Does change in isolated lumbar extensor muscle function correlate with good clinical outcome? A secondary analysis of data on change in isolated lumbar extension strength, pain, and disability in chronic low back pain

Reliability of a Trunk Flexion and Extensor Muscle Strength Test with Hand-Held and Isokinetic Dynamometers in Female Athletes

An accurate trunk muscle strength assessment seems very important to design and individualize training and rehabilitation programs in clinical and sport settings. Hand-held dynamometers (HHDs) are interesting alternatives to isokinetic dynamometers for assessing trunk isometric muscle strength because they are inexpensive instruments and easy to use. This cross-sectional observational study aimed to examine the reliability of two novel sitting tests for assessing trunk flexion and extension isometric strength using an HHD and their relationship with two other novel isometric tests that use an isokinetic dynamometer. Twenty-four female amateur athletes (age: 24.5 ± 2.64 years; body height: 164.45 ± 6.33 cm; body mass: 63.17 ± 10.35 kg) participated in this study. A test-retest design was carried out one-week apart to examine the reliability. The relationship and the degree of agreement between the HHD and the isokinetic dynamometer measurements were analysed using Pearson correlation and Bland-Altman analysis, respectively. In general, the reliability of all isometric strength tests was good, with ICCs ranging from 0.65 to 0.87 and typical error < 15%. Pearson correlations were moderate, with values of r = 0.47 (R2 = 0.22) and r = 0.42 (R2 = 0.18) for flexion and extension strength, respectively. Bland-Altman plots showed no agreement between HHDs and isokinetic measurements. All trunk isometric tests using both, an isokinetic dynamometer and HHDs, provide reliable measurements for assessing trunk flexion and extension strength. According to the comparative analysis, both measurement types are different and cannot be used interchangeably. Health and sport professionals should choose the test that best suits the biomechanical characteristics required for functional goals or success in a given sport.

Do Improved Trunk Mobility and Isometric Strength Correlate with Improved Pain and Disability after Multimodal Rehabilitation for Low Back Pain?

Objective  To determine the correlation between posttreatment trunk range of motion (ROM) and isometric strength (TIS) and pain and disability in patients who underwent multimodal rehabilitation for low back pain (LBP). Methods  In this prospective cohort study, 122 patients undergoing multimodal rehabilitation for LBP were analyzed. The pre- and posttreatment numerical pain rating scale (NPRS) and the Oswestry disability index (ODI) scores, as well as trunk ROM and TIS were compared. The Pearson correlation was used to determine correlation between posttreatment clinical outcomes and ROM and TIS. Results  At the end of treatment, the mean NPRS ( p  < 0.0001) and ODI ( p  < 0.0001) scores, mean trunk extension ( p  < 0.0001), and flexion ( p  < 0.0001) ROMs improved significantly. Similarly, posttreatment, the mean extension ( p  < 0.0001) and flexion ( p  < 0.0001) TISs improved significantly. There was a weak correlation between the NPRS score and ROM extension (r = -0.24, p  = 0.006) and flexion strength (r = -0.28, p  = 0.001), as well as between the ODI score and TIS extension (r = -0.30, p  = 0.0007) and flexion (r = -0.28, p  = 0.001). Conclusion  Despite significant improvement in pain, disability, trunk ROM, and TIS with multimodal treatment, there was a weak correlation between posttreatment pain and function and trunk ROM and TIS. Improvement in pain and function with physical rehabilitation treatment for LBP is a complex phenomenon and needs further investigation.

Rehabilitation therapy using the HUBER platform in chronic non-specific low back pain: a randomized controlled trial

BACKGROUND

Non-specific chronic low back pain (NSCLBP) refers to a complex condition that involves structural, biomechanical, cognitive, psychological, social, and lifestyle issues. First-line therapies include physical therapy and exercise, as well as psychological follow-up and pain medication.

AIM

The aim of this study was to assess the impact of a 6-week center-based program using a multi-axis motorized platform (HUBER) connected with force sensors, that allows the patients to execute isometric exercises on the spine flexion-to-extension ratio at 60 and 120°/s, pain, trunk flexibility, and disability.

DESIGN

The design of the study was prospective, active control, parallel-group, assessor-blinded, randomized controlled trial.

SETTING

The setting was outpatients physical therapy clinic.

POPULATION

The population analyzed presented NSCLBP.

METHODS

Seventy individuals with NSCLBP were randomized into 2 intervention arms (1:1 ratio): 1/standard rehabilitation group (STAND) with physiotherapy, balneotherapy and cycloergometer exercises and 2/HUBER rehabilitation group (HUB) with physiotherapy, balneotherapy and HUBER exercises. Both programs lasted 6 weeks, with 4 sessions of 2 hours each per week.

RESULTS

Each group reported statistically significant improvements on the isokinetic spine strength, flexibility of the trunk, lumbar joint mobility, muscular endurance of the trunk and of the lower limbs, pain score and disability (P<0.05). The spine flexion/extension ratio at 60˚/s improved similarly between groups (-22.23 for HUB, and -13.04 for STAND; P=0.178) with a greater effect size in HUB. Only HUB reported a significant improvement in the spine flexion-to-extension ratio at 120˚/s (from 87.3 to 78.6, P=0.012). HUB reported a greater decrease in the Oswestry Disability Index (-16.83) compared to STAND (-12.11), with a statistically significant effect between groups (P=0.036).

CONCLUSIONS

Exercises performed on the HUBER platform added to physiotherapy and balneotherapy are as effective as a standard rehabilitation program with physiotherapy, balneotherapy and cycloergometer exercises to improve isokinetic spine strength, lumbar joint mobility, flexibility and muscular endurance of the trunk and the lower limbs. In addition, exercising with the HUBER platform result in a greater reduction in disability compared to a standard rehabilitation program (clinicalTrials.gov: NCT05437016).

CLINICAL REHABILITATION IMPACT

A variety of intervention techniques, including supervised exercise and manual therapy are now used to manage persistent NSCLBP. The added value of the HUBER device on disability suggests that the platform could be beneficial.

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.

Reliability and criterion validity of handheld dynamometry for measuring trunk muscle strength in people with and without chronic non-specific low back pain

BACKGROUND

Evaluating trunk strength is an important aspect of the physical examination of people with low back pain (LBP). Thus, reliable, valid, and easily applied measurement tools are needed to quantify trunk muscle strength and monitor changes in response to interventions.

OBJECTIVES

To determine within-day and between-day test re-test reliability and criterion validity of a handheld dynamometer (HHD) to evaluate maximum isometric trunk strength in people with chronic LBP and asymptomatic individuals.

DESIGN

Reliability and criterion validity study.

METHODS

Twenty adult participants with chronic, non-specific LBP and 35 asymptomatic individuals participated. Isometric trunk flexion, extension, and rotation strength were evaluated with the HHD (Active force 2) and the within-day and between-day reliability were determined with intraclass correlation coefficients (ICC2,1) and the standard error of the measurements (SEM), minimal detectable change (MDC), and the limits of agreement (LOA) using Bland-Altman plots. Criterion validity was evaluated using Pearson correlation coefficients to compare HHD measurements to isokinetic dynamometry for both isometric trunk flexion and extension strength.

RESULTS

Good to excellent within-day and between-day reliability was observed for people with LBP and asymptomatic individuals with (ICC2,1) of 0.73-0.93 and 0.62-0.92 respectively. A moderate to strong correlation was found between measurements with the HHD and the isokinetic dynamometer with a correlation of r = 0.68-0.78 and r = 0.56-0.59 for people with LBP and asymptomatic participants respectively.

CONCLUSION

A HHD is a reliable, valid, and clinically applicable tool for the measurement of trunk strength in adults with and without chronic LBP.

Is assessing trunk muscle endurance in military with sub-acute and chronic low back pain clinically meaningful?

Introduction

Trunk muscle endurance (TME) tests are commonly used by clinicians to assess muscle performance changes in response to rehabilitation in patients with low back pain (LBP). The aim of this study was to assess the responsiveness of three TME-tests in patients with LBP and to evaluate the relationships between changes in TME and improvement in self-reported function.

Materials and Methods

Eighty-four LBP patients were evaluated at baseline and after completion of a 6-week training program. Function was assessed with the modified Oswestry Disability Index (ODI) while TME was estimated using three tests: (1) the Biering-Sørensen, (2) the side bridge endurance tests (both sides), and (3) the trunk flexor endurance test. The standardized response mean (SRM) and the minimal clinical important difference (MCID) for each TME-test, and the relationships between changes in TME and improvement in ODI were calculated.

Results

SRMs were small to large for TME-tests (range: 0.43-0.82), and large for the ODI (2.85) and no clinically useful MCID was identified for the TME-tests (area under the curve below 0.70). No significant correlations were found between changes in the TME and change in ODI scores (r < 0.15; all P > 0.05).

Conclusion

Our results show a weak responsiveness of TME-tests in patients with LBP. There was no association between endurance performance change and self-reported functional change. TME-tests may not be a key component of rehabilitation monitoring in patients with LBP.

Lumbar Kinematics Assessment of Patients with Chronic Low Back Pain in Three Bridge Tests Using Miniaturized Sensors

Lumbar muscle atrophy, diminished strength, stamina, and increased fatigability have been associated with chronic nonspecific low back pain (LBP). When evaluating patients with LBP, trunk or core stability, provided by the performance and coordination of trunk muscles, appears to be essential. Several clinical tests have been developed to identify deficiencies in trunk performance, demonstrating high levels of validity and reproducibility. The most frequently prescribed tests for assessing the core body muscles are the prone plank bridge test (PBT), the side bridge test (SBT), and the supine bridge test (SUBT). However, quantitative assessments of the kinematics of the lumbar spine during their execution have not yet been conducted. The purpose of our study was to provide objective biomechanical data for the assessment of LBP patients. The lumbar spine ranges of motion of 22 healthy subjects (Group A) and 25 patients diagnosed with chronic LBP (Group B) were measured using two inertial measurement units during the execution of the PBT, SUBT, and SBT. Statistically significant differences between the two groups were found in all three tests' kinematic patterns. This quantitative assessment of lumbar spine motion transforms the three bridge tests into an objective biomechanical diagnostic tool for LPBs that may be used to assess the efficacy of applied rehabilitation programs.

Fascial manipulation and its application for low back pain treatment

Low back pain is one of the most common musculosceletal disorder and it has multifactorial etiology. It is considered to be the leading cause of global disability. It is the most frequent cause of activity limitation that can, eventually, result in disability, decreased quality of life, and work absenteeism. Low back pain manifests in different forms - acute, subacute and chronic. Within clinical examination it is a collected anamnesis, a general examination and functional testing from each patient. The importance of physical activity in the treatment of low back pain is generally accepted. However, an increase in physical activity has been suggested to be both a preventive factor and a possible risk factor for low back pain. There is an evidence for an association between high physical workloads and back injury. Treatment of low back pain includes many different types of exercises and physical therapy. Fascial manipulations has showed a great effectiveness in the treatment of low back pain in the general population, but also among the athletes.

Adherence and Effect of Home-Based Rehabilitation with Telemonitoring Support in Patients with Chronic Non-Specific Low Back Pain: A Pilot Study

Home-based exercises have been on the rise recently. This pilot study aimed to assess the adherence and effect of a home-based rehabilitation programme using telemonitoring in patients with chronic non-specific low back pain (CNLBP). Twenty-seven patients with CNLBP were enrolled in the study, each of whom underwent a neurological assessment, including patient-oriented measures and a functional assessment-a battery of tests that comprehensively evaluated trunk muscle function. The rehabilitation programme lasted 18 weeks and included daily home-based exercises. A mobile application or an exercise diary was used to monitor compliance. Adherence to the programme was excellent for both the diary and mobile application groups, with 82.3% in the diary group exercising at least once a day and 72.9% twice a day, and 94.8% in the mobile application group exercising at least once a day and 86.6% twice a day. Both patient-oriented and functional outcomes improved significantly; however, the relative changes of the parameters in these two groups did not correlate, which supports the idea that trunk muscle function does not directly relate to patient complaints and that CNLBP is a multifactorial issue. This model of rehabilitation programme should be used in clinical practice, as its adherence and effectiveness seem noticeable.

Synergistic Effect of Increased Total Protein Intake and Strength Training on Muscle Strength: A Dose-Response Meta-analysis of Randomized Controlled Trials

Background

Protein supplementation augments muscle strength gain during resistance training. Although some studies focus on the dose-response relationship of total protein intake to muscle mass or strength, the detailed dose-response relationship between total protein intake and muscle strength increase is yet to be clarified, especially in the absence of resistance training.

Objective

We aimed to assess the detailed dose-response relationship between protein supplementation and muscle strength, with and without resistance training.

Design

Systematic review with meta-analysis.

Data Sources

PubMed and Ichushi-Web (last accessed on March 23, 2022).

Eligibility Criteria

Randomized controlled trials investigating the effects of protein intake on muscle strength.

Synthesis Methods

A random-effects model and a spline model.

Results

A total of 82 articles were obtained for meta-analyses, and data from 69 articles were used to create spline curves. Muscle strength increase was significantly augmented only with resistance training (MD 2.01%, 95% CI 1.09–2.93) and was not augmented if resistance training was absent (MD 0.13%, 95% CI − 1.53 to 1.79). In the dose-response analysis using a spline model, muscle strength increase with resistance training showed a dose-dependent positive association with total protein intake, which is 0.72% (95% CI 0.40–1.04%) increase in muscle strength per 0.1 g/kg body weight [BW]/d increase in total protein intake up to 1.5 g/kg BW/d, but no further gains were observed thereafter.

Conclusion

Concurrent use of resistance training is essential for protein supplementation to improve muscle strength. This study indicates that 1.5 g/kg BW/d may be the most appropriate amount of total protein intake for maintaining and augmenting muscle strength along with resistance training.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40798-022-00508-w.

Effectiveness of resisted training through translation of the pelvis in chronic low back pain

BACKGROUND

Resisted training of the trunk muscles improves outcomes in chronic low back pain (CLBP). The Itensic b-effect machine was designed to provide resisted training through posterior translation of the pelvis in a seated, forward-tilted position, in contrast with traditional machines that involve extension of the trunk.

OBJECTIVE

To study the effectiveness of lumbopelvic training on the Itensic b-effect machine in individuals with CLBP.

METHODS

Participants were allocated to 4 weeks of either progressive Itensic (I) training in addition to an education/exercise (EE) program (I+EE group, n= 23) or the education/exercise program alone (EE group, n= 22).

PRIMARY OUTCOME

Roland Morris Disability Questionnaire (RMDQ).

SECONDARY OUTCOMES

pain (0-10 numeric rating scale), trunk extensor endurance (Sorensen test), motor control (thoraco-lumbar dissociation test) and mobility (finger-to-floor test).

RESULTS

RMDQ score improved more in the I+EE group than in the EE group (with a between-group difference at the pos-test). Pain and mobility improved in the I+EE group only, motor control improved in both groups with no between-group difference and the Sorensen test did not improve significantly in either group.

CONCLUSIONS

Resisted posterior pelvic translation using the Itensic machine in addition to an education/exercise program improved disability, pain and mobility more than the education/exercise program alone.

Effects of an Intensive 6-Week Rehabilitation Program with the HUBER Platform in the Treatment of Non-Specific Chronic Low Back Pain: A Pilot Study

Non-specific chronic low back pain (NSCLBP) is defined as a complex disorder involving structural, biomechanical, cognitive, psychological, social, and lifestyle factors. Non-pharmacological approaches such as exercise and physical therapy have been proposed in first-line treatments, along with psychological follow-up and pain medication if needed. Our objective was to evaluate the effectiveness of an intensive rehabilitation program with HUBER (a multi-axis motorized platform equipped with force sensors, allowing patients to perform physical exercises in an isometric mode) on the spine flexion-to-extension ratio at 60 and 120°/s, pain, and trunk flexibility in individuals with NSCLBP. Twelve participants underwent a clinical evaluation including isokinetic spine strength and participated in a 6-week rehabilitation program with HUBER 360 Evolution. The main findings of this pilot study show that the flexor/extensor ratios at 60°, the flexibility of the hamstring and quadriceps, and muscular endurance of the trunk, disability, and quality of life were significantly improved at the end of the rehabilitation program (p < 0.05). Low back pain and analgesic medication were also reduced. Exercising with the HUBER Platform seems to be effective in managing NSCLBP but a randomized study with a larger sample size and a control group is necessary.

Changes in the International Classification of Functioning, Disability, and Health Components "Activity/Participation" as Predicted Through Patient-Reported Outcomes Along With Comprehensive Back Pain Rehabilitation

OBJECTIVES

The World Health Organization (WHO) recommended the International Classification of Functioning, Disability and Health (ICF) but its use in clinical practice is sparse. This study investigated the limitations and restrictions in the most relevant brief ICF core set categories for chronic low back pain (cLBP) as automatically predicted from routinely measured outcomes using a novel, validated mapping algorithm.

MATERIALS AND METHODS

Of 2718 cLBP patients recruited, data from 1541 (64% females) were available from before and at the end of 6 months comprehensive outpatient rehabilitation. Assessments included the Roland Morris Disability Questionnaire (RMDQ) and Pain Disability Index (PDI) questionnaires, the percentage of patients with predicted limitations and restrictions in important activity and participation ICF categories, bodily functional measurements, pain intensity, and anxiety/depression (EQ-5D).

RESULTS

At baseline, both the RMDQ and the PDI measures were within the third of the lowest disability scores whilst 80% of the patients had limitations with "maintaining a body position" and 30% with "walking" ICF categories. Intervention-associated gains in the maximum isometric lumbar extension and flexion strength and the lumbar range of motion were significant overall, but improvements in patients' ICF limitations/restrictions varied. Anxiety/depression, lumbar range of motion, and extension strength all had a significant impact on the majority of the ICF categories, whereas flexion strength had none.

DISCUSSION

The rate of patients with predicted limitations/restrictions in activity/participation ICF core categories for cLBP partly mirrored disability levels and the impact of the body function scores on these limitations/restrictions in ICF categories was varied. Thus, assessing problems in the ICF activity/participation core categories is of relevance to clinical practice for both treatment goal setting and intervention planning. This may be achieved by computer-generated mapping without additional time burden.

Assessment of Lumbar Extensor Muscles in the Context of Trunk Function, a Pilot Study in Healthy Individuals

A comprehensive assessment of trunk function, including the lumbar extensor muscles, appears to be important in various conditions affecting axial musculature. This pilot cross-sectional observational study aimed to define a battery of tests that comprehensively assess trunk muscle function (strength and muscular endurance). Sixty subjects without low back pain (LBP) underwent measurement of isometric lower back extensor strength using a hand-held dynamometer (HHD) in three positions; measurement of respiratory muscle strength; and Biering-Sørensen, prone-plank, and side-bridge tests. The repeatability, short-term and long-term reliability using the HHD device in different postural positions was confirmed. The greatest isometric lower back extensor strength was generated in the sitting position by male subjects. Time of effort in the Biering-Sørensen test was longer in women and older subgroups than in men and younger individuals, although this was not the case for the other two muscular endurance tests. This pilot monitoring of trunk muscle strength and endurance in healthy volunteers may lead to a better understanding of trunk muscle function. Based on this methodological background, the authors aim to use the defined battery of tests in their further studies in a group of patients with LBP and certain neuromuscular diseases to verify its usefulness in clinical practice.

Motor performance and back pain in children and adolescents: A systematic review

BACKGROUND AND OBJECTIVE

Motor performance during childhood and adolescence is recognized as a relevant determinant of present and future health, but its effects on back pain (BP) remain unclear. In this systematic review, we aimed to identify the association between motor performance and BP in children and adolescents.

DATABASES AND DATA TREATMENT

A literature search was performed in the MEDLINE, Scopus, Embase, SPORTDiscus and CINAHL databases. We included cross-sectional, cohort, case-control and controlled clinical trials (data from control groups). The inclusion criteria were as follows: (a) participants aged 6-19 years; (b) assessment motor performance components; (c) assessment of BP and (d) reported measures of association. The risk of bias was assessed by the Downs and Black instrument and the quality of evidence by the grading of recommendations, assessment, development and evaluation (GRADE).

RESULTS

A total of 2360 articles were identified, 25 of which were included in our systematic review. Of the 25 studies, 19 were evaluated as having a low risk of bias. GRADE indicated that 20 studies presented low or very low quality. Most of the studies evaluated flexibility (n = 16), muscle endurance (n = 18) and muscle strength (n = 9). Aerobic capacity, balance and speed were also examined in some studies (n < 5). Overall, motor performance (flexibility, muscle endurance, muscle strength, aerobic capacity, balance and speed) was not associated with BP. Most of the results were inconsistent because of the lack of studies, risk of bias and low quality of evidence. Only trunk extensor muscle endurance was associated with decreased BP with moderate quality of the supporting evidence. Prospective studies with a low risk of bias are warranted to further clarify this relationship in childhood and adolescence and findings may support more targeted and effective health promotion interventions.

SIGNIFICANCE

This systematic review shows that motor performance (flexibility, muscle endurance, muscle strength, aerobic capacity, balance and speed) was not associated with BP in children and adolescents. Most of the results were inconsistent because of the lack of studies, risk of bias and low quality of evidence. Only trunk extensor muscle endurance was associated with decreased BP with moderate quality of supporting evidence.

Exposure to Sustained Flexion Impacts Lumbar Extensor Spinae Muscle Fiber Orientation

The lumbar extensor spinae (LES) has an oblique orientation with respect to the compressive axis of the lumbar spine, allowing it to counteract anterior shear forces. This mechanical advantage is lost as spine flexion angle increases. The LES orientation can also alter over time as obliquity decreases with age and is associated with decreased strength and low back pain. However, it is unknown if LES orientation is impacted by recent exposures causing adaptations over shorter timescales. Hence, the effects of a 10-minute sustained spine flexion exposure on LES orientation, thickness, and activity were investigated. Three different submaximally flexed spine postures were observed before and after the exposure. At baseline, orientation (P < .001) and thickness (P = .004) decreased with increasingly flexed postures. After the exposure, obliquity further decreased at low (pairwise comparison P < .001) and moderately (pairwise comparison P = .008) flexed postures. Low back creep occurred, but LES thickness did not change, indicating that decreases in orientation were not solely due to changes in muscle length at a given posture. Activation did not change to counteract decreases in obliquity. These changes encompass a reduced ability to offset anterior shear forces, thus increasing the potential risk of anterior shear-related injury or pain after low back creep-generating exposures.

Comparing the effects of aquatic exercises with or without high intensity on the functional status, muscular endurance, and performance of patients with chronic low back pain

BACKGROUND

The prevalence of low back pain is lower when physical fitness (aerobic and muscular) is higher. Strength exercises are important for subjects with low back pain, but there are few studies on the inclusion of aerobic exercise in low back pain programs. The aim of this study was to compare the effects of aquatic exercises with or without high-intensity component on the functional status, lumbar and abdominal muscle endurance, and performance of subjects with chronic low back pain.

METHODS

Forty-eight volunteers between 20 and 60 years old were randomly allocated to an experimental group AEDWR (aquatic exercises plus deep-water running group, N.=25) or to a control group AE (aquatic exercises only group, N.=23). The dependent variables included functional status (Repeated Sit-to-Stand test), lumbar (Sorensen test) and abdominal (One Minute Abdominal test) muscle endurance, and physical performance (Maximum Physical Fitness test), which were measured before and after the 9-week intervention and at 21 weeks of follow-up.

RESULTS

Lumbar endurance was higher in the AEDWR group at the end of the treatment, with a mean difference (MD) of 43.2 seconds, 95% confidence intervals (CI) (9.6; 76.7), P=0.01, d̅=0.74, and better in the follow-up with MD=40.2 seconds, 95% CI (7.1; 73.3), P=0.02, d̅=0.71, than in the AE group. Participant performance also improved on the 9^th week in the AEDWR group, with an MD=0.53 kgf, 95% CI (0.008; 0.98), P=0.02, d̅=0.60.

CONCLUSIONS

The addition of deep-water running exercise to aquatic exercises improved lumbar muscle endurance and performance when compared with aquatic exercises only, and this effect was maintained during the follow-up to lumbar muscle endurance.

Evaluation isometric and isokinetic of trunk flexor and extensor muscles with isokinetic dynamometer: A systematic review

OBJECTIVE

To systematically review the literature analyzing the reliability and characteristics of the protocols of isokinetic and isometric evaluation of the trunk flexor and extensor muscles with isokinetic dynamometer.

METHODS

This is a systematic review using PubMed, CENTRAL, LILACS, PEDro and SCOPUS databases, searching the oldest records up to December 2019. The risk of bias, the methodological quality and the level of evidence were evaluated using the COSMIN checklist.

RESULTS

Fourteen articles have met the criteria and have been included in this study. All the articles performed an isometric or isokinetic evaluation of the trunk muscles with the isokinetic dynamometer and presented an analysis of the protocol's reliability using the intraclass correlation coefficient. Five articles had excellent reliability (0.93-0.98). Most of the studies presented doubtful and inconsistent psychometric values for reliability, because they used a short period between tests. The level of evidence to the fourteen selected articles for reliability was moderate.

CONCLUSIONS

Although the studies present limitations in methodological quality, it was possible to identify highly reliable patterns in the parameters employed and to present recommendations for the assessment of trunk flexor and extensor muscles in the isokinetic dynamometer, both for assessment in the sitting position and orthostatic.

Sarcopenia and Back Muscle Degeneration as Risk Factors for Back Pain: A Comparative Study

Study Design

Case-control study.

Purpose

To investigate the independent associations of back pain with sarcopenia and with back muscle degeneration, and to introduce a new risk index for back muscle degeneration.

Overview of Literature

The Asian Working Group for Sarcopenia recommends diagnosis using handgrip strength, gait speed, and skeletal muscle mass. However, these criteria do not strongly reflect back muscle degeneration.

Methods

Patients who completed a questionnaire on back-pain between October 2016 and October 2017 were enrolled in this study. Appendicular skeletal muscle index (ASMI), cross-sectional area (CSA) index, fatty infiltration (FI) rate of the paraspinal muscles, and lumbar extensor strength index (LESI) were measured and compared between no back-pain and back-pain group. Correlations between LESI and ASMI, CSA index, and FI rate were analyzed. The back-pain group was further divided according to ASMI into sarcopenia and non-sarcopenia subgroups and by our newly developed back muscle degeneration risk index based on correlation coefficients between LESI and CSA index, FI rate. Differences in ASMI, CSA index, FI rate, LESI, and Visual Analog Scale (VAS) score between subgroups were analyzed.

Results

The ASMI, CSA index, FI rate, and LESI differed significantly between back-pain and pain-free groups. The LESI demonstrated the strongest correlation with FI rate. There were no significant differences in VAS score and back muscle degeneration index in the back-pain group when divided according to the presence of sarcopenia. However, there was a significant difference in VAS score between back-pain patients when classified according to high and low back muscle degeneration risk index.

Conclusions

We suggest that the degree of back pain is more strongly associated with back muscle degeneration than with sarcopenia. This back muscle degeneration risk index, reflecting both back muscle morphology and function, could be a useful parameter for evaluation of back pain and muscle degeneration.

Heavier- and lighter-load isolated lumbar extension resistance training produce similar strength increases, but different perceptual responses, in healthy males and females

OBJECTIVES

Muscles dominant in type I muscle fibres, such as the lumbar extensors, are often trained using lighter loads and higher repetition ranges. However, literature suggests that similar strength adaptations can be attained by the use of both heavier- (HL) and lighter-load (LL) resistance training across a number of appendicular muscle groups. Furthermore, LL resistance exercise to momentary failure might result in greater discomfort.

DESIGN

The aims of the present study were to compare strength adaptations, as well as perceptual responses of effort (RPE-E) and discomfort (RPE-D), to isolated lumbar extension (ILEX) exercise using HL (80% of maximum voluntary contraction; MVC) and LL (50% MVC) in healthy males and females.

METHODS

Twenty-six participants (n = 14 males, n = 12 females) were divided in to sex counter-balanced HL (23 ± 5 years; 172.3 ± 9.8 cm; 71.0 ± 13.1 kg) and LL (22 ± 2 years; 175.3 ± 6.3 cm; 72.8 ± 9.5 kg) resistance training groups. All participants performed a single set of dynamic ILEX exercise 1 day/week for 6 weeks using either 80% (HL) or 50% (LL) of their MVC to momentary failure.

RESULTS

Analyses revealed significant pre- to post-intervention increases in isometric strength for both HL and LL, with no significant between-group differences (p > 0.05). Changes in strength index (area under torque curves) were 2,891 Nm degrees 95% CIs [1,612-4,169] and 2,865 Nm degrees 95% CIs [1,587-4,144] for HL and LL respectively. Changes in MVC were 51.7 Nm 95% CIs [24.4-79.1] and 46.0 Nm 95% CIs [18.6-73.3] for HL and LL respectively. Mean repetitions per set, total training time and discomfort were all significantly higher for LL compared to HL (26 ± 8 vs. 8 ± 3 repetitions, 158.5 ± 47 vs. 50.5 ± 15 s, and 7.8 ± 1.8 vs. 4.8 ± 2.5, respectively; all p < 0.005).

CONCLUSIONS

The present study supports that that low-volume, low-frequency ILEX resistance exercise can produce similar strength increases in the lumbar extensors using either HL or LL. As such personal trainers, trainees and strength coaches can consider other factors which might impact acute performance (e.g. effort and discomfort during the exercise). This data might prove beneficial in helping asymptomatic persons reduce the risk of low-back pain, and further research, might consider the use of HL exercise for chronic low-back pain symptomatic persons.