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1.  Contribution of Hamstring Fatigue to Quadriceps Inhibition Following Lumbar Extension Exercise 
The purpose of this study was to determine the contribution of hamstrings and quadriceps fatigue to quadriceps inhibition following lumbar extension exercise. Regression models were calculated consisting of the outcome variable: quadriceps inhibition and predictor variables: change in EMG median frequency in the quadriceps and hamstrings during lumbar fatiguing exercise. Twenty-five subjects with a history of low back pain were matched by gender, height and mass to 25 healthy controls. Subjects performed two sets of fatiguing isometric lumbar extension exercise until mild (set 1) and moderate (set 2) fatigue of the lumbar paraspinals. Quadriceps and hamstring EMG median frequency were measured while subjects performed fatiguing exercise. A burst of electrical stimuli was superimposed while subjects performed an isometric maximal quadriceps contraction to estimate quadriceps inhibition after each exercise set. Results indicate the change in hamstring median frequency explained variance in quadriceps inhibition following the exercise sets in the history of low back pain group only. Change in quadriceps median frequency explained variance in quadriceps inhibition following the first exercise set in the control group only. In conclusion, persons with a history of low back pain whose quadriceps become inhibited following lumbar paraspinal exercise may be adapting to the fatigue by using their hamstring muscles more than controls.
Key PointsA neuromuscular relationship between the lumbar paraspinals and quadriceps while performing lumbar extension exercise may be influenced by hamstring muscle fatigue.QI following lumbar extension exercise in persons with a history of LBP group may involve significant contribution from the hamstring muscle group.More hamstring muscle contribution may be a necessary adaptation in the history of LBP group due to weaker and more fatigable lumbar extensors.
PMCID: PMC3818676  PMID: 24198683
Superimposed burst technique; electromyography; spectral median frequency; correlation and regression; low back pain
2.  Reduced Quadriceps Activation After Lumbar Paraspinal Fatiguing Exercise 
Journal of Athletic Training  2006;41(1):79-86.
Context: Although poor paraspinal muscle endurance has been associated with less quadriceps activation (QA) in persons with a history of low back pain, no authors have addressed the acute neuromuscular response after lumbar paraspinal fatiguing exercise.
Objective: To compare QA after lumbar paraspinal fatiguing exercise in healthy individuals and those with a history of low back pain.
Design: A 2 × 4 repeated-measures, time-series design.
Setting: Exercise and Sport Injury Laboratory.
Patients or Other Participants: Sixteen volunteers participated (9 males, 7 females; 8 controls and 8 with a history of low back pain; age = 24.1 ± 3.1 years, height = 173.4 ± 7.1 cm, mass = 72.4 ± 12.1 kg).
Intervention(s): Subjects performed 3 sets of isometric lumbar paraspinal fatiguing muscle contractions. Exercise sets continued until the desired shift in lumbar paraspinal electromyographic median power frequency was observed. Baseline QA was compared with QA after each exercise set.
Main Outcome Measure(s): An electric burst was superimposed while subjects performed a maximal quadriceps contraction. We used the central activation ratio to calculate QA = (FMVIC/[FMVIC + FBurst])* 100, where F = force and MVIC = maximal voluntary isometric contractions. Quadriceps electromyographic activity was collected at the same time as QA measurements to permit calculation of median frequency during MVIC.
Results: Average QA decreased from baseline (87.4% ± 8.2%) after the first (84.5% ± 10.5%), second (81.4% ± 11.0%), and third (78.2% ± 12.7%) fatiguing exercise sets. On average, the group with a history of low back pain showed significantly more QA than controls. No significant change in quadriceps median frequency was noted during the quadriceps MVICs.
Conclusions: The quadriceps muscle group was inhibited after lumbar paraspinal fatiguing exercise in the absence of quadriceps fatigue. This effect may be different for people with a history of low back pain compared with healthy controls.
PMCID: PMC1421484  PMID: 16619099
superimposed burst technique; quadriceps muscle inhibition; low back pain
3.  Jogging Kinematics After Lumbar Paraspinal Muscle Fatigue 
Journal of Athletic Training  2009;44(5):475-481.
Abstract
Context:
Isolated lumbar paraspinal muscle fatigue causes lower extremity and postural control deficits.
Objective:
To describe the change in body position during gait after fatiguing lumbar extension exercises in persons with recurrent episodes of low back pain compared with healthy controls.
Design:
Case-control study.
Setting:
Motion analysis laboratory.
Patients or Other Participants:
Twenty-five recreationally active participants with a history of recurrent episodes of low back pain, matched by sex, height, and mass with 25 healthy controls.
Intervention(s):
We measured 3-dimensional lower extremity and trunk kinematics before and after fatiguing isometric lumbar paraspinal exercise.
Main Outcome Measure(s):
Measurements were taken while participants jogged on a custom-built treadmill surrounded by a 10-camera motion analysis system.
Results:
Group-by-time interactions were observed for lumbar lordosis and trunk angles (P < .05). A reduced lumbar spine extension angle was noted, reflecting a loss of lordosis and an increase in trunk flexion angle, indicating increased forward trunk lean, in healthy controls after fatiguing lumbar extension exercise. In contrast, persons with a history of recurrent low back pain exhibited a slight increase in spine extension, indicating a slightly more lordotic position of the lumbar spine, and a decrease in trunk flexion angles after fatiguing exercise. Regardless of group, participants experienced, on average, greater peak hip extension after lumbar paraspinal fatigue.
Conclusions:
Small differences in response may represent a necessary adaptation used by persons with recurrent low back pain to preserve gait function by stabilizing the spine and preventing inappropriate trunk and lumbar spine positioning.
doi:10.4085/1062-6050-44.5.475
PMCID: PMC2742456  PMID: 19771285
gait analysis; spine
4.  Neuromuscular Fatigue During a Modified Biering-Sørensen Test in Subjects with and Without Low Back Pain 
Studies employing modified Biering-Sørenson tests have reported that low back endurance is related to the potential for developing low back pain. Understanding the manner in which spinal musculature fatigues in people with and without LBP is necessary to gain insight into the sensitivity of the modified Biering-Sørenson test to differentiate back health. Twenty male volunteers were divided into a LBP group of subjects with current subacute or a history of LBP that limited their activity (n = 10) and a control group (n = 10). The median frequency of the fast Fourier transform was calculated from bilateral surface electromyography (EMG) of the upper lumbar erector spinae (ULES), lower lumbar erector spinae (LLES) and biceps femoris while maintaining a prescribed modified Biering-Sørensen test position and exerting isometric forces equivalent to 100, 120, 140 and 160% of the estimated mass of the head-arms-trunk (HAT) segment. Time to failure was also investigated across the percentages of HAT. Fatigue time decreased with increasing load and differences between groups increased as load increased, however these differences were not significant. Significant differences in the EMG median frequency between groups occurred in the right biceps femoris (p ≤ 0.05) with significant pairwise differences occurring at 140% for the left biceps femoris and at 160% for the right biceps femoris. There were significant pairwise differences at 120% for average EMG of the right biceps femoris and at 140% for the right ULES, and right and left biceps femoris (p ≤ 0.05). The modified Biering-Sørensen test as usually performed at 100% HAT is not sufficient to demonstrate significant differences between controls and subjects with varying degrees of mild back disability based on the Oswestry classification.
Key pointsThe results do not wholly support the modified Biering-Sørensen test utilizing resistance of 100% HAT to discern differences in fatigue in subjects with mild low back pain.A greater activation of the biceps femoris by low back pain individuals probably contributed to the lack of significant differences in back fatigue times.The possibility exists that subjects with more sophisticated strategies could yield higher fatigue times despite inferior neuromuscular fatigue and the existence of low back pain.
PMCID: PMC3794498  PMID: 24149491
Endurance; electromyography; median frequency; back muscles; healthy subjects
5.  Effects of Exercise Induced Low Back Pain on Intrinsic Trunk Stiffness and Paraspinal Muscle Reflexes 
Journal of biomechanics  2012;46(4):801-805.
The purpose of this study was to 1) compare trunk neuromuscular behavior between individuals with no history of low back pain (LBP) and individuals who experience exercise-induced LBP (eiLBP) when pain free, and 2) investigate changes in trunk neuromuscular behavior with eiLBP. Seventeen young adult males participated including eight reporting recurrent, acute eiLBP and nine control participants reporting no history of LBP. Intrinsic trunk stiffness and paraspinal muscle reflex delay were determined in both groups using sudden trunk flexion position perturbations 1-2 days following exercise when the eiLBP participants were experiencing an episode of LBP (termed post-exercise) and 4-5 days following exercise when eiLBP had subsided (termed post-recovery). Post-recovery, when the eiLBP group was experiencing minimal LBP, trunk stiffness was 26% higher in the eiLBP group compared to the control group (p=0.033) and reflex delay was not different (p=0.969) between groups. Trunk stiffness did not change (p=0.826) within the eiLBP group from post-exercise to post-recovery, but decreased 22% within the control group (p=0.002). Reflex delay decreased 11% within the eiLBP group from post-exercise to post-recovery (p=0.013), and increased 15% within the control group (p=0.006). Although the neuromuscular mechanisms associated with eiLBP and chronic LBP may differ, these results suggest that previously-reported differences in trunk neuromuscular behavior between individuals with chronic LBP and healthy controls reflect a combination of inherent differences in neuromuscular behavior between these individuals as well as changes in neuromuscular behavior elicited by pain.
doi:10.1016/j.jbiomech.2012.11.023
PMCID: PMC3568223  PMID: 23182221
low back pain; exercise; trunk stiffness; reflex
6.  Effect of Lumbar Stabilization and Dynamic Lumbar Strengthening Exercises in Patients With Chronic Low Back Pain 
Annals of Rehabilitation Medicine  2013;37(1):110-117.
Objective
To compare the effects of lumbar stabilization exercises and lumbar dynamic strengthening exercises on the maximal isometric strength of the lumbar extensors, pain severity and functional disability in patients with chronic low back pain (LBP).
Methods
Patients suffering nonspecific LBP for more than 3 months were included prospectively and randomized into lumbar stabilization exercise group (n=11) or lumbar dynamic strengthening exercise group (n=10). Exercises were performed for 1 hour, twice weekly, for 8 weeks. The strength of the lumbar extensors was measured at various angles ranging from 0° to 72° at intervals of 12°, using a MedX. The visual analog scale (VAS) and the Oswestry Low Back Pain Disability Questionnaire (ODQ) were used to measure the severity of LBP and functional disability before and after the exercise.
Results
Compared with the baseline, lumbar extension strength at all angles improved significantly in both groups after 8 weeks. The improvements were significantly greater in the lumbar stabilization exercise group at 0° and 12° of lumbar flexion. VAS decreased significantly after treatment; however, the changes were not significantly different between the groups. ODQ scores improved significantly in the stabilization exercise group only.
Conclusion
Both lumbar stabilization and dynamic strengthening exercise strengthened the lumbar extensors and reduced LBP. However, the lumbar stabilization exercise was more effective in lumbar extensor strengthening and functional improvement in patients with nonspecific chronic LBP.
doi:10.5535/arm.2013.37.1.110
PMCID: PMC3604220  PMID: 23525973
Exercise; Low back pain; Muscle strength; Abdominal muscle; Rehabilitation
7.  Lumbar Multifidus Muscle Thickness Does Not Predict Patients With Low Back Pain Who Improve With Trunk Stabilization Exercises 
Objective
To understand lumbar multifidus (LM) muscle activation as a clinical feature to predict patients with low back pain (LBP) who are likely to benefit from stabilization (STB) exercises.
Design
Prospective, cohort study.
Setting
Outpatient physical therapy clinics.
Participants
Persons with LBP were recruited for this study. Subjects (N=25) were classified as either eligible to receive STB exercises or ineligible on the basis of current clinical prediction rules.
Interventions
Six weeks of STB treatment.
Main Outcome Measures
Before and after treatment, subjects underwent rehabilitative ultrasound imaging to quantify LM-muscle activation and completed disability and pain questionnaires. Analyses were performed to examine the (1) relation between LM-muscle activation and current clinical features used to predict patients with LBP likely to benefit from STB exercises, (2) LM-muscle activation between the STB-eligible and STB-ineligible groups before and after STB treatment, and (3) relation between LM-muscle activation before STB treatment and (a) disability and (b) pain outcomes after treatment for both groups.
Results
No relation was found between LM-muscle activation and the number of clinical features. Before STB treatment, LM-muscle activation between the STB-eligible and STB-ineligible groups did not differ. After STB treatment, LM-muscle activation differed between the groups; however, this interaction was because the LM-muscle activation for the STB-eligible group decreased after treatment while that for the STB-ineligible group increased after treatment. Finally, only the STB-eligible group had a significant reduction in disability following treatment; however, no relation was found between LM-muscle activation before treatment and (a) disability or (b) pain outcomes after treatment in the STB-eligible group.
Conclusions
LM-muscle activation does not appear to be a clinical feature that predicts patients with LBP likely to benefit from STB exercises.
doi:10.1016/j.apmr.2012.12.001
PMCID: PMC3677852  PMID: 23228626
Clinical prediction rule; Exercise; Low back pain; Rehabilitation
8.  Back and hip extensor muscles fatigue in healthy subjects: task-dependency effect of two variants of the Sorensen test 
European Spine Journal  2008;17(12):1721-1726.
Paraspinal muscle fatigability during various trunk extension tests has been widely investigated by electromyography (EMG), and its task-dependency is established recently. Hip extensor muscle fatigability during the Sorensen test has been reported. The aim of the present experiments was to evaluate the task-dependency of back and hip extensor muscle fatigue during two variants of the Sorensen test. We hypothesized that the rate of muscular fatigue of the hip and back extensor muscles varies according to the test position. Twenty healthy young males with no history of low back pain volunteered to participate in this cross-sectional study. They were asked to perform two body weight-dependent isometric back extension tests (S1 = Sorensen test; S2 = modified Sorensen on a 45° Roman chair). Surface EMG activity of the paraspinal muscles (T10 and L5 levels) and hip extensor muscles (gluteus maximus; biceps femoris) was recorded, and muscular fatigue was assessed through power spectral analysis of the EMG data by calculating the rate of median power frequency change. We observed hip extensor muscle fatigue simultaneously with paraspinal muscle fatigue during both Sorensen variants. However, only L5 level EMG fatigue indices showed a task-dependency effect between S1 and S2. Hip extensor muscles appear to contribute to load sharing of the upper body mass during both Sorensen variants, but to a different extent because L5 level fatigue differs between the Sorensen variants. Our findings suggest that task-dependency has to be considered when EMG variables are compared between two types of lumbar muscle-fatiguing tasks.
doi:10.1007/s00586-008-0782-y
PMCID: PMC2587667  PMID: 18813961
Erector spinae; Hip extensors; Sorensen test; Muscle fatigability; Task-dependency
9.  Characterization of the Muscle Electrical Properties in Low Back Pain Patients by Electrical Impedance Myography 
PLoS ONE  2013;8(4):e61639.
Objectives
This study aims to investigate the electrical properties of lumbar paraspinal muscles (LPM) of patients with acute lower back pain (LBP) and to study a new approach, namely Electrical Impedance Myography (EIM), for reliable, low-cost, non-invasive, and real-time assessment of muscle-strained acute LBP.
Design
Patients with muscle-strained acute LBP (n = 30) are compared to a healthy reference group (n = 30). Electrical properties of LPM are studied.
Background
EIM is a novel technique under development for the assessment of neuromuscular disease. Therefore, it is speculated that EIM can be employed for the assessment of muscle-strained acute LBP.
Methods
Surface electrodes, in 2-electrode configurations, was used to measure the electrical properties of patient's and healthy subject's LPM at six different frequencies (0.02, 25.02, 50.02, 1000.02, 3000.02, and 5000.02 kHz), with the amplitude of the applied voltage limited to 200 mV. Parameters of impedance (Z), extracellular resistance (Re), intracellular resistance (Ri), and the ratio of extracellular resistance to intracellular resistance (Re/Ri) of LBP patient's and healthy subject's LPM were assessed to see if significant difference in values obtained in muscle-strained acute LBP patients existed.
Results
Intraclass correlation coefficient (ICC) showed that all measurements (ICC>0.96 for all studying parameters: Z, Re, Ri, and Re/Ri) had good reliability and validity. Significant differences were found on Z between LBP patient's and healthy subject's LPM at all studying frequencies, with p<0.05 for all frequencies. It was also found that Re (p<0.05) and Re/Ri (p<0.05) of LBP patient's LPM was significant smaller than that of healthy subjects while Ri (p<0.05) of LBP patient's LPM was significant greater than that of healthy subjects. No statistical significant difference was found between the left and right LPM of LBP patients and healthy subjects on the four studying parameters.
Conclusion
EIM is a promising technique for assessing muscle-strained acute LBP.
doi:10.1371/journal.pone.0061639
PMCID: PMC3632516  PMID: 23630604
10.  Influences of trunk muscles on lumbar lordosis and sacral angle 
European Spine Journal  2005;15(4):409-414.
Background: The strength of abdominal muscle and back extensors or their balances are commonly mentioned as major indicators of potential low back pain (LBP). Former studies on anthropometrics in terms of trunk muscle strength seemed to lack precision in methodology. Furthermore, the extension-flexion ratio, which is a good parameter of trunk muscle balance, was not as much studied as simple maximum torques in this area of study. Objectives: To investigate relationship between trunk muscle strength and lumbar lordosis, sacral angle in patients who did not show significant abnormal findings on their simple lateral radiograph. Methods: Thirty-one subjects were participated and their mean age was 35. Lumbar simple lateral radiograph was taken and lordotic angle was obtained by altered Cobb’s method. Sacral angle was also examined on the same film. The relationship between these angles and muscle strength (isometric maximum torques and ratios of them) was investigated by the correlation analysis. Results: None of the isometric maximum torques was related to sacral angle or lordotic angle. However, the ratio of extension to flexion was significantly related to the lordotic angle (Pearson’s correlation coefficient=0.491, p<0.01). Other ratios were not related to any of the angles. Conclusions: An imbalance in trunk muscle strength can influence significantly lordotic curve of lumbar spine and might be one risk factor for potential low back pain.
doi:10.1007/s00586-005-0976-5
PMCID: PMC3489319  PMID: 16151709
Lordosis; Sacral angle; Isometric measurement; Abdominal muscle function
11.  Short term modulation of trunk neuromuscular responses following spinal manipulation: a control group study 
Background
Low back pain (LBP) is one of the most frequent musculoskeletal conditions in industrialized countries and its economic impact is important. Spinal manipulation therapy (SMT) is believed to be a valid approach in the treatment of both acute and chronic LBP. It has also been shown that SMT can modulate the electromyographic (EMG) activity of the paraspinal muscle. The purpose of this study was to investigate, in a group of patients with low back pain, the persistence of changes observed in trunk neuromuscular responses after a spinal manipulation (SMT).
Methods
Sixty adult participants with LBP performed a block of 5 flexion-extension movements. Participants in the experimental group (n=30) received lumbar SMT whereas participants in the control group (n=30) were positioned similarly for the treatment but did not receive SMT. Blocks of flexion-extension movements were repeated immediately after the manipulation as well as 5 and 30 minutes after SMT (or control position). EMG activity of paraspinal muscles was recorded at L2 and L5 level and kinematic data were collected to evaluate the lumbo-pelvic kinematics. Pain intensity was noted after each block. Normalized EMG, pain intensity and lumbo-pelvic kinematics were compared across experimental conditions.
Results
Participants from the control group showed a significant increase in EMG activity during the last block (30 min) of flexion-extension trials in both flexion and full-flexion phases at L2. Increase in VAS scores was also observed in the last 2 blocks (5 min and 30 min) in the control group. No significant group x time interaction was seen at L5. No significant difference was observed in the lumbo-pelvic kinematics.
Conclusion
Changes in trunk neuromuscular control following HVLA spinal manipulation may reduce sensitization or muscle fatigue effects related to repetitive movement. Future studies should investigate short term changes in neuromuscular components, tissue properties and clinical outcomes.
doi:10.1186/1471-2474-14-92
PMCID: PMC3602072  PMID: 23496876
Spinal manipulation; Electromyography; Kinematics; Flexion-relaxation phenomenon
12.  Reliability of lumbar dynamometry measurements in patients with chronic low back pain with test-retest measurements on different days 
European Spine Journal  1997;6(1):54-62.
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. Thirtyone 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.
doi:10.1007/BF01676575
PMCID: PMC3454637  PMID: 9093828
Chronic low back pain; Isostation; Reliability; Learning effect
13.  Kinematic analysis of dynamic lumbar motion in patients with lumbar segmental instability using digital videofluoroscopy 
European Spine Journal  2009;18(11):1677-1685.
The study design is a prospective, case–control. The aim of this study was to develop a reliable measurement technique for the assessment of lumbar spine kinematics using digital video fluoroscopy in a group of patients with low back pain (LBP) and a control group. Lumbar segmental instability (LSI) is one subgroup of nonspecific LBP the diagnosis of which has not been clarified. The diagnosis of LSI has traditionally relied on the use of lateral functional (flexion–extension) radiographs but use of this method has proven unsatisfactory. Fifteen patients with chronic low back pain suspected to have LSI and 15 matched healthy subjects were recruited. Pulsed digital videofluoroscopy was used to investigate kinematics of lumbar motion segments during flexion and extension movements in vivo. Intersegmental linear translation and angular displacement, and pathway of instantaneous center of rotation (PICR) were calculated for each lumbar motion segment. Movement pattern of lumbar spine between two groups and during the full sagittal plane range of motion were analyzed using ANOVA with repeated measures design. Intersegmental linear translation was significantly higher in patients during both flexion and extension movements at L5–S1 segment (p < 0.05). Arc length of PICR was significantly higher in patients for L1–L2 and L5–S1 motion segments during extension movement (p < 0.05). This study determined some kinematic differences between two groups during the full range of lumbar spine. Devices, such as digital videofluoroscopy can assist in identifying better criteria for diagnosis of LSI in otherwise nonspecific low back pain patients in hope of providing more specific treatment.
doi:10.1007/s00586-009-1147-x
PMCID: PMC2899390  PMID: 19727854
Videofluoroscopy; Lumbar spine; Segmental instability; Kinematics; Motion
14.  Relationship Between the Hip and Low Back Pain in Athletes Who Participate in Rotation-Related Sports 
Context
Hip function has been proposed to be related to low back pain (LBP) because of the anatomical proximity of the hip and lumbopelvic region. To date, findings have been inconclusive, possibly because the samples studied were heterogeneous. Sub-grouping samples based on characteristics such as activity demand, LBP classification, and sex might clarify research findings.
Objective
To describe and summarize studies that examine 3 factors proposed to be important to the study of the hip–LBP relationship.
Design
Review of cross-sectional studies.
Setting
Academic healthcare center and research laboratory.
Subjects
3 groups: athletes with a history of LBP who regularly participate in rotation-related sports, athletes without a history of LBP who are active but do not regularly participate in rotation-related sports, and athletes without a history of LBP who participate in rotation-related sports.
Main Outcome
Hip range of motion and hip–lumbopelvic region coordination.
Measures
Hip range of motion was measured with an inclinometer. Coordination was examined based on kinematics obtained with a 3-dimensional motion-capture system.
Result
Differences among groups were found based on activity demand, LBP classification, and sex.
Conclusion
When assessing athletes with and without LBP, characteristics such as activity demand, LBP classification, and sex should be considered.
PMCID: PMC2699456  PMID: 19321907
classification; gender; sex; activity
15.  Trunk Muscles Strength as a Risk Factor for Nonspecific Low Back Pain: A Pilot Study 
Annals of Rehabilitation Medicine  2014;38(2):234-240.
Objective
To investigate the effects of asymptomatic back muscle weakness and spinal deformity on low back pain (LBP).
Methods
Sixty healthy subjects without LBP participated in this study. Radiography and an isokinetic/isometric dynamometer were used to respectively measure spinal scoliosis/lordosis and the strength of the trunk flexors/extensors. After 2 years, 48 subjects visited the hospital again and LBP episodes, its severity and the Korean version of the Oswestry Disability Index were assessed. Differences between the group with LBP and the group without LBP were evaluated and the association with LBP incidence and severity was determined.
Results
Sex, age, and trunk strength were significantly different in both group. Sex and age were significantly positive associated with LBP incidence. The isometric trunk flexor and extensor strength, maximum isokinetic trunk flexor and extensor strength were significantly and negatively associated with the LBP severity. The maximum isokinetic trunk extensor and maximum isometric trunk extensor strength was significantly negative associated with the LBP incidence.
Conclusion
LBP incidence is associated with isometric and isokinetic trunk extensor weakness, whereas LBP severity is associated with age, sex, isokinetic trunk extensor and flexor weakness, isometric trunk extensor and flexor weakness.
doi:10.5535/arm.2014.38.2.234
PMCID: PMC4026610  PMID: 24855618
Low back pain; Muscle weakness; Muscle strength dynamometer; Age; Sex
16.  Low back pain and physical exercise in leisure time in 38-year-old men and women: A 25-year prospective cohort study of 640 school children 
European Spine Journal  1997;6(3):181-186.
A cohort of 38-year-old men and women were studied for leisure time physical exercise in relation to low back pain (LBP), education, work, social class and smoking by a self-administered questionnaire. At the age of 14 years, the subjects had been interviewed by their school doctor regarding history of LBP and radiographs of the thoracic and lumbar spine were taken. The results show no positive correlation between radiographic changes and LBP in the adolescent period and decreased physical activity in adulthood. Physical activity for at least 3 h/week reduces the risk of LBP measured as lifetime, 1-year and point prevalence. Eighty-five percent of the subjects who reported taking physical exercise for at least 3 h/week had participated in sports activity almost constantly since their school days and these reported being in better condition than the rest of the cohort. Otherwise they did not have a healthier mode of life. No physical exercise during leisure time was associated with a short school education, un-skilled work, unemployment and sickness, low social class, divorce, living in an apartment and smoking. Sixty percent had never or not for many years been interested in participating in sports. Badminton and tennis were the most common sports practised (36%), followed by gymnastics (32%), ball games — soccer and team handball - (25%), running (20%) and swimming (18%). Gymnastics and swimming seem to reduce LBP significantly. Our results show a falling interest in participating in sports activities over time, with 68% of the subjects being members of an athletic association previously, but only 29% currently. Women were more physically inactive during leisure time, probably because of their dual role. Logistic regression analysis indicates that physical activity is related to a long school education, high social class and regular sports activity over time.
doi:10.1007/BF01301433
PMCID: PMC3454613  PMID: 9258636
Physical activity during leisure time; Sports activity; Cohort study
17.  The addition of manipulation to an extension-oriented intervention for a patient with chronic LBP 
Objective and importance:
There is a paucity of research investigating the combined interventions of direction-specific lumbar exercise and manipulation for individuals with low back pain (LBP) who exhibit centralization or a directional preference. The purpose of this report was to describe the management and outcomes of a patient with chronic LBP who met two categories of the revised treatment based classification (TBC) approach initially described by Delitto and colleagues.
Clinical presentation:
A 55-year-old female with a 15-year history of right LBP/leg pain demonstrated centralization of symptoms with repeated extension and met four out of five criteria on the clinical prediction rule for thrust manipulation.
Interventions:
The patient was treated for seven physical therapy sessions, once a week for seven weeks. Lumbar thrust manipulation and extension-oriented interventions were combined throughout the course of care. The patient experienced a decrease on the modified Oswestry disability index score from 26 to 8%, an increase in the patient-specific functional scale score from 5.6 to 9.4, and patient-report of full return to pain-free activity at discharge.
Conclusion:
A patient with chronic LBP reported a clinically meaningful improvement after seven visits of manipulation and extension-oriented interventions. Further research should compare the effectiveness of combining interventions for individuals who meet the two TBC groups of manipulation and extension-specific exercise compared with performing either intervention alone.
doi:10.1179/2042618612Y.0000000014
PMCID: PMC3578194  PMID: 24421612
Thrust manipulation; Extension specific exercise; Directional preference; Chronic low back pain; Treatment based classification; Motor control; Clinical decision making
18.  EMG analysis of lumbar paraspinal muscles as a predictor of the risk of low-back pain 
European Spine Journal  2010;19(7):1145-1152.
Studies of EMG power spectra have established associations between low-back pain (LBP) and median frequency (MF). This 2-year prospective study investigates the association of LBP with EMG variables over time. 120 health care workers underwent paraspinal EMG measurements and assessment of back pain disability. The EMG recordings were performed under isometric trunk extension at 2/3 maximum voluntary contraction and acquired from erector spinae muscles at the level of L4/L5. 108 (90%) subjects were reviewed at a minimum 2-year follow up. 16 out of 93 subjects with no history of chronic low-back pain became worse as measured by time off work, disability, reported pain and self-assessment rating. The value of the EMG variable half-width at inception demonstrated significant association with changes in subject’s outcome measure and their own assessment of their LBP at follow up (p < 0.05). Based on self-assessment data, subjects with no history of chronic LBP with half-width of greater than 56 Hz were at threefold greater risk of developing back pain compared with the remainder of the population (p = 0.045). The value of the initial median frequency (IMF) and MF slope at inception were also associated with the subjects’ own assessment of LBP at follow up. Subjects with an IMF greater than 49 Hz were at 5.8-fold greater risk of developing back pain compared with the remainder of the population (p = 0.014). EMG variables recorded from lumbar paraspinal muscles can identify a sub group of subjects at increased risk of developing low-back pain in the future.
doi:10.1007/s00586-010-1277-1
PMCID: PMC2900021  PMID: 20127260
EMG; Low back pain; Paraspinal muscles; Prediction; Cohort study
19.  Effect of functional lumbar stabilization exercises on pain, disability, and kinesiophobia in women with menstrual low back pain: a preliminary trial 
Journal of Chiropractic Medicine  2013;12(3):160-167.
Objective
The purpose of this preliminary study was to investigate the effect of functional lumbar stabilization exercises on pain, disability, and kinesiophobia in women with menstrual low back pain (LBP).
Methods
Thirty women with menstrual LBP participated in the study. Subjects were assigned to a control group (n = 10, mean age = 25.1 ± 4.7 years) and an intervention group (n = 20, mean age = 21.7±2.4 years). Treatment for the intervention group consisted of functional lumbar stabilization exercises, 10 repetitions each, 3 times a day, for 3 consecutive months. The women in the control group received no exercise and performed their regular activity daily living. Pain intensity using a Numeric Pain Scale (NPS), Oswestry Disability Index (ODI), Roland-Morris Questionnaire (RMQ), and Tampa Scale of Kinesiophobia (TSK) was collected at baseline and at the end of 3 months in both groups.
Results
Statistical analysis (paired t test) revealed a significant decrease in NPS, ODI, RMQ, and TSK after treatment in the intervention group. No significant difference in NPS, ODI, RMQ, or TSK was found between pre- and postmeasurement scores in the control group. In the analysis of covariance, controlling for pretest scores, a significant difference was found between the 2 groups in the postmeasurement score of NPS (P = .01), ODI (P < .001), RMQ (P = .002), and TSK (P = .04).
Conclusion
Lumbar stabilization exercises were shown to improve pain, disability, and kinesiophobia during menstrual LBP for subjects who participated in this preliminary study compared to those who did not receive the intervention.
doi:10.1016/j.jcm.2013.08.005
PMCID: PMC3838710  PMID: 24396316
Low back pain; Menstruation; Exercise; Pain; Disability
20.  Magnetic Resonance Imaging of the Lumbar Spine in Young Arabs with Low Back Pain 
Asian Spine Journal  2012;6(4):249-256.
Study Design
A prospective study.
Purpose
To Investigate the prevalence of magnetic resonance imaging (MRI) changes of the lumbar spine in low back pain (LBP) and the associated risk factors in young Arab population.
Overview of Literature
Studies on the prevalence of MRI findings and their relationship with LBP have been conducted; these have occurred in adult populations in developed countries. The prevalence of MRI changes in the young Arab population with LBP is not known.
Methods
Two hundred and fourteen patients of Arab origin in the 16 to 29 year age group with LBP symptoms underwent MRI examinations. The prevalence of MRI changes in the lumbar spine and associated risk factors were determined and compared to age, race, and gender-matched controls.
Results
A majority (64%) of the patients with LBP (138 out of 214) were found to have MRI evidence of degenerative disc disease (DD) compared to 10% (22 out of 214) in the control group. The majority (61%) of patients had multiple level disease, most commonly involving the lowest 2 disc levels. Reduced signal of the disc followed by disc bulge was the most common MRI features seen in the symptomatic subjects. Obesity correlated with MRI prevalence of abnormalities, while activity demonstrated a positive trend.
Conclusions
The MRI prevalence of DD among the young Arab patients with LBP is high when compared to other reports in literature. Obesity correlated with MRI prevalence of abnormalities while activity demonstrated a positive trend.
doi:10.4184/asj.2012.6.4.249
PMCID: PMC3530699  PMID: 23275808
Magnetic resonance imaging; Lumbar spine; Disc; Degeneration; Prevalence; Young; Arabs
21.  Effect of Hamstring Flexibility on Hip and Lumbar Spine Joint Excursions During Forward Reaching Tasks in Individuals With and Without Low Back Pain 
Objective
To examine the correlation between hamstring flexibility and hip and lumbar spine joint excursions during standardized reaching and forward bending tasks.
Design
Retrospective analysis of data obtained during two previous prospective studies that examined kinematics and kinetics during forward bending tasks in individuals with and without low back pain (LBP).
Setting
The two previous studies were conducted in the Motor Control Lab at Ohio University.
Participants
Data from a total of 122 subjects from two previous studies. Study 1: 86 subjects recovered from an episode of acute LBP (Recovered). Study 2 (unpublished findings): 18 chronic low back pain subjects (LBP) and 18 healthy matched controls (Healthy).
Interventions
Not Applicable.
Main Outcome Measure
Correlation values between hamstring flexibility as measured by straight leg raise (SLR) and amount of hip and lumbar spine joint excursions used during standardized reaching and forward bending tasks.
Results
No significant correlation was found between hamstring flexibility and hip and lumbar joint excursions during forward bending tasks in the LBP or Recovered groups. Straight leg raise had a significant negative correlation with lumbar spine excursions during reaching tasks to a low target in the Healthy group (Right SLR: P=.011, Left SLR: P=.004).
Conclusions
Hamstring flexibility is not strongly related to the amount of lumbar flexion used to perform forward bending tasks in individuals who have chronic LBP or who have recovered from LBP. More research needs to be conducted to examine the influence of hamstring flexibility on observed movement patterns to further evaluate the efficacy of flexibility training in the rehabilitation of patients with low back pain.
doi:10.1016/j.apmr.2010.04.003
PMCID: PMC2909693  PMID: 20599054
Hip joint; Low back pain; Range of motion; articular; Rehabilitation
22.  Study protocol title: a prospective cohort study of low back pain 
Background
Few prospective cohort studies of workplace low back pain (LBP) with quantified job physical exposure have been performed. There are few prospective epidemiological studies for LBP occupational risk factors and reported data generally have few adjustments for many personal and psychosocial factors.
Methods/design
A multi-center prospective cohort study has been incepted to quantify risk factors for LBP and potentially develop improved methods for designing and analyzing jobs. Due to the subjectivity of LBP, six measures of LBP are captured: 1) any LBP, 2) LBP ≥ 5/10 pain rating, 3) LBP with medication use, 4) LBP with healthcare provider visits, 5) LBP necessitating modified work duties and 6) LBP with lost work time. Workers have thus far been enrolled from 30 different employment settings in 4 diverse US states and performed widely varying work. At baseline, workers undergo laptop-administered questionnaires, structured interviews, and two standardized physical examinations to ascertain demographics, medical history, psychosocial factors, hobbies and physical activities, and current musculoskeletal disorders. All workers’ jobs are individually measured for physical factors and are videotaped. Workers are followed monthly for the development of low back pain. Changes in jobs necessitate re-measure and re-videotaping of job physical factors. The lifetime cumulative incidence of low back pain will also include those with a past history of low back pain. Incident cases will exclude prevalent cases at baseline. Statistical methods planned include survival analyses and logistic regression.
Discussion
Data analysis of a prospective cohort study of low back pain is underway and has successfully enrolled over 800 workers to date.
doi:10.1186/1471-2474-14-84
PMCID: PMC3599364  PMID: 23497211
Epidemiology; Ergonomics; Cohort; Low back pain; NIOSH lifting equation
23.  A longitudinal study for incidence of low back pain and radiological changes of lumbar spine in asymptomatic Japanese military young adults 
European Spine Journal  2012;22(2):453-458.
Introduction
The relation between radiological abnormalities on lumbar spine and low back pain (LBP) has been debated, presumably because of potential biases related to heterogeneity in selection of the subjects, radiological abnormalities at entry, or its cross-sectional observation in nature. Therefore, the aim of this study of a selected population of asymptomatic Japanese Self Defense Forces (JSDF) young adults male with normal lumbar radiographs was to investigate the incidence of newly developed lumbar degenerative changes at middle age and to study their association to LBP.
Subjects and methods
In 1990, 84 JSDF male military servicemen aged 18 years, without a history of LBP and radiological abnormal findings, were enrolled. After 20 years, 84 subjects were underwent repeated X-ray and completed questionnaires on current LBP and lifestyle factors.
Results
The prevalence of LBP was demonstrated 59 %, with 85 % of them showing mild pain. Analysis of lumbar radiographs revealed that 48 % had normal findings and 52 % had degenerative changes. The association between LBP and life style factors was not demonstrated. Lumbar spine in subjects with LBP was more degenerated than in those without. Although disc space narrowing and LBP did not achieve a statistical significance, a significant correlation existed between vertebral osteophyte and LBP in univariate and multivariate analysis (OR 3.0; 95 % CI 1.227–7.333).
Discussion and conclusions
This longitudinal study demonstrated the significant association between vertebral osteophyte and incidence of mild LBP in initially asymptomatic and radiologically normal subjects. These data provide the additional information concerning the pathology of LBP, but further study is needed to clarify the clinical relevance.
doi:10.1007/s00586-012-2488-4
PMCID: PMC3555629  PMID: 22926435
Longitudinal study; Low back pain; Vertebral osteophytes; Military personnel
24.  Effect of Individual Strengthening Exercises for Anterior Pelvic Tilt Muscles on Back Pain, Pelvic Angle, and Lumbar ROMs of a LBP Patient with Flat Back 
Journal of Physical Therapy Science  2013;25(10):1357-1358.
[Purpose] The purpose of this paper is to report the effect of individual strengthening exercises for the anterior pelvic tilt muscles on back pain, pelvic tilt angle, and lumbar ROM of a low back pain (LBP) patient with flat back. [Subject] A 37 year-old male, who complained of LBP pain at L3-5 levels with flat back, participated. [Methods] He performed the individual strengthening exercises for anterior pelvic tilt muscles (erector spinae,iliopsoas, rectus femoris). [Results] Pelvic tilt angles of the right and left sides were recovered to normal ranges. His lumbar ROMs increased, and low back pain decreased. [Conclusion] We suggest that individual resistance exercises are a necessary approach for effective and fast strengthening of pelvic anterior tilt muscles in LBP with flat back.
doi:10.1589/jpts.25.1357
PMCID: PMC3820203  PMID: 24259793
Anterior pelvic tilt; Flat back syndrome; LBP
25.  Rest versus exercise as treatment for patients with low back pain and Modic changes. a randomized controlled clinical trial 
BMC Medicine  2012;10:22.
Background
Clinical experience suggests that many patients with Modic changes have relatively severe and persistent low back pain (LBP), which typically appears to be resistant to treatment. Exercise therapy is the recommended treatment for chronic LBP, however, due to their underlying pathology, Modic changes might be a diagnostic subgroup that does not benefit from exercise. The objective of this study was to compare the current state-of-the art treatment approach (exercise and staying active) with a new approach (load reduction and daily rest) for people with Modic changes using a randomized controlled trial design.
Methods
Participants were patients from an outpatient clinic with persistent LBP and Modic changes. They were allocated using minimization to either rest therapy for 10 weeks with a recommendation to rest for two hours daily and the option of using a flexible lumbar belt or exercise therapy once a week for 10 weeks. Follow-up was at 10 weeks after recruitment and 52 weeks after intervention and the clinical outcome measures were pain, disability, general health and global assessment, supplemented by weekly information on low back problems and sick leave measured by short text message (SMS) tracking.
Results
In total, 100 patients were included in the study. Data on 87 patients at 10 weeks and 96 patients at one-year follow-up were available and were used in the intention-to-treat analysis. No statistically significant differences were found between the two intervention groups on any outcome.
Conclusions
No differences were found between the two treatment approaches, 'rest and reduced load' and 'exercise and staying active', in patients with persistent LBP and Modic changes.
Trial Registration
ClinicalTrials.gov: NCT00454792
doi:10.1186/1741-7015-10-22
PMCID: PMC3348080  PMID: 22376791

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