Diagnostic accuracy and reliability of muscle strength and endurance measurements in patients with chronic low back pain

The Role of Back Muscle Dysfunctions in Chronic Low Back Pain: State-of-the-Art and Clinical Implications

Changes in back muscle function and structure are highly prevalent in patients with chronic low back pain (CLBP). Since large heterogeneity in clinical presentation and back muscle dysfunctions exists within this population, the potential role of back muscle dysfunctions in the persistence of low back pain differs between individuals. Consequently, interventions should be tailored to the individual patient and be based on a thorough clinical examination taking into account the multidimensional nature of CLBP. Considering the complexity of this process, we will provide a state-of-the-art update on back muscle dysfunctions in patients with CLBP and their implications for treatment. To this end, we will first give an overview of (1) dysfunctions in back muscle structure and function, (2) the potential of exercise therapy to address these dysfunctions, and (3) the relationship between changes in back muscle dysfunctions and clinical parameters. In a second part, we will describe a framework for an individualised approach for back muscle training in patients with CLBP.

Association of accelerometer-measured physical activity, back static muscular endurance and abdominal obesity with radicular pain and non-specific low back pain

Low back pain (LBP) is the leading cause of disability worldwide and often associated with lifestyle factors. However, studies further examining the role of these lifestyle factors in non-specific low back pain in comparison with radicular pain are sparse. The aim of this cross sectional study was to investigate how diverse lifestyle factors are associated with LBP. The study population of 3385 middle aged adults with and without low back pain was drawn from a large Birth 1966 Cohort. Outcome measures were steps per day, abdominal obesity, physical activity and endurance of the back muscles. Back static muscular endurance, abdominal obesity and physical activity were measured by means of the Biering-Sørensen test, waist circumference and a wrist worn accelerometer, respectively. Logistic regression analysis was applied to estimate associations of back static muscular endurance, abdominal obesity and accelerometer-measured physical activity with non-specific low back pain and radicular pain. An additional 1000 steps per day were associated with 4% lower odds of having non-specific low back pain. Participants with abdominal obesity had 46% higher odds of having radicular pain, whereas increases of 10 s in back static muscular endurance and 10 min in daily vigorous physical activity were associated with 5% and 7% lower odds of having radicular pain, respectively. In this population-based study, non-specific low back pain and radicular pain were associated with different lifestyle and physical factors at midlife. Non-specific low back pain was associated only with the average daily number of steps, whereas abdominal obesity was the strongest determinant of radicular pain, followed by vigorous physical activity and back static muscular endurance. The findings of this study contribute to better understand the role of lifestyle factors in both non-specific low back pain and radicular pain. Future longitudinal studies are required to explore causality.

A novel physical functioning test to complement subjective questionnaires in chronic low back pain assessments

BACKGROUND CONTEXT

Lifting disability commonly affects patients with chronic low back pain (CLBP) and may not correlate with the existing lifting-related physical assessment tests, such as the loaded forward reach (LFR) test.

PURPOSE

The Lift and Place (LAP) test was developed to assess lifting disability in CLBP based on known risk factors. The LAP test was compared with established physical assessment test, including the LFR test and self-reported disability questionnaires.

STUDY DESIGN/SETTING

This cross-sectional study measured self-reported disability questionnaires along with LAP and other physical assessment test results PATIENT SAMPLE: Eighty three CLBP and 82 asymptomatic participants aged 18 to 55 with normal BMI according to WHO classification.

OUTCOME MEASURES

Oswestry disability index (ODI), Roland-Morris disability questionnaire (RMDQ), Numerical Pain Rating Scale, Trunk Extensor Endurance test, 5 Repetition Sit-To-Stand test, LAP and LFR test.

METHODS

Physical assessment test scores were compared between the two groups. The correlation of assessment test scores with ODI and RMDQ in patients with CLBP was calculated. Receiver operating characteristic (ROC) curve analysis was performed to calculate the area under the curve (AUC) of each assessment tests. Assessment tests, ODI, and RMDQ were measured twice for CLBP patients on separate days to calculate the test-retest intraclass correlation (ICC) reliability. Two researchers scored the assessment tests independently to calculate the inter-rater ICC.

RESULTS

Patients with CLBP were slower in the LAP test (CLBP vs asymptomatic: 21.6±4.9 s vs 18.6±3.6 s) and had shorter reach in the LFR test (CLBP vs asymptomatic: 33.6±6.0 cm vs 36.3±6.6 cm). The LAP was correlated with both ODI (r=0.418) and RMDQ (r=0.390), while the LFR was not. In the ROC analysis, the LAP and LFR bore AUCs of 0.685 and 0.379, respectively. Their test-retest ICCs were 0.913 and 0.858, and their inter-rater ICCs were 0.997 and 0.969, respectively.

CONCLUSIONS

The LAP test demonstrated higher reliability and significant correlation with the ODI and RMDQ, indicating its potential as performance assessment for lifting disability in CLBP. Further studies should investigate the use of LAP and other physical assessments for rapid CLBP screening.

The Relationship between Ergometric Treadmill or Bicycle Performance and Isokinetic Trunk Strength - a Retrospective Analysis

The relationship between trunk strength and athletic performance is well known. In the past, trunk strength and athletic performance were measured in field tests. Previous studies encouraged sport-specific analyses. The goal of this study was to investigate whether there is a relation between ergometrically measured treadmill or bicycle endurance and isokinetic trunk strength. This retrospective analysis included 1334 bicycle and 1838 treadmill ergometry examinations in 1149 subjects. Bicycle and treadmill ergometer performance were analysed in relation to isokinetic trunk strength. Statistics were performed by Pearson correlation and mixed or generalised linear models. Higher treadmill and bicycle power correlated with higher isokinetic trunk strength, with highest absolute trunk strength in the treadmill group. For both running and cycling endurance, a positive correlation with trunk strength could be quantified in regression models. Increased ergometry endurance and lower flexion/extension ratios are connected weakly. Ergometry performance had the strongest correlation with extension trunk strength (r=0.312-0.398 for bicycle ergometry and r=0.168-0.229 for treadmill ergometry, p<0.001). We encourage prospective studies using both kinds of ergometry to evaluate the effect of trunk strengthening to enhance sport-specific endurance performance. Weight-adapted trunk strength values showed overall greater correlation to trunk strength and we recommend the use of weight-adapted values.

The functional lumbar index: Validation of a novel clinical assessment tool for individuals with low back pain

STUDY DESIGN

Retrospective Diagnostic Cohort Study.

LEVEL OF EVIDENCE

Level 3b.

OBJECTIVES

To examine the concurrent and predictive validity of a novel clinical assessment tool, the Functional Lumbar Index (FLI).

BACKGROUND

Lumbar surgeries have increased exponentially in the past decade, adding to healthcare costs without improving outcomes. Limitations in clinicians' abilities to identify those individuals who are most likely to benefit from surgery may be enhanced with an effective physical assessment tool.

METHODS

The FLI was assessed on 291 individuals (179 conservative and 113 pre-surgical) seeking care for low-back pain (LBP) over a 2.5-year period. The FLI consists of several physical performance tests (PPT) with a novel criterion-based scoring system. Pearson correlations and Poisson regression analysis were used to establish concurrent and predictive validity at alpha = 0.05.

RESULTS

The subscale FLI components showed good to excellent inter-rater reliability with intraclass correlation coefficient values as follows: front plank = .993, right side plank = .824, left side plank .861, Sorensen = 0.836, overhead squat = 0.937. A statistically significant, moderate negative correlation was observed between FLI and modified Oswestry Disability Index (r = -0.540, p < .001). Regression analysis showed the FLI as the only significant predictor (p = .004) of failed conservative management for individuals with LBP. An ROC curve showed significant group prediction of the FLI with an AUC of 0.788 (p < .001) and cut-off score of 7.5.

CONCLUSION

The FLI is a reliable and valid measure for predicting failed conservative care management in patients with LBP. Clinicians are encouraged to use the FLI as part of their physical assessment when screening individuals with LBP who might need surgical intervention. Further research is needed to determine validity of the FLI in other patient populations.

PUBLIC TRIAL REGISTRY

N/A.

Investigation of the relationship between the clinical evaluation results of lumbar region muscles with cross-sectional area and fat infiltration

BACKGROUND

The relationship between the endurance of the lumbar paraspinal muscles and morphological changes needs to be clarified. In this context, the importance can be revealed of increasing the endurance level of the paraspinal muscles in the prevention and treatment of low back diseases.

OBJECTIVE

The aim of this study was to examine the relationship between the clinical evaluation results of the cross-sectional area (CSA) and fat infiltration of the lumbar deep paraspinal muscles.

METHODS

The study included 37 patients with mechanical low back pain (mechanical), 41 patients with lumbar hernia without root compression (discopathy) and 36 healthy individuals as a control group. The functional status of the lumbar deep paraspinal muscles was evaluated clinically with muscle endurance tests. The fat infiltration and CSA of the muscles were evaluated on axial MRI sections at the L3-S1 level.

RESULTS

The mean values of the prone bridge, Biering-Sorenson, and trunk flexion tests were seen to be highest in the control group and lowest in the discopathy group (p< 0.001). In all tests, the longest test period was obtained at < 10% fat infiltration and the shortest at > 50% fat infiltration. It was observed that as the amount of fat infiltration of the muscles increased, the test times were shortened. There was no significant relationship between the endurance level and the CSA of the groups.

CONCLUSION

The study results demonstrated that the endurance of the paraspinal muscles is associated with the fat infiltration of the muscles. In patients with chronic low back pain, information about muscle morphology and degeneration can be obtained with simple endurance tests without the need for further measurements. On clinical examination, a weak endurance level of the paraspinal muscles indicates the presence of a low back problem and an increase in the amount of fat infiltration.

Reliability of trunk strength measurements with an isokinetic dynamometer in non-specific low back pain patients: A systematic review

BACKGROUND

Imbalance or decreased trunk strength has been associated with non-specific low back pain (NSLBP).

OBJECTIVE

This systematic review aimed (I) to evaluate the quality of evidence of studies evaluating the reliability of trunk strength assessment with an isokinetic dynamometer in NSLBP patients, (II) to examine the reliability of trunk strength assessment using an isokinetic dynamometer in NSLBP patients and (III) to determine the most reliable protocol for trunk strength assessment in NSLBP patients.

METHOD

PRISMA guidelines were followed. Three databases were used: PubMed, Scopus, and Web of Science with the following keywords: Isokinetic, Dynamometer, Trunk strength testing, Muscle testing, Isokinetic measurement, CORE, Abdominal muscles, Abdominal wall, Torso, Trunk, Spine, Reliability and, Reproducibility. We included only test-retest studies, focused on the reliability of isometric and isokinetic strength assessed with an isokinetic dynamometer in NSLBP adults' patients, published in English and from inception to March 30, 2021. The methodological quality was evaluated with the CAT scale and QAREL checklist.

RESULTS

Five hundred and seventy-seven articles were retrieved, of which five are included in this review. Three articles provide good quality of evidence, the reliability of trunk strength assessment in NSLBP patients is excellent, and the most reliable protocol for isometric assessment is in a seated position (ICC = 0.94-0.98) and for isokinetic strength in standing position, at 60∘/s and 120∘/s (ICC = 0.98).

CONCLUSION

There is good quality evidence regarding the trunk strength assessment's reliability. Reliability is excellent in NSLBP patients; however, a familiarization process should be considered to obtain clinically reliable data. The most reliable protocol is in a seated position for isometric strength and a standing position for isokinetic strength.

Reliability of Field-Based Fitness Tests in Adults: A Systematic Review

BACKGROUND

Physical fitness is a powerful predictor of morbidity and mortality, and is therefore a useful indicator for public health monitoring. To assess physical fitness, field-based tests are time-efficient, inexpensive, have minimal equipment requirements, and can be easily administered to a large number of individuals.

OBJECTIVE

The objective of this systematic review was to examine the reliability of existing field-based fitness tests used in adults aged 19-64 years.

METHODS

A systematic search of two electronic databases (MEDLINE and Web of Science) was conducted from inception to 8 June 2021 by two independent researchers. Each study was classified as high, low, or very low quality according to the description of the participants, the time interval between measurements, the description of the results, and the appropriateness of statistics. Three levels of evidence (strong, moderate, and limited) were established according to the number of studies and the consistency of their findings. The study protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO reference number, CRD42019118480).

RESULTS

Of 17,010 records identified, 129 original studies examining the reliability of field-based fitness tests in adults were considered eligible. The reliability was assessed of tests of cardiorespiratory fitness (33 studies: 30 of high quality), musculoskeletal fitness (92 studies: 78 of high quality), and motor fitness (22 studies, all of high quality). There was strong evidence indicating: (i) the high reliability of the cardiorespiratory fitness tests: 20-m shuttle run, 6-min step, and 6-min walk; (ii) the high reliability of the musculoskeletal fitness tests: handgrip strength, back-leg strength, Sorensen, trunk flexion sustained, 5-reps sit-to-stand, sit-and-reach and toe-touch, and moderate reliability bilateral side bridge and prone bridge tests; and (iii) the moderate reliability and low reliability, respectively, of the motor fitness tests T-test and single-leg stand. We found moderate evidence indicating the moderate or high reliability of the following tests: Chester, sit-up, partial curl-up, flexion-rotation trunk, timed stair ascent, pull-up, bent-arm hang, standing broad jump, hop sequence, trunk lift, timed-up-and-go, and hexagon agility. Evidence for the reliability of balance and gait speed tests was inconclusive. Other field-based fitness tests demonstrated limited evidence, mainly due to there being only few studies.

CONCLUSIONS

This review provides an evidence-based proposal of the more reliable field-based fitness tests for adults aged 19-64 years. Our findings identified a need for more high-quality studies designed to assess the reliability of field-based tests of lower and upper body explosive and endurance muscular strength, and motor fitness (i.e., balance and gait speed tests) in adults.

Trunk muscle function and its association with functional limitations in sedentary occupation workers with and without chronic nonspecific low back pain

BACKGROUND

The function of trunk muscles in chronic nonspecific low back pain (CNLBP) is controversially discussed, and trunk muscle function in sedentary occupation workers is poorly understood.

OBJECTIVE

To investigate whether muscle function differs between sedentary occupation workers with and without CNLBP and to determine the association between functional limitations and muscle function.

METHODS

This study included 32 sedentary occupation workers (16 workers with CNLBP and 16 age- and sex-matched workers without CNLBP). Group differences in isokinetic trunk flexion-extension strength, muscle cocontraction, endurance time (Biering-Sorensen test) and electromyographic muscle fatigue were assessed. The association of these parameters and Oswestry Disability Index (ODI) score were examined in the CNLBP group.

RESULTS

Participants with CNLBP had lower trunk extensor (-20%) and flexor (-18%) strength and less cocontraction (-22%) than participants without CNLBP, but due to large variability in both groups these differences were not statistically significant. Trunk muscle endurance and fatigue were comparable between groups. Variance in endurance time explained 28% of variance in the ODI-score in the CNLBP group (R2= 0.277).

CONCLUSIONS

In patients with CNLBP, greater functional disability was associated with lower endurance. Further evidence is necessary to elucidate whether specifically training endurance performance may be beneficial for sedentary occupation workers.

Interdisciplinary Co-Design Research Practice in the Rehabilitation of Elderly Individuals with Chronic Low Back Pain from a Senior Care Center in South Korea

The rehabilitation practices encounter multifaceted problems inherent in the current context of the elderly with chronic low back pain (LBP). We addressed a particular multifaceted problem in the current context using an interdisciplinary co-design research practice that consists of three phases: context exploration, patient-expert interaction, and patient-centered rehabilitation. Using an empirical study integrated with this practice, we investigated 30 Korean elderly patients suffering from LBP and introduced an exercise program design. In the context exploration phase, we found that the elderly patients neglected proper posture during work causing spine instability and resultantly developing chronic LBP. The patient–expert interaction phase explored latissimus dorsi (LD) and lumbar erector spinae (LES) muscles as the back trunk muscles that had caused LBP in most of these elderly patients. In the patient-centered rehabilitation phase, we designed an exercise program with exercise protocols and an exercise object for flexion and extension of trunk muscle relaxation and stabilization. Using electromyography (EMG), we found that the exercise program significantly increased the muscle activation levels of the muscles and reduced LBP. Our practice defines and addresses a multifaceted problem with several challenges both in healthcare design and the problem itself. This integrated approach can easily be expanded and adapted to other domain-related research projects that possess characteristics of complex problems.

Effect of Six-Week Resistance and Sensorimotor Training on Trunk Strength and Stability in Elite Adolescent Athletes: A Randomized Controlled Pilot Trial

Intervention in the form of core-specific stability exercises is evident to improve trunk stability. The purpose was to assess the effect of an additional 6 weeks sensorimotor or resistance training on maximum isokinetic trunk strength and response to sudden dynamic trunk loading (STL) in highly trained adolescent athletes. The study was conducted as a single-blind, 3-armed randomized controlled trial. Twenty-four adolescent athletes (14f/10 m, 16 ± 1 yrs.;178 ± 10 cm; 67 ± 11 kg; training sessions/week 15 ± 5; training h/week 22 ± 8) were randomized into resistance training (RT; n = 7), sensorimotor training (SMT; n = 10), and control group (CG; n = 7). Athletes were instructed to perform standardized, center-based training for 6 weeks, two times per week, with a duration of 1 h each session. SMT consisted of four different core-specific sensorimotor exercises using instable surfaces. RT consisted of four trunk strength exercises using strength training machines, as well as an isokinetic dynamometer. All participants in the CG received an unspecific heart frequency controlled, ergometer-based endurance training (50 min at max. heart frequency of 130HF). For each athlete, each training session was documented in an individual training diary (e.g., level of SMT exercise; 1RM for strength exercise, pain). At baseline (M1) and after 6 weeks of intervention (M2), participants’ maximum strength in trunk rotation (ROM:63°) and flexion/extension (ROM:55°) was tested on an isokinetic dynamometer (concentric/eccentric 30°/s). STL was assessed in eccentric (30°/s) mode with additional dynamometer-induced perturbation as a marker of core stability. Peak torque [Nm] was calculated as the main outcome. The primary outcome measurements (trunk rotation/extension peak torque: con, ecc, STL) were statistically analyzed by means of the two-factor repeated measures analysis of variance (α = 0.05). Out of 12 possible sessions, athletes participated between 8 and 9 sessions (SMT: 9 ± 3; RT: 8 ± 3; CG: 8 ± 4). Regarding main outcomes of trunk performance, experimental groups showed no significant pre–post difference for maximum trunk strength testing as well as for perturbation compensation (p &gt; 0.05). It is concluded, that future interventions should exceed 6 weeks duration with at least 2 sessions per week to induce enhanced trunk strength or compensatory response to sudden, high-intensity trunk loading in already highly trained adolescent athletes, regardless of training regime.

Isometric and isokinetic muscle strength measurements of the lumbar flexors and extensors with BioniX Sim3 Pro in patients with chronic low back pain: A pilot study

BACKGROUND

The World Health Organization states that low back pain is the leading cause for disability worldwide. Patients with chronic low back pain (CLBP) show important decreases in lumbar strength and can now be assessed by using the new isokinetic dynamometer BioniX Sim3 Pro which offers very detailed measurements.

OBJECTIVE

To compare lumbar flexion and extension strength values, as well as extension-flexion ratio (EFR) based on isokinetic velocity and gender, for patients with CLBP on the BioniX Sim3 Pro.

METHODS

A retrospective analysis was performed on data from 20 men and 22 women with CLBP. Maximum torque in flexion and extension was measured isometrically and isokinetically. Statistical analysis was performed on these parameters.

RESULTS

EFR shows a downward trend with increasing speed of measurement (isometric to isokinetic 30∘/s and isokinetic 30∘/s to isokinetic 90∘/s, respectively): in men from 1.21 to 1.04 (p< 0.001) and from 1.04 to 0.93 (p= 0.207). In women, EFR decreased from 1.41 to 1.13 (p< 0.001) and from 1.13 to 1.00 (p= 0.144).

CONCLUSIONS

Patients with CLBP have a decreased strength in lumbar extension and flexion compared to the age-corrected normal values of Bionix Sim3 Pro. With increasing speed of testing protocol, a decrease in EFR is observed in this population.

Reliability of Sonography Measures of the Lumbar Multifidus and Transversus Abdominis during Static and Dynamic Activities in Subjects with Non-Specific Chronic Low Back Pain

PURPOSE

The purpose of this study was to investigate the test-retest reliability of ultrasound (US) thickness measurements and the muscle contraction ratio (CR) of lumbar multifidus (LM) and transversus abdominis (TA) muscles in participants with and without nonspecific chronic low back pain (NCLBP).

METHODS

A total of 62 participants (37 with NCLBP, 25 without NCLBP) with participated in the study. The within-day and between-day reliability of US thickness measurements and CR in a lying (supine for TA and prone for LM) and sitting positions for both muscles (sitting on a gym ball with both feet on the ground or lifting one foot off the floor) were assessed. Reliability analysis was performed with intraclass correlations (ICCs) for these two static and dynamic positions.

RESULTS

Test-retest reliability was calculated to be good to high for the static position (ICC = 0.72-0.95) and the dynamic position (ICC = 0.74-0.94) sonographic measurements in both group of TA measurement. Test-retest reliability of LM measurements was good to high for the static position (ICC = 0.82-0.95) and the dynamic position (ICC = 0.85-0.97) sonographic measurements in both groups.

CONCLUSIONS

US imaging is a highly reliable method for the assessment of TA and LM thickness muscles in the dynamic position in participants with and without NCLBP. The CR measures may be adequately reliable in assessing the function of the TA and LM muscles in participants with NCLBP and healthy ones.

Assessment of isokinetic trunk muscle strength and its association with health-related quality of life in patients with degenerative spinal deformity

Background

A considerable portion of the elderly population are increasingly afflicted by degenerative spinal deformity (DSD), which seriously affects patient health-related quality of life (HRQoL). HRQoL index is used across many studies to show correlations between radio-graphical alignment, disability, and pain in patients with DSD. However, imaged structural deformity represents only one aspect for consideration, namely, the disability effect of DSD. We assessed the isokinetic strength of trunk muscle in patients with degenerative spinal deformity (DSD), and investigated its relationship with HRQoL.

Methods

In total, 38 patients with DSD (DSD group) and 32 healthy individuals (control group) were recruited. Both groups were homogeneous for age, weight, height and body mass index (BMI). Assessments were performed using the isokinetic dynamometer IsoMed-2000; trunk extensor, flexor strength and flexion/extension (F/E) ratios were explored concentrically at speeds of 30°, 60° and 120° per second. The grip strength of both hands was measured using a hand-held dynamometer. Visual analogue scale (VAS) scores, the Oswestry Disability Index (ODI), a Roland-Morris disability questionnaire (RDQ), and a 36-item Short Form Health Survey (SF-36) evaluated patient HRQoL. Correlations between trunk strength and HRQoL were analyzed.

Results

When compared with the control group, the DSD group showed lower trunk extensor strength at three velocity movements, and higher F/E ratios at 60° and 120°/s (p < 0.05). Both groups exhibited similar trunk flexor strength and grip strength (p > 0.05). In DSD group, trunk extensor strength at 60°/s was negatively associated with ODI and RDQ (p < 0.05). A negative relationship between trunk flexor strength at 120°/s and ODI was also recorded (p < 0.05). In addition, trunk extensor strength at 60°/s and trunk flexor strength at 120°/s were positively correlated with physical functioning and role-physical scores according to the SF-36 (p < 0.05).

Conclusions

We identified isolated trunk extensor myopathy in DSD, which causes an imbalance in trunk muscle strength. Isokinetic trunk extensor strength at 60°/s and trunk flexor strength at 120°/s can predict disability, and decrease physical HRQoL in DSD patients.

The Relevance of Dual Tasking for Improving Trunk Muscle Endurance After Back Surgery

OBJECTIVE

To determine the effect of dual tasking on trunk muscle endurance in patients after lumbar diskectomy.

DESIGN

Cross-sectional study.

SETTING

Rehabilitation hospital setting.

PARTICIPANTS

Individuals (N=14) undergoing primary lumbar diskectomy.

INTERVENTION

Using a randomized design on 2 separate days, muscle endurance was evaluated during prone bridging and Biering-Sorensen tests. Each test was randomly performed under 2 cognitive conditions: single task without cognitive condition and self-regulated dual task (ie, mathematical task).

MAIN OUTCOME MEASURES

The primary outcomes were time to failure and pain assessed by the visual analog scale from 0 to 100 mm. The secondary outcomes were kinesiophobia assessed by the Tampa Scale and disability assessed by the Oswestry Disability Index. Associations were tested using a repeated measures analysis of variance with relevant interaction test.

RESULTS

A significant interaction between condition, endurance tests, and kinesiophobia (P=.005) was found. The post hoc comparison showed positive effects between cognitive conditions in both endurance tests (prone bridging test: mean difference, 15.7s; 95% confidence interval [CI], 7.5-24s; P=.001; Biering-Sorensen test: mean difference, 7.9s; 95% CI, 1.9-14s; P=.014). The linear regression analysis between the Tampa Scale for Kinesiophobia and the difference of time to failure between cognitive conditions showed a positive correlation only during the Biering-Sorensen test (r=0.80; P=.001).

CONCLUSIONS

A self-regulated dual task increases trunk muscle endurance in patients after lumbar diskectomy. The results suggest that the difference observed in time to failure between the single task and dual task is associated with fear avoidance, especially during back extension. This strategy seems especially relevant for patients with high levels of fear avoidance and may be used to improve trunk muscle endurance.

Efficacy of the Pilates versus general exercises versus educational workshops on neuromuscular parameters: A randomized controlled trial

INTRODUCTION

Muscle strength, flexibility and changes in muscle recruitment patterns are usually associated to low back pain (LBP). Physical exercises can reverse the adverse changes associated to LBP.

OBJECTIVES

Compare Pilates, general exercises and educational workshop on muscle flexibility, strength and recruitment of the trunk extensor muscles in women with LBP.

METHODS

Forty-six women were randomly divided into Pilates group (PG, n = 16), general exercise group (GEG, n = 15), and educational group (EG, n = 15). This study sought to determine flexibility, muscle strength, and muscle recruitment of right (RIL), left (LIL) iliocostalis lumbar; right (RMU) and left (LMU) lumbar multifidus muscles. Both PG and GEG performed 16 exercise sessions, while EG attended 4 workshops. Statistical analysis used data sample from Shapiro-Wilk test, Pearson's correlation, multivariate analysis, mixed variance analysis, and Cohen's index.

RESULTS

Flexibility showed no differences (p > 0.05). Muscle strength increased in the intragroup analysis for PG (p = 0.003) and GEG (p = 0.002); however, the intergroup analysis presented no difference. Intergroup showed statistically significant differences for the recruitment of RMU in PG (p < 0.001). Intragroup analysis presented differences after interventions in PG for RIL (p = 0.001); in GEG for LIL (p = 0.005); and in EG for RIL (p = 0.007), LIL (p = 0.002) and RMU (p < 0.001).

CONCLUSIONS

None of the groups showed flexibility improvements. PG and GEG increased muscle strength through intragroup analysis. Intergroup analysis showed an increase in recruitment of the RMU muscle in PG and all groups demonstrated significant improvements in the intragroup analysis.

[The lumbar flexion-relaxation phenomen as a diagnostic test in assessment of lumbar impairment. Sensitivity and specificity]

OBJECTIVE

To define the role of the flexion-relaxation phenomenon (FRP), assessed through ratios (FRR), as a diagnostic test to define impairment in patients with chronic low back pain (CLBP).

MATERIAL AND METHOD

The study sample consisted of 180 participants (16 healthy volunteers and 164 patients on work disability due to CLBP), who were consecutively referred for evaluation at the Biomechanics Laboratory of a workplace accident insurance company from January 2012 to December 2017. The evaluations consisted of an isometric dynamometry test, a kinematic test and assessment of the FRP phenomenon. Minimum criteria were established in the performance of the tests for their acceptance as valid for the study. Lumbar impairment or clinical recovery was defined on the basis of the results of the dynamometry and kinematic tests. The FRP response was assessed with FRRs. A total of 4 different ratios were taken for analysis with ROC curves.

RESULTS

A total of 86 valid tests were obtained (16 classified as lumbar impairment and 71 as recovered cases). The best ratio obtained an area under the ROC curve of 0.87, with a sensitivity of 0.84, a specificity of 0.87, and a positive predictive value of 97%.

CONCLUSIONS

The FRP test, along with dynamometry and kinematic evaluations, is effective in identifying lumbar impairment and is the easiest test for patients with CLBP to perform.

Effects of Chiropractic Care on Strength, Balance, and Endurance in Active-Duty U.S. Military Personnel with Low Back Pain: A Randomized Controlled Trial

Objectives: To investigate whether chiropractic care influences strength, balance, and/or endurance in active-duty United States military personnel with low back pain (LBP). Design: This study employed a prospective randomized controlled trial using a pragmatic treatment approach. Participants were randomly allocated to 4 weeks of chiropractic care or to a wait-list control. Interventions: Chiropractic care consisted of spinal manipulation, education, advice, and reassurance. Settings/Location: Naval Air Technical Training Center branch clinic at the Naval Hospital Pensacola Florida. Subjects: One hundred ten active-duty military personnel 18-40 years of age with self-reported LBP. Outcome measures: Isometric pulling strength from a semisquat position was the primary outcome. Secondary outcomes were single-leg balance with eyes open and eyes closed, and trunk muscle endurance using the Biering-Sorensen test. Patient-reported outcomes such as pain severity and disability were also measured. Outcomes were measured at baseline and 4 weeks. Linear mixed-effects regression models over baseline and 4 weeks were used for analysis. Results: Participants had mean age of 30 years (18-40), 17% were female, 33% were non-white, and 86% reported chronic LBP. Mean maximum pulling strength in the chiropractic group increased by 5.08 kgs and decreased by 7.43 kgs in the wait-list group, with a statistically significant difference in mean change between groups (p = 0.003). Statistically significant differences in mean change between groups were also observed in trunk muscle endurance (13.9 sec, p = 0.002) and balance with eyes closed (0.47 sec, p = 0.01), but not in balance with eyes open (1.19 sec, p = 0.43). Differences in mean change between groups were statistically significant in favor of chiropractic for LBP-related disability, pain intensity and interference, and fear-avoidance behavior. Conclusions: Active-duty military personnel receiving chiropractic care exhibited improved strength and endurance, as well as reduced LBP intensity and disability, compared with a wait-list control.

Chronic Fatigue, Physical Impairments and Quality of Life in Women with Endometriosis: A Case-Control Study

AIM

To explore endometriosis-related fatigue (ERF), health-related fitness, sleep quality, and health-related quality of life (HRQoL) in women with endometriosis in comparison with matched controls.

METHODS

Twenty-five affected women and twenty-five age and height-matched women without endometriosis were included. ERF was assessed through the Piper Fatigue Scale; health-related fitness was assessed through the Schöber, flamingo, and 6-min walking tests and dynamometry; and body composition was assessed through impedanciometry. Self-perceived physical fitness, sleep quality, and HRQoL were assessed through the International Fitness Scale, the Pittsburgh Sleep Quality Index, and the 12-item Short Form Health Survey, respectively.

RESULTS

Affected women exhibited higher levels of ERF than controls, increased fat mass, and physical deconditioning (reduced back strength, lumbar flexibility, body balance, and functional capacity, p-values < 0.050). Moreover, cases also had poorer perceived physical fitness, sleep quality, and HRQoL (p-value < 0.050). Finally, we observed deteriorated health-related fitness, sleep quality, and HRQoL in those women with endometriosis with higher levels of ERF.

CONCLUSIONS

This study constitutes the first evidence that women with endometriosis describe a generalized physical deconditioning, even more pronounced in affected women with higher levels of ERF. Further studies assessing the efficacy of rehabilitation interventions to face these physical impairments in women with endometriosis are warranted.

A Meta-Analysis of the Reliability of Four Field-Based Trunk Extension Endurance Tests

This meta-analysis aimed to estimate the inter- and intra-tester reliability of endurance measures obtained through trunk extension field-based tests and to explore the influence of the moderators on the reliability estimates. The reliability induction rate of trunk extension endurance measures was also calculated. A systematic search was conducted using various databases, and subsequently 28 studies were selected that reported intraclass correlation coefficients for trunk extension endurance measures. Separate meta-analyses were conducted using a random-effects model. When possible, analyses of potential moderator variables were carried out. The inter-tester average reliability of the endurance measure obtained from the Biering-Sorensen test was intraclass correlation coefficient (ICC) = 0.94. The intra-session reliability estimates of the endurance measures recorded using the Biering-Sorensen test, the prone isometric chest raise test, and the prone double straight-leg test were ICC = 0.88, 0.90, and 0.86, respectively. The inter-session average reliability of the endurance measures from the Biering-Sorensen test, the prone isometric chest raise test, and the dynamic extensor endurance test were ICC = 0.88, 0.95, and 0.99, respectively. However, due to the limited evidence available, the reliability estimates of the measures obtained through the prone isometric chest raise, prone double straight-leg, and dynamic extensor endurance tests should be considered with a degree of caution. Position control instruments, tools, and familiarization session demonstrated a statistical association with the inter-session reliability of the Biering-Sorensen test. The reliability induction rate was 72.8%. Only the trunk extension endurance measure obtained through the Biering-Sorensen test presented sufficient scientific evidence in terms of reliability to justify its use for research and practical purposes.

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.

Short-Term Training and Detraining Effects of Supervised vs. Unsupervised Resistance Exercise in Aging Adults

Orange, ST, Marshall, P, Madden, LA, and Vince, RV. Short-term training and detraining effects of supervised vs. unsupervised resistance exercise in aging adults. J Strength Cond Res 33(10): 2733-2742, 2019-This study compared the effects of a 4-week supervised (SUP) resistance training program and unsupervised (UNSUP) resistance training program followed by 12 weeks of detraining (DET). Thirty-six healthy aging adults (age: 53.6 ± 3.6 years; body mass index: 28.3 ± 5.1 kg·m) were randomly allocated to an SUP group (n = 17) or a UNSUP group (n = 19). Participants completed 3 training sessions per week using resistance bands and body weight movements. Measures of physical performance were administered at baseline, at the end of the training program, and after the DET period. Function was assessed with the 6-minute walk test (6MWT), timed up-and-go (TUG), 30-second chair sit-to-stand (STS), stair-climb test (SCT), 40-m fast-paced walk test (FPWT) and sit-and-reach test (SRT), whereas the isometric midthigh pull (IMTP) and hand grip test were used to measure muscle strength. After training, improvements in performance were found in the 6MWT, TUG, 30-second chair STS, SCT, FPWT, SRT, and IMTP (p ≤ 0.05), with no significant differences between groups (p > 0.05). In addition, most of the training-induced improvements remained significantly above baseline values after the DET period (p ≤ 0.05). No significant between-group differences were observed after training or DET (p > 0.05). Four weeks of either SUP or UNSUP resistance training is sufficient to substantially improve muscle strength and function in aging adults, and these gains are largely preserved after prescribed exercise cessation. Home-based resistance training seems to be a practical and effective alternative to traditional SUP programs that may help circumvent many barriers to physical activity in aging adults.

Electromyographic evaluation of trunk core muscles during Pilates exercise on different supporting bases

OBJECTIVE

To evaluate the electromyographic (EMG) activity of the rectus abdominis (RA) and internal oblique (IO) muscles during Pilates exercise on different trunk supporting bases.

METHODS

Sixteen female Pilates practitioners participated in the study. EMG of the RA and OI muscles was evaluated during the double leg stretch (DLS) exercise on three different supporting bases - mat, long box, and short box. Trunk stability varies according to the size and type of the base. To normalize the data, the RMS value (EMG) obtained during the DLS exercise was divided by the RMS value from the torque test - the maximal voluntary isometric contraction (MVIC) - and multiplied by 100 (%MVIC). One-way repeated-measured analysis of variance (ANOVA) and Bonferroni tests were used to compare data concerning the supporting bases and Student t-test regarding the muscles (p < 0.05).

RESULTS

The comparison among the bases involving each muscle - RA or IO (p < 0.05) - showed significant difference (%MVIC) between the mat and the short box. No significant difference was observed between the muscles concerning the exercise on the mat (p = 0.9266), on the long box (p = 0.5113) and on the short box (p = 0.2972).

CONCLUSION

The short box increased the activity of the rectus abdominis and internal oblique muscles during exercise. The DLS exercise was able to challenge the stability of the trunk and thus recruit its stabilizer and mobilizer muscles at the same intensity.

Reliability and validity of three isometric back extensor strength assessments with different test postures

Objective

To compare the test-retest reliability and validity of three simple maximal isometric back extensor strength (BES) assessment protocols with different test postures, and to recommend an optimal clinical protocol to quantify BES.

Methods

Asymptomatic adults, aged over 45 years, were assessed for maximal isometric BES using external fixation of dynamometers, with the subject in standing, prone and sitting positions, respectively. Measurements were repeated at a one-week interval to examine test-retest reliability. Validation was performed by comparing with results obtained from isokinetic dynamometer assessments.

Results

Out of a total of 60 included participants, intra-class correlation coefficients (ICC) were 0.92, 0.93 and 0.90 in standing, prone and sitting positions, respectively. Correlation analyses revealed acceptable convergent validity in the standing and prone position (r = 0.50 and 0.54, respectively), whereas tests conducted in the sitting position showed a relatively low validity (r = 0.32). Among the three protocols, measurement error was lowest in the prone position.

Conclusions

Maximal isometric BES assessment in the prone position was shown to be the most reliable and valid protocol, and may be considered the preferred option for assessing BES in clinical practice.

Reliability of isometric and isokinetic trunk flexor strength using a functional electromechanical dynamometer

Aim

To determine the absolute and relative reliability of functional trunk tests, using a functional electromechanical dynamometer to evaluate the isokinetic strength of trunk flexors and to determine the most reliable assessment condition, in order to compare the absolute and relative reliability of mean force and peak force of trunk flexors and to determine which isokinetic condition of evaluation is best related to the maximum isometric.

Methods

Test-retest of thirty-seven physically active male student volunteers who performed the different protocols, isometric contraction and the combination of three velocities (V₁ = 015 m s⁻¹ , V₂ = 0.30 m  s⁻¹, V₃ = 0.45 m s⁻¹) and two range of movement (R₁ = 25% cm ; R₂ = 50% cm) protocols.

Results

All protocols to evaluate trunk flexors showed an absolute reliability provided a stable repeatability for isometric and dynamic protocols with a coefficient of variation (CV) being below 10% and a high or very high relative reliability (0.69 < intraclass correlation coefficient [ICC] > 0.86). The more reliable strength manifestation (CV = 6.82%) to evaluate the concentric contraction of trunk flexors was mean force, with 0.15 m  s⁻¹ and short range of movement (V₁R₁) condition. The most reliable strength manifestation to evaluate the eccentric contraction of trunk flexors was peak force, with 0.15 m  s⁻¹ and a large range of movement (V₁R_2; CV = 5.07%), and the most reliable way to evaluate isometric trunk flexors was by peak force (CV = 7.72%). The mean force of eccentric trunk flexor strength with 0.45 m  s⁻¹ and short range of movement (V₃R₁) condition (r = 0.73) was best related to the maximum isometric contraction.

Conclusion

Functional electromechanical dynamometry is a reliable evaluation system for assessment of trunk flexor strength.

Trunk peak torque, muscle activation pattern and sudden loading compensation in adolescent athletes with back pain

OBJECTIVE

To evaluate trunk peak torque and muscle activation pattern during isokinetic and sudden trunk loading (STL) between adolescent athletes with/without back pain.

METHODS

Nine adolescent athletes with back pain (BP) (m/f 2/7; 15.6 ± 1.2 y; 177 ± 9 cm; 67 ± 13 kg; 22.5 ± 9.8 h/week) and nine matched controls (m/f 2/7; 15.7 ± 1.4 y; 177 ± 12 cm; 65 ± 9 kg; 16.5 ± 8.0 h/week training) were included. Trunk strength in rotation and flexion/extension was assessed. Sudden trunk loading was measured during eccentric extension and rotation (30∘/s) with additional perturbation. Trunk muscle activity was measured using a 12 lead-EMG (electromyography). Main outcome measures were peak torque [Nm] and MVC normalized EMG-amplitudes (RMS [%]) for each muscle. Additionally, the mean EMG-RMS for four areas of the trunk was calculated (right/left ventral, right/left dorsal).

RESULTS

Back pain showed lower trunk peak torque for all conditions in extension/flexion, but not for rotation. EMG amplitudes were increased for BP athletes with statistical significant differences for dorsal muscles in rotation and extension (p< 0.0042), not for ventral muscles in flexion.

CONCLUSIONS

The evaluation of strength and muscle activity in isokinetic and sudden trunk loading presents altered trunk function in adolescent back pain athletes. Training interventions focusing on trunk strength and muscular activation pattern appears reasonable.

Features of trunk muscle weakness in patients with ankylosing spondylitis: A cross-sectional study

BACKGROUND

Ankylosing spondylitis (AS) is an inflammatory autoimmune disorder that manifested with sacroiliitis at its early stage and developed extensive inflammation with syndesmophytes of the lumbar, thoracic and cervical spines at its later stage. In the present study, we characterized the trunk isometric strength in patients with AS with different disease severity, defined by the radiological images.

METHODS

In a cross-sectional study conducted in a university-affiliated hospital, thirty-eight male AS patients (23 in the early AS group whose radiological findings showed no syndesmophyte, Modified Stoke Ankylosing Spinal Score (m-SASSS <3); and 15 in the syndesmophyte group, m-SASSS ≥24), and 22 healthy controls were recruited. All subjects received assessments of maximum isometric strength of trunk flexor and extensor muscles at a variety of trunk postures measured by an isokinetic device.

RESULTS

Under all examined trunk postures, the syndesmophyte AS patient group had the lowest isometric trunk muscle strength among the three groups. The flexion/extension ratio, defined by the ratio between isometric trunk flexor and extensor strengths, was highest among the three groups.

CONCLUSIONS

Trunk muscle strength significantly decreases in patients with syndesmophyte AS. The decrease of trunk muscle is inhomogeneous, which is more profound in extensor than in flexor muscles.

Reliability and agreement of isometric functional trunk and isolated lumbar strength assessment in healthy persons and persons with chronic nonspecific low back pain

OBJECTIVES

to assess intra/inter-operator reliability and agreement of maximum isometric abdominal and back muscle strength in a functional trunk and isolated lumbar protocol, using an isokinetic dynamometer, in healthy persons and persons with chronic nonspecific low back pain (CNSLBP).

DESIGN

Test-retest.

SETTING

Participants performed two assessments consisting of two protocols on the Biodex 3 system, evaluating maximum isometric back and abdominal strength in a functional trunk and isolated lumbar position. During the first assessment, each protocol was executed twice, supported by different operators.

PARTICIPANTS

Healthy persons (n = 20) and persons with CNSLBP (n = 20).

MAIN OUTCOME MEASURES

Intraclass Correlation (ICC), Standard Error of Measurement (SEM and %SEM), and Minimal Detectable Change (MDC) of muscle strength outcomes and seat positioning characteristics were calculated.

RESULTS

Intra/inter reliability of muscle strength outcomes was excellent (ICC: 0.94-0.98), while seat positioning characteristics varied from low to high (ICC: 0-0.94). For muscle strength outcomes, %SEM ranged from 4.7 to 9.2% and MDC ranged from 14.3 to 29.8 Nm in trunk flexion and 39.1-68.5 Nm in trunk extension.

CONCLUSIONS

The Biodex 3 system can be used reliably to assess maximum isometric trunk muscle strength with the aforementioned protocols in healthy persons and persons with CNSLBP. All muscle strength outcomes showed comparable agreement (%SEM < 10%).

Assessment of chiropractic care on strength, balance, and endurance in active-duty U.S. military personnel with low back pain: a protocol for a randomized controlled trial

BACKGROUND

Low back pain (LBP) is a common cause of disability among U.S. military personnel. Approximately 20% of all diagnoses resulting in disability discharges are linked to back-related conditions. Because LBP can negatively influence trunk muscle strength, balance, and endurance, the military readiness of active-duty military personnel with LBP is potentially compromised. Chiropractic care may facilitate the strengthening of trunk muscles, the alteration of sensory and motor signaling, and a reduction in pain sensitivity, which may contribute to improving strength, balance, and endurance for individuals with LBP. This trial will assess the effects of chiropractic care on strength, balance, and endurance for active-duty military personnel with LBP.

METHODS/DESIGN

This randomized controlled trial will allocate 110 active-duty military service members aged 18-40 with non-surgical acute, subacute, or chronic LBP with pain severity of ≥2/10 within the past 24 h. All study procedures are conducted at a single military treatment facility within the continental United States. Participants are recruited through recruitment materials approved by the institutional review board, such as posters and flyers, as well as through provider referrals. Group assignment occurs through computer-generated random allocation to either the study intervention (chiropractic care) or the control group (waiting list) for a 4-week period. Chiropractic care consists primarily of spinal manipulation at a frequency and duration determined by a chiropractic practitioner. Strength, balance, and endurance outcomes are obtained at baseline and after 4 weeks. The primary outcome is a change between baseline and 4 weeks of peak isometric strength, which is measured by pulling on a bimanual handle in a semi-squat position. Secondary outcomes include balance time during a single-leg standing test and trunk muscle endurance with the Biering-Sorensen test. Patient-reported outcomes include pain severity, disability measured with the Roland Morris Disability Questionnaire, symptom bothersomeness, PROMIS-29, Fear Avoidance Beliefs Questionnaire, expectations of care, physical activity, and global improvement.

DISCUSSION

This trial may help inform further research on biological mechanisms related to manual therapies employed by chiropractic practitioners.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02670148 Registered on 1 February 2016.

Reliability of physical functioning tests in patients with low back pain: a systematic review

PURPOSE

The aim of this study was to provide a comprehensive overview of physical functioning tests in patients with low back pain (LBP) and to investigate their reliability.

DATA SOURCES

A systematic computerized search was finalized in four different databases on June 24, 2017: PubMed, Web of Science, Embase, and MEDLINE.

STUDY SELECTION

Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines were followed during all stages of this review. Clinical studies that investigate the reliability of physical functioning tests in patients with LBP were eligible. The methodological quality of the included studies was assessed with the use of the Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) checklist. To come to final conclusions on the reliability of the identified clinical tests, the current review assessed three factors, namely, outcome assessment, methodological quality, and consistency of description.

DATA SYNTHESIS

A total of 20 studies were found eligible and 38 clinical tests were identified. Good overall test-retest reliability was concluded for the extensor endurance test (intraclass correlation coefficient [ICC]=0.93-0.97), the flexor endurance test (ICC=0.90-0.97), the 5-minute walking test (ICC=0.89-0.99), the 50-ft walking test (ICC=0.76-0.96), the shuttle walk test (ICC=0.92-0.99), the sit-to-stand test (ICC=0.91-0.99), and the loaded forward reach test (ICC=0.74-0.98). For inter-rater reliability, only one test, namely, the Biering-Sörensen test (ICC=0.88-0.99), could be concluded to have an overall good inter-rater reliability. None of the identified clinical tests could be concluded to have a good intrarater reliability.

CONCLUSIONS

Further investigation should focus on a better overall study methodology and the use of identical protocols for the description of clinical tests. The assessment of reliability is only a first step in the recommendation process for the use of clinical tests. In future research, the identified clinical tests in the current review should be further investigated for validity. Only when these clinimetric properties of a clinical test have been thoroughly investigated can a final conclusion regarding the clinical and scientific use of the identified tests be made.

Reliability and Validity of a New Method for Isometric Back Extensor Strength Evaluation Using A Hand-Held Dynamometer

Objective

To investigate the reliability and validity of a new method for isometric back extensor strength measurement using a portable dynamometer.

Methods

A chair equipped with a small portable dynamometer was designed (Power Track II Commander Muscle Tester). A total of 15 men (mean age, 34.8±7.5 years) and 15 women (mean age, 33.1±5.5 years) with no current back problems or previous history of back surgery were recruited. Subjects were asked to push the back of the chair while seated, and their isometric back extensor strength was measured by the portable dynamometer. Test-retest reliability was assessed with intraclass correlation coefficient (ICC). For the validity assessment, isometric back extensor strength of all subjects was measured by a widely used physical performance evaluation instrument, BTE PrimusRS system. The limit of agreement (LoA) from the Bland-Altman plot was evaluated between two methods.

Results

The test-retest reliability was excellent (ICC=0.82; 95% confidence interval, 0.65–0.91). The Bland-Altman plots demonstrated acceptable agreement between the two methods: the lower 95% LoA was −63.1 N and the upper 95% LoA was 61.1 N.

Conclusion

This study shows that isometric back extensor strength measurement using a portable dynamometer has good reliability and validity.

Effectiveness of Lumbopelvic Exercise in Colon Cancer Survivors: A Randomized Controlled Clinical Trial

INTRODUCTION

This study evaluated the effectiveness of lumbopelvic exercise in improving health-related fitness, anthropometric measurements, and body composition in colon cancer survivors (CCS).

METHODS

Forty-six CCS (35% female, n = 14) were assigned to two groups for this randomized controlled clinical trial: a trunk muscle stabilization exercise program group (CO-CUIDATE) and a usual-care group. The CO-CUIDATE program was conducted for 8 wk (three times per week). The primary end point was isometric abdominal strength measured using the trunk curl test. The secondary end points used were isometric back strength, functional capacity, lower-body flexibility, weight, and anthropometric measurements evaluated at baseline, after the physical exercise program and after 6 months of follow-up. A trained member of the research group with 5 yr of experience working with cancer patients and who was blinded to the patient group assessed the variables. All physical tests were conducted with multiple observations.

RESULTS

The adherence to intervention was 88.36%, and two dropouts (10.5%) were recorded. Minor side effects, including discomfort with the exercises in the first sessions, were reported by the participants. ANOVA demonstrated significant differences in group-time interactions for isometric abdominal strength (F = 7.7; P = 0.001), functional capacity (F = 4.6; P = 0.015), lower-body flexibility (right, F = 4.3, P = 0.021 and left, F = 3.6, P = 0.034), and waist circumference (F = 5.7; P = 0.07), which were the best values for the CO-CUIDATE group. No significant changes in isometric back strength, weight, hip circumference or body composition were observed.

CONCLUSION

An 8-wk program based on stabilization exercises is a promising strategy to increase health-related fitness and to reduce waist circumference in CCS. An exercise program based on lumbopelvic exercise is a feasible intervention to improve the control of deep abdominal muscles and health-related fitness.

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.

Relationship between trunk function evaluated using the trunk righting test and physical function in patients with knee osteoarthritis

[Purpose] The present study was to validate the importance of the trunk function evaluated by trunk righting test (TRT) with motor function in patients with knee osteoarthritis (OA) and to show the clinical use of TRT. [Subjects and Methods] This study included 50 patients with knee osteoarthritis who underwent total knee arthroplasty in our hospital. Correlations between physical functional test, such as muscle strength, balance function, and performance and TRT were statistically evaluated. [Results] The independent factors for ipsilateral TRT were maximal isometric knee extensor strength test and ipsilateral step test. The operator and non-operator side TRT were significantly associated with TUG. [Conclusion] The results showed that the physical functions are correlated with the trunk function evaluated by TRT of patients with knee OA, suggesting that healthcare workers must take into consideration the trunk function, as well as lower extremity function to improve physical function.

Whole-body vibration training as a workplace-based sports activity for employees with chronic low-back pain

The goal of this randomized and controlled study was to examine whether whole-body vibration (WBV) training is able to reduce back pain and physical disability in seated working office employees with chronic low-back pain in a real-world setting. A total of 41 subjects (68.3% female/mean age 45.5±9.1 years/mean BMI 26.6±5.2) were randomly allocated to an intervention group (INT [n=21]) or a control group (CON [n=20]). The INT participated in WBV training 2.5 times per week for 3 months. The primary outcome was the change in the Roland and Morris disability questionnaire (RMQ) score over the study period. In addition, secondary outcomes included changes in the Oswestry Disability Index (ODI), the Work Ability Index Questionnaire, the quality of life questionnaire SF-36, the Freiburger activity questionnaire, and an isokinetic test of the musculature of the trunk. Compliance with the intervention in the INT reached a mean of 81.1%±31.2% with no long-lasting unwanted side effects. We found significant positive effects of 3 months of WBV training in the INT compared to the CON regarding the RMQ (P=.027), the ODI (P=.002), the SF-36 (P=.013), the Freiburger activity questionnaire (P=.022), the post-interventional sick-leave in the INT (P=.008), and trends regarding a positive effect of the intervention on the muscular capacity of the muscles of the trunk in flexion. WBV training seems to be an effective, safe, and suitable intervention for seated working employees with chronic low-back pain.

Pain and functional outcomes after outpatient physiotherapy in patients with low back pain

BACKGROUND

Physiotherapy treatment programs are recommended in the rehabilitation of low back pain (LBP). Rehabilitation institutions are increasingly asked to demonstrate the outcomes of their intensive physiotherapy services.

AIM

To describe pain and functional outcome measures following a 6-month outpatient physiotherapy treatment program in patients with LBP.

METHODS

A total of 85 patients were analysed after being treated with a combination of physiotherapeutic treatment modalities 2-3 days weekly. Pain and disability were measured before, 3 and 6 months after the onset of treatment. Isometric trunk muscle strength for flexion and extension and flexibility of dorsal trunk and thigh structures were measured before and 6 months after treatment.

RESULTS

After 6 months, pain at rest decreased from a median of 4.0 to 0.0 (p < 0.01) and pain during activity from a median of 5.5 to 2.0 on the numeric rating scale (p < 0.001). The Roland-Morris Disability (RMDQ) score decreased from a median of 7.0 to 3.0 (p < 0.001). Mean trunk muscle flexion strength increased from 133.7 to 156.0 Nm and for extension from 235.5 to 278.3 Nm (p < 0.001). Flexibility was improved from a mean of -5.9 to -1.4 cm (p < 0.001). A moderate correlation between pain at rest and RMDQ score was found after 3 (r = 0.532, p < 0.01) and 6 months (r = 0.508, p < 0.01).

CONCLUSIONS

Patients with LBP who were treated with the physiotherapeutic treatment program showed a clinically relevant reduction of pain and disability with improved trunk muscle strength and flexibility. Reductions in pain and disability do not seem to correlate with increased trunk muscle strength and flexibility. No conclusions can be declared about long-term changes after the intervention.

Validity and test-retest reliability of a novel simple back extensor muscle strength test

OBJECTIVES

To develop and determine convergent validity and reliability of a simple and inexpensive clinical test to quantify back extensor muscle strength.

METHODS

Two testing sessions were conducted, 7 days apart. Each session involved three trials of standing maximal isometric back extensor muscle strength using both the novel test and isokinetic dynamometry. Lumbar spine bone mineral density was examined by dual-energy X-ray absorptiometry. Validation was examined with Pearson correlations (r). Test-retest reliability was examined with intraclass correlation coefficients and limits of agreement. Pearson correlations and intraclass correlation coefficients are presented with corresponding 95% confidence intervals. Linear regression was used to examine the ability of peak back extensor muscle strength to predict indices of lumbar spine bone mineral density and strength.

RESULTS

A total of 52 healthy adults (26 men, 26 women) aged 46.4 ± 20.4 years were recruited from the community. A strong positive relationship was observed between peak back extensor strength from hand-held and isokinetic dynamometry (r = 0.824, p < 0.001). For the novel back extensor strength test, short- and long-term reliability was excellent (intraclass correlation coefficient = 0.983 (95% confidence interval, 0.971-0.990), p < 0.001 and intraclass correlation coefficient = 0.901 (95% confidence interval, 0.833-0.943), p < 0.001, respectively). Limits of agreement for short-term repeated back extensor strength measures with the novel back extensor strength protocol were -6.63 to 7.70 kg, with a mean bias of +0.71 kg. Back extensor strength predicted 11% of variance in lumbar spine bone mineral density (p < 0.05) and 9% of lumbar spine index of bone structural strength (p < 0.05).

CONCLUSION

Our novel hand-held dynamometer method to determine back extensor muscle strength is quick, relatively inexpensive, and reliable; demonstrates initial convergent validity in a healthy population; and is associated with bone mass at a clinically important site.

Rate of force development and muscle activation of trunk muscles in women with and without low back pain: A case-control study

OBJECTIVE

To evaluate the rate of force development (RFD) and the rate of electromyography rise (RER) of global and local trunk muscles in women with and without low back pain.

DESIGN

Cross-sectional study.

SETTING

Laboratory setting.

PARTICIPANTS

Twenty-eight women divided into low back pain (LBP, n = 14) and control groups (CG, n = 14) participated in this study.

MAIN OUTCOME MEASURES

Subjects performed isometric contractions of trunk using an isokinetic dynamometer, and simultaneously the electromyography (EMG) signals were collected for global (rectus abdominis and longissimus thoracic) and local (internal oblique and multifidus) muscles. All variables were calculated using Matlab software.

RESULTS

Symptomatic subjects showed lower RFD during trunk extension and it was correlated to a reduced RER mainly in the trunk extensor musculature (p < 0.05). During trunk flexion, LBP exhibited a delayed time to reach peak RFD (p < 0.05) compared to CG. RER for global anterior muscle was higher than for local muscle (p < 0.05) and it was more persistent in asymptomatic women. CG also presented greater activation amplitude for both agonist and antagonist trunk muscles, mainly the global ones.

CONCLUSION

Symptomatic women showed lower RFD and it was correlated to a reduced capacity of rapid muscle activation mainly in the trunk extensor musculature.

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.

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.

Telehealth system: A randomized controlled trial evaluating the impact of an internet-based exercise intervention on quality of life, pain, muscle strength, and fatigue in breast cancer survivors

BACKGROUND

The chronicity status of breast cancer survivors suggests a growing need for cancer rehabilitation. Currently, the use of technology is a promising strategy for providing support, as reflected in the emergence of research interest in Web-based interventions in cancer survivorship.

METHODS

A randomized controlled trial was conducted that included a total of 81 participants who had completed adjuvant therapy (except hormone treatment) for stage I to IIIA breast cancer. Participants were randomly assigned to an 8-week Internet-based, tailored exercise program (n = 40) or to a control group (n = 41).The instruments used at baseline, 8 weeks, and 6-month follow-up were the European Organization for Research and Treatment of Cancer Quality-of-Life Questionnaire Core 30 and its breast cancer module, the Brief Pain Inventory, the handgrip dynamometer, the isometric abdominal test, the back dynamometer, the multiple sit-to-stand test, and the Piper Fatigue Scale.

RESULTS

After the intervention, the telerehabilitation group had significantly improved scores for global health status, physical, role, cognitive functioning, and arm symptoms (all P < .01) as well as pain severity (P = .001) and pain interference (P = .045) compared with the control group. Significant improvements also were observed favoring the telerehabilitation group for affected and nonaffected side handgrip (both P = .006), abdominal, back and lower body strength (all P < .01), and total fatigue (P < .001). These findings were maintained after 6 months of follow-up, except for role functioning, pain severity, and nonaffected side handgrip. Analysis was based on an intention-to-treat principle.

CONCLUSIONS

This program may improve adverse effects and maintain benefits in breast cancer survivors. The results of this study have encouraging implications for cancer care. Cancer 2016;122:3166-74. © 2016 American Cancer Society.

Effects of a 16-week Pilates exercises training program for isometric trunk extension and flexion strength

OBJECTIVE

To evaluate the effects of Pilates exercises designed to improve isometric trunk extension and flexion strength of muscles in women with chronic low back pain (cLBP).

PARTICIPANTS

Female volunteers with cLBP were divided into an experimental group (EG; n = 27) and a control group (CG; n = 27).

INTERVENTION

Pilates exercises were performed twice per week by the EG; the duration of each session was 60 min. The program lasted for 16 weeks; thus patients underwent a total of 32 exercise sessions.

RESULTS

The maximum isometric waist bending strength of the EG had improved significantly (p = 0.001) after 16 weeks of the Pilates program. The results of trunk flexion muscle endurance tests significantly depended on the trunk extension muscle endurance before the intervention, and at 1 month (r = 0.723, p < 0.001) and 2 months (r = 0.779, p < 0.001) after the Pilates exercise program. At the end of the 16-week exercise program, cLBP intensity decreased by 2.01 ± 0.8 (p < 0.05) in the EG, and this reduction persisted for 1 month after completion of the program.

CONCLUSIONS

At 1 and 2 months after cessation of the Pilates exercise program the pain intensified and the functional state deteriorated much faster than the maximum trunk muscle strength. Therefore, it can be concluded that, to decrease pain and improve functional condition, regular exercise (and not only improved strength and endurance) is required. We established that, although the 16-week lumbar stabilization exercise program increased isometric trunk extension and flexion strength and this increase in strength persisted for 2 months, decreased LBP and improved functional condition endured for only 1 month.

Reliability of the endurance test for the erector spinae muscle

Abstract Introduction: The low resistance of the erector spinae has been seen as a risk factor for developing chronic low back pain. The test of the erector spinae muscle endurance advocated by Biering-Sorensen has been used to assess the strength of the erector spinae muscle. Modifications of the measuring instrument require reliability studies. Objective: To evaluate the measurement of the erector spinae muscle endurance and the standard error of measurement (SEM) of the modified Biering-Sorensen test of erector spinae in women with chronic low back pain. Methods: Forty-eight sedentary women, aged 52 ±7, suffering from chronic low back pain, were tested. The position adopted was the prone position without the trunk on the examining table. Fixations were performed with straps at the ankles, knees and pelvis. The patient was instructed to maintain the shoulder blades in contact with the stadiometer as long as possible. The measurement was repeated, with measures 15 minutes apart. Results: Considering the confidence limits of Bland & Altman, - 40 and 68 seconds, the SEM was13 seconds and SEM% was 22. The ICC = 0.87 with p = 0.001. The first test was equal to 54 ± 36 seconds, and the retest = 67 ± 40 seconds. Conclusion: The endurance test of the erector spinae showed moderate reliability. Therefore, we suggest that, despite its applicability in clinical practice, the results should be interpreted carefully because the differences in mean erector spinae endurance of up to 13 seconds may be related to measurement error.

Reliability of ultrasound imaging for the assessment of lumbar multifidi thickness in older adults with chronic low back pain

BACKGROUND AND PURPOSE

Ultrasound imaging (USI) has been shown to be a reliable measure for direct assessment of the lumbar multifidi among younger adults. However, given age- and chronic low back pain (CLBP)-related spinal changes, similar studies are needed before clinical use of USI among older adults with CLBP. The goals of this study were to evaluate intra- and interexaminer reliability for USI assessment of multifidi thickness at rest and during a contraction and to determine standard error of measurement values (SEMs) and minimal detectable change values (MDCs) among older adults with CLBP.

METHODS

Thirty-one adults, aged 60 to 85 years, with CLBP were recruited. Two examiners performed USI assessments of multifidus thickness at rest and during a contralateral lower extremity lift. Intraclass correlation coefficients (ICCs) were used to estimate inter- and intraexaminer reliability. Additionally, SEMs and MDCs were calculated.

RESULTS

All USI measurement techniques demonstrated excellent within-day, interexaminer procedural reliability (ICCs: 0.82-0.85) and good-to-excellent between-day, interexaminer procedural reliability (ICCs: 0.72-0.79). The SEMs ranged from 0.36 to 0.46 cm; MDCs ranged from 1.01 to 1.26 cm. Regardless of the measurement technique, examiner 1, the more experienced examiner, demonstrated lower SEMs and MDCs than examiner 2.

DISCUSSION

Lower ICCs, greater SEMs, and greater MDCs for USI multifidus thickness assessment in older adults with CLBP, when compared with previously published, procedural reliability results for younger adults with and without low back pain, may indicate that imaging is more challenging in this patient population. Factors, such as examiner training and participant anthropometrics, may impact reliability.

CONCLUSIONS

Good-to-excellent intra- and interexaminer USI procedural reliability may provide clinicians a direct assessment technique for clinical evaluation of the lumbar multifidi in older adults with CLBP. SEMs and MDCs may allow for accurate interpretation of USI assessments in this population.

mDurance: A Novel Mobile Health System to Support Trunk Endurance Assessment

Low back pain is the most prevalent musculoskeletal condition. This disorder constitutes one of the most common causes of disability worldwide, and as a result, it has a severe socioeconomic impact. Endurance tests are normally considered in low back pain rehabilitation practice to assess the muscle status. However, traditional procedures to evaluate these tests suffer from practical limitations, which potentially lead to inaccurate diagnoses. The use of digital technologies is considered here to facilitate the task of the expert and to increase the reliability and interpretability of the endurance tests. This work presents mDurance, a novel mobile health system aimed at supporting specialists in the functional assessment of trunk endurance by using wearable and mobile devices. The system employs a wearable inertial sensor to track the patient trunk posture, while portable electromyography sensors are used to seamlessly measure the electrical activity produced by the trunk muscles. The information registered by the sensors is processed and managed by a mobile application that facilitates the expert's normal routine, while reducing the impact of human errors and expediting the analysis of the test results. In order to show the potential of the mDurance system, a case study has been conducted. The results of this study prove the reliability of mDurance and further demonstrate that practitioners are certainly interested in the regular use of a system of this nature.

Characteristics of Back Muscle Strength in Patients with Scheduled for Lumbar Fusion Surgery due to Symptomatic Lumbar Degenerative Diseases

Study Design

Cross sectional study.

Purpose

To evaluate characteristics of back muscle strength in patients scheduled for lumbar fusion surgery.

Overview of Literature

Little is known regarding muscle strength in patients with symptomatic lumbar degenerative diseases who require fusion surgery.

Methods

Consecutive 354 patients scheduled for posterior lumbar interbody fusion due to symptomatic degenerative diseases were approached for participation. 316 patients were enrolled. Before surgery, muscle strength was assessed by measuring maximal isometric extension strength at seven angular positions (0°, 12°, 24°, 36°, 48°, 60°, and 72°) and mean isometric strength was calculated. The Oswestry Disability Index (0-100) and visual analogue scale (0-100) for back pain were recorded. Muscle strength was compared according to gender, age (<60, 60-70, and ≥70 years) and scheduled fusion level (short, <3; long, ≥3).

Results

Isometric strength was significantly decreased compared with previously reported results of healthy individuals, particularly at extension positions (0°-48°, p<0.05). Mean isometric strength was significantly lower in females (p<0.001) and older patients (p<0.05). Differences of isometric strength between short and long level fusion were not significantly different (p>0.05). Isometric strengths showed significant, but weak, inverse correlations with age and Oswestry Disability Index (r<0.4, p<0.05).

Conclusions

In patients with symptomatic lumbar degenerative diseases, back muscle strength significantly decreased, particularly at lumbar extension positions, and in females and older patients.

Whole body vibration exercise for chronic low back pain: study protocol for a single-blind randomized controlled trial

Background

Low back pain affects approximately 80% of people at some stage in their lives. Exercise therapy is the most widely used nonsurgical intervention for low back pain in practice guidelines. Whole body vibration exercise is becoming increasingly popular for relieving musculoskeletal pain and improving health-related quality of life. However, the efficacy of whole body vibration exercise for low back pain is not without dispute. This study aims to estimate the effect of whole body vibration exercise for chronic low back pain.

Methods/Design

We will conduct a prospective, single-blind, randomized controlled trial of 120 patients with chronic low back pain. Patients will be randomly assigned into an intervention group and a control group. The intervention group will participate in whole body vibration exercise twice a week for 3 months. The control group will receive general exercise twice a week for 3 months. Primary outcome measures will be the visual analog scale for pain, the Oswestry Disability Index and adverse events. The secondary outcome measures will include muscle strength and endurance of spine, trunk proprioception, transversus abdominis activation capacity, and quality of life. We will conduct intention-to-treat analysis if any participants withdraw from the trial.

Discussion

Important features of this study include the randomization procedures, single-blind, large sample size, and a standardized protocol for whole body vibration in chronic low back pain. This study aims to determine whether whole body vibration exercise produces more beneficial effects than general exercise for chronic low back pain. Therefore, our results will be useful for patients with chronic low back pain as well as for medical staff and health-care decision makers.

Trial registration

Chinese Clinical Trial Registry: ChiCTR-TRC-13003708.