Spinal muscle evaluation using the Sorensen test: a critical appraisal of the literature

Adaptations in trunk-pelvis coordination variability in response to fatiguing exercise

BACKGROUND

During walking, variability in how movement is coordinated between body segments from stride to stride facilitates adaptation to changing environmental or task constraints. Magnitude of this inter-segmental coordination variability is reduced in patient populations and may also decrease in response to muscle fatigue. Previously, stride-to-stride variability has been quantified with the Vector Coding (VC) method, however recent research introduced a new Ellipse Area Method (EAM) to avoid statistical artifacts associated with VC.

RESEARCH QUESTION

Determine changes in trunk-pelvis coordination variability during walking turns in response to fatiguing exercise and to compare coordination variability quantified with VC to the EAM method.

METHODS

15 young adults (mean age: 23.7 (±3.2) years) performed 15 trials of a 90-degree walking turn before and after fatiguing paraspinal muscle exercise. Angular kinematics of the trunk and pelvis segments in the axial plane were quantified using three-dimensional motion capture. Stride to stride variability of axial coordination between the trunk and pelvis pre- and post-fatigue was calculated using both VC and EAM methods. Magnitudes of pre- and post-fatigue variability for VC and EAM were compared with paired t-tests and relationship between the magnitude of variability for the two methods was calculated using Pearson correlation coefficients.

RESULTS

Using both analytical approaches, trunk-pelvis coordination variability decreased significantly post-fatiguing exercise across the stride cycle and within the stance phase of the turn (p < 0.034 for all comparisons). Average magnitudes of variability calculated with VC and EAM were highly correlated. Time series cross correlations pre-post fatigue ranged from 0.81 to 0.98.

SIGNIFICANCE

In healthy individuals, magnitude of trunk-pelvis stride-to-stride coordination variability is reduced following fatiguing exercise but the temporal distribution of variability across the stride cycle is maintained. This finding is robust to the method used to quantify coordination variability.

Association between core stability and physical function, functional performance in patients with systemic sclerosis

OBJECTIVE

To investigate the association of core stability with physical function and functional performance in patients with systemic sclerosis (SSc).

METHODS

Forty patients who met the American College of Rheumatology / European League Against Rheumatism 2013 classification criteria for SSc were included in the cross-sectional study. For evaluation of core stability, trunk muscle endurance and trunk muscle strength were assessed. Trunk extensor and trunk flexor endurance tests were used for assessment of trunk muscle endurance. Trunk muscle strength was measured with a hand-held dynamometer and modified sit-up test. To measure physical function the Health Assessment Questionnaire Disability Index (HAQ-DI) and to measure functional performance 6-minute walking test (6MWT) and sit-to-stand test (STS) were used.

RESULTS

Patients with SSc had lower mean trunk extensor and flexor endurance test times (49.87 ± 30.81 and 32.17 ± 15.42 seconds, respectively), modified sit-up test repetition (17.42 ± 7.81) and trunk extensor and flexor muscle strength (7.48 ± 2.29 kg and 6.20 ± 1.68 kg, respectively) when compared to the reference values in healthy individuals. All measurements were used to evaluate core stability associated with HAQ-DI score, 6DMWT walking distance and STS test duration (all P < .05).

CONCLUSION

Patients with SSc have markedly reduced core stability and this negatively affects the physical function and functional performance. Therefore, this study highlights the importance of trunk muscle in patients with SSc. We suggest that not only upper-lower extremity muscles, but also trunk muscle strength and endurance should be measured and core stability exercises can be added to the training programs to maintain and/or improve physical functions and functional performance in SSc patients.

Effects of trunk extensor eccentric exercise on lipid profile and glycaemic response

Objectives

A number of previous studies reported physiological responses and adaptations after eccentric muscle contraction of limb muscles. In contrast, no study has determined physiological response after eccentric contraction of trunk muscles. The purpose of the present study was to compare the functional and metabolic changes after eccentric or concentric exercises of trunk extensor muscles.

Methods

In this randomised, crossover study, 10 men performed a single bout of 50 maximal voluntary concentric and eccentric contractions of the trunk extensor with an interval of 2 weeks between bouts. The activities of the paraspinal muscles were recorded during concentric and eccentric contractions. Muscle soreness, muscle function, blood lipid profiles and glycaemic responses were measured before, immediately after and at 24, 48, 72 and 96 hours after each bout.

Results

The lumbar multifidus and iliocostalis lumborum activities during eccentric contractions were significantly higher than those during concentric contractions (p<0.05). The maximal strength and muscle endurance of the trunk extensor were not decreased even after the eccentric contractions. Compared with concentric contractions, muscle soreness was significantly increased at 24, 48, 72 and 96 hours after eccentric contractions (p<0.05). The TG, TC and LDL-C were significantly lower at 48, 72 and 96 hours after eccentric contractions (p<0.05), while blood glucose levels and HOMA-IR were significantly greater at 48 and 72 hours after eccentric contractions (p<0.05).

Conclusion

This study indicated that eccentric contractions of the trunk extensor had positive effects on the lipid profile and the glycaemic response.

Effectiveness of a Group-Based Progressive Strength Training in Primary Care to Improve the Recurrence of Low Back Pain Exacerbations and Function: A Randomised Trial

Low back pain (LBP) is the leading cause of disability and one of the most common reasons for physician visits in primary care, with a 33% rate of recurrence during the first year. However, the most optimal exercise program in this context remains unknown. The objective was to evaluate the effectiveness of a group-based progressive strength training program in non-specific chronic LBP (CLBP) patients in primary care on pain recurrence and physical function. Eighty-five patients with non-specific CLBP were separated into two groups (Intervention group: completed a progressive strength training program 3 days per week for 8 weeks; Control group: received the usual care). The intervention group showed a recurrence rate of 8.3%, while the control group had a recurrence rate of 33.3% and a shorter time until the first recurrent episode. The intervention group showed increased lumbar extensor strength, left-hand handgrip strength, and reduced the number of pain sites compared with the control group. Results also showed greater odds for reducing LBP intensity and disability in the intervention group. In conclusion, a group-based progressive strength training program is a more effective and efficient alternative than Back-School programs and can easily be carried out in the primary health care context.

Spatial Distribution and Asymmetry of Surface Electromyography on Lumbar Muscles of Soldiers with Chronic Low Back Pain

This study investigated spatial distribution and asymmetry of surface electromyography on lumbar muscles during a sustained contraction in soldiers with and without chronic low back pain. Twenty healthy soldiers and twenty chronic low back pain (CLBP) soldiers had performed the Sorensen test with a duration of 60 seconds. The corresponding muscle fatigue, spatial distribution, and the asymmetry of muscle activity over bilateral paraspinal lumbar regions were measured by the high-density surface electromyography (HDsEMG). The paired and independent samples t-tests were performed to compare the degree of muscle fatigue and asymmetry. The repeated-measures analyses of variance (ANOVA) were used to compare spatial distribution between groups and muscle fatigue. The baseline characteristics of soldiers between groups were comparable. CLBP soldiers had significantly less muscle fatigue on both sides of erector spinae compared to healthy ones. The spatial distribution was significantly associated with the group factor but independent of muscle fatigue. In addition, the asymmetry of erector spinae activity in the CLBP soldiers was significantly higher than the healthy one. In conclusion, uneven spatial distribution and asymmetry of lumbar muscle activity play significant roles in CLBP patients. The HDsEMG could be used as an objective method in distinguishing the function of the erector spinae between healthy individuals and CLBP patients during 1 min sustained contraction.

What Psychosocial and Physical Characteristics Differentiate Office Workers Who Develop Standing-Induced Low Back Pain? A Cross-Sectional Study

This study examines demographic, physical and psychosocial factors associated with an increase in low back pain (LBP) during a one-hour standing task. A cross-sectional survey with 40 office workers was conducted. The primary outcome was pain severity during a one-hour standing task recorded every 15 min using a 100 mm Visual Analogue Scale (VAS). Participants were defined as pain developers (PD), if they reported a change in pain of ≥10 mm from baseline, or non-pain developers (NPD). Physical outcomes included participant-rated and examiner-rated trunk and hip motor control and endurance. Self-report history of LBP, physical activity, psychosocial job characteristics, general health and pain catastrophising were collected. Fourteen participants were PD. Hip abduction, abdominal and spinal muscle endurance was lower for PD (p ≤ 0.05). PD had greater self-reported difficulty performing active hip abduction and active straight leg raise tests (p ≤ 0.04). Those reporting a lifetime, 12 month or 7-day history of LBP (p < 0.05) and lower self-reported physical function (p = 0.01) were more likely to develop LBP during the standing task. In conclusion, a history of LBP, reduced trunk and hip muscle endurance and deficits in lumbopelvic/hip motor control may be important to consider in office workers experiencing standing-induced LBP.

Benefits of a four-week functional restoration program in chronic low back pain patients and three-month follow-up: focus on paraspinal muscle aerobic metabolism responses to exercise

BACKGROUND

Chronic low back pain (CLBP) is a major health concern characterized by paraspinal muscle fatigability. This can be improved following a functional restoration program. Muscle fatigability can be related to impairment in aerobic metabolism responses. In this study, we investigated paraspinal muscles aerobic metabolism in CLBP patients before and after a functional restoration program, in order to determine if the enhancement in patients' condition following the program is associated to changes in metabolism responses.

METHODS

Twenty-two CLBP patients (11 women, 11 men; 41.6±1.8 years; 73.7±3.1 kg; 1.74±0.02 m) were evaluated before and after a 4-week functional restoration program, with exercise therapy as the main component. Three months later, 12 patients were seen for a follow-up visit. During each testing session, patients performed a five-minute isokinetic trunk extension exercise in measuring pulmonary gas exchanges and paraspinal muscle oxygenation. Mechanical efficiency and onset V̇O<inf>2</inf> kinetics were also calculated, in addition to usual questionnaires and exercises designed to evaluate psychosocial and physical factors.

RESULTS

At the end of the program, paraspinal muscle oxygenation, mechanical efficiency, and the V̇O<inf>2</inf> onset kinetics were improved (P<0.05). All measures remained stable during the three-month follow-up except for paraspinal muscle oxygenation, which deteriorated (P<0.05). Return-to-work was associated with the level of workday physical activities and to a decrease in fear-avoidance beliefs.

CONCLUSIONS

At the end of the program, aerobic metabolism responses were improved in paraspinal muscles in patients. These improvements were not associated with return-to-work, which was primarily influenced by socio-psychological factors.

Comparison of Hip and Lumbopelvic Performance Between Chronic Low Back Pain Patients Suited for the Functional Optimization Approach and Healthy Controls

STUDY DESIGN

Cross-sectional study.

OBJECTIVE

We explored the differences between chronic low back pain (CLBP) patients suited for the functional optimization approach and healthy controls in isometric hip-strength and lumbar-endurance tests and determined classificatory cutoff values for strength and endurance tests and ratios.

SUMMARY OF BACKGROUND DATA

To optimize the treatment effect for CLBP, some approaches have classified patients into homogeneous subgroups matched to specific treatments. We evaluated CLBP patients suited for the functional optimization approach, who seek care because they experience symptoms during activities with high physical demands, although they are relatively asymptomatic.

METHODS

Three hundred fifty subjects (healthy controls, 170; CLBP patients, 180) were stratified by age (18-40 and 41-65 yrs), sex, and physical activity level. The CLBP patients had an Oswestry Disability Index score < 20% and a Numeric Pain Rating Scale score < 3. The subjects underwent hip abductor, extensor, and flexor isometric strength tests; a deep abdominal function test; and lateral/frontal bridge and lumbar flexor/extensor endurance tests.

RESULTS

Relative to the healthy controls, the CLBP patients showed significantly (P > 0.05) higher strength scores in the hip flexor and deep abdominal function tests but lower endurance in the lateral and frontal bridge and lumbar flexor and extensor tests. The cutoff values of the lumbar flexor test and the lumbar flexor/extensor, lateral bridge/lumbar flexor, frontal bridge/lumbar flexor, and hip extensor/flexor test ratios showed acceptable accuracy (AUC = 0.84, 0.82, 0.79, 0.75, and 0.73, respectively).

CONCLUSION

In lumbopelvic and hip-performance tests, CLBP patients suited for the functional optimization approach showed differences from healthy controls. These patients could be discriminated from healthy controls on the basis of accurate cutoff values for strength and endurance tests and ratios, which should be considered in treatment decision-making when patients need to return to activities with higher physical demands.

LEVEL OF EVIDENCE

2.

Individuals With Recurrent Low Back Pain Exhibit Significant Changes in Paraspinal Muscle Strength After Intramuscular Fine Wire Electrode Insertion

OBJECTIVE

To examine how insertion and presence of intramuscular fine-wire electromyography electrodes (IFWEs) in lumbar multifidus affect paraspinal muscle strength, endurance, and activation in persons with and without recurrent lower back pain (RLBP) during activities that require high levels of muscle contraction.

DESIGN

Case-control with randomization of conditions.

SETTING

Clinical research laboratory.

PARTICIPANTS

Forty participants age 18 to 40 years were recruited (18 female; mean age = 25.5 years); 20 with a history of RLBP were compared to a matching control group of 20 without RLBP.

INTERVENTIONS

Each participant was tested under three conditions over three sessions. On Session 1, the baseline condition, we assessed muscle performance without IFWE insertion. On Sessions 2 and 3, participants were randomly alternated between two experimental conditions: (1) wire-in, in which the IFWE was inserted and remained within the muscle during testing; and (2) wire-out, in which the IFWE was inserted and immediately removed.

MAIN OUTCOME MEASUREMENTS

Lumbar spinal extensor peak strength, endurance, and normalized electromyography (EMG) amplitude during the endurance test.

RESULTS

Individuals with RLBP showed a significant decrease in peak strength during conditions that involved IFWE insertion and tend to experience more pain during muscle testing. Both groups exhibited similar levels of performance and muscle activation during the endurance test.

CONCLUSION

Our findings indicate that individuals with RLBP exhibited reduced lumbar extensor strength in response to IFWE insertion to the deep paraspinal muscles. This behavior is different from those without RLBP. Researchers should carefully consider the use of IFWE in individuals with RLBP during high exertion activities.

Health and Fitness Benefits But Low Adherence Rate: Effect of a 10-Month Onsite Physical Activity Program Among Tertiary Employees

OBJECTIVE

The aim of this study was to assess the effects of a 10-month structured physical activity intervention implemented within the workplace on overall health indicators among tertiary (office workers) employees.

METHODS

In this quasi-experimental study, 224 employees followed a 10-month worksite physical activity program. Overall health was assessed at baseline, after 5 months, and by the end of the intervention.

RESULTS

Fat mass percentage decreased significantly. There was a time effect favoring push-ups, abdominal strength, flexibility, heart rate postexercise, heart rate +30 seconds, and heart rate +60 seconds postexercise. Anxiety, depression, and eating habits also improved. In total, 45% of participants completed the whole intervention.

CONCLUSION

Although a structured on-site physical activity program supports improved health indicators, adherence remains a concern and requires specialists to develop new strategies.

Natural aging course of paraspinal muscle and back extensor strength in community-dwelling older adults (sarcopenia of spine, SarcoSpine): a prospective cohort study protocol

INTRODUCTION

Sarcopenia in the lumbar paraspinal muscles is receiving renewed attention as a cause of spinal degeneration. However, there are few studies on the precise concept and diagnostic criteria for spinal sarcopenia. Here, we develop the concept of spinal sarcopenia in community-dwelling older adults. In addition, we aim to observe the natural ageing process of paraspinal and back muscle strength and investigate the association between conventional sarcopenic indices and spinal sarcopenia.

METHODS AND ANALYSIS

This is a prospective observational cohort study with 120 healthy community-dwelling older adults over 4 years. All subjects will be recruited in no sarcopenia, possible sarcopenia or sarcopenia groups. The primary outcomes of this study are isokinetic back muscle strength and lumbar paraspinal muscle quantity and quality evaluated using lumbar spine MRI. Conventional sarcopenic indices and spine specific outcomes such as spinal sagittal balance, back performance scale and Sorenson test will also be assessed.

ETHICS AND DISSEMINATION

Before screening, all participants will be provided with oral and written information. Ethical approval has already been obtained from all participating hospitals. The study results will be disseminated in peer-reviewed publications and conference presentations.

TRIAL REGISTRATION NUMBER

NCT03962530.

Core stability and balance in patients with ankylosing spondylitis

The main purpose of this study was to compare core stability and balance between ankylosing spondylitis (AS) patients and healthy controls. AS patients diagnosed according to the Modified New York criteria and healthy age- and sex-matched controls were included in the study. Clinical status of AS patients was assessed using Bath AS Disease Activity Index (BASDAI), Bath AS Functional Index (BASFI), Bath AS Spinal Mobility Index (BASMI). For evaluation of core stability, static and dynamic core endurance and hip strength were assessed. Trunk flexor and extensor endurance, lateral side bridge tests for static core endurance; modified sit-up test for dynamic core endurance were used. Hip strength was measured with a hand-held dynamometer. Biodex Balance System was used to assess static and dynamic balance. Bilateral standing static and dynamic postural stability, single leg standing postural stability and limits of stability test results were recorded. 64 AS patients (40 male, 24 female) and 64 healthy controls (39 male, 25 female) were assessed. Static and dynamic core endurance test results, hip abductor strength were significantly higher in control group than AS group (p < 0.05). Static postural stability and left leg postural stability test results were significantly better in control group than AS group (p < 0.05). Overall, forward, backward, and right, limits of stability test results were significantly higher in control group (p < 0.05). The results of our study demonstrate that AS has negative effects on core stability and balance. It would be beneficial to add core stability and balance training to AS patients' rehabilitation program.

Tests to Measure Core Stability in Laboratory and Field Settings: Reliability and Correlation Analyses

Although core stability (CS) has been assessed through many different tests, the relationships among them are currently unknown. The main objective was to analyze the relationship between 5 representative tests used to assess CS in: (1) laboratory settings: Sudden Loading Test (SLT) and Stable and Unstable Sitting Test (SUST) and (2) field settings: Biering-Sørensen Test (BST), 3-Plane Core Strength Test, and Double-Leg Lowering Test. The reliability of these tests was also examined. In total, 33 recreationally active males performed the tests twice. The relationship between all variables was examined using Pearson correlation coefficient in those variables with a good reliability. Only stiffness and angular displacement in the SLT, dynamic unstable tasks in the SUST, and the holding time in the BST showed good reliability (intraclass correlation coefficient: .63-.91, typical error: 9.8%-21.0%). Few and low correlations were observed between the SLT, SUST, and BST. Despite finding several significant correlations among the dynamic unstable tasks of the SUST (r ≥ .807, P < .01), no correlations were found between the loading directions of the SLT. The absence of correlations between these tests suggests that CS measurements are not generalizable, as they probably assess different dimensions of CS, or in the case of the BST, a different capacity (ie, trunk extensor endurance).

PILATES TRAINING INDUCES CHANGES IN THE TRUNK MUSCULATURE OF ADOLESCENTS

ABSTRACT Introduction The Pilates Method may be an appropriate form of exercise for improving trunk muscle strength, which can be a predictor of pain and musculoskeletal problems. Objective The objective of this study was to assess the effects of the Pilates Method on muscle strength and endurance of the extensor and flexor muscles of the trunk in a group of adolescents. Methods The sample consisted of 101 high-school students divided into two groups: an experimental group (EG=81) and a control group (CG=20). The intervention was carried out twice a week for six weeks. Each session lasted 55 minutes, and was divided into three parts: warm-up, main part, and cool down. Muscle strength was assessed by the Sörensen Test and the Bench Trunk-curl Test. The paired sample T-test, the T- test for independent samples, and Pearson’s correlation coefficient were applied. The size of the effect (d) was determined. Results The EG showed significant improvements in both tests (+34.77 points; +18.55 points, respectively). No changes were observed in the CG. The effect size was high (d>1.15) for both tests, which means that the results were improved in a large proportion of the participants. The control group showed a decline in strength of the trunk musculature. In the experimental group, both boys and girls showed significant improvements in both tests. This strength increase was enhanced for a large proportion of boys and girls (d>1.15). The effect size was high (d>1.15) for both tests and for both sexes. Conclusion Six-weeks after implementing the Pilates Method in Physical Education lessons, the muscle strength of the flexor and extensor muscles of the trunk in adolescents was improved. Level of Evidence II; Therapeutic studies-Investigation of treatment results.

Exercise, fitness and musculoskeletal health of undergraduate nursing students: A cross-sectional study

AIMS

To describe the exercise, physical fitness and musculoskeletal health of nursing students.

BACKGROUND

Nursing students are prone to musculoskeletal disorders restricting work ability. Physical fitness and leisure-time exercise may affect responses to workplace exposures and risk for work-related musculoskeletal disorders.

DESIGN

A cross-sectional study.

METHOD

Between August 2013 and April 2015, a convenience sample of 111 nursing students performed submaximal exercise tests. Nursing work, exercise and musculoskeletal health were surveyed and analysed descriptively.

RESULTS

Students' mean age was 30.0 years, 89.2% were female and 20.0% worked in nursing while studying. Highest annual prevalence of musculoskeletal trouble was in low back (45.6%), neck (32.0%) and shoulder (18.5%) regions. Most exercised regularly but did not meet weekly cardiorespiratory, resistance, neuromotor and flexibility exercise recommendations and had poor to average fitness levels. Approximately 40% were overweight or obese; 26.1% had risk for obesity-related disease.

CONCLUSIONS

Interventions to improve nursing students' physical condition before entering the nursing workforce appear warranted.

IMPACT

Imbalance between physical work capacity and demanding workloads increases musculoskeletal disorder risk amongst undergraduate nursing students. A large proportion studied reported recent musculoskeletal trouble (particularly low back, neck and shoulder). They exhibited modifiable characteristics of overweight/obese, poor fitness and inadequate leisure-time exercise, predisposing them to work-related musculoskeletal disorders. Undergraduate preparation should raise nursing students' health literacy about physical fitness and ways to achieve it, for their musculoskeletal health and work capacity. Improving nursing students' fitness may enhance their work preparedness and help them achieve longevity in this physically demanding occupation.

Postural cueing increases multifidus activation during stabilization exercise in participants with chronic and recurrent low back pain: An electromyographic study

Persons with low back pain (LBP) have demonstrated altered morphology and function of the deep multifidus (DM). This study examined the effects of postural cueing for increased lumbar lordosis on DM and longissimus thoracis (LT) activation during lumbar stabilization exercises (LSE) performed by persons with LBP. Nine adults with a history of chronic or recurrent LBP were recruited. Fine-wire EMG data was collected while participants performed 10 LSE's in neutral posture and with postural cueing. Percent maximum voluntary isometric contraction of L5 DM and T12 LT, and ratios of activation (DM/LT) were analyzed. There was a significant main effect for posture on DM activation (p < 0.001), indicating greater activation levels during exercises performed with postural cueing vs. neutral posture. LT activation did not increase significantly with postural cueing. Following a significant 1-way repeated measures ANOVA (p = 0.034) for the postural cueing condition, pairwise comparisons demonstrated significantly higher DM/LT activation ratios for prone leg lift, variable-angle Roman chair at 15°, bridging, and bilateral arm and leg lift. These results suggest postural cueing can be used across a range of LSE intensities to increase DM activation without a significant increase in LT activation in patients with chronic or recurrent LBP.

The effects of Pilates vs. aerobic training on cardiorespiratory fitness, isokinetic muscular strength, body composition, and functional tasks outcomes for individuals who are overweight/obese: a clinical trial

Background

Some studies have been conducted to verify the effects of Pilates for individuals who are obese, but conclusive results are not yet available due to methodological concerns. The present study aims to verify and compare the effects of Pilates and aerobic training on cardiorespiratory fitness, isokinetic muscular strength, body composition, and functional task outcomes for individuals who are overweight/obese.

Methods

Of the sixty participants, seventeen were allocated to the control group, since the intervention protocol (Pilates or walking sessions) was during their working hours. The remaining 44 participants were randomly allocated to one of two experimental groups (Pilates (n = 22)) or aerobic groups (n = 21).The Pilates and aerobic groups attended 60-min exercise sessions, three times per week for 8 weeks. The aerobic group performed walking training at a heart rate corresponding to the ventilatory threshold. The Pilates group performed exercises on the floor, resistance apparatus, and 1-kg dumbbells. The control group received no intervention. All volunteers were evaluated at the beginning and end of the intervention. The following assessments were conducted: food intake, cardiorespiratory maximal treadmill test, isokinetic strength testing, body composition and anthropometry, abdominal endurance test, trunk extensor endurance test, flexibility test and functional (stair and chair) tests.

Results

There was no significant difference pre- and post-intervention in calorie intake [F(2, 57) = 0.02744, p = 0.97)]. A significant improvement in oxygen uptake at ventilatory threshold (p = 0.001; d = 0.60), respiratory compensation point (p = 0.01; d = 0.48), and maximum effort (p = 0.01; d = 0.33) was observed only in the Pilates group. Isokinetic peak torque for knee flexor and extensor muscles did not change for any groups. Lean mass (p = 0.0005; d = 0.19) and fat mass (p = 0.0001; d = 0.19) improved only in the Pilates group. Waist and hip circumference measurements decreased similarly in both experimental groups. Abdominal test performance improved more in the Pilates group (p = 0.0001; d = 1.69) than in the aerobic group (p = 0.003; d = 0.95). Trunk extensor endurance and flexibility improved only in the Pilates group (p = 0.0003; d = 0.80 and p = 0.0001; d = 0.41, respectively). The Pilates group showed greater improvement on the chair and stair tests (p = 0.0001; d = 1.48 and p = 0.003; d = 0.78, respectively) than the aerobic group (p = 0.005; d = 0.75 and p = 0.05; d = 0.41, respectively).

Conclusion

Pilates can be used as an alternative physical training method for individuals who are overweight or obese since it promotes significant effects in cardiorespiratory fitness, body composition, and performance on functional tests.

Sørensen test performance is driven by different physiological and psychological variables in participants with and without recurrent low back pain

Time to task failure (TTF) on the Sørensen test predicts low back pain (LBP), but mechanisms driving TTF may vary in those with and without recurrent LBP. To determine the physiological and psychological predictors of TTF, 48 sex, age, and BMI matched participants (24 Healthy, 24 LBP) completed psychological surveys, maximal strength assessments, and the Sørensen test. A two-way ANOVA revealed no significant effects of group (p = 0.75) or sex (p = 0.21) on TTF. In the full sample, linear regression analyses revealed that normalized Median Power Frequency (MPF) slope of the Erector Spinae (β = 0.350, p < 0.01), the Biceps Femoris (β = 0.375, p < 0.01), and self-efficacy (β = 0.437, p < 0.01) predicted TTF. In the Healthy group, normalized MPF slope of the Erector Spinae (β = 0.470, p < 0.01), the Biceps Femoris (β = 0.437, p < 0.01), and self-efficacy (β = 0.330, p = 0.02) predicted TTF. In the LBP group, trunk mass (β = -0.369, p = 0.04) and self-efficacy (β = 0.450, p = 0.02) predicted TTF. In sum, self-efficacy consistently predicts performance, while trunk mass appears to negatively influence TTF only for those with recurrent LBP.

Predictors for Nonspecific Low Back Pain in Rubber Farmers: A 1-Year Prospective Cohort Study

High prevalence of low back pain (LBP) has been reported among farmers. A number of contributing factors have been associated with LBP. However, predictors for LBP in this population are unknown. This longitudinally designed study aimed to identify the predictors of LBP in a sample of rubber farmers whose work involves heavy manual labor. Three hundred and twenty-seven rubber farmers, aged 18 to 70 years who reported no LBP in the previous year, were face-to-face interviewed and examined physically. The incidence of LBP was assessed monthly. The 12-month incidence of LBP in the cohort was 35%. Having a history of LBP (hazard ratio = 1.55, 95% confidence interval = 1.05-2.30) and an active job (hazard ratio = 1.98, 95% confidence interval = 1.16-3.40) were the predictors for the new onset of LBP in this sample. These 2 factors could therefore potentially be targeted to prevent or reduce the incidence of LBP in rubber farmers.

Effect of Work-Related Sedentary Time on Overall Health Profile in Active vs. Inactive Office Workers

Objective: While public health strategies are developed to fight sedentary behaviors and promote physical activity, some professional activities, and especially tertiary ones, have been pointed out for their highly sedentary nature. Although workplace physical activity programs are increasingly proposed by companies to their employees in order to increase their physical activity levels, sitting and screen time remain extremely high. The main aim of this work was to compare health indicators between active and inactive tertiary employees with similar high levels of sedentariness. Secondly, we questioned the effects of a 5-month workplace physical activity program on overall health indicators among initially active and inactive tertiary employees.

Methods: Anthropometric measurements, body composition (bio-impedance), physical fitness (cardiorespiratory and musculoskeletal fitness) and health-related quality of life and perception of health status (self-reported questionnaires) were assessed among 193 active and inactive tertiary employees before (T0) and after a 5-month workplace physical activity intervention (T1), composed of 2 physical sessions per week.

Results: Significant improvements were found in performance of push-ups (p < 0.001), back muscle strength (p < 0.001) fat mass (p < 0.01) and waist circumference (p < 0.05) in active compared with inactive employees both at baseline and at the end of the program. Health perception (p < 0.001) was significantly different between groups at T0 but not at T1. However, no significant difference was observed for fat-free mass, BMI, workplace well-being and lower and upper limbs muscle strength. The variations between T0 and T1 demonstrate that, while all the studied parameters progressed positively during the 5-month program, health perception (p < 0.001), back muscle strength (p < 0.05) and BMI (tendency) showed a significantly higher progression in the inactive compared with the active group.

Conclusion: Health indicators might not be improved among active tertiary employees compared with inactive ones, which might be due to the high level of sedentariness characterizing their occupational task.Structured on-site physical activity programs can improve health in both initially active and inactive employees.

Effects of Volume Training on Strength and Endurance of Back Muscles: A Randomized Controlled Trial

CONTEXT

Strength/resistance training volume has historically been supported in the American College of Sports Medicine recommendations. However, for the back muscles, exercise prescription related to the number of sets, such as single versus multiple, is not well established in the literature.

OBJECTIVE

The purpose of this study was to compare the effects of 2 training volumes on strength and endurance of back-extensor muscles in untrained young participants with regard to a repeated-measures design.

DESIGN

Randomized controlled trial.

SETTING

Laboratory of functional evaluation and human motor performance.

PARTICIPANTS

Forty-four untrained young participants (mean age = 21 y) were randomized into single-set (n = 14), multiple-set (MSG, n = 15), and untrained control (n = 15) groups.

INTERVENTION

The single-set group and MSG underwent a 10-week progressive resistance training program (2 d/wk) using a 45° Roman chair.

MAIN OUTCOME MEASURES

Back maximal strength (dynamometer) and isometric and dynamic endurance (time limit, trunk extension-flexion cycles, and electromyography muscle fatigue estimates).

RESULTS

The results showed differences between the MSG and control group for isometric endurance time (mean = 19.8 s; 95% confidence interval, -44.1 to 4.8), but without time intervention significance. Significant improvement after training (P < .05) was found predominantly during dynamic endurance (number of repetitions) for both the MSG (+61%) and single-set group (+26%) compared with preintervention, whereas the control group reported no benefit. There was no significant (P > .05) difference in either strength or electromyography estimates after training.

CONCLUSIONS

Both multiple and single volume training were efficient in promoting better back endurance during dynamic performance based on mechanical variables (time and number of repetitions).

Insertion and Presence of Fine-Wire Intramuscular Electrodes to the Lumbar Paraspinal Muscles Do Not Affect Muscle Performance and Activation During High-Exertion Spinal Extension Activities

BACKGROUND

Low back pain (LBP) is commonly associated with paraspinal muscle dysfunctions. A method to study deep lumbar paraspinal (ie, multifidus) muscle function and neuromuscular activation pattern is intramuscular electromyography (EMG). Previous studies have shown that the procedure does not significantly impact muscle function during activities involving low-level muscle contractions. However, it is currently unknown how muscular function and activation are affected during high-exertion contractions.

OBJECTIVE

To examine the effects of insertion and presence of fine-wire EMG electrodes in the lumbar multifidus on muscle strength, endurance, and activation profiles during high-exertion spinal extension muscle contractions.

DESIGN

Single-blinded, repeated measures intervention trial.

SETTING

University clinical research laboratory PARTICIPANTS: Twenty individuals between the ages of 18-40 free of recent and current back pain.

METHODS

Muscle performance was assessed during 3 conditions (with [WI] and without [WO] presence of intramuscular electrodes, and insertion followed by removal [IO]). Isometric spinal extension strength was assessed with a motorized dynamometer. Muscle endurance was assessed using the Sorensen test with neuromuscular activation profiles analyzed during the endurance test.

MAIN OUTCOME MEASUREMENTS

Spinal extensor muscle strength, endurance, and activation.

RESULTS

Our data showed no significant difference in isometric strength (P = .20) between the 3 conditions. A significant difference in muscle endurance was found (P = .03). Post hoc analysis showed that the muscle endurance in the IO condition was significantly higher than the WO condition (161.3 ± 58.3 versus 142.1 ± 48.2 seconds, P = .04), likely due to a learning effect. All 3 conditions elicited minimal pain (range 0-4/10) and comparable muscle activation profiles.

CONCLUSION

Our findings suggested the sonographically guided insertion and presence of fine-wire intramuscular EMG electrodes in the lumbar multifidus muscles had no significant impact on spinal extension muscle function. This study provides evidence that implementing intramuscular EMG does not affect muscle performance during high-exertion contractions in individuals with no current back pain.

LEVEL OF EVIDENCE

II.

Identifying Subgroups of Patients With Chronic Nonspecific Low Back Pain Based on a Multifactorial Approach: Protocol For a Prospective Study

Background

Low back pain, especially nonspecific chronic low back pain (LBP), the leading cause of disability worldwide, represents both social and economic problems. Different therapeutic management techniques can be used, but their effects vary. Clinicians and researchers attribute the variation in the efficacy of therapeutic and management techniques to the heterogeneity of the nonspecific chronic low back pain population, and they agree that nonspecific chronic LBP must be subgrouped.

Objective

This study aims to identify nonspecific chronic LBP subgroups based on a multifactorial approach, including biomechanical, physical, and psychosocial data.

Methods

A total of 100 nonspecific chronic LBP patients and 30 healthy participants aged between 18 and 60 years will be recruited for this prospective study. A psychosocial profile will be established using questionnaires on anxiety, depression, functional disability, pain, fear of pain, avoidance belief, and physical activity. A physical capacity evaluation will be conducted. It will evaluate flexibility of the hips, lumbar spine, and lateral thoracolumbar segment, as well as trunk (extensor and flexor) muscle endurance. The subjects will perform functional daily life activities, such as walking, object lifting, forward bending, sit-to-stand, stand-to-sit, balance, and usual postures. Full body kinematics, kinetics, and surface electromyography of the trunk and hip muscles will be assessed during these tasks. The clustering classification methods for the statistical analysis will be determined according to the data and will be used to identify the subgroups of nonspecific chronic LBP patients.

Results

Data collection started in September 2017 and will be completed with the inclusion of all the participants (100 nonspecific chronic LBP and 30 control). The study results will be published in peer-reviewed journals and presented at relevant international conferences.

Conclusions

Numerous studies have showed that the therapeutic management of nonspecific chronic LBP is difficult and has inconstant effects caused by the complexity and heterogeneity of nonspecific chronic LBP. Identifying subgroups with a multifactorial approach is more comprehensive and closer to the pathophysiology of nonspecific chronic LBP. It also represents benefit interests and a challenge both clinically and socially. The perspective of this study is expected to support clinicians for a more adapted therapeutic management for each subgroup.

Effects of Lumbar Strengthening Exercise in Lower-Limb Amputees With Chronic Low Back Pain

Objective

To analyze the effect of lumbar strengthening exercise in lower-limb amputees with chronic low back pain.

Methods

We included in this prospective study 19 lower-limb amputees who had experienced low back pain for longer than 6 months. Participants were treated with 30-minute lumbar strengthening exercises, twice weekly, for 8 weeks. We used the visual analog scale (VAS), and Oswestry low back pain disability questionnaire, and measured parameters such as iliopsoas length, abdominal muscle strength, back extensor strength, and back extensor endurance. In addition, we assessed the isometric peak torque and total work of the trunk flexors and extensors using isokinetic dynamometer. The pre- and post-exercise measurements were compared.

Results

Compared with the baseline, abdominal muscle strength (from 4.4±0.7 to 4.8±0.6), back extensor strength (from 2.6±0.6 to 3.5±1.2), and back extensor endurance (from 22.3±10.7 to 46.8±35.1) improved significantly after 8 weeks. The VAS decreased significantly from 4.6±2.2 to 2.6±1.6 after treatment. Furthermore, the peak torque and total work of the trunk flexors and extensors increased significantly (p<0.05).

Conclusion

Lumbar strengthening exercise in lower-limb amputees with chronic low back pain resulted in decreased pain and increased lumbar extensor strength. The lumbar strengthening exercise program is very effective for lower-limb amputees with chronic low back pain.

Effect of a 5-Month Worksite Physical Activity Program on Tertiary Employees Overall Health and Fitness

OBJECTIVE

This pilot study questions the effects of a worksite physical activity program on health and fitness in tertiary employees.

METHODS

Ninety-five employees were randomly assigned to Control (CON); Novice (NOV); Experienced group (EXP). The NOV and EXP groups followed a 5-month worksite physical activity program (at least two sessions/week). Body composition, physical activity level and physical fitness, eating habits, health perception, sleep quality, pain, and quality of life were assessed.

RESULTS

Fat mass decreased in NOV and EXP; the distance covered during the 6-minute walking test, push-ups, squat jump increased for NOV and EXP group. Physical activity level, health perception, quality of sleep, and eating habits were improved in NOV.

CONCLUSION

This study underlines for the first time the beneficial effects of such worksite programs among tertiary employees on overall health and the feasibility of its design.

Psychometric Properties of a Clinical Strength Assessment Protocol in People with Multiple Sclerosis

BACKGROUND

Strength training in people with multiple sclerosis (MS) is an important component of rehabilitation, but it can be challenging for clinicians to quantify strength accurately and reliably. This study investigated the psychometric properties of a clinical strength assessment protocol using handheld dynamometry and other objective, quantifiable tests for the lower extremities and trunk in people with MS.

METHODS

This study determined discriminant validity between 25 participants with MS and 25 controls and between participants with MS who had higher versus lower disability; test-retest reliability across 7 to 10 days; and response stability. The protocol included handheld dynamometry measurements of ankle dorsiflexion, knee flexion and extension; hip flexion, extension, abduction, and adduction; and trunk lateral flexion. Muscular endurance tests were used to measure trunk extension, trunk flexion, and ankle plantarflexion.

RESULTS

The protocol discriminated between participants with MS and controls for all muscles tested (P < .001-.003). The protocol also discriminated between low- and moderate-disability groups (P = .001-.046) for 80% of the muscles tested. Test-retest reliability intraclass correlation coefficients were high (0.81-0.97). Minimal detectable change as a percentage of the mean was 13% to 36% for 85% of muscles tested.

CONCLUSIONS

This study provides evidence for the discriminant validity, test-retest reliability, and response stability of a strength assessment protocol in people with MS. This protocol may be useful for tracking outcomes in people with MS for clinical investigations and practice.

Lumbar muscle structure and function in chronic versus recurrent low back pain: a cross-sectional study

BACKGROUND CONTEXT

Heterogeneity exists within the low back pain (LBP) population. Some patients recover after every pain episode, whereas others suffer daily from LBP complaints. Until now, studies rarely make a distinction between recurrent low back pain (RLBP) and chronic low back pain (CLBP), although both are characterized by a different clinical picture. Clinical experiences also indicate that heterogeneity exists within the CLBP population. Muscle degeneration, like atrophy, fat infiltration, alterations in muscle fiber type, and altered muscle activity, compromises proper biomechanics and motion of the spinal units in LBP patients. The amount of alterations in muscle structure and muscle function of the paraspinal muscles might be related to the recurrence or chronicity of LBP.

PURPOSE

The aim of this experimental study is to evaluate differences in muscle structure (cross-sectional area and lean muscle fat index) and muscle activity of the multifidus (MF) and erector spinae (ES) during trunk extension, in patients with RLBP, non-continuous CLBP, and continuous CLBP.

STUDY DESIGN AND SETTING

This cross-sectional study took place in the university hospital of Ghent, Belgium. Muscle structure characteristics and muscle activity were assessed by magnetic resonance imaging (MRI).

PATIENT SAMPLE

Fifty-five adults with non-specific LBP (24 RLBP in remission, 15 non-continuous CLBP, 16 continuous CLBP) participated in this study.

OUTCOME MEASURES

Total cross-sectional area, muscle cross-sectional area, fat cross-sectional area, lean muscle fat index, T2-rest and T2-shift were assessed.

METHODS

A T1-weighted Dixon MRI scan was used to evaluate spinal muscle cross-sectional area and fat infiltration in the lumbar MF and ES. Muscle functional MRI was used to evaluate the muscle activity of the lumbar MF and ES during a lumbar extension exercise. Before and after the exercise, a pain assessment was performed. This study was supported by grants from the Special Research Fund of Ghent University (DEF12/AOP/022) without potential conflict of interest-associated biases in the text of the paper.

RESULTS

Fat cross-sectional area and lean muscle fat index were significantly higher in MF and ES in continuous CLBP compared with non-continuous CLBP and RLBP (p<.05). No differencesbetween groups were found for total cross-sectional area and muscle cross-sectional area in MF or ES (p>.05). Also, no significant differences between groups for T2-rest were established. T2-shift, however, was significantly lower in MF and ES in RLBP compared with, respectively, non-continuous CLBP and continuous CLBP (p<.05).

CONCLUSIONS

These results indicate a higher amount of fat infiltration in the lumbar muscles, in the absence of clear atrophy, in continuous CLBP compared with RLBP. A lower metabolic activity of the lumbar muscles was seen in RLBP replicating a relative lower intensity in contractions performed by the lumbar muscles in RLBP compared with non-continuous and continuous CLBP. In conclusion, RLBP differs from continuous CLBP for both muscle structure and muscle function, whereas non-continuous CLBP seems comparable with RLBP for lumbar muscle structure and with continuous CLBP for lumbar muscle function. These results underline the differences in muscle structure and muscle function between different LBP populations.

Effects of a Worksite Supervised Adapted Physical Activity Program on Trunk Muscle Endurance, Flexibility, and Pain Sensitivity Among Vineyard Workers

OBJECTIVES

In viticulture, the prevalence of low back pain is particularly high among vineyard workers exposed to sustained and awkward postures. One promising setting for low back pain prevention resides in the implementation of workplace physical activity.

METHODS

This nonrandomized pilot study aims at evaluating the effects of a worksite supervised adapted physical activity program among 17 vineyard workers volunteered to enter either an intervention group (n = 10) or a control group (n = 7).The intervention group followed a physical activity program for 8 weeks involving (1) 15 minutes of warm-up every working day and (2) two weekly 1-hour adapted physical activity sessions targeting trunk muscle endurance and flexibility. The control group was advised to continue normal physical activity. Evaluations were carried out at weeks 0, 4, 8, and 12. Physical capacity was assessed using flexibility tests for the trunk, along with trunk muscle flexor and extensor endurance tests. Finally, pain sensitivity was evaluated by assessing pressure pain thresholds over 14 anatomical locations in the low back region.

RESULTS

For the intervention group, the endurance of the trunk extensor and flexor significantly increased from baseline to week 8 as well as the pressure pain thresholds. No change was observed for the control group over the same period.

CONCLUSIONS

These encouraging results in combination with the high adherence rate set interesting foundations for the promotion of worksite supervised adapted physical activity and, most likely, offer a new promising approach to prevent low back pain among vineyard workers.

The impact of continuous use of lumbosacral orthoses on trunk motor performance: a systematic review with meta-analysis

BACKGROUND CONTEXT

Lumbosacral orthosis (LSO) is prescribed by general practitioners for the management of low back pain. It may be speculated that continuous use of an LSO for a prolonged period reduces mechanical loading to the trunk muscle in daily living and results in impairments of the trunk muscle.

PURPOSE

This study aims to investigate whether trunk motor performances are impaired by the continuous use of an LSO.

STUDY DESIGN/SETTING

This is a systematic review with meta-analysis.

MATERIALS AND METHODS

A systematic search was undertaken using PubMed, EMBASE, MEDLINE, CINAHL, SCOPUS, and Cochrane Library from inception to November 2016. Inclusion criteria were (1) the use of an LSO for ≥2 days, (2) the use of a soft LSO designed for musculoskeletal conditions, (3) absence of cointervention except education, and (4) measures of trunk motor performance. The following were excluded: (1) studies with insufficient data and (2) studies with poor methodological quality (<9/16) in the modified McMaster Critical Review Form for Quantitative Studies. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) system was used to determine the quality of evidence.

RESULTS

Data of eight studies were analyzed. The most common measures for motor performances were the maximum strength of the trunk flexors and extensors and the endurance and fatigability of the trunk extensors. In all measures, 95% confidence intervals of the pooled standardized mean difference between the control or preintervention group and the intervention or postintervention group included zero. Further, quality of evidence ranged from low to very low in the GRADE system in all findings of the meta-analyses.

CONCLUSIONS

The meta-analyses demonstrated no negative effect by the continuous use of an LSO for 1-6 months. However, the quality of evidence ranged from low to very low, and more high-quality trials are required to draw a definitive conclusion on the impact of the continuous use of an LSO on trunk motor performances.

Hip abductor, trunk extensor and ankle plantar flexor endurance in females with and without patellofemoral pain

BACKGROUND

Previous studies have reported strength deficit in hip abduction, extension and external rotation in females with patellofemoral pain (PFP) when compared with healthy control; however, there is conflicting evidence for a decrease in hip muscle endurance. Therefore, it seems important to evaluate hip muscle endurance in females with PFP. Moreover, trunk extensor and ankle plantar flexor endurance have not yet been evaluate in females with PFP.

OBJECTIVE

To compare hip abductor, trunk extensor and ankle plantar flexor endurance between females with and without PFP.

METHODS

Twenty females with PFP (mean age, 21.1 years) and 76 healthy females (mean age, 20.5 years) were recruited. Subject performed three endurance clinical tests: (1) The hip abductor isometric endurance test, (2) The Sorensen test and (3) The heel rise test. Group differences were assessed using an independent t tests, or Mann-Whitney U tests for non-normally distributed data.

RESULTS

Subjects with PFP exhibited significantly lower hip abductor, trunk extensor and ankle plantar flexor endurance than healthy controls. On average, subjects with PFP had deficits of 16% in hip abduction, 14% in trunk extension and 26% in ankle plantar flexion.

CONCLUSION

Females with PFP exhibited diminished hip abductor, trunk extensor and ankle plantar flexor endurance compared to healthy controls.

Cross-cultural Adaptation, Reliability, and Validity of the Yoruba Version of the Roland-Morris Disability Questionnaire

STUDY DESIGN

A translation, cross-cultural adaptation, and psychometric analysis.

OBJECTIVE

The aim of this study was to translate, cross-culturally adapt, and validate the Yoruba version of the RMDQ.

SUMMARY OF BACKGROUND DATA

The Roland-Morris Disability Questionnaire (RMDQ) is a valid outcome tool for low back pain (LBP) in clinical and research settings. There seems to be no valid and reliable version of the RMDQ in the Nigerian languages.

METHODS

Following the Guillemin criteria, the English version of the RMDQ was forward and back translated. Two Yoruba translated versions of the RMDQ were assessed for clarity, common language usage, and conceptual equivalence. Consequently, a harmonized Yoruba version was produced and was pilot-tested among 20 patients with nonspecific long-term LBP (NSLBP) for cognitive debriefing. The final version of the Yoruba RMDQ was tested for its construct validity and re-retest reliability among 120 and 87 patients with NSLBP, respectively.

RESULTS

Pearson product moment correlation coefficient (r) of 0.82 was obtained for reliability of the Yoruba version of the RMDQ. The test-retest reliability of the Yoruba RMDQ yielded Cronbach alpha 0.932, while the intraclass correlation (ICC) ranged between 0.896 and 0.956. The analysis of the global scores of both the English and Yoruba versions of the RMDQ yielded ICC value of between 0.995 (95% confidence interval 0.996-0.997), with the item-by-item Kappa agreement ranging between 0.824 and 1.000. The external validity of RMDQ using Quadruple Visual Analogue Scale was r = -0.596 (P = 0.001). The Yoruba version of the RMDQ had no floor/ceiling effects, as no patient achieved either of the maximum or the minimum possible scores.

CONCLUSION

The Yoruba version of the RMDQ has excellent reliability and validity and may be an appropriate outcome tool for clinical and research purposes among Yoruba-speaking patients with LBP.

LEVEL OF EVIDENCE

3.

Reliability assessment and correlation analysis of 3 protocols to measure trunk muscle strength and endurance

Different methods have been developed to quantify trunk muscle strength and endurance. However, some important protocol characteristics are still unclear, hindering the selection of the most suitable tests in each specific situation. The aim of this study was to examine the reliability and the relationship between 3 representative tests of the most common type of protocols used to assess trunk muscle strength and endurance. Twenty-seven healthy men performed each test twice spaced 1 month apart.Trunk strength and endurance were evaluated with an isokinetic dynamometer and 2 field tests including Biering-Sørensen test and Flexion-rotation trunk test. All tests showed a good relative consistency (intraclass correlation coefficient [ICC]> 0.75), except for the isokinetic endurance variables which had low-moderate reliability (0.37 < ICC > 0.65). Absolute reliability seemed slightly better in the isokinetic protocol than in the field tests, which showed about 12% of test-retest score increase. No significant correlations were found between test scores. After a familiarisation period for the field tests, the 3 protocols can be used to obtain reliable measures of trunk muscle strength and endurance. Based on the correlation analysis, these measures are not related, which highlights the importance of selecting the most suitable trunk test for each situation.

Does the inclusion of spinal manipulative therapy in multimodal treatment regimens result in better outcomes in chronic low back pain? A systematic review

Low back pain (LBP) is the most common musculoskeletal disorder. It is costly, both health wise and socioeconomically. Spinal manipulative therapy (SMT) is a popular and well researched conservative management of chronic LBP. However, little is known about its role cum effectiveness as part of multimodal treatment regimens. The aim of this systematic review is to examine the evidence of the effectiveness of SMT as part of a multimodal regimen in the management of chronic LBP. Eligible studies were identified by searching Medline, Embase, PEDro, CINAHL, AMED, and the Cochrane Central Register of controlled trials. Randomized controlled trials (RCTs) on patients with chronic mechanical LBP were considered. Data from four RCTs (430 participants) were included in this review. All four had a low risk of bias. Three studies found a statistically significant improvement in pain and function at both short term and long term in the group that received SMT as part of a multimodal treatment regimen. Heterogeneity in the nature of the interventions that made up the treatment regimen, comparison interventions, duration of treatment and follow-up periods were identified. There is moderate quality evidence that the addition of SMT to multimodal treatment regimens for chronic LBP results in better outcomes in terms of pain and function as compared to other conservative interventions.

Low back pain characterized by muscle resistance and occupational factors associated with nursing

Objective

to identify the occupational factors associated with low back pain using a surveillance tool and to characterize the low back pain by the resistance of the extensor muscles of the vertebral column among nursing professionals at an Intensive Care Unit.

Methods

Cross-sectional study. The workers answered a questionnaire about occupational factors and participated in a resistance test of the extensor muscles of the vertebral column. Associations were established through Student's T-test or Mann-Whitney's U-test and correlations using Pearson's test.

Results

Out of 48 participants, 32 (67%) suffered from low pain. For the resistance test, the subjects suffering from low back pain endured less time in comparison with asymptomatic subjects, but without significant differences (p=0.147). The duration of the pain episode showed a significant negative correlation (p=0.016) with the results of the resistance test though. The main factors identified as causes of low back pain were biomechanical and postural elements, conditions of the muscle structure and physical and organizational conditions.

Conclusions

the main occupational factors associated with the low back pain were the posture and the characteristics of the physical and organizational conditions. In addition, the extensor muscles of the column showed a trend towards lesser resistance for workers in pain. This evidence is important when considering prevention and treatment strategies.

Influence of Lumbar Muscle Fatigue on Trunk Adaptations during Sudden External Perturbations

Introduction: When the spine is subjected to perturbations, neuromuscular responses such as reflex muscle contractions contribute to the overall balance control and spinal stabilization mechanisms. These responses are influenced by muscle fatigue, which has been shown to trigger changes in muscle recruitment patterns. Neuromuscular adaptations, e.g., attenuation of reflex activation and/or postural oscillations following repeated unexpected external perturbations, have also been described. However, the characterization of these adaptations still remains unclear. Using high-density electromyography (EMG) may help understand how the nervous system chooses to deal with an unknown perturbation in different physiological and/or mechanical perturbation environments.

Aim: To characterize trunk neuromuscular adaptations following repeated sudden external perturbations after a back muscle fatigue task using high-density EMG.

Methods: Twenty-five healthy participants experienced a series of 15 sudden external perturbations before and after back muscle fatigue. Erector spinae muscle activity was recorded using high-density EMG. Trunk kinematics during perturbation trials were collected using a 3-D motion analysis system. A two-way repeated measure ANOVA was conducted to assess: (1) the adaptation effect across trials; (2) the fatigue effect; and (3) the interaction effect (fatigue × adaptation) for the baseline activity, the reflex latency, the reflex peak and trunk kinematic variables (flexion angle, velocity and time to peak velocity). Muscle activity spatial distribution before and following the fatigue task was also compared using t-tests for dependent samples.

Results: An attenuation of muscle reflex peak was observed across perturbation trials before the fatigue task, but not after. The spatial distribution of muscle activity was significantly higher before the fatigue task compared to post-fatigue trials. Baseline activity showed a trend to higher values after muscle fatigue, as well as reduction through perturbation trials. Main effects of fatigue and adaptation were found for time to peak velocity. No adaptation nor fatigue effect were identified for reflex latency, flexion angle or trunk velocity.

Conclusion: The results show that muscle fatigue leads to reduced spatial distribution of back muscle activity and suggest a limited ability to use across-trial redundancy to adapt EMG reflex peak and optimize spinal stabilization using retroactive control.

Comparison of Lateral Abdominal Muscle Thickness and Cross Sectional Area of Multifidus in Adolescent Soccer Players with and without Low Back Pain: A Case Control Study

BACKGROUND

Low back pain (LBP) is a common complaint amongst adolescent athletes. While different studies have shown association between LBP and trunk muscle thickness in the general population, few articles have studied it in adolescent athletes.

OBJECTIVES

The aim of this study is to compare lateral abdominal muscle thickness and function, and cross sectional area (CSA) of lumbar multifidus (LM) in adolescent soccer players with and without LBP.

METHODS

In total, 28 adolescent soccer players with and without LBP, from the premier league participated in this study. The thickness of external oblique, internal oblique and transversus abdominis and the CSA of the LM muscles at L4 level on both sides were measured at rest and contraction via ultrasound imaging (USI). In addition, leg length discrepancy, hamstring flexibility, active lumbar forward flexion, and isometric muscle endurance of trunk extensors were measured in both groups. (study design/setting: case control study).

RESULTS

The mean (SD) age in LBP group and non-LBP group were 14.0 (1.1) and 14.1 (0.9) years, respectively. There was no significant difference in baseline characteristics of participants between groups. Findings showed no significant difference between LBP and non-LBP groups comparing all measured variables.

CONCLUSIONS

The data obtained support that there is not a correlation between abdominal muscle thickness and CSA of the lumbar multifidi and LBP in adolescent soccer players. These findings suggest that other factors rather than the thickness of deep trunk muscles may play a more significant role in the etiology of LBP in adolescent soccer players.

Associations between Trunk Extension Endurance and Isolated Lumbar Extension Strength in Both Asymptomatic Participants and Those with Chronic Low Back Pain

BACKGROUND

Strength and endurance tests are important for both clinical practice and research due to the key role they play in musculoskeletal function. In particular, deconditioning of the lumbar extensor musculature has been associated with low back pain (LBP). Due to the relationship between strength and absolute endurance, it is possible that trunk extension (TEX) endurance tests could provide a proxy measure of isolated lumbar extension (ILEX) strength and thus represent a simple, practical alternative to ILEX measurements. Though, the comparability of TEX endurance and ILEX strength is presently unclear and so the aim of the present study was to examine this relationship.

METHODS

Thirty eight healthy participants and nineteen participants with non-specific chronic LBP and no previous lumbar surgery participated in this cross-sectional study design. TEX endurance was measured using the Biering-Sorensen test. A maximal ILEX strength test was performed on the MedX lumbar-extension machine.

RESULTS

A Pearson's correlation revealed no relationship between TEX endurance and ILEX strength in the combined group (r = 0.035, p = 0.793), the chronic LBP group (r = 0.120, p = 0.623) or the asymptomatic group (r = -0.060, p = 0.720).

CONCLUSIONS

The results suggest that TEX is not a good indicator of ILEX and cannot be used to infer results regarding ILEX strength. However, a combination of TEX and ILEX interpreted together likely offers the greatest and most comprehensive information regarding lumbo-pelvic function during extension.

Study protocol for Norwegian Psychomotor Physiotherapy versus Cognitive Patient Education in combination with active individualized physiotherapy in patients with long-lasting musculoskeletal pain - a randomized controlled trial

Background

Norwegian Psychomotor Physiotherapy (NPMP) has been an established treatment approach for more than 50 years, although mostly in the Scandinavian countries, and is usually applied to patients with widespread and long-lasting musculoskeletal pain and/or psychosomatic disorders. Few studies have been investigating outcome of NPMP and no randomized clinical trials (RCT) have been systematically tried out on individuals.

Methods/design

This is a study protocol for a pragmatic, single blinded RCT, which will take place in a city of Norway. The participants will be block randomized either to receive NPMP or Cognitive Patient Education in combination with active individualized physiotherapy (COPE-PT). The intervention will reflect usual care and will be conducted in physiotherapy clinics by five experienced physiotherapists in each of the two treatment approaches.

Discussion

The findings of the present study may give an important contribution to our knowledge of the outcome of NPMP, on patients with long-lasting widespread musculoskeletal pain and/or pain located to the neck and shoulder region.

Trial registration

The study has been registered with ClinicalTrials.gov (June 9 th 2015, NCT02482792).

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1159-8) contains supplementary material, which is available to authorized users.