-density sEMG (HDsEMG) signals were recorded from the lumbar erector spinae (ES) with a 64-electrode grid, and torque signals were recorded with an isokinetic dynamometer. Coherence and cross-correlation analyses were applied between the filtered interference HDsEMG and torque signals for each submaximal contraction. Principal component analysis was used to reduce dimensionality of HDsEMG data and improve the HDsEMG-based torque estimation. sEMG-torque coherence was quantified in the δ(0-5 Hz) frequency bandwidth. Regional differences in sEMG-torque coherence were also evaluated by creating topographical coherence maps. sEMG-torque coherence in the δ band and sEMG-torque cross-correlation increased with the increase in torque in the controls but not in the CLBP group (p = 0.018, p = 0.030 respectively). As torque increased, the CLBP group increased sEMG-torque coherence in more cranial ES regions, while the opposite was observed for the controls (p = 0.043). Individuals with CLBP show reductions in sEMG-torque relationships possibly due to the use of compensatory strategies and regional adjustments of ES-sEMG oscillatory activity.

Topics: Electromyography; Humans; Low Back Pain; Lumbosacral Region; Paraspinal Muscles; Torque

Individuals with chronic low back pain (CLBP) commonly present with increased trunk muscle fatigability; typically assessed as reduced time to task failure during non-functional isometric contractions. Less is known about the specific neuromuscular responses of individuals with CLBP during dynamic fatiguing tasks. We investigate the regional alteration in muscle activation and peak torque exertion during a dynamic isokinetic fatiguing task in individuals with and without CLBP.. Similar levels of muscle activation and number of repetitions were observed for both groups (p > 0.05). However, the CLBP group exerted lower levels of peak torque for both flexion and extension moments (p < 0.05). The centre of lumbar erector spinae activity was shifted cranially in the CLBP group throughout the task (p < 0.05), while the control participants showed a more homogenous distribution of muscle activity.. People with CLBP displayed altered and potentially less efficient activation of their lumbar erector spinae during a dynamic fatiguing task. Future studies should consider using high-density EMG biofeedback to optimise the spatial activation of the paraspinal musculature in people with low back pain (LBP).

Topics: Adult; Case-Control Studies; Chronic Disease; Electromyography; Exercise Therapy; Female; Humans; Isometric Contraction; Low Back Pain; Male; Muscle Fatigue; Paraspinal Muscles; Torque; Young Adult

The World Health Organization states that low back pain is the leading cause for disability worldwide. Patients with chronic low back pain (CLBP) show important decreases in lumbar strength and can now be assessed by using the new isokinetic dynamometer BioniX Sim3 Pro which offers very detailed measurements.. To compare lumbar flexion and extension strength values, as well as extension-flexion ratio (EFR) based on isokinetic velocity and gender, for patients with CLBP on the BioniX Sim3 Pro.. A retrospective analysis was performed on data from 20 men and 22 women with CLBP. Maximum torque in flexion and extension was measured isometrically and isokinetically. Statistical analysis was performed on these parameters.. EFR shows a downward trend with increasing speed of measurement (isometric to isokinetic 30∘/s and isokinetic 30∘/s to isokinetic 90∘/s, respectively): in men from 1.21 to 1.04 (p< 0.001) and from 1.04 to 0.93 (p= 0.207). In women, EFR decreased from 1.41 to 1.13 (p< 0.001) and from 1.13 to 1.00 (p= 0.144).. Patients with CLBP have a decreased strength in lumbar extension and flexion compared to the age-corrected normal values of Bionix Sim3 Pro. With increasing speed of testing protocol, a decrease in EFR is observed in this population.

Topics: Adult; Exercise; Female; Humans; Isometric Contraction; Low Back Pain; Male; Muscle Strength; Muscle, Skeletal; Pilot Projects; Reference Values; Retrospective Studies; Torque

Soccer as a sport has a very high injury rate and low back pain (LBP) is considered to be the most common overuse injury typically occurring in the back and spine in elite soccer players.. This study aimed to investigate differences in knee muscle strength and muscle imbalances in soccer players according to lower back pain.. One hundred and thirty-six male professional soccer players (20.49 ± 3.73 years, 76.57 ± 8.24 kg, 182.63 ± 6.73 cm) volunteered for the study. The isokinetic dynamometer PrimaDOC (EASYTECH, Italy) was used to assess the hamstring and quadriceps strength at the selected speeds of 60∘/s, whereas the Roland-Morris Disability Questionnaire (RDQ) was used as a health status measure to assess physical disability caused by low back pain.. A univariate analysis of variance has shown that there is a statistically significant difference among the groups divided into Absolute peak torque right knee flexors, Absolute peak torque left knee flexors, Ratio between hamstrings and quadriceps strength right leg, and Ratio between hamstrings and quadriceps strength left leg based on the RDQ scores. On the other hand, no other significant differences among the groups were found in other parametersCONCLUSION: The current study indicates that knee muscle strength variables, resulting from an isokinetic testing, have the potential to discriminate between soccer players with and without a history of low back pain. However, low back pain is a multidimensional phenomenon and knee muscle strength or imbalance alone cannot be expected to explain low back pain.

Topics: Adolescent; Adult; Athletes; Humans; Italy; Knee; Low Back Pain; Male; Muscle Strength; Muscle, Skeletal; Soccer; Torque; Young Adult

Although delayed onset of the deep abdominal muscles activity in subjects with non-specific chronic low back pain (CLBP) has been suggested to be related to trunk rotational torque, no study has examined the onsets associated with non-specific CLBP during a variety of tasks with different trunk rotational torque. The aim of this study is to compare the onsets of deep abdominal muscles activity among tasks with different trunk rotational torques in subjects with and without non-specific CLBP.. Twelve subjects with non-specific CLBP and 13 control subjects were included. They performed 8 types of upper limb movements. The onsets of muscular activity of bilateral internal oblique-transversus abdominis (IO-TrA) and trunk rotational torque due to the upper limb movements were measured using a surface electromyography and a three-dimensional motion analysis system.. In non-specific CLBP group, right IO-TrA activities were significantly delayed during tasks with left trunk rotational torque compared with the control (P < 0.05), while onsets of the left IO-TrA activities were significantly later than those of the control during tasks with right rotational torque of the trunk (P < 0.05). There were no significant differences in onsets of both sides IO-TrA during tasks without trunk rotational torque between non-specific CLBP and control groups (P > 0.05).. The onsets of IO-TrA activities in subjects with non-specific CLBP were delayed during tasks with rotational torque of the trunk in the opposite direction, suggesting a possibility that delayed onset of the deep abdominal muscles during rotational torque of the trunk might be etiology of chronic low back pain.

Topics: Abdominal Muscles; Abdominal Oblique Muscles; Adult; Chronic Disease; Disability Evaluation; Electromyography; Female; Humans; Low Back Pain; Male; Movement; Muscle Contraction; Pain Measurement; Torque; Young Adult

Characteristics of muscle activity, represented by surface electromyography (EMG), have revealed differences between patients with low back pain (LBP) and healthy adults; how they relate to functional and clinical parameters remains unclear. The purpose of the current study was to examine the correlation between frequency characteristics of EMG (analysed using continuous wavelet transform (CWT) analysis) and patients' self-rated score of disability.. This is a case-control study with 15 patients with mechanical LBP without radicular symptoms. Patients were recruited from the orthopaedic clinic at Charing Cross Hospital. Ten healthy adults were recruited from the staff working in the hospital and associated university. Patients completed the Roland-Morris Disability Questionnaire (RMDQ) and bilateral EMG activity was obtained from erector spinae at vertebral levels L4 and T12. Subjects performed three brief maximal voluntary isometric contractions (MVICs) of the back extensors and the torque was measured using a dynamometer. CWT was applied to the EMG signals of each muscle in a 200 ms window centred around the peak torque obtained during the MVICs. The ratio (low/high frequencies) of the energy, the peak power and the frequency of the peak power were calculated for each recording site, averaged and correlated with the individual's RMDQ score.. Patients had lower peak power (T12 and L4) and lower frequency of the peak power (at T12) than the healthy adults. Additionally, RMDQ positively correlated to the average ratio of energy at T12 (r=0.63; p=0.012), that is, greater self-rated disability corresponded to a dominant distribution of energy in the lower frequencies.. The current findings reveal alterations in EMG profile and its association with self-related back pain disability, suggesting that spectral characteristics of EMG reflect muscle function.

Topics: Adult; Back; Case-Control Studies; Cohort Studies; Diagnostic Self Evaluation; Electromyography; Female; Humans; Low Back Pain; Male; Middle Aged; Movement; Muscle Contraction; Muscle Strength; Paraspinal Muscles; Spine; Surveys and Questionnaires; Torque

To investigate the short- and long-term reliability of isometric trunk strength measurements in patients with chronic low back pain in different age groups.. Test-retest reliability study.. A total of 210 patients (age groups 18-39, 40-59 and 60-90 years).. Patients performed testing at baseline, 1-2 days (day 2) and 6 weeks.. Only the oldest age group showed similar extension strength on all three test days All age groups showed significant changes in rotation and flexion scores from baseline to 6 weeks. Younger age groups (18-39 and 40-59 years) showed significant increases in extension, flexion, and rotation strength at both short-term (baseline to day 2) and long-term (baseline to 6 weeks) retests, but not from day 2 to 6 weeks. In patients over 60 years of age the smallest real differences normalized to baseline (%) were smaller from day 2 to 6 weeks than from baseline to 6 weeks. Long-term intraclass correlation coefficients were lowest between baseline and 6 weeks. No relevant impacts of feelings, motivation, or pain on reliability were detected.. Reliability of isometric trunk strength measurements in patients with chronic low back pain is similar in older and younger patients. Short-term test repetition a few days after baseline is recommended, if clinically feasible, and especially in research evaluating the effects of exercise on strength.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Aging; Exercise; Female; Humans; Isometric Contraction; Low Back Pain; Male; Middle Aged; Muscle Strength; Muscle, Skeletal; Range of Motion, Articular; Reproducibility of Results; Torque; Torso; Young Adult

Investigation and discrimination of neuromuscular variables related to the complex aetiology of low back pain could contribute to clarifying the factors associated with symptoms.. Analysing the discriminative power of neuromuscular variables in low back pain.. This study compared muscle endurance, proprioception and isometric trunk assessments between women with low back pain (LBP, n=14) and a control group (CG, n=14). Multivariate analysis of variance and discriminant analysis of the data were performed.. The muscle endurance time (s) was shorter in the LBP group than in the CG (p=0.004) with values of 85.81 (37.79) and 134.25 (43.88), respectively. The peak torque (Nm/kg) for trunk extension was 2.48 (0.69) in the LBP group and 3.56 (0.88) in the GG (p=0.001); for trunk flexion, the mean torque was 1.49 (0.40) in the LBP group and 1.85 (0.39) in the CG (p=0.023). The repositioning error (degrees) before the endurance test was 2.66 (1.36) in the LBP group and 2.41 (1.46) in the CG (p=0.664), and after the endurance test, it was 2.95 (1.94) in the LBP group and 2.00 (1.16) in the CG (p=0.06). Furthermore, the variables showed discrimination between the groups (p=0.007), with 78.6% of the individuals with low back pain correctly classified in the LBP group. In turn, variables related to muscle activation showed no difference in discrimination between the groups (p=0.369).. Based on these findings, the clinical management of low back pain should consist of both resistance and strength training, particularly in the extensor muscles.

Topics: Adolescent; Adult; Case-Control Studies; Discriminant Analysis; Electromyography; Exercise Test; Female; Humans; Isometric Contraction; Low Back Pain; Physical Endurance; Proprioception; Torque; Visual Analog Scale; Young Adult

Individuals with a history of low back pain (LBP) may present with decreased hip-abduction strength and increased trunk or gluteus maximus (GMax) fatigability. However, the effect of hip-abduction exercise on hip-muscle function has not been previously reported.. To compare hip-abduction torque and muscle activation of the hip, thigh, and trunk between individuals with and without a history of LBP during repeated bouts of side-lying hip-abduction exercise.. Repeated measures.. Clinical laboratory.. 12 individuals with a history of LBP and 12 controls.. Repeated 30-s hip-abduction contractions.. Hip-abduction torque, normalized root-mean-squared (RMS) muscle activation, percent RMS muscle activation, and forward general linear regression.. Hip-abduction torque reduced in all participants as a result of exercise (1.57 ± 0.36 Nm/kg, 1.12 ± 0.36 Nm/kg; P < .001), but there were no group differences (F = 0.129, P = .723) or group-by-time interactions (F = 1.098, P = .358). All participants had increased GMax activation during the first bout of exercise (0.96 ± 1.00, 1.18 ± 1.03; P = .038). Individuals with a history of LBP had significantly greater GMax activation at multiple points during repeated exercise (P < .05) and a significantly lower percent of muscle activation for the GMax (P = .050) at the start of the third bout of exercise and for the biceps femoris (P = .039) at the end of exercise. The gluteal muscles best predicted hip-abduction torque in controls, while no consistent muscles were identified for individuals with a history of LBP.. Hip-abduction torque decreased in all individuals after hip-abduction exercise, although individuals with a history of LBP had increased GMax activation during exercise. Gluteal muscle activity explained hip-abduction torque in healthy individuals but not in those with a history of LBP. Alterations in hip-muscle function may exist in individuals with a history of LBP.

Topics: Adolescent; Adult; Electromyography; Female; Hip Joint; Humans; Low Back Pain; Male; Muscle Contraction; Muscle Fatigue; Muscle Strength; Muscle Strength Dynamometer; Muscle, Skeletal; Pain Measurement; Thigh; Thorax; Torque

Changes in sensorimotor function and increased trunk muscle fatigability have been identified in patients with chronic low back pain (cLBP). This study assessed the control of trunk force production in conditions with and without local erector spinae muscle vibration and evaluated the influence of muscle fatigue on trunk sensorimotor control.. Twenty non-specific cLBP patients and 20 healthy participants were asked to perform submaximal isometric trunk extension torque with and without local vibration stimulation, before and after a trunk extensor muscle fatigue protocol. Constant error (CE), variable error (VE) as well as absolute error (AE) in peak torque were computed and compared across conditions. Trunk extensor muscle activation during isometric contractions and during the fatigue protocol was measured using surface electromyography (sEMG).. Force reproduction accuracy of the trunk was significantly lower in the patient group (CE = 9.81 ± 2.23 Nm; AE = 18.16 ± 3.97 Nm) than in healthy participants (CE = 4.44 ± 1.68 Nm; AE = 12.23 ± 2.44 Nm). Local erector spinae vibration induced a significant reduction in CE (4.33 ± 2.14 Nm) and AE (13.71 ± 3.45 Nm) mean scores in the patient group. Healthy participants conversely showed a significant increase in CE (8.17 ± 2.10 Nm) and AE (16.29 ± 2.82 Nm) mean scores under vibration conditions. The fatigue protocol induced erector spinae muscle fatigue as illustrated by a significant decrease in sEMG median time-frequency slopes. Following the fatigue protocol, patients with cLBP showed significant decrease in sEMG root mean square activity at L4-5 level and responded in similar manner with and without vibration stimulation in regard to CE mean scores.. Patients with cLBP have a less accurate force reproduction sense than healthy participants. Local muscle vibration led to significant trunk neuromuscular control improvements in the cLBP patients before and after a muscle fatigue protocol. Muscle vibration stimulation during motor control exercises is likely to influence motor adaptation and could be considered in the treatment of cLBP. Further work is needed to clearly identify at what levels of the sensorimotor system these gains are achievable.

Topics: Adult; Electromyography; Female; Humans; Isometric Contraction; Low Back Pain; Male; Middle Aged; Muscle Fatigue; Muscle Stretching Exercises; Muscle, Skeletal; Physical Therapy Modalities; Sensorimotor Cortex; Torque; Torso; Vibration; Young Adult

Motion systems must cope with internal and external disturbances affecting the envisioned movement program. In science responses to disturbances are used to characterize system properties. Recently, evidence has been collected that self-stability due to the mechanical response of a system can greatly contribute to safe guarding proper operation of the system and to follow up an envisioned task. Here we review research in our laboratory on the kinematic response of standing subjects to sudden pulls inflicted by a motor, and the kinetics of runners crossing a track with a bump. We find that in both cases the first responses are dominated by system compliance. Thereby damage is avoided and the tasks are secured. Preparation to the observed disturbance does not seem to have the goal to compensate quickly but to enhance the scope of the reaction and its economy.

Topics: Adult; Biomechanical Phenomena; Compliance; Electromyography; Female; Functional Laterality; Gait; Humans; Low Back Pain; Male; Models, Neurological; Motor Neurons; Movement; Muscle Contraction; Postural Balance; Proprioception; Running; Torque; Weight-Bearing

A relationship between the muscles that stabilize the lumbar spine and the lower extremity exists that may result in neuromuscular and biomechanical changes during prolonged aerobic exercise in those with low back pain.. Twenty recreationally active adults with healthy lower extremity joints, 7 with recurring episodes of low back pain performed a standard 15-minute aerobic exercise protocol on a treadmill. Quadriceps torque during a maximal isometric voluntary contraction, quadriceps central activation ratio and superimposed burst torque as measured with the superimposed burst technique, and vastus lateralis median frequency were recorded before and after treadmill exercise. A burst of electrical stimuli was superimposed during maximal knee extension causing a transient increase in torque. Quadriceps central activation was calculated as the ratio between maximal volitional and superimposed burst torques. We recorded vastus lateralis surface Electromyography (EMG) during knee extension contractions and calculated the median frequency.. We observed a 12.4% reduction in the quadriceps central activation ratio after aerobic exercise in participants with recurrent low back pain; healthy controls only experienced a 1.7% reduction. There was no change in quadriceps median frequency following aerobic exercise.. Deteriorated quadriceps function following aerobic exercise was observed in patients with recurrent episodes of low back pain who had healthy knee joints. This reduction is mediated by a central process that may arise from poor strength and endurance in the muscles surrounding the spine, which is common in persons with recurrent low back pain.

Topics: Adult; Electromyography; Exercise; Humans; Low Back Pain; Quadriceps Muscle; Torque; Young Adult

The purpose of this study was to validate a 3D dynamic virtual model for lifting tasks against a validated link segment model (LSM). A face validation study was conducted by collecting x, y, z coordinate data and using them in both virtual and LSM models. An upper body virtual model was needed to calculate the 3D torques about human joints for use in simulated lifting styles and to estimate the effect of external mechanical devices on human body. Firstly, the model had to be validated to be sure it provided accurate estimates of 3D moments in comparison to a previously validated LSM. Three synchronised Fastrak units with nine sensors were used to record data from one male subject who completed dynamic box lifting under 27 different load conditions (box weights (3), lifting techniques (3) and rotations (3)). The external moments about three axes of L4/L5 were compared for both models. A pressure switch on the box was used to denote the start and end of the lift. An excellent agreement [image omitted] was found between the two models for dynamic lifting tasks, especially for larger moments in flexion and extension. This virtual model was considered valid for use in a complete simulation of the upper body skeletal system. This biomechanical virtual model of the musculoskeletal system can be used by researchers and practitioners to give a better tool to study the causes of LBP and the effect of intervention strategies, by permitting the researcher to see and control a virtual subject's motions.

Topics: Adult; Biomechanical Phenomena; Biomedical Engineering; Humans; Imaging, Three-Dimensional; Lifting; Low Back Pain; Lumbar Vertebrae; Male; Models, Biological; Movement; Torque; User-Computer Interface

Clinical data suggest that active limb movements may be associated with early lumbopelvic motion and increased symptoms in people with low back pain.. Forty-one people without low back pain who did not play rotation-related sports and 50 people with low back pain who played rotation-related sports were examined. Angular measures of limb movement and lumbopelvic motion were calculated across time during active knee flexion and active hip lateral rotation in prone using a three-dimensional motion capture system. Timing of lumbopelvic motion during the limb movement tests was calculated as the difference in time between the initiation of limb movement and lumbopelvic motion normalized to limb movement time.. During knee flexion and hip lateral rotation, people with low back pain demonstrated a greater maximal lumbopelvic rotation angle and earlier lumbopelvic rotation, compared to people without low back pain (P<0.05).. The data suggest that people with low back pain who play rotation-related sports may move their lumbopelvic region to a greater extent and earlier during lower limb movements than people without low back pain. Because people perform many of their daily activities in early to midranges of joint motion the lumbopelvic region may move more frequently across the day in people with low back pain. The increased frequency may contribute to increased lumbar region tissue stress and potentially low back pain symptoms. Lower limb movements, therefore, may be important factors related to the development or persistence of low back pain.

Topics: Adult; Biomechanical Phenomena; Case-Control Studies; Female; Hip Joint; Humans; Low Back Pain; Lower Extremity; Lumbosacral Region; Male; Motion; Movement; Pelvis; Range of Motion, Articular; Torque

A relationship exists between lumbar paraspinal muscle fatigue and quadriceps muscle activation. The objective of this study was to determine whether hip and knee joint moments during jogging changed following paraspinal fatiguing exercise. Fifty total subjects (25 with self-reported history of low back pain) performed fatiguing, isometric lumbar extension exercise until a shift in EMG median frequency corresponding to a mild level of muscle fatigue was observed. We compared 3-dimensional external joint moments of the hip and knee during jogging before and after lumbar paraspinal fatigue using a 10-camera motion analysis system. Reduced external knee flexion, knee adduction, knee internal rotation and hip external rotation moments and increased external knee extension moments resulted from repetitive lumbar paraspinal fatiguing exercise. Persons with a self-reported history of LBP had larger knee flexion moments than controls during jogging. Neuromuscular changes in the lower extremity occur while resisting knee and hip joint moments following isolated lumbar paraspinal exercise. Persons with a history of LBP seem to rely more heavily on quadriceps activity while jogging.

Topics: Adult; Computer Simulation; Exercise; Female; Gait; Hip Joint; Humans; Knee Joint; Low Back Pain; Lumbar Vertebrae; Male; Models, Biological; Muscle Contraction; Muscle Fatigue; Muscle, Skeletal; Running; Torque; Young Adult

To quantify trunk muscle capability and controllability in different angles and levels of isometric exertion using a torque tracking system.. To investigate the effect of biaxial isometric exertions on the maximum capability of trunk and to examine the effect of angle and level of isometric exertion on trunk controllability during the tracking task in upright posture.. Combined motions of trunk at varying exertion levels occur in most daily and occupational activities and are important risk factors of low back pain. Few studies have investigated trunk capability and controllability during multidirectional activities with different exertion levels.. Eighteen asymptomatic young male subjects performed isometric contractions of trunk muscles in 8 angles and 3 levels of exertion. The tracking system included a target, which was a thick line with a round endpoint. Subjects were asked to track the target line (path) and match the endpoint while maintaining torque for 3 seconds by exerting isometric contraction against B200 Isostation. The initial part of the tracking task was named path tracking phase and the final part, endpoint matching phase. Trunk capability was determined by measuring peak torque values obtained during maximal voluntary exertions. Trunk controllability was determined by measuring constant error and variable error during tracking tasks. Analysis of variance with repeated measures design was used to test the effects of angle and level of exertion on trunk capability and controllability.. Trunk capability was significantly decreased during biaxial exertions (P < 0.001). Constant error and variable error were significantly affected by angle (P < 0.001) and level (P < 0.001) of exertion during both phases of the tracking task.. Trunk capability and controllability were significantly decreased during biaxial exertions. Higher exertion levels had a major negative impact on trunk controllability in both uniaxial and biaxial exertions. The results suggested that combined exertions and more strenuous efforts may impair trunk neuromuscular control, increasing the risk of low back pain.

Topics: Abdomen; Adult; Back; Humans; Isometric Contraction; Low Back Pain; Male; Models, Biological; Muscle, Skeletal; Physical Exertion; Posture; Risk Factors; Torque; Young Adult

The purpose of this study was to characterize the force-time profile of the McTimoney toggle-torque-recoil (MTTR) technique.. Two licensed chiropractors trained in the McTimoney Method applied MTTR thrusts to a tabletop where a dynamic load cell had been mounted. Each clinician applied 10 thrusts (5 with each hand) to the load cell in a repeated measures design. Peak forces, time durations, and time to peak force were computed from each of the force-time histories. Descriptive statistics were performed to compare the forces, durations, and times to peak force of the MTTR thrusts. A Mann-Whitney U test compared variables between the 2 clinicians, whereas a Wilcoxon signed-rank test compared right- and left-handed thrusts within clinicians.. Considering all MTTR thrusts, the average peak force was 87.22 N (SD = 24.18 N), the average overall thrust duration was 36.38 milliseconds (SD = 9.58 milliseconds), and the average time to peak force was 12.31 milliseconds (S.D. = 4.39 milliseconds). No significant differences in mean peak force, duration, or time to peak force were observed between clinicians. When comparing intraclinician right and left hand thrusts, differences in peak force and duration were observed individually (P < .05).. For the 2 chiropractors tested, MTTR thrusts were relatively lower in peak force and appreciably faster than other commonly used chiropractic techniques. Future work aims to investigate the relationships between the force-time profiles of MTTR thrusts and resultant physiologic and clinical responses.

Topics: Biomechanical Phenomena; Chiropractic; Humans; Low Back Pain; Manipulation, Spinal; Pain Measurement; Pressure; Time Factors; Torque

This study measured the twist angle of the lumbar region and the surface electromyogram (EMG) and examined their mutual relation to elucidate the degree and influence of factors of "twist" in nursing techniques as a cause of lower back pain. Using a goniometer (two-way angle and twist sensors) and an EMG(SX230; DKH Co., Ltd.), we conducted measurements by affixing the goniometer on the lumbar vertebral column and EMG sensor at four points of right and left sides of L2 and L4 (of the erector muscle of the spine). The measured nursing techniques were three common methods of "transferring a patient from bed to wheelchair," which is said to impart a heavy load on the lumbar region. Results show that the correlation value between the twist angle rate and mean energy is likely to be greater, suggesting that the magnitude of the load on the lumbar region should be related to the twist speed rather than to the twist angle of the movement itself.

Topics: Electromyography; Female; Humans; Low Back Pain; Lumbosacral Region; Moving and Lifting Patients; Observation; Torque; Weight-Bearing

Activities involving axial trunk rotations/moments are common and are considered as risk factors for low back disorders. Previous biomechanical models have failed to accurately estimate the trunk maximal axial torque exertion. Moreover, the trunk stability under maximal torque exertions has not been investigated.. A nonlinear thoracolumbar finite element model along with the Kinematics-driven approach is used to study biomechanics of maximal axial torque generation during upright standing posture. Detailed anatomy of trunk muscles with six distinct fascicles for each abdominal oblique muscle on each side is considered. While simulating an in vivo study of maximal axial torque exertion, effects of antagonistic coactivities, coupled moments and maximum muscle stress on results are investigated.. Predictions for trunk axial torque strength and relative muscle activities compared well with reported measurements. Trunk strength in axial torque was only slightly influenced by variations in coupled moments. Presence of abdominal antagonistic coactivities and alterations in maximum strength of muscles had, however, greater effect on maximal torque exertion. Abdominal oblique muscles play crucial role in generating moments in all three planes while back muscles are mainly effective in balancing moments in sagittal/coronal planes. Trunk stability is not of a concern in maximum axial torque exertions nor is it improved by antagonistic abdominal coactivities.. In contrast to previous biomechanical model studies, the Kinematics-driven approach accurately predicts the trunk response in maximal isometric axial torque exertions by taking into account detailed anatomy of abdominal oblique muscles while satisfying equilibrium requirements in all planes/directions. In maximal torque exertions, the spine is at much higher risk of tissue injury due to large segmental loads than of instability.

Topics: Abdomen; Biomechanical Phenomena; Computer Simulation; Humans; Isometric Contraction; Low Back Pain; Models, Biological; Movement; Muscle, Skeletal; Physical Exertion; Posture; Predictive Value of Tests; Spine; Thorax; Torque

Several investigators have suggested that passive tissue characteristics of the lumbar region may be altered in people with low back pain. Passive stiffness of the lumbar region has been examined during physiological movements in healthy individuals and intersegmental spine mobility and stiffness have been examined in people with and people without low back pain. However, no investigators have examined differences in passive tissue characteristics of the lumbar region during a physiological movement between people with and people without low back pain.. Subjects were moved passively through a trunk lateral bending motion on a passive movement device. Lumbar region kinematics were measured with a motion capture system and force required to move the subject was measured with a force transducer. Lumbar region extensibility was defined as the maximum excursion of the lumbar region. Passive elastic energy was defined as the area under the torque-lumbar region angle curve. Differences in lumbar region extensibility and passive elastic energy between sides were examined in people with and people without low back pain (n=41).. People in the Rotation with Extension low back pain subgroup demonstrated greater asymmetry of passive elastic energy than people without low back pain (P=0.04). There were no differences between groups in symmetry of lumbar region extensibility (P=0.37).. Asymmetry in passive elastic energy of the lumbar region may be related to the low back pain problem in the Rotation with Extension subgroup. The asymmetry in passive elastic energy may be associated with asymmetry of loading on the spine, which has been reported to be a risk factor for low back pain. Thus, it may be important to consider the asymmetry when planning an intervention strategy for people in the Rotation with Extension subgroup.

Topics: Adult; Biomechanical Phenomena; Elasticity; Female; Humans; Low Back Pain; Lumbosacral Region; Male; Movement; Physical Therapy Modalities; Spine; Torque

The current study examined the validity and reliability of a new system that was developed to measure lumbar region passive stiffness and end range of motion during a trunk lateral bending movement in vivo. Variables measured included force, end range lumbar region motion, torque, lumbar region stiffness, and passive elastic energy. Validity of the force measurements was examined using standard weights. Validity of lumbar region angle measurements was examined using an instrumented trunk with an electrogoniometer. Reliability of the measurements between trials within a session was examined in a sample of 50 people (25 men, 25 women; mean +/- standard deviation age = 30.7 +/- 8.9 yr); 31 people reported a history of chronic or recurrent low back pain (LBP) and 19 reported no prior history of LBP. The end range lumbar region motion and force measurements demonstrated an excellent linear relationship with the criterion standard measures. Average error between the criterion standard and observed measurements was minimal for all measurements. For reliability testing, the majority of intraclass correlation coefficient values were >0.75. The validity and reliability of the current system are sufficient to examine lumbar region stiffness and end range of motion in people with and people without LBP.

Topics: Adult; Biomechanical Phenomena; Chi-Square Distribution; Elasticity; Electromyography; Equipment Design; Female; Humans; Isometric Contraction; Low Back Pain; Lumbosacral Region; Male; Movement; Physical Therapy Modalities; Range of Motion, Articular; Reproducibility of Results; Torque; Transducers

To determine the risk factors associated with complain of low back pain. A cross sectional study was done from June 2004 until August 2005. Seven hundred and sixty commercial vehicle drivers from 11 bus companies in central, northern and eastern regions in Malaysia participated in this study. Modified Nordic questionnaire was used to determine the prevalence of low back pain; Maestro human vibration meter was used to measure the personal R.M.S values of lateral, anterior-posterior and vertical axes. Modified Owas was used to assess the awkward posture of the driver torso namely, bending forward movement, leaning, sitting straight and twisting. Profile of Mood States (POMS) was used to evaluate the mood states of bus drivers with complain of low back pain. A high prevalence of low back pain (60.4%) among Malaysian commercial vehicle drivers was found. Logistic regression analysis controlling for age, income, education level and non occupational activities revealed that the following factors were related to low back pain: Tension-anxiety [1.080, 95% CI 1.041-1.121], depression dejection [1.047, 95% CI 1.023-1.072], anger-hostility [1.053, 95% CI 1.027-1.081], fatigue [1.132, 95% CI 1.089-1.177] and confusion [1.114, 95% CI 1.061-1.169] of POMS, length of employment [1.001, 95% CI 1.0-1.003], steering wheel adjustment [1.521, 95% CI 1.101-2.101], perception of exposing to vibration [1.943, 95% CI 1.389-2.719]. In conclusion, combinations of risks lead to high increase of low back pain complain among Malaysian bus drivers.

Topics: Adult; Commerce; Cross-Sectional Studies; Humans; Irritable Mood; Low Back Pain; Malaysia; Middle Aged; Motor Vehicles; Occupational Diseases; Pain Measurement; Posture; Prevalence; Risk Assessment; Risk Factors; Stress, Psychological; Surveys and Questionnaires; Torque; Vibration; Workforce

To study the influence of 10 min of cyclic twisting motion on abdominal and back muscle activities.. Repetitive (cyclic) occupational activity was identified by many epidemiological reports to be a risk factor for the development of work-related musculoskeletal disorders. Biomechanical and physiological confirmation, however, is lacking.. Trunk muscle electromyography (EMG) was recorded while participants performed a continuous 10-min maximum lumbar cyclic twisting to the left, and maximum isometric twist to the left and right sides was measured before and after the exercise.. Abdominal muscles contracted symmetrically, independent of twisting direction. The left posterior muscles' integrated EMG (IEMG) decreased during the exercise, whereas the IEMG of the right posterior muscle increased. Simultaneously with increased antagonist coactivity level of the right posterior muscles after the exercise, decrease in maximal isometric left twisting torque was observed. The abdominal muscles did not exhibit any significant changes during the exercise. After the exercise, the right abdominals demonstrated a significant increase in effort, which was independent of the direction of the maximal effort isometric test.. The change in muscle activity is attributed to neuromuscular compensation for the development of laxity and microdamage in the soft tissue (ligaments, discs, facet capsules, etc.) of the lumbar spine.. The results of this study increase understanding of the risk factors associated with low back disorder induced by labor-intensive occupations that involve cyclic lateral twisting.

Topics: Adult; Back; Biomechanical Phenomena; Cumulative Trauma Disorders; Electromyography; Female; Humans; Isometric Contraction; Low Back Pain; Lumbosacral Region; Male; Muscle, Skeletal; Occupational Diseases; Risk Factors; Torque; Torsion Abnormality

This study aims to explore factors associated with low back pain (LBP) that required treatment from health care provider among non-emergency ambulance transfer workers.. A cross-sectional study was conducted to 38 workers of a major hospital in Hong Kong. The influences of four categories of risk factors (personal, physical, psychosocial, and exposure factors) in the prevalence of LBP were investigated by objective measurement and self-reported questionnaires. A modified Nordic musculoskeletal symptoms survey and sick leave record were used to document the prevalence of LBP. Univariate analyses followed by multiple logistic regression analyses were used to explore the risk factors associated with LBP cases.. The results revealed that LBP was associated with age (OR=0.75, CI=0.56-1.00, P < 0.05), perceived effort (OR=7.95, CI=1.46-43.27, P < 0.05), job satisfaction (OR=4.18 CI=1.42-12.33, P < 0.01), and flexor peak torque at 120 degrees /s (OR=1.09 CI= 0.99-1.19, P=0.07).. This study suggests that workers' perceived exertion has an valuable role in assessing risk at this workplace. A high perceived exertion at work can signal the need for work adjustment or modification to avoid progression of low back disorder to persistent pain or intense pain. The effects of work adjustment or modification in affected workers needs to be systematically investigated.

Topics: Adult; Age Factors; Allied Health Personnel; Ambulances; Cross-Sectional Studies; Hong Kong; Humans; Job Satisfaction; Low Back Pain; Male; Muscle, Skeletal; Physical Exertion; Risk Factors; Surveys and Questionnaires; Torque

The control of force and its between-trial variability are often taken as critical determinants of motor performance. Subjects performed isometric trunk flexion and extension forces without and with experiment pain to examine if pain yields changes in the control of trunk forces. The objective of this study is to determine if experimental low back pain modifies trunk isometric force production.. Ten control subjects participated in this study. They were required to exert 50 and 75% of their isometric maximal trunk flexion and extension torque. In a learning phase preceding the non painful and painful trials, visual and verbal feedbacks were provided. Then, subjects were asked to perform 10 trials without any feedback. Time to peak torque, time to peak torque variability, peak torque variability as well as constant and absolute error in peak torque were calculated. Time to peak and peak dF/dt were computed to determine if the first peak of dF/dt could predict the peak torque achieved.. Absolute and constant errors were higher in the presence of a painful electrical stimulation. Furthermore, peak torque variability for the higher level of force was increased with in the presence of experimental pain. The linear regressions between peak dF/dt, time to peak dF/dt and peak torque were similar for both conditions. Experimental low back pain yielded increased absolute and constant errors as well as a greater peak torque variability for the higher levels of force. The control strategy, however, remained the same between the non painful and painful condition. Cutaneous pain affects some isometric force production parameters but modifications of motor control strategies are not implemented spontaneously.. It is hypothesized that adaptation of motor strategies to low back pain is implemented gradually over time. This would enable LBP patients to perform their daily tasks with presumably less pain and more accuracy.

Topics: Adult; Electric Stimulation; Humans; Isometric Contraction; Low Back Pain; Lumbosacral Region; Male; Skin; Time Factors; Torque

The main objective of the present study was to investigate the benefits of exposure to a variety of movements versus exposure to the same movements on overprediction of pain and behavioural performance on a final behavioural test in a sample of chronic low back pain (CLBP) patients. Eighty-four CLBP patients were requested to perform four behavioural tests. Patients were assigned to two experimental conditions. The final behavioural test was the same for all patients. The first three behavioural tests consisted of three different movements in condition 1 and of three times the same movement in condition 2. During each behavioural test, baseline pain, expected pain and experienced pain were recorded. Furthermore, the peak torque and the variability of the produced muscle strength during the final behavioural test were assessed. Replicating and extending previous research, we found that patients overpredicted pain during a threatening behavioural test. Furthermore, pain-related fear and pain catastrophizing showed to be unique predictors of the peak torque of the final behavioural test. No support was found for our hypothesis that varied exposure facilitates generalization of exposure effects. Possible reasons for the failure to find an advantageous effect of varied-stimulus exposure and ideas for future research are discussed.

Topics: Adult; Chronic Disease; Exercise Test; Fear; Female; Humans; Low Back Pain; Male; Movement; Muscle, Skeletal; Pain Measurement; Severity of Illness Index; Torque; Wounds and Injuries

To assess the activities of paraspinal and abdominal muscles during therapeutic exercises for the treatment of patients with nonspecific chronic low back pain (CLBP), and to study the effects of active physical rehabilitation on these activities.. A cross-sectional study comparing muscle activities during 18 stabilization exercises, and a prospective follow-up of patients with CLBP during rehabilitation.. Rehabilitation clinic in university hospital in Finland.. Nine volunteers (5 men, 4 women) aged 27 to 58 years.. Three months of active outpatient rehabilitation (4 to 6 times in a rehabilitation clinic, supplemented with self-motivated exercise at home) supervised by a physiotherapist.. Surface electromyography was recorded bilaterally from L5 level paraspinal, rectus abdominis, and obliquus externus abdominis muscles. The recorded signal was averaged and normalized to the maximal electromyographic amplitude obtained during the maximal voluntary contraction. The measurements were taken before and after the exercise treatment period.. CLBP patients showed variable trunk muscle activity patterns during the different therapeutic exercises, similar to those that we reported earlier in healthy subjects. The maximal trunk isometric extension (pre, 147.3+/-75.9Nm; post, 170.1+/-72.3Nm) and flexion (pre, 72.0+/-37.9Nm; post, 93.5+/-42.5Nm) torques did not show a significant changes during the exercise period. However, trunk rotation-flexion torque (pre, 52.9+/-26.5Nm; post, 82.4+/-65.8Nm) increased significantly (35.8%) after the exercise period (P<.05). The corresponding maximal electromyographic amplitudes of back and abdominal muscles remained unchanged. Disability, as assessed by visual analog scale and Oswestry Disability Index, did not change.. The CLBP patients performed therapeutic exercises with similar abdominal and back extensor muscle activities in the same way as the healthy subjects in our earlier studies. In this study, active physical rehabilitation had no effect on the abdominal and back muscle activities or on pain and functional disability indices.

Topics: Abdominal Muscles; Adult; Chronic Disease; Cross-Sectional Studies; Electromyography; Exercise Therapy; Female; Humans; Low Back Pain; Lumbosacral Region; Male; Middle Aged; Muscle, Skeletal; Rotation; Torque

The objective of the study was to assess the changes in the mechanical load on the low-back when shifting from a self-chosen to a recommended patient-handling technique. Nine female health care workers without formal education in patient-handling carried out 8 different tasks involving moving, turning and lifting situations. By means of a dynamic 3D biomechanical model of the lower part of the body, peak torque, compression and shear forces at the L4/L5 joint were compared using the two different patient-handling techniques. In 5 of the 8 tasks, a significant reduction was observed in spinal loading. Application of the recommended technique decreased the compression value significantly for all tasks with a mean value above 3000 N. For the two tasks with the highest compression values when using the self-chosen technique (4223, 4446 N), the loading was reduced with 36% and 25%, respectively. If the principles behind the recommended technique are implemented and maintained, a decrease in the risk of low-back disorders during patient-handling should thus be expected.

Topics: Adult; Analysis of Variance; Back; Biomechanical Phenomena; Caregivers; Electromyography; Female; Humans; Lifting; Low Back Pain; Lumbar Vertebrae; Patient Transfer; Stress, Mechanical; Task Performance and Analysis; Torque

This study was conducted to determine the pattern, magnitude, and phasic inter-relationship of the trunk muscles in maximal isometric and graded isometric axial rotational contractions and compare them with those previously observed from the same subjects in the same experimental session in dynamic conditions. In 50 normal young healthy subjects (27 male and 23 female), after a suitable skin preparation, bipolar silver-silver chloride recessed pregelled surface electrodes were placed on external oblique, internal oblique, rectus abdominis, pectoralis major, latissimus dorsi, erector spinae at T(10) and L(3) levels bilaterally with 2 cm interelectrode distance. EMG signals from grounded subjects were suitably preamplified and amplified by a fully isolated system. These subjects were stabilized in an upright-seated posture in the Axial Rotation Tester (AROT), which was placed in isometric mode for force and rotation output from the AROT. The 14 channels of EMG, the force and the rotation were sampled at 1 kHz. The subjects initially registered their isometric maximal voluntary contraction (MVC) on both sides which was used for reference and then performed their 25%, 50% and 75% of MVC bilaterally in an isometric mode in a random order. The EMG magnitude, the slope of the rise of the EMG, and the phasic interrelationship of muscles were analyzed. The results showed that female sample generated only 65% of torque of their male counterparts. There were no significant differences between the male and the female samples in the EMG variables. Exertions to the left and to the right were not significantly different from each other for the measured variables. However, the magnitude contribution of the muscles and the slope of rise of EMG were significantly different in two directions (p<0.001). The phasic interrelationship of the external obliques, the latissimus dorsi and the erector spinae were different from other muscles (p<0.01). With the increasing grades of contraction the latissimus dorsi and the external obliques increased their magnitude significantly whereas that of the erectores spinae underwent a decrease in proportionate terms (but not in absolute magnitude) suggesting their role as stabilizers but not as rotators.

Topics: Adult; Back; Electromyography; Female; Humans; Isometric Contraction; Low Back Pain; Male; Muscle, Skeletal; Posture; Rotation; Torque

General practice in many team sports is to have the athletes who do not start in a game sit on a bench while waiting to play. The purpose of this study was to examine the effect of a warm-up followed by bench rest on the stiffness of the lumbar spine in athletes.. Nine varsity-level volleyball players volunteered to have their lumbar-spine stiffness measured. The protocol consisted of an initial stiffness measurement followed by a 30-min warm-up, then another stiffness measurement, then 30 min of bench rest, and finally a third stiffness measurement.. In general, lumbar spine stiffness increased as a result of bench rest after a warm-up. This effect was seen in both the spine extension and lateral bend axes but not in the flexion or axial twist axes. However, there was no decrease in stiffness associated with the active warm-up portion of the task.. It was concluded that a warm-up followed by bench rest does lead to an increase in stiffness of the lumbar spine, suggesting this practice is not in the best interest of reducing the risk of back injury or optimal performance.

Topics: Adult; Biomechanical Phenomena; Electromyography; Humans; Low Back Pain; Lumbar Vertebrae; Male; Range of Motion, Articular; Sports; Torque

The studies carried out on the lumbar spine, using an isokinetic type machine, showed the importance of the extensor muscles and the force they develop, compared with the flexor muscles. Both the sitting and standing positions were used without determining the better position. MAIN OBJECTIVE OF THE STUDY: To determine how the patients position influenced the performance of the muscles. We also studied a new parameter : the angle to maximal peak torque (APT).. 17 healthy subjects and 19 suffering from low back pain were chosen. We perform the test in both positions for each subject. We compare in each group the peak torque of the extensor and flexor muscles on both positions and the angle of this torque.. Low back pain subjects flexor/extensor ratio were 1.71 sitting and 1.56 standing. Healthy subjects showed normal ratio of 0.69 and 0.84.. The position of the subject has no influence on the results in the low back pain subjects, and the sitting position is preferred. The angle of development of the maximal peak torque in both groups of muscles was very interesting, especially in the subjects suffering from low back pain and shines a new light on the different functions of the muscles of the low back pain suffering subjects and the healthy subjects. This angle (APT) is inversed in low back pain subjects who develop more torque for the extensors in extension of the spine.

Topics: Adult; Biomechanical Phenomena; Female; Humans; Kinetics; Low Back Pain; Lumbar Vertebrae; Male; Middle Aged; Muscle, Skeletal; Posture; Torque

The present study was carried out to examine possible mechanisms of back muscle dysfunction by assessing a stabilising and a torque-producing back muscle, the multifidus (MF) and the iliocostalis lumborum pars thoracis (ICLT), respectively, in order to identify whether back pain patients showed altered recruitment patterns during different types of exercise. In a group of healthy subjects (n=77) and patients with sub-acute (n=24) and chronic (51) low back pain, the normalised electromyographic (EMG) activity of the MF and the ICLT (as a percentage of maximal voluntary contraction) were analysed during coordination, stabilisation and strength exercises. The results showed that, in comparison with the healthy subjects, the chronic low back pain patients displayed significantly lower (P=0.013) EMG activity of the MF during the coordination exercises, indicating that, over the long term, back pain patients have a reduced capacity to voluntarily recruit the MF in order to obtain a neutral lordosis. In contrast, during the stabilisation exercises, no significant differences between patients and controls were found for the normalised EMG activity of the two muscles. These findings indicated that, during low-load exercises, no insufficiencies in back muscle recruitment were evident in either subacute or chronic back pain patients. During the strength exercises, the normalised activity of both back muscles was significantly lower in chronic low back pain patients (P=0.017 and 0.003 for the MF and ICLT, respectively) than in healthy controls. Pain, pain avoidance and deconditioning may have contributed to these lower levels of EMG activity during intensive back muscle contraction. The possible dysfunction of the MF during coordination exercises and the altered activity of both muscles during strength exercises may be of importance in symptom generation, recurrence or maintenance of low back pain.

Topics: Acute Disease; Adult; Back; Chronic Disease; Electromyography; Exercise Therapy; Female; Humans; Low Back Pain; Male; Middle Aged; Muscle Contraction; Muscle, Skeletal; Torque; Volition

To investigate whether subgroups of patients with chronic low back pain show differences in treatment outcome, measured with the Roland Disability Questionnaire. (RDQ).. The study was carried out in a rehabilitation centre.. Eighty-four patients with chronic low back pain participated in this study.. Patients followed a multidisciplinary treatment programme that primarily targets physical aspects. DESIGN AND MAIN OUTCOME MEASURE: Based on pretreatment lumbar dynamometry results and Symptom Checklist (SCL-90) scores, patients were divided into subgroups. The dynamometry subgroups were: performances lower than healthy subjects (expected performance), performances comparable with those of healthy subjects (normal performance) and inconsistent performances (submaximal performance). The SCL-90 subgroups were: a total score of 'average' or lower compared with a population of chronic pain patients (low psychological score) and a total score of 'above average' or higher compared with this population (high psychological score). Patients answered the RDQ in the week before (RDQ1; n = 84) and after treatment (RDQ2; n = 78) to investigate whether the subgroups show differences in outcome expressed as the percentage change between RDQ2 and RDQ1, (%RDQ2-1). A %RDQ2-1 > or = 20% was classified as an improvement.. Improvement on disability level > or = 20% is shown in 64% and 55% of the patients with 'normal' and 'expected' lumbar dynamometry performances and low psychological scores compared with only 33% and 25% of those with high psychological scores. Patients with submaximal performances show hardly any changes in disability level and there are no differences betweenthose with low psychological scores (14%) and those reporting high scores (0%).. The fact that patient subgroups with differences in treatment outcome can be defined using lumbar dynamometry and psychological questionnaires suggests that these instruments might facilitate treatment indication in clinical practice.

Topics: Adult; Attitude to Health; Chronic Disease; Disability Evaluation; Female; Humans; Low Back Pain; Lumbar Vertebrae; Male; Movement; Muscle, Skeletal; Surveys and Questionnaires; Torque; Treatment Outcome

Sudden, unexpected loading on the low back is associated with a high incidence of low back pain. Experiments in which sudden loading was applied during standing revealed increased compression forces on the spine and increased trunk angle, which may cause injury to the spine and hence explain this association. During a more dynamic daily activity, i.e. lifting, this could not be demonstrated, which may be due to experimental constraints. We therefore reinvestigated the loading of the low back when subjects were lifting an unexpectedly heavy object. Ten males lifted boxes, weighing 1.6 or 6.6 kg, at a self-selected lifting velocity. In some trials the mass of these boxes was unexpectedly increased by 10 kg. The ground reaction forces, body movements and trunk muscle activity were measured and from these, the L5/S1 torques and compression forces were estimated. Underestimation of the mass did not lead to an increase in low back loading. This finding was independent of the mass the subjects were expecting to lift. In conclusion, no evidence was found to support inference regarding causality of the association between sudden loading and low back pain during whole body lifting movements.

Topics: Adult; Biomechanical Phenomena; Humans; Lifting; Low Back Pain; Lumbosacral Region; Male; Torque; Weight Perception; Weight-Bearing

Twisted trunk postures during tractor driving are associated with low-back pain. The purposes of this study were to quantify the muscle activity as a function of twisting angle, to quantify the range of motion (ROM) during active trunk rotation and to determine whether there were any differences between tractor drivers and office workers and between twisting direction for these variables. The subjects performed exertions in a seated position, twisting from the neutral position to the end of the ROM. The results showed that external oblique and erector spinae had significantly different activation patterns depending on twisting direction. For the contralateral external oblique and the ipsilateral erector spinae, the muscle effort required to twist the trunk was low up to about 20 degrees twisting angle, then the muscle effort needed to twist the trunk increased progressively. No significant differences due to occupation or twisting direction were found. The result implies that work in twisted trunk postures might be a risk factor for low-back pain.

Topics: Adult; Back; Cumulative Trauma Disorders; Electromyography; Humans; Low Back Pain; Male; Movement; Muscle, Skeletal; Occupational Diseases; Occupations; Posture; Torque

The purpose of this study was to measure the torque, the magnitude of the electromyogram (EMG) signal and the phase relationship of 14 muscles during trunk axial rotation. Fifty normal healthy volunteers (27 males and 23 females) with no lower-back injury participated in the study. The subjects were seated in an upright position in the axial rotation tester (AROT) after applying surface electrodes bilaterally to the following muscles: pectoralis major, rectus abdominis, external oblique, internal oblique, latissimus dorsi, and erector spinae at T10 and L3. They were stabilized from the hip down, and the shoulder harness of the AROT was applied to their shoulders. These subjects performed maximal isometric axial rotations to the left and right in a random order. The torque and 14 channels of EMG were monitored, and their magnitude, slope of the increase in magnitude, and timing of the anticipation and onset activity were determined. The results revealed that the females produced 65% of the torque of their male counterparts. The pattern and magnitude of EMG in performing these tasks were significantly different between males and females (P<0.01). Males generated the greatest activity in their ipsilateral latissimus dorsi followed by their contralateral external oblique muscles. In the females, maximal EMG activity was observed in their contralateral pectoralis muscle. Thus, under the current experimental conditions, the females employed a different muscle recruitment strategy compared to the males. Each muscle involved in axial rotation was significantly different from the other (P < 0.01). The timing pattern for these activities was inconsistent, implying that there is no fixed-order phasic recruitment of the torso muscles during maximal isometric axial rotation.

Topics: Adolescent; Adult; Back; Electromyography; Female; Humans; Isometric Contraction; Low Back Pain; Male; Muscle, Skeletal; Posture; Rotation; Torque

A correlative design using stepwise regression analysis.. To explore the variation in spinal isometric strength that can be accounted for by anticipation of pain, sensory perception of pain, functional disability belief, and the fear-avoidance belief in chronic low back pain patients.. Several biobehavioral factors contribute to the persistence of pain behavior in chronic patients. Recent studies suggest a need to explore the relation between reduced physical performance and the sensory and cognitive perception of pain.. Sixty-three patients with chronic low back pain 20 to 56 years of age participated in this study. Visual Analogs Scales, the Fear-Avoidance Belief questionnaire, and the Disability Belief questionnaire were used to measure the sensory and cognitive dimensions of pain. Spinal isometric strength was measured by the Medx lumbar extension machine.. Analysis of variance and the stepwise regression analysis demonstrated that anticipation of pain and the fear-avoidance belief about physical activity significantly predicted variation in the spinal isometric strength deficit P < 0. 001. True pain experienced during the testing and answers to the Disability Belief questionnaire were not related.. The results of this study strongly support the hypothesis that spinal physical capacity in chronicity is not explained solely by the sensory perception of pain. The anticipation of pain and the fear-avoidance belief about physical activities were the strongest predictors of the variation in physical performance.

Topics: Acute Disease; Adult; Avoidance Learning; Fear; Female; Humans; Isometric Contraction; Low Back Pain; Lumbosacral Region; Male; Middle Aged; Pain Measurement; Regression Analysis; Torque

Measurement of the time-varying characteristics of the frequency content of trunk muscle electromyography is a method to quantify the amount of fatigue endured by workers during industrial tasks, as well as a tool that may guide the training and rehabilitation of healthy and injured workers. Quantification of the change of signal power within specific frequency ranges may shed greater insight into the fatigue process. Sixteen healthy male subjects performed isometric trunk extension at 70% of their maximum voluntary contraction. Surface electromyography from medial and lateral erector spinae, and latissimus dorsi locations were processed using the short-time Fourier transform (STFT) and wavelet transform. Linear regression quantified the time rate of change of median frequency as well as frequency specific STFT filter and wavelet scale measures. The median frequency from the short-time Fourier transform declined by 22 Hz/min from an initial value of 77 Hz on average. The wavelet and STFT filter measures demonstrated this decline to be caused by a reduction in 209-349 Hz signal power in addition to an increase in 7-88 Hz signal power. A significant reduction in median frequency and significant elevation in 13-22 Hz wavelet signal component was detected in about 90% of the cases, indicating their use for detecting and quantifying fatigue.

Topics: Adult; Electromyography; Exercise Test; Fourier Analysis; Humans; Isometric Contraction; Linear Models; Low Back Pain; Male; Muscle Fatigue; Signal Processing, Computer-Assisted; Time Factors; Torque

To obtain reference data for future studies of patients with low back pain, back muscle fatigue was studied by surface electromyography at L1 and L5 lumbar levels in 55 healthy subjects exerting 80% of maximal voluntary contraction of the back extensors in a sitting position. Reference data were the initial value and rate of decrease (slope) of the median frequency during the contraction. The aim was also to study the effects of contraction time, gender differences, electrode locations and correlations with torque, age and subjective ratings. Initial median frequency was 52 Hz +/- 7.5, with no difference between electrode locations; steeper slopes were found at L5 level (-0.44%/s +/- 0.25) than at L1 (-0.36%/s +/- 0.26). No right-left differences and no gender differences were found for these parameters. A correlation was observed between slope and initial median frequency, higher for men (r approximately -0.7) than for women (r approximately -0.5). Intersubject coefficient of variation for the slope was smallest for the longest (45 seconds) recording time (60-70%), but still much higher than for the initial median frequency (14%). The torque and the subjective ratings of fatigue showed no correlation with the electromyography variables. We conclude that the same reference values can be used for men and women. Owing to the large intersubject range of the slope, the clinical use of this variable may, however, be impeded.

Topics: Adult; Back; Electromyography; Female; Humans; Low Back Pain; Male; Middle Aged; Muscle Contraction; Muscle Fatigue; Reference Values; Sex Factors; Torque

A 5-year prospective study.. To investigate trunk muscle weakness as a risk factor for low back pain in asymptomatic volunteers.. Muscle strength has not been sufficiently studied as a risk factor for low back pain.. The study participants included 30 male and 37 female volunteers (mean age, 17 +/- 2 years), who neither reported nor had ever been treated for low back pain. Trunk muscle strength was measured isokinetically (60 degrees/sec), using the trunk extension and flexion and torso rotation units. The peak torques of the volunteers' extension, flexion, rightward rotation, and leftward rotation were measured, and the agonist/antagonist ratios were calculated as extension/flexion and left rotation/right rotation ratio. The volunteers then were followed prospectively for 5 years to determine the incidence of low back pain and were classified into a non-low back pain group (volunteers with no low back pain during the 5-year follow-up period) and a low back pain group (volunteers who experienced low back pain during this period).. The low back pain group consisted of 8 male and 10 female volunteers. There were no significant differences between the non-low back pain group and the low back pain group regarding age, height, weight, the peak torque values, or the left rotation/right rotation ratio. However, the extension/flexion ratio of the low back pain group (men, 0.96 +/- 0.27; women, 0.77 +/- 0.19) demonstrated significantly lower values than that of the non-low back pain group (1.23 +/- 0.28 and 1.00 +/- 0.16 for men and women, respectively, P < 0.05).. An imbalance in trunk muscle strength, i.e., lower extensor muscle strength than flexor muscle strength, might be one risk factor for low back pain.

Topics: Adolescent; Adult; Female; Humans; Isometric Contraction; Low Back Pain; Lumbosacral Region; Male; Muscle Weakness; Muscle, Skeletal; Prospective Studies; Risk Factors; Torque

To evaluate the effects of angle and hand position during variable-angle Roman chair (VARC) back extension exercise on lumbar paraspinal electromyographic (EMG) activity.. Descriptive, repeated measures.. University-based musculoskeletal research laboratory.. Two female and eight male volunteers recruited from a university setting.. Surface integrated EMG activity was recorded from the L3-L4 paraspinal region during 24 10-second repetitions of dynamic back extension exercise, each consisting of a unique VARC angle (six total) and subject hand position (four total). Lumbar paraspinal surface integrated EMG activity measured in millivolts per repetition was used for analysis.. Significant lumbar paraspinal EMG activity was evident during each of the 24 repetitions (p < or = .05), with a 104% increase in activity noted between the lowest and highest. EMG activity increased progressively among hand positions and as the VARC angle became more horizontal. VARC angle affected EMG activity more than hand position, but the greatest impact on EMG activity was produced by modifying both angle and hand position.. Lumbar paraspinal EMG activity can be altered during VARC back extension exercise by changing angle and hand position. Clinicians can use these data to develop progressive resistance exercise programs using the VARC apparatus.

Topics: Adult; Biomechanical Phenomena; Electromyography; Equipment Design; Exercise Therapy; Female; Hand; Humans; Low Back Pain; Lumbosacral Region; Male; Muscle, Skeletal; Physical Endurance; Posture; Range of Motion, Articular; Torque; Weight-Bearing

To evaluate the relation between variability of the torque curves and factors such as age, gender, measurement speeds, and period from low back pain (LBP) onset at isokinetic trunk strength testing.. Observational.. Hospital.. One hundred forty-three consecutive LBP patients (acute, subacute, and chronic) who received physical therapy, and 200 healthy volunteer subjects.. The variability of the torque curves is an indicator of consistency of effort, and was measured as the coefficient of variance (CV) at different measurement speeds in isokinetic trunk flexion/extension strength testing.. The CV was lower in men than in women at the faster measurement speed. LBP patients had higher CV values than healthy subjects. The CV was different according to gender and measurement speed, but not different according to age and periods from LBP onset.. The CV was affected by measurement speed and gender, but not by age or period from LBP onset. Because the CV was higher in LBP patients than in healthy subjects, this value may be usable as an adjunctive index of LBP.

Topics: Abdomen; Acute Disease; Adolescent; Adult; Age Factors; Aged; Aged, 80 and over; Case-Control Studies; Chronic Disease; Female; Humans; Isotonic Contraction; Low Back Pain; Male; Middle Aged; Muscle Weakness; Range of Motion, Articular; Sex Factors; Thorax; Torque

Poor muscle strength, relative to the physical demands of specific jobs, is considered a risk factor for low back pain. To gain an understanding of the underlying mechanisms, this study questioned whether muscle strength was related to task performance and low back load in nursing tasks. Trunk extension, elbow flexion and knee extension strength were therefore measured in 17 nurses. The independent effects of muscle strength on task duration, jerkiness of effort and L5-S1 torque were investigated as the nurses performed several patient handling tasks. Despite a large variation in muscle strength within the subject population, no effect of strength on task duration, jerkiness or L5-S1 torques was observed. In conclusion, poor muscle strength was found not to be related to increased low back load. If 'weaker' nurses were to be at a higher risk, it would be due to a reduced capability to withstand the mechanical load, rather than to an increased mechanical load.

Topics: Adult; Biomechanical Phenomena; Female; Humans; Lifting; Low Back Pain; Male; Muscle Weakness; Nursing Staff; Occupational Diseases; Risk Factors; Task Performance and Analysis; Torque; Workload

The purpose of this study was to investigate which demographic parameters are most important in relation to lumbar dynamometry performance in patients with chronic low back pain (LBP). Forty-five chronic LBP patients participated in this study. Gender, age, weight and height were determined and a lumbar dynamometry measurement was carried out, using the Isostation B200. Student's t-test, ANOVA techniques and correlation coefficients were used to investigate the relationships between each demographic parameter and lumbar dynamometry performance. Stepwise multiple linear regression analyses were performed afterwards to determine which demographic parameters are most important in relation to lumbar dynamometry performance. Results indicate significant relationships (1) between gender, height, weight and all lumbar dynamometry parameters and (2) between age and three of the six isometric torque parameters. No significant relationship was found between age and maximum velocity parameters. Results of the stepwise multiple linear regression analyses show that the demographic parameters explain 27-47% of the variance in maximum isometric strength parameters and 19-25% of the variance in maximum velocity parameters. Gender is the most important demographic parameter, being related to nearly all maximum isometric torque parameters (percentage explained variance 6-37%) and height is the only important demographic parameter related to the velocity parameters (percentage explained variance 19-25%). Weight and age account for only a small amount of variance in lumbar dynamometry parameters (percentage explained variance 5-7%), meaning that these parameters are non-relevant predictors.

Topics: Adult; Body Height; Female; Humans; Isometric Contraction; Linear Models; Low Back Pain; Lumbar Vertebrae; Male; Muscle, Skeletal; Range of Motion, Articular; Sex Factors; Torque

Lumbar dynamometry is a potentially useful method for assessing the state of trunk muscles in low back pain (LBP) patients. The purpose of this study was to assess the reliability of lumbar dynamometry measurements in chronic LBP patients by conducting test-retest measurements on different days. Thirty-one men and 14 women with chronic LBP participated in this study. The experiments consisted of three sets of lumbar dynamometry measurements (Isostation B200) carried out on three different days with a 2- to 3-day interval. A standard protocol was administered to all subjects, consisting of a range-of-motion measurement about each axis, a 5 s maximum isometric trial about each axis and five dynamic repetitions about each axis against a resistance set at 25% and at 50% of the maximum isometric torque. Correlation coefficients and regression analysis were used to detect possible learning effects. One-way anova and regression analysis were used to assess the reliability of the measurements. High coefficients were found for the correlation between the first and second lumbar dynamometry measurements. Regression analysis showed that the differences between those measurements were not significant. This means that there was no learning effect operating between the first and second lumbar dynamometry measurements. One-way anova showed a reliability higher than 0.90 for the torque and velocity parameters. Reliability for the range-of-motion parameters was somewhat lower: between 0.76 and 0.94. Regression analysis showed no significant differences between the second and third measurements for the torque and velocity parameters. For range-of-motion parameters significant differences were found. From this study it can be concluded that the Isostation B200 provides reliable measures of torque and velocity parameters, but measures of the range-of-motion parameters are unreliable. No learning effect operates between the first and second lumbar dynamometry measurements, which means that a single measurement, with prior warming up and practice, is sufficient to assess the performance of the LBP patient.

Topics: Adult; Analysis of Variance; Equipment and Supplies; Evaluation Studies as Topic; Female; Humans; Learning; Low Back Pain; Lumbosacral Region; Male; Methods; Muscle, Skeletal; Range of Motion, Articular; Regression Analysis; Torque