Circulating Adipokines in Predicting the Transition from Acute to Persistent Low Back Pain

OBJECTIVES

Cytokines such as tumor necrosis factor (TNF) contribute to the transition from acute to persistent pain. Despite increasing incidence of obesity and its linkage with chronic pain and inflammation, cytokines predominantly produced by adipose tissue (adipokines) have received little attention. Here we aimed to explore the longitudinal trajectory of adipokines from the onset of acute low back pain (LBP) and identify combinations of adipokines and/or other features that predict outcome.

METHODS

Individuals with acute LBP (less than two weeks after onset) who had either recovered (no pain, N = 15) or remained unrecovered (no reduction/increase in pain, N = 13) at six months and 15 controls were retrospectively selected from a larger prospective cohort. Participants provided blood for the measurement of TNF, interleukin-6 (IL-6), resistin, visfatin, adiponectin, leptin, and C-reactive protein (CRP), and completed questionnaires related to pain/disability, depression, and sleep at baseline. LBP participants repeated measurements at six months.

RESULTS

Compared with controls, acute LBP individuals had higher TNF and CRP but lower adiponectin. In LBP, unrecovered individuals had higher TNF at both time points, but lower CRP at baseline and leptin at six months. Although combined low CRP, high TNF, and depressive symptoms at baseline predicted poor recovery, the primary adipokines leptin, resistin, visfatin, and adiponectin did not.

CONCLUSIONS

Primary adipokines did not add to the prediction of poor LBP outcome that has been identified for the combination of low CRP, high TNF, and depressive symptoms in acute LBP. Whether adipokines play a role in LBP persistence in overweight/obese individuals requires investigation.

Exploration of shear wave elastography measures of the iliotibial band during different tasks in pain-free runners

OBJECTIVES

To determine whether shear wave velocity (SWV) of the iliotibial band (ITB): i) increases with active and passive static tasks, and a dynamic task, ii) differs between ITB regions, iii) changes after exposure to running. Additionally, it aimed to determine the between-day reliability.

DESIGN

Case series & test-retest.

SETTING

Human movement unit laboratory.

PARTICIPANTS

Fifteen runners.

MAIN OUTCOME MEASURES

SWV was measured unilaterally in three regions of the ITB (proximal, middle and distal), during six tasks: rest and contraction (pre- and post-running), modified Ober test, standing, pelvic drop, and weight shift.

RESULTS

Compared to rest, SWV was higher during contraction and Ober test in the distal and middle regions, and higher for the middle region in standing and pelvic drop. No differences were found between regions. A tendency of decreased SWV was observed after running. Compared to the start of the dynamic task, SWV was greater at the end of the movement. Reliability was moderate-to-good for the middle region in the standing tasks (ICCs = 0.68 to 0.84).

CONCLUSION

SVW of the ITB was higher under passive or active tension. Comparisons between tasks/regions need to be considered in light of the small sample size and poor repeatability of some regions/conditions.

Coordination of hip and spine to maintain equilibrium in unstable sitting revealed by spectral analysis

Unstable sitting paradigms have been used to assess the trunk's contribution to postural control. The coordination of spine or hip with an unstable seat that underpin postural control during this task remain unclear. This study aimed to address this issue using analysis in the frequency domain. Seventy-two healthy pain-free participants maintained balance while sitting on a seat fixed to a hemisphere. Angular motion of seat, spinal regions (lower lumber, lumbar, upper lumbar, and thoracic), and hip was recorded with a three-dimensional (3-D) motion capture system. Coordination between spinal regions and hip with the seat was quantified using cross-spectral analyses. In the sagittal plane, amplitude spectrum of hip and lumbar segments were higher than other segments, coherence between these segments and the seat was high, and their motion was generally opposite in direction to the seat. In the frontal plane, amplitude spectrum of lower lumbar and lumbar segments, but not the hip, were higher than other segments, and coherently moved in the opposite direction to the seat. Segments closest to the seat made a direction-specific and greater contribution to maintenance of equilibrium than upper body segments, which were more limited during unstable sitting. Although eye closure and higher body mass index involved larger amplitude of center of pressure movement, rather than inferring poor control, this was associated with enhanced coordination between segments and seat. Understanding how hip/spine segments are coordinated with the seat is important to interpret postural strategies used to maintain equilibrium and to interpret observations for other populations (e.g., back pain).NEW & NOTEWORTHY This is the first multidirectional spectral analysis of how the hip and spine coordinate during unstable sitting and how different factors impact this coordination. Seat movement was coherently counteracted (out-of-phase) by angular motion of the hip and lower lumbar spine in the sagittal plane and by the lumbar spine in the frontal plane. Although higher BMI and balancing with eyes closed increased movement amplitude, this did not compromise coordination between segments to control balance, instead, coherence increased.

Tensor Fascia Latae Muscle Structure and Activation in Individuals With Lower Limb Musculoskeletal Conditions: A Systematic Review and Meta-Analysis

BACKGROUND

Dysfunction of the tensor fascia latae (TFL) muscle is often clinically implicated in many musculoskeletal disorders.

OBJECTIVE

To systematically review the literature of the TFL muscle to determine whether there are differences in its structure and activation between individuals with and without lower limb musculoskeletal conditions.

DATA SOURCES

A comprehensive search in MEDLINE, EMBASE, CINHAL, and LILACS was undertaken from year of inception to 9 July 2019.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies that directly investigated the structure or activity of the TFL muscle between individuals with a lower limb musculoskeletal condition and a pain-free control group.

RESULTS

Seventeen studies were included (n = 556 participants), eight reporting structure and ten activation of the TFL muscle. Conditions included lateral hip pain, hip joint pathology, ACL injury, iliotibial band syndrome, and patellofemoral joint osteoarthritis. Meta-analysis identified with low confidence (p value = 0.07) a small tendency towards hypertrophy in the affected side of participants with hip joint diseases (SMD 0.37, 95% CI [- 0.02, 0.77]). Moderate effect sizes were found for a higher cross-sectional area of the TFL/sartorius ratio in abductor tendon tear (SMD 0.74; 95% CI [0.05, 1.43, p value = 0.04), and for a smaller body mass normalized TFL volume in patellofemoral joint osteoarthritis (SMD - 0.61; 95% CI [- 1.23, 0.00], p value = 0.05). Normalised electromyography (EMG) amplitude did not differ between groups for any condition, but when EMG was analysed as linear envelopes or synergies, some differences in pattern of TFL activation were observed between individuals with lateral hip pain and controls. Timing of TFL activation did not differ between individuals with knee conditions and controls.

CONCLUSIONS AND IMPLICATIONS

Common clinical assumptions of the role of TFL muscle in lower limb musculoskeletal conditions are not well investigated and poorly supported by current research. There are contradictory findings on the muscle size of TFL. Differing methodology in muscle activation studies precludes a clear interpretation for comparison between groups.

PROSPERO REGISTRATION NUMBER

CRD42017076160.

Efficacy of a Combination of Conservative Therapies vs an Education Comparator on Clinical Outcomes in Thumb Base Osteoarthritis: A Randomized Clinical Trial

IMPORTANCE

A combination of conservative treatments is commonly used in clinical practice for thumb base osteoarthritis despite limited evidence for this approach.

OBJECTIVE

To determine the efficacy of a 6-week combination of conservative treatments compared with an education comparator.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, parallel trial with 1:1 allocation ratio among people aged 40 years and older with symptomatic and radiographic thumb base osteoarthritis in a community setting in Australia.

INTERVENTIONS

The intervention group (n = 102) received education on self-management and ergonomic principles, a base-of-thumb splint, hand exercises, and diclofenac sodium, 1%, gel. The comparator group (n = 102) received education on self-management and ergonomic principles alone. Intervention use was at participants' discretion from 6 to 12 weeks.

MAIN OUTCOMES AND MEASURES

Hand function (Functional Index for Hand Osteoarthritis; 0-30) and pain (visual analog scale; 0-100 mm) were measured at week 6 (primary time point) and week 12. An α of .027 was used at week 6 to account for co-primary outcomes.

RESULTS

Of the 204 participants randomized, 195 (96%) and 194 (95%) completed follow-ups at 6 and 12 weeks, respectively; the mean (SD) age of the population was 65.6 (8.1) years, and 155 (76.0%) were female. At week 6, hand function improved significantly more in the intervention group than the comparator (between-group difference, -1.7 units; 97.3% CI, -2.9 to -0.5; P = .002). This trend was sustained at 12 weeks (-2.4 units; 95% CI, -3.5 to -1.3; P < .001). Pain scores improved similarly at week 6 (between-group difference, -4.2 mm; 97.3% CI, -11.3 to 3.0; P = .19). At week 12, pain reduction was significantly greater in the intervention group (-8.6 mm; 95% CI, -15.2 to -2.0; P = .01). There were 34 nonserious adverse events, all in the intervention group-mostly skin reactions and exercise-related pain exacerbations.

CONCLUSIONS AND RELEVANCE

In this randomized clinical trial of people with thumb base osteoarthritis, combined treatments provided small to medium and potentially clinically beneficial effects on hand function but not pain.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry Identifier: ACTRN12616000353493.

Methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system: a systematic review

ABSTRACT

Mechanism-based classification of pain has been advocated widely to aid tailoring of interventions for individuals experiencing persistent musculoskeletal pain. Three pain mechanism categories (PMCs) are defined by the International Association for the Study of Pain: nociceptive, neuropathic, and nociplastic pain. Discrimination between them remains challenging. This study aimed to build on a framework developed to converge the diverse literature of PMCs to systematically review methods purported to discriminate between them; synthesise and thematically analyse these methods to identify the convergence and divergence of opinion; and report validation, psychometric properties, and strengths/weaknesses of these methods. The search strategy identified articles discussing methods to discriminate between mechanism-based categories of pain experienced in the musculoskeletal system. Studies that assessed the validity of methods to discriminate between categories were assessed for quality. Extraction and thematic analysis were undertaken on 184 articles. Data synthesis identified 200 methods in 5 themes: clinical examination, quantitative sensory testing, imaging, diagnostic and laboratory testing, and pain-type questionnaires. Few methods have been validated for discrimination between PMCs. There was general convergence but some disagreement regarding findings that discriminate between PMCs. A combination of features and methods, rather than a single method, was generally recommended to discriminate between PMCs. Two major limitations were identified: an overlap of findings of methods between categories due to mixed presentations and many methods considered discrimination between 2 PMCs but not others. The results of this review provide a foundation to refine methods to differentiate mechanisms for musculoskeletal pain.

Upper limb position affects pain-free grip strength in individuals with lateral elbow tendinopathy

BACKGROUND AND PURPOSE

Pain-free grip (PFG) force is commonly used to monitor treatment outcomes in lateral elbow tendinopathy (LET); however, it is unclear whether changes in forearm and elbow position affect PFG force values. This study aims to examine the effect of elbow/shoulder and forearm position on non-normalised and normalised PFG force in individuals with unilateral LET.

METHODS

A cohort study including 21 subjects with clinically diagnosed unilateral LET (13 females, mean [SD] age 50 [8] years) performed PFG force (symptomatic arm) and maximal grip (asymptomatic arm) tasks using four upper limb positions: (1) shoulder neutral, elbow flexed (90°), forearm pronated; (2) shoulder neutral, elbow flexed (90°), forearm neutral; (3) shoulder flexed (90°), elbow extended, forearm pronated; and (4) shoulder flexed (90°), elbow extended, forearm neutral. PFG force was normalised to the maximal grip of the asymptomatic side. Repeated-measures analyses of variance were used to compare non-normalised and PFG force normalised to maximal grip between positions.

RESULTS

Both non-normalised and normalised PFG forces were greater in position 2 than position 1, position 3 and position 4 (elbow-by-forearm interaction non-normalised p = 0.002, normalised p = 0.004). There were no differences between positions 1, 3 and 4 for either non-normalised or normalised PFG strength.

DISCUSSION

This study shows that PFG force was higher when performed with forearm neutral supination/pronation, elbow flexion and shoulder neutral than other tested positions, and irrespective of whether PFG force was normalised to the maximal grip force of the contralateral limb. This indicates that arm position should be standardised for comparison.

Non-uniform Effects of Nociceptive Stimulation to Motoneurones during Experimental Muscle Pain

Nociceptive stimulation is predicted to uniformly inhibit motoneurone pools of painful muscles and those producing painful movements. Although reduced motoneurone discharge rate during pain provides some evidence, recent data show evidence of increased excitability of some motoneurones. These observations suggest non-uniform effects of nociception on motoneurone excitability. More direct measures are required, but this is difficult to assess as few measures enable in vivo evaluation of motoneurone excitability in humans. We investigated changes in motoneurone excitability during experimental pain using two methods in separate experiments: (i) estimation of the time-course of motoneurone afterhyperpolarization (AHP) from interval death rate analysis of interspike intervals of single motor unit discharge; and (ii) probability of early motoneurone discharge to a descending volley excited using transcranial magnetic stimulation (TMS). Tibialis anterior motor units were recorded with fine-wire electrodes before, during and after painful infusion of 5% hypertonic saline into the muscle. Activation of 17 units (16 participants) could be used for AHP analysis. Data show shortened (n = 11) and lengthened (n = 6) AHP time-course. Increased (n = 6) and decreased (n = 6) probability of early motoneurone discharge were observed in the TMS experiment. These convergent observations suggest non-uniform effects of nociceptive stimulation on motoneurone pools. This does not support the hypothesis that nociceptive input induces uniform inhibition of painful muscle. Instead, interpretation of results implies redistribution of activity between motor units, with possible benefit for unloading painful tissues. This finding supports an interpretation that differs from the generally accepted view in pain physiology regarding adaptation to motor function in pain.

Influence of transducer orientation on shear wave velocity measurements of the iliotibial band

Tissue anisotropy influences estimation of mechanical properties of connective tissues, such as the iliotibial band (ITB). This study investigated the influence of ultrasound transducer rotation and tilt on shear wave velocity (SWV, an index of stiffness) measurements of the ITB and the intra-rater repeatability of SWV measurements in the longitudinal direction. SWV was measured unilaterally (dominant limb) using ultrasound shear wave elastography in the middle region of the ITB in supine at rest (20-25° knee flexion) in ten healthy volunteers (4 females). A 3-dimensional video system provided real-time feedback of probe orientation with respect to the thigh. Measurements were made at 10° increments of probe rotation, from longitudinal to transverse alignment relative to the approximate direction of ITB fibres, and 5-10° tilts about the longitudinal and sideways axes of the transducer. One-way repeated measures ANOVA compared SWV between angles and tilts. Intraclass correlation coefficients (ICCs) and standard error of measurement (SEM) were used to calculate repeatability for two to five (longitudinal only) repetitions. SWV was greatest when the transducer was aligned to ITB fibres (longitudinal: 10.5 ± 1.7 m/s) and lowest when perpendicular (transverse: 5.8 ± 2.4 m/s). Compared to longitudinal alignment, SWV decreased significantly (p < 0.01) when the transducer was rotated 20° or more. Tilted measurements did not differ between angles. Intra-rater repeatability was excellent with the average of two measurements (ICC = 0.99, 95% CI 0.95, 0.99; SEM = 0.31 m/s). These findings show that SWV changes with orientation relative to fibre direction. Transducer orientation requires careful control to ensure comparable measures.

New insights into intrinsic foot muscle morphology and composition using ultra-high-field (7-Tesla) magnetic resonance imaging

Background

The intrinsic muscles of the foot are key contributors to foot function and are important to evaluate in lower limb disorders. Magnetic resonance imaging (MRI), provides a non-invasive option to measure muscle morphology and composition, which are primary determinants of muscle function. Ultra-high-field (7-T) magnetic resonance imaging provides sufficient signal to evaluate the morphology of the intrinsic foot muscles, and, when combined with chemical-shift sequences, measures of muscle composition can be obtained. Here we aim to provide a proof-of-concept method for measuring intrinsic foot muscle morphology and composition with high-field MRI.

Methods

One healthy female (age 39 years, mass 65 kg, height 1.73 m) underwent MRI. A T1-weighted VIBE – radio-frequency spoiled 3D steady state GRE – sequence of the whole foot was acquired on a Siemens 7T MAGNETOM scanner, as well as a 3T MAGNETOM Prisma scanner for comparison. A high-resolution fat/water separation image was also acquired using a 3D 2-point DIXON sequence at 7T. Coronal plane images from 3T and 7T scanners were compared. Using 3D Slicer software, regions of interest were manually contoured for each muscle on 7T images. Muscle volumes and percentage of muscle fat infiltration were calculated (muscle fat infiltration % = Fat/(Fat + Water) x100) for each muscle.

Results

Compared to the 3T images, the 7T images provided superior resolution, particularly at the forefoot, to facilitate segmentation of individual muscles. Muscle volumes ranged from 1.5 cm³ and 19.8 cm³, and percentage muscle fat infiltration ranged from 9.2–15.0%.

Conclusions

This proof-of-concept study demonstrates a feasible method of quantifying muscle morphology and composition for individual intrinsic foot muscles using advanced high-field MRI techniques. This method can be used in future studies to better understand intrinsic foot muscle morphology and composition in healthy individuals, as well as those with lower disorders.

Which Exercise for Low Back Pain? (WELBack) trial predicting response to exercise treatments for patients with low back pain: a validation randomised controlled trial protocol

INTRODUCTION

Exercise therapy is the most recommended treatment for chronic low back pain (LBP). Effect sizes for exercises are usually small to moderate and could be due to the heterogeneity of people presenting with LBP. Thus, if patients could be better matched to exercise based on individual factors, then the effects of treatment could be greater. A recently published study provided evidence of better outcomes when patients are matched to the appropriate exercise type. The study demonstrated that a 15-item questionnaire, the Lumbar Spine Instability Questionnaire (LSIQ), could identify patients who responded best to one of the two exercise approaches for LBP (motor control and graded activity). The primary aim of the current study isill be to evaluate whether preidentified baseline characteristics, including the LSIQ, can modify the response to two of the most common exercise therapies for non-specific LBP. Secondary aims include an economic evaluations with a cost-effectiveness analysis.

METHODS AND ANALYSIS

Participants (n=414) will be recruited by primary care professionals and randomised (1:1) to receive motor control exercises or graded activity. Participants will undergo 12 sessions of exercise therapy over an 8-week period. The primary outcome will be physical function at 2 months using the Oswestry Disability Index. Secondary outcomes will be pain intensity, function and quality of life measured at 2, 6 and 12 months. Potential effect modifiers will be the LSIQ, self-efficacy, coping strategies, kinesiophobia and measures of nociceptive pain and central sensitisation. We will construct linear mixed models with terms for participants (fixed), treatment group, predictor (potential effect modifier), treatment group×predictor (potential effect modifier), physiotherapists, treatment group×physiotherapists and baseline score for the dependent variable.

ETHICS AND DISSEMINATION

This study received ethics approval from the Hamilton Integrate Research Ethics Board. Results will be submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT04283409.

A critical review of the biopsychosocial model of low back pain care: time for a new approach?

PURPOSE

Low back pain (LBP) is the leading cause of disability worldwide. Clinical research advocates using the biopsychosocial model (BPS) to manage LBP, however there is still no clear consensus regarding the meaning of this model in physiotherapy and how best to apply it. The aim of this study was to investigate how physiotherapy LBP literature enacts the BPS model.

MATERIAL AND METHODS

We conducted a critical review using discourse analysis of 66 articles retrieved from the PubMed and Web of Science databases.

RESULTS

Analysis suggest that many texts conflated the BPS with the biomedical model [Discourse 1: Conflating the BPS with the biomedical model]. Psychological aspects were almost exclusively conceptualised as cognitive and behavioural [Discourse 2: Cognition, behaviour, yellow flags and rapport]. Social context was rarely mentioned [Discourse 3: Brief and occasional social underpinnings]; and other broader aspects of care such as culture and power dynamics received little attention within the texts [Discourse 4: Expanded aspects of care].

CONCLUSION

Results imply that multiple important factors such as interpersonal or institutional power relations, cultural considerations, ethical, and social aspects of health may not be incorporated into physiotherapy research and practice when working with people with LBP.IMPLICATIONS FOR REHABILITATIONWhen using the biopsychosocial model with patients with low back pain, researchers narrowly focus on biological and cognitive behavioural aspects of the model.Social and broader aspects such as cultural, interpersonal and institutional power dynamics, appear to be neglected by researchers when taking a biopsychosocial approach to the care of patients with low back pain.The biopsychosocial model may be inadequate to address complexities of people with low back pain, and a reworking of the model may be necessary.There is a lack of research conceptualising how physiotherapy applies the biopsychosocial model in research and practice.

Trunk stiffness decreases and trunk damping increases with experimental low back pain

Movement adaptations to low back pain (LBP) are believed to protect the painful area. Increased trunk stiffness and decreased trunk damping have been shown in people with recurrent LBP. However, no study has examined these properties using external force perturbations to the trunk during acute LBP when protective adaptations might be expected to have most relevance. Adaptations to an acute painful stimulus via unilateral injection of hypertonic saline into the right longissimus muscle were assessed using a trunk force perturbation paradigm and a mass-spring-damper model to describe effective trunk dynamical properties. Equal weights (15% body weight) were connected to the front and back of the trunk via a cable. Either one was dropped at random to perturb the trunk. Effective trunk dynamical properties were estimated in fourteen males (mean (standard deviation) age 25 (6) years) assuming that trunk movement can be modelled as a second order linear system. Effective trunk dynamical properties were compared before, during and after the experimentally induced painful period. Estimates of effective trunk stiffness (K) decreased and damping (B) increased during pain compared to both before ([mean contrast, 95% CI] K: -403 [-651 to -155] Nm^-1, B: 28 [9-50] Nms^-1) and after (K: -324 [-58 to -591] Nm^-1, B: 20 [4-33] Nms^-1) the experimentally induced painful period. We interpret our results to show that, when challenged by a step force perturbation, a healthy system adapts to noxious input by controlling trunk velocity rather than trunk displacement, in contrast to observations during remission from recurrent clinical LBP.

Effects of a six-week exercise intervention on function, pain and lumbar multifidus muscle cross-sectional area in chronic low back pain: A proof-of-concept study

INTRODUCTION

Exercise with the Functional Re-adaptive Exercise Device (FRED) has previously been shown to activate the lumbar multifidus (LM) and transversus abdominis (TrA) muscles in non-symptomatic volunteers. This study aimed to determine the effects of a six-week FRED exercise intervention on pain intensity, patient-reported function and LM cross sectional area (CSA) in people with chronic non-specific low back pain (LBP).

METHODS

Thirteen participants undertook six weeks of FRED exercise for up to 15 min, three times per week. At six weeks pre-, immediately pre-, immediately post-, and six and 15 weeks post-intervention, participants completed the Numeric Pain Rating Scale, Patient-Specific Functional Scale, and ultrasound imaging was used to assess the size of the LM muscles at L5 level. Changes in outcomes were assessed using effect size, confidence intervals and minimum clinically important difference (MCID).

RESULTS

There was no improvement in pain intensity following the intervention. Patient-reported function improved by at least twice the MCID for all follow-up assessments compared to immediately pre-intervention (d = 4.20-6.58). Lumbar multifidus CSA showed a large effect size increase from immediately pre-intervention to immediately post-intervention (d = 0.8-1.1); this was maintained at six weeks post-intervention (not measured at 15 weeks post-intervention).

CONCLUSION

Six weeks of FRED exercise improved physical function in all 13 participants with chronic non-specific LBP who took part in this study and most participants' lumbar multifidus muscle CSA. On this basis, it may be an effective intervention for people with chronic LBP and should now be tested in a randomised controlled trial.

Pelvic floor muscle training for women with lumbopelvic pain: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

It has been suggested that pelvic floor dysfunction may contribute to the development of lumbopelvic pain as a result of changes in trunk muscle control. However, there is limited evidence that pelvic floor muscle training (PFMT) can improve clinical outcomes in women with lumbopelvic pain.

DATABASES AND DATA TREATMENT

Six databases were searched for randomized controlled trials (RCTs) comparing the effectiveness of PFMT to other conservative interventions (usual physiotherapy care or minimal intervention), no treatment or placebo interventions on pain and disability in women with lumbopelvic pain.

RESULTS

We included eight RCTs totalling 469 participants. PFMT was more effective than minimal intervention for lumbopelvic pain [mean difference (MD) 15.9/100 (95% confidential interval (CI), 8.2 to 23.6; p = 0.00; I²  = 3.92%)] and disability [standardized mean difference (SMD) 0.5 (95% CI 0.1-0.9; p = 0.00; I²  = 0%)] during pregnancy. PFMT was more effective than usual physiotherapy care for pain (MD 11.7/100 [95% CI 7.5-15.9; p = 0.00; I²  = 94.14%]) and disability (SMD 0.3 (95% CI 0.0-0.6; p = 0.01; I²  = 82.54%]) in non-pregnant women. Effect sizes were in general of arguable clinical relevance.

CONCLUSIONS

Overall, the certainty of the evidence was very low to low. There is no conclusive evidence that the addition of PFMT to usual physiotherapy care or minimal intervention is superior to minimal intervention and usual care alone given the small number of studies and high levels of heterogeneity of included studies. Further well-designed trials are needed to establish the effectiveness of PFMT for lumbopelvic pain in women.

Novel insight into pressurization of the male and female urethra through application of a multi-channel fibre-optic pressure transducer: Proof of concept and validation

Purpose

To confirm feasibility of recording pressure along the length of the urethra using a multi-sensor fibre-optic pressure catheter; to identify the spatial and temporal features of changes in pressure along the urethra at sites related to specific striated pelvic floor muscles; and to investigate the relationship between urethral pressures and activation of individual pelvic floor muscles estimated from ultrasound imaging.

Materials and Methods

Proof-of-concept study including one male (47 years old) and one female (33 years old). A multi-sensor fibre optic pressure catheter (10 mm sensor separation) was inserted into the urethra. Pressure data were recorded simultaneously with trans-perineal ultrasound imaging measures of pelvic floor muscle activity during sub-maximal and maximal voluntary contractions and evoked coughs.

Results

Pressure changes along the urethra were recorded in all tasks in both participants. Face validity of interpretation of pressure measures with respect to individual muscles was supported by correlation with ultrasound-measured displacements induced by the relevant muscles. Onset of pressure increase occurred in a distal to proximal sequence in the urethra of the male but not the female during voluntary contraction. Peak urethral pressures varied in location, timing and amplitude between tasks. Evoked cough induced in the greatest urethral pressure increase across all tasks for both participants.

Conclusions

The high spatial resolution pressure catheter provide viable and valid recordings of urethral pressure in a male and female. Data provide preliminary evidence of sex differences in spatial and temporal distribution of urethral pressure changes.

Corticomotor reorganization during short-term visuomotor training in the lower back: A randomized controlled study

INTRODUCTION

Accumulating evidence suggests that motor skill training is associated with structural and functional reorganization of the primary motor cortex. However, previous studies have focussed primarily upon the upper limb, and it is unclear whether comparable reorganization occurs following training of other regions, such as the lower back. Although this holds important implications for rehabilitation, no studies have examined corticomotor adaptations following short-term motor training in the lower back.

METHOD

The aims of this study were to (a) determine whether a short-term lumbopelvic tilt visuomotor task induced reorganization of the corticomotor representations of lower back muscles, (b) quantify the variability of corticomotor responses to motor training, and (c) determine whether any improvements in task performance were correlated with corticomotor reorganization. Participants were allocated randomly to perform a lumbopelvic tilt motor training task (n = 15) or a finger abduction control task involving no lumbopelvic movement (n = 15). Transcranial magnetic stimulation was used to map corticomotor representations of the lumbar erector spinae before, during, and after repeated performance of the allocated task.

RESULTS

No relationship between corticomotor reorganization and improved task performance was identified. Substantial variability was observed in terms of corticomotor responses to motor training, with approximately 50% of participants showing no corticomotor reorganization despite significant improvements in task performance.

CONCLUSION

These findings suggest that short-term improvements in lower back visuomotor task performance may be driven by changes in remote subcortical and/or spinal networks rather than adaptations in corticomotor pathways. However, further research using tasks of varying complexities and durations is required to confirm this hypothesis.

Pericapsular hip muscle activity in people with and without femoroacetabular impingement. A comparison in dynamic tasks

OBJECTIVES

Compare anterior pericapsular muscle activity between individuals with and without femoroacetabular impingement syndrome (FAIS) during dynamic tasks, to investigate whether muscle activity is consistent with a role in retracting the capsule to prevent impingement and active restraint of the femoral head in walking.

DESIGN

Cross-sectional.

SETTING

University-laboratory.

PARTICIPANTS

Thirteen athletes with FAIS and 13 pain-free controls.

MAIN OUTCOME MEASURES

Muscle activity was recorded using fine-wire (Iliocapsularis, iliacus and anterior gluteus minimus) and surface (rectus femoris) electromyography (EMG), during three hip flexion tasks (active and assisted hip flexion; squatting) and four walking trials.

RESULTS

Iliocapsularis EMG amplitude was no different between active and assisted hip flexion tasks around 90° of hip flexion in FAIS. There was no difference in EMG between groups in squatting. The pattern of burst activity preceding peak hip extension in iliacus, iliocapsularis, and anterior gluteus minimus was similar in both groups during walking.

CONCLUSION

In FAIS, similar activation of iliocapsularis during active and assisted hip flexion, despite reduced flexion torque demand in the latter, suggests a role in capsular retraction or enhanced hip joint protection. Pericapsular muscle activity in advance of peak hip extension during walking is consistent with a proposed contribution to femoral head control.

How do people in China think about causes of their back pain? A predominantly qualitative cross-sectional survey

Background

Low back pain (LBP) is the second highest cause of health burden in China. Delayed recovery, poor clinical outcomes and persistence of LBP are associated with negative pain beliefs about LBP. Chinese philosophies are nested into the daily life of people in China, which is likely to influence pain beliefs. However, there is lack of knowledge about people’s discourses regarding their LBP in China. The primary aim of this study was to explore the discourses underlying the beliefs of people in China about what causes their persistent or recurrent LBP. The secondary aim was to investigate the sources of these pain beliefs.

Methods

People (n = 152) from South Central, East and North Mainland China with LBP completed an online survey about what they believed caused their persistent or recurrent LBP and where these understandings came from. Potential causes of persistent or recurrent LBP were explored qualitatively using discourse analysis. The sources of these discourses were assessed by descriptive statistics with conventional content analysis.

Results

Five discourses were identified to underpin participants’ beliefs about what caused their persistent or recurrent LBP, namely: (1) biomedical problems (66.4%), (2) unbalanced lifestyle (48.7%), (3) menstruation and ‘kidney’ status (9.2%), (4) the ‘Five Elements’ imbalance (7.9%), and (5) energy status (5.9%). Most participants responded that their pain beliefs were based on information derived from healthcare professionals (59.2%), followed by the internet (24.3%) and family (23.0%).

Conclusions

People from moderately and well-developed parts of Mainland China think predominantly in line with a Western biomedical viewpoint about their LBP. Traditional Chinese medicine related pain beliefs mainly to the concept of ‘balance’ were evident on contemporary Chinese society’s understandings of LBP. These cultural beliefs could be relevant to consider in LBP management and involve healthcare professionals, family and patient in this process.

Reliability of recurrence quantification analysis of postural sway data. A comparison of two methods to determine recurrence thresholds

Ageing affects balance control resulting in a greater amplitude of sway and alterations in structure of the sway time series. Recurrence quantification analysis (RQA) has been used to determine the structure of center-of-pressure (CoP; a measure that reflects standing postural control) data as a means to quantify how CoP repeats itself / recurs below a certain threshold. This study aimed to determine how the method of threshold determination, below which a recurrence is defined, affects the within-session reliability of RQA in an elderly population. Within-session reliability of RQA of CoP motion in the anterior-posterior and mediolateral directions was assessed in 267 individuals (>65 years old) when standing on firm or foam surface with eyes open or closed for each of two recurrence threshold methods. One threshold method sets the recurrence threshold level such that the recurrence rate is fixed to 5%, the other method sets the recurrence threshold based on 27% of the mean distance between all points from which recurrences are quantified. Reliability across four 30-s balance trials within each of four balance conditions (firm vs. foam, eyes open vs. closed) was determined using intra-class correlation, standard error of measurement and minimal detectable change. ICCs were better, the standard error of measurement and minimal detectable change were smaller when the recurrence threshold was set to 5% using the fixed recurrence threshold. Fixing recurrence rate improves the within session reliability of RQA and could increase sensitivity to identify fall risk.

Consensus for experimental design in electromyography (CEDE) project: Amplitude normalization matrix

The general purpose of normalization of EMG amplitude is to enable comparisons between participants, muscles, measurement sessions or electrode positions. Normalization is necessary to reduce the impact of differences in physiological and anatomical characteristics of muscles and surrounding tissues. Normalization of the EMG amplitude provides information about the magnitude of muscle activation relative to a reference value. It is essential to select an appropriate method for normalization with specific reference to how the EMG signal will be interpreted, and to consider how the normalized EMG amplitude may change when interpreting it under specific conditions. This matrix, developed by the Consensus for Experimental Design in Electromyography (CEDE) project, presents six approaches to EMG normalization: (1) Maximal voluntary contraction (MVC) in same task/context as the task of interest, (2) Standardized isometric MVC (which is not necessarily matched to the contraction type in the task of interest), (3) Standardized submaximal task (isometric/dynamic) that can be task-specific, (4) Peak/mean EMG amplitude in task, (5) Non-normalized, and (6) Maximal M-wave. General considerations for normalization, features that should be reported, definitions, and "pros and cons" of each normalization approach are presented first. This information is followed by recommendations for specific experimental contexts, along with an explanation of the factors that determine the suitability of a method, and frequently asked questions. This matrix is intended to help researchers when selecting, reporting and interpreting EMG amplitude data.

What type of exercise is most effective for people with knee osteoarthritis and co-morbid obesity?: The TARGET randomized controlled trial

OBJECTIVE

Different exercise types may yield different outcomes in osteoarthritis (OA) subgroups. The objective was to directly compare effectiveness of two exercise programs for people with medial knee OA and co-morbid obesity.

DESIGN

We performed a participant- and assessor-blinded randomized controlled trial. 128 people ≥50 years with medial knee OA and body mass index ≥30 kg/m² were recruited from the community. Interventions were home-based non-weight bearing (NWB) quadriceps strengthening or weight bearing (WB) functional exercise for 12 weeks. Primary outcomes were change in overall knee pain (numeric rating scale, range 0-10) and difficulty with physical function (Western Ontario and McMaster Universities Osteoarthritis Index, 0-68) over 12 weeks. Secondary outcomes included other pain measures, physical function, quality-of-life, global changes, physical performance, and lower-limb muscle strength.

RESULTS

123 (96%) participants were retained. There was no evidence of a between-group difference in change in pain (mean difference 0.73 units (95% confidence intervals (0.05,1.50)) or function (2.80 units (-1.17,6.76)), with both groups reporting improvements. For secondary outcomes, the WB group had greater improvement in quality-of-life (-0.043 units (-0.085,-0.001)) and more participants reporting global improvement (overall: relative risk 1.40 (0.98,2.01); pain 1.47 (0.97,2.24); function 1.43 (1.04,1.98). Although adverse events were minor, more NWB group participants reported ≥1 adverse event (26/66 (39%) vs 14/62 (23%), p = 0.04).

CONCLUSIONS

Both exercise types similarly improved primary outcomes of pain and function and can be recommended for people with knee OA and obesity. WB exercise may be preferred given fewer adverse events and potential additional benefits on some secondary outcomes.

REGISTRATION

Prospectively registered (Australian New Zealand Clinical Trials Registry #12617001013358, 14/7/2017).

Design, Delivery, Maintenance, and Outcomes of Peer-to-Peer Online Support Groups for People With Chronic Musculoskeletal Disorders: Systematic Review

Background

Online support groups (OSGs) are one way for people with chronic diseases, their family or friends, and health professionals to communicate, gain information, and provide social support. As the number of peer-to-peer OSGs for chronic musculoskeletal conditions grows, it is important to gain insight into the different designs of groups available, who is accessing them, if and how they may be effective, and what strategies are being used to implement or increase consumer engagement.

Objective

The objectives of this systematic review of people with musculoskeletal conditions were to (1) describe the design features (functions, usage options, moderation, and expert input) of peer-to-peer OSGs, (2) describe the characteristics of the individuals using peer-to-peer OSGs, (3) synthesize the evidence on outcomes of participation, and (4) identify strategies used in the delivery and maintenance of OSGs.

Methods

A search comprising terms related to the population (people with musculoskeletal disorders) and the intervention (peer-to-peer OSGs) was conducted in 6 databases. Results were filtered from 1990 (internet inception) to February 2019. Studies identified in the search were screened according to predefined eligibility criteria using a 2-step process. Quantitative studies were appraised by 2 reviewers using the Risk Of Bias In Non-Randomized Studies of Interventions tool. Qualitative studies were appraised by 2 different reviewers using the Critical Appraisal Skills Programme checklist. Extracted data were synthesized narratively.

Results

We examined 21 studies with low to moderate risk of bias. Of these studies, 13 studies included OSGs hosted on public platforms, 11 studies examined OSGs that were conducted in English, and 6 studies used moderators or peer leaders to facilitate engagement. Studies either reported the number of OSG members (n=1985 across all studies) or the number of posts (range: 223-200,000). The majority of OSG members were females who were not full-time employees and with varied levels of education. There were no randomized controlled trials measuring the efficacy of OSGs. Qualitative and quantitative studies identified empowerment, social support, self-management behavior, and health literacy as primary constructs to measure OSG efficacy. Neutral or marginal improvement was reported in these constructs. Sharing experiences and a greater level of engagement appeared to have an important influence on OSGs efficacy. The extent to which members posted on the website influenced engagement.

Conclusions

Across a diverse range of designs, languages, included features, and delivery platforms, peer-to-peer OSGs for chronic musculoskeletal conditions attract predominantly female participants of all ages and education levels. The level of participation of a member appears to be related to their perceived benefit, health literacy, and empowerment. Future studies are needed to identify which design and maintenance strategies have superior efficacy and whether there are concomitant improvements in health outcomes for people with chronic musculoskeletal conditions resulting from participation in OSGs.

Trial Registration

PROSPERO International Prospective Register of Systematic Reviews CRD42018090326; https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42018090326

Hypogravity reduces trunk admittance and lumbar muscle activation in response to external perturbations

Reduced paraspinal muscle size and flattening of spinal curvatures have been documented after spaceflight. Assessment of trunk adaptations to hypogravity can contribute to development of specific countermeasures. In this study, parabolic flights were used to investigate spinal curvature and muscle responses to hypogravity. Data from five trials at 0.25 g, 0.50 g, and 0.75 g were recorded from six participants positioned in a kneeling-seated position. During the first two trials, participants maintained a normal, upright posture. In the last three trials, small-amplitude perturbations were delivered in the anterior direction at the T₁₀ level. Spinal curvature was estimated with motion capture cameras. Trunk displacement and contact force between the actuator and participant were recorded. Muscle activity responses were collected by intramuscular electromyography (iEMG) of the deep and superficial lumbar multifidus, iliocostalis lumborum, longissimus thoracis, quadratus lumborum, transversus abdominis, obliquus internus, and obliquus externus muscles. The root mean square iEMG and the average spinal angles were calculated. Trunk admittance and muscle responses to perturbations were calculated as closed-loop frequency-response functions. Compared with 0.75 g, 0.25 g resulted in lower activation of the longissimus thoracis (P = 0.002); lower responses of the superficial multifidus at low frequencies (P = 0.043); lower responses of the superficial multifidus (P = 0.029) and iliocostalis lumborum (P = 0.043); lower trunk admittance (P = 0.037) at intermediate frequencies; and stronger responses of the transversus abdominis at higher frequencies (P = 0.032). These findings indicate that exposure to hypogravity reduces trunk admittance, partially compensated by weaker stabilizing contributions of the paraspinal muscles and coinciding with an apparent increase of deep abdominal muscle activity.NEW & NOTEWORTHY This study presents for the first time novel insights into the adaptations to hypogravity of spinal curvatures, trunk stiffness, and paraspinal muscle activity. We showed that exposure to hypogravity reduces the displacement of the trunk by an applied perturbation, partially compensated by weaker stabilizing contributions of the paraspinal muscles and concomitant increase in abdominal muscle responses. These findings may have relevance for future recommendations for planetary surface explorations.

Influence of body position on dynamics of the pelvic floor measured with transperineal ultrasound imaging in men

AIMS

This paper aims to evaluate the feasibility of transperineal ultrasound imaging (TPUS) for visualizing the motion of pelvic landmarks associated with striated pelvic floor muscle contraction in men in standing; to compare the locations of pelvic landmarks between sitting and standing; and to compare the effects of different body positions on measures of pelvic floor muscle contraction.

METHODS

Thirty-five men awaiting prostatectomy volunteered to participate. Participants performed three repetitions of submaximal pelvic floor contraction in sitting and again in standing. Movement of pelvic landmarks with contraction was recorded using an ultrasound imaging transducer placed on the perineum.

RESULTS

The feasibility of TPUS in men in standing was demonstrated through the visualization of three out of four pelvic landmarks in more than 95% of images in the standing position. Analysis of pelvic landmarks and their respective relationships with muscle shortening demonstrated that the anorectal junction and urethrovesical junction were lower and the estimated length of puborectalis was shorter in standing than sitting. The mid-urethra (striated urethral sphincter) and anorectal junction (puborectalis) landmark displaced further cranially in standing than sitting.

CONCLUSIONS

TPUS can be used to visualize three pelvic landmarks in men with cancerous prostates. Puborectalis is shorter at rest in standing than sitting, and elevation of the mid-urethra and the anorectal junction is more in standing than sitting. Together these findings indicate that feedback for pelvic floor muscle training is possible in both positions, but the position needs to be standardized for a comparative assessment.

Potential Unintended Effects of Standardized Pain Questionnaires: A Qualitative Study

OBJECTIVE

Low back pain is a common musculoskeletal condition with substantial individual and societal costs. Standardized self-report questionnaires are commonly used in clinical practice to identify prognostic risk factors and tailor interventions for low back pain. However, most of these low back pain questionnaires have been developed in Western cultures and may not be clinically applicable to other cultures. These cultural aspects have not been explored. This study aimed to investigate the cultural assumptions underlying back pain questionnaires and the potential implications of using standardized questionnaires with non-Western populations.

DESIGN

An interpretive qualitative design was employed.

SUBJECTS

Participants (N = 16) self-identified as coming from culturally and linguistically diverse backgrounds.

METHODS

Data collection and analysis were guided by thematic analysis. Four focus groups of three to five participants were conducted during which participants discussed two questionnaires commonly used in low back pain settings: the Fear-Avoidance Beliefs Questionnaire and Örebro Musculoskeletal Pain Questionnaire.

RESULTS

Analysis identified four themes: questionnaires affect the patient-clinician encounter; results are not only about back pain; questionnaires affect people's understanding of their back pain; and results potentially affect people's lives beyond their back condition.

CONCLUSIONS

Findings suggest that questionnaires could potentially negatively affect the patient-clinician rapport and lead to inaccurate and unanticipated results when used with culturally and linguistically diverse populations. Findings are also likely to be applicable to people with low back pain more broadly, regardless of culture. Implications include a need for cultural sensitivity when using questionnaires, greater consideration of when to use these measures, and adaptations to the use/design of standardized questionnaires.

Do features of randomized controlled trials of pelvic floor muscle training for postprostatectomy urinary incontinence differentiate successful from unsuccessful patient outcomes? A systematic review with a series of meta-analyses

AIMS

Efficacy of pelvic floor muscle training (PFMT) for postprostatectomy incontinence (PPI) differs between randomized clinical trials (RCT). This might be explained by variation in content/delivery of PFMT (eg, biofeedback, muscles targeted, and time of commencement of training). This review investigated whether outcome of meta-analysis differs based on presence or not of specific RCT features.

METHODS

PubMed, CINAHL, EMBASE, Physiotherapy Evidence Database (PEDro), and Cochrane were searched for RCTs that investigated efficacy of PFMT on PPI. PFMT details and outcomes were extracted. Methodological quality and comprehensiveness of PFMT reporting was assessed using the PEDro scale and Consensus on Reporting Template, respectively. Effect size and 95% confidence intervals were calculated for incontinence rate at 3 months. To identify features that influenced efficacy, separate meta-analyses were performed for studies with and without specific features.

RESULTS

Twenty-two trials were included, and 15 were used for meta-analysis of 3-month outcomes. Overall, meta-analysis showed reduced incontinence with PFMT (risk ratio [RR] = 0.85; I² = 55%; P = .005). Meta-analyses showed better outcomes for PFMT than control groups when the study included preoperative PFMT (RR = 0.76; I² = 30%; P = .006), biofeedback (RR = 0.73; I² = 58%; P = .006), instruction to contract around the urethra (RR = 0.9; I² = 43%; P = .009), a control group without PFMT instruction (RR = 0.85; I² = 69%; P = .05), inclusion of all men irrespective of continence status (RR = 0.84; I² = 30%; P = .003) and continence defined as no leakage (RR = 0.85; I² = 48%; P = .05).

CONCLUSIONS

Preoperative PFMT, biofeedback, urethral instructions, no PFMT instruction for controls, inclusion of all men, and continence defined as no leakage are features associated with successful patient outcomes. Future studies should consider these features in design of interventions and pooling data for meta-analysis.

What Triggers an LBP Flare? A Content Analysis of Individuals' Perspectives

OBJECTIVE

For many, low back pain (LBP) is a lifelong condition with symptoms varying over time. Previous studies have investigated long-term risk factors and triggers for onset of LBP. No study has examined causes for less distinct fluctuations of symptoms, such as "flares," which individuals with LBP identify as a significant and worrisome part of LBP. As little is known about what triggers this type of fluctuation, we aimed to investigate individuals' perspectives on LBP flare triggers.

METHODS

We conducted an online survey of 130 people with LBP, asking what they think triggers their flares. Data were qualitatively examined using content analysis.

RESULTS

Most participants identified biomedical (84.8%) triggers, endorsing physical/biological factors to explain the flare occurrence. Themes included active movements (35% of participants), static postures (28.1%), overdoing a task (5.3%), biomechanical dysfunction (4.4%), comorbidities (4%), lack of exercise (3.3%), work (1.8%), and medications (1.5%). Nonbiomedical triggers were reported by 15.2% and included psychosocial and contextual factors, including psychological state (6%), weather (5%), sleep (2%), diet (1.2%), and fatigue (1%). These results indicate that individuals consider biomedical factors to be the main triggers of LBP flares, but some acknowledge nonbiomedical triggers.

CONCLUSIONS

Study findings contrast with current pain theories, which suggest that there is a need for a reduced emphasis on biomedical causes of LBP pain, especially when persistent. Recognition of patients' views on causes of LBP flares is crucial to better guide clinical practice and inform further research. The validity of triggers identified by LBP patients requires further investigation.

Reconsideration of pelvic floor muscle training to prevent and treat incontinence after radical prostatectomy

Urinary incontinence is common after radical prostatectomy. Pelvic floor muscle training provides a plausible solution. Although early trials provided promising results, systematic reviews have questioned the efficacy of this intervention. A major consideration is that most clinical trials in men have applied principles developed for pelvic floor muscle training for stress urinary incontinence in women, despite differences in anatomy between sexes and differences in the mechanisms for continence/incontinence. Literature regarding continence control in men has been conflicting and often based on erroneous anatomy. New understanding of continence mechanisms in men, including the complex contribution of multiple layers of striated pelvic floor muscles, and detailed consideration of the impact of radical prostatectomy on continence anatomy and physiology, have provided foundations for a new approach to pelvic floor muscle training to prevent and treat incontinence after prostatectomy. An approach to training can be designed to target the pathophysiology of incontinence. This approach relies on principles of motor learning and exercise physiology, in a manner that is tailored to the individual patient. The aims of this review are to consider new understanding of continence control in men, the mechanisms for incontinence after radical prostatectomy, and to review the characteristics of a pelvic floor muscle training program designed to specifically target recovery of continence after prostatectomy.

Deep hip muscle activation during squatting in femoroacetabular impingement syndrome

BACKGROUND

Deep hip muscle retraining is a common objective of non-operative management for femoroacetabular impingement (FAI) syndrome. These muscles are considered to have an important role in hip joint stabilization, however, it is unclear whether their function is altered in the presence of hip pathology. This exploratory study aimed to investigate activation patterns of the hip muscles during two squatting tasks in individuals with and without FAI syndrome.

METHODS

Fifteen individuals with FAI syndrome (symptoms, clinical examination and imaging) and 14 age- and sex-comparable healthy controls underwent testing. Intramuscular fine-wire and surface electrodes recorded electromyographic activity of selected deep and superficial hip muscles during the squatting tasks. Activation patterns from individual muscles were compared between-groups using a wavelet-based linear mixed effects model (P < 0.05).

FINDINGS

There were no between-group differences for squat depth or speed during descent or ascent for either task. Participants with FAI syndrome exhibited patterns of activation that differed significantly to controls across all muscles (P < 0.05) when squatting using their preferred strategy. Unlike controls, participants with FAI syndrome exhibited a pattern of activation for obturator internus during descent that was similar in amplitude to ascent, despite the contrasting contraction type (i.e. eccentric vs concentric).

INTERPRETATION

Individuals with FAI syndrome appear to implement a protective strategy as the hip descends towards the impingement position. Future studies should examine patients prospectively to establish whether these strategies are counterproductive for pathology and warrant rehabilitation.

Building a Collaborative Model of Sacroiliac Joint Dysfunction and Pelvic Girdle Pain to Understand the Diverse Perspectives of Experts

BACKGROUND

Pelvic girdle pain (PGP) and sacroiliac joint (SIJ) dysfunction/pain are considered frequent contributors to low back pain (LBP). Like other persistent pain conditions, PGP is increasingly recognized as a multifactorial problem involving biological, psychological, and social factors. Perspectives differ between experts and a diversity of treatments (with variable degrees of evidence) have been utilized.

OBJECTIVE

To develop a collaborative model of PGP that represents the collective view of a group of experts. Specific goals were to analyze structure and composition of conceptual models contributed by participants, to aggregate them into a metamodel, to analyze the metamodel's composition, and to consider predicted efficacy of treatments.

DESIGN

To develop a collaborative model of PGP, models were generated by invited individuals to represent their understanding of PGP using fuzzy cognitive mapping (FCM). FCMs involved proposal of components related to causes, outcomes, and treatments for pain, disability, and quality of life, and their connections. Components were classified into thematic categories. Weighting of connections was summed for components to judge their relative importance. FCMs were aggregated into a metamodel for analysis of the collective opinion it represented and to evaluate expected efficacy of treatments.

RESULTS

From 21 potential contributors, 14 (67%) agreed to participate (representing six disciplines and seven countries). Participants' models included a mean (SD) of 22 (5) components each. FCMs were refined to combine similar terms, leaving 89 components in 10 categories. Biomechanical factors were the most important in individual FCMs. The collective opinion from the metamodel predicted greatest efficacy for injection, exercise therapy, and surgery for pain relief.

CONCLUSIONS

The collaborative model of PGP showed a bias toward biomechanical factors. Most efficacious treatments predicted by the model have modest to no evidence from clinical trials, suggesting a mismatch between opinion and evidence. The model enables integration and communication of the collection of opinions on PGP.

Consensus for experimental design in electromyography (CEDE) project: Electrode selection matrix

The Consensus for Experimental Design in Electromyography (CEDE) project is an international initiative which aims to guide decision-making in recording, analysis, and interpretation of electromyographic (EMG) data. The quality of the EMG recording, and validity of its interpretation depend on many characteristics of the recording set-up and analysis procedures. Different electrode types (i.e., surface and intramuscular) will influence the recorded signal and its interpretation. This report presents a matrix to consider the best electrode type selection for recording EMG, and the process undertaken to achieve consensus. Four electrode types were considered: (1) conventional surface electrode, (2) surface matrix or array electrode, (3) fine-wire electrode, and (4) needle electrode. General features, pros, and cons of each electrode type are presented first. This information is followed by recommendations for specific types of muscles, the information that can be estimated, the typical representativeness of the recording and the types of contractions for which the electrode is best suited. This matrix is intended to help researchers when selecting and reporting the electrode type in EMG studies.

Low back pain websites do not meet the needs of consumers: A study of online resources at three time points

BACKGROUND

The popularity of the Internet as a source of health-related information for low back pain (LBP) is growing. Although research has evaluated information quality in health-related websites, few studies have considered whether content and presentation match consumer preferences.

OBJECTIVE

The aim of this study was to evaluate whether LBP website content and presentation matched preferences of consumers with LBP, whether matching preference of consumers changed over 8 years as recognition of people-centred healthcare has developed and whether this differs between countries of Internet searching.

METHOD

The most prominent and top 20 LBP websites were identified using common search engines in 2010, 2015 and 2018. Websites identified in the top 20 in 2010 were followed up if not identified in 2015 and 2018. Two reviewers independently evaluated websites with a 16-item checklist developed from research of consumer preferences. In 2015, websites were identified using searches conducted using IP addresses from Australia, the United States of America (USA), the United Kingdom and Canada. After removal of duplicates, 55 websites were evaluated in 2010. In 2015 and 2018, 33 and 28 new sites, respectively, were identified, and 37 previous websites were re-evaluated.

RESULTS

In 2010 and 2015, websites predominantly originated from USA and were sponsored by "for-profit" organisations. In 2018, most websites originated from Australian "not-for-profit" organisations. None of the websites provided information on all content areas. At least 55% of websites were rated as poor or fair. No site rated as excellent overall. There was some worsening over time. Country of search did not affect results.

CONCLUSION

Websites retrieved using typical searches did not meet information and presentation preferences of people with LBP.

Electrical Stimulation of Back Muscles Does Not Prime the Corticospinal Pathway

OBJECTIVES

To investigate whether peripheral electrical stimulation (PES) of back extensor muscles changes excitability of the corticospinal pathway of the stimulated muscle and synergist trunk muscles.

METHODS

In 12 volunteers with no history of low back pain (LBP), intramuscular fine-wire electrodes recorded electromyography (EMG) from the deep multifidus (DM) and longissimus muscles. Surface electrodes recorded general EMG from the erector spinae and abdominal muscles. Single- and paired-pulse transcranial magnetic stimulation (TMS) paradigms tested corticospinal excitability, short-interval intracortical inhibition (SICI-2 and 3 ms), and intracortical facilitation (ICF) optimized for recordings of DM. Active motor threshold (aMT) to evoke a motor-evoked potential (MEP) in DM was determined and stimulation was applied at 120% of this intensity. PES was provided via electrodes placed over the right multifidus. The effect of 20-min PES (ramped motor activation) was studied.

RESULTS

Mean aMT for DM was 42.7 ± 10% of the maximal stimulator output. No effects of PES were found on MEP amplitude (single-pulse TMS) for any trunk muscles examined. There was no evidence for changes in SICI or ICF; that is, conditioned MEP amplitude was not different between trials after PES.

CONCLUSION

Results indicate that, unlike previous reports that show increased corticospinal excitability of limb muscles, PES of back muscles does not modify the corticospinal excitability. This difference in response of the motor pathway of back muscles to PES might be explained by the lesser importance of voluntary cortical drive to these muscles and the greater role of postural networks. Whether PES influences back muscle training remains unclear, yet the present results suggest that potential effects are unlikely to be explained by the effects of PES at corticospinal level with the parameters used in this study.

Comparison of weight bearing functional exercise and non-weight bearing quadriceps strengthening exercise on pain and function for people with knee osteoarthritis and obesity: protocol for the TARGET randomised controlled trial

Background

Clinical guidelines recommend exercise as a core treatment for individuals with knee osteoarthritis (OA). However, the best type of exercise for clinical benefits is not clear, particularly in different OA subgroups. Obesity is a common co-morbidity in people with knee OA. There is some evidence suggesting that non-weight bearing exercise may be more effective than weight bearing exercise in patients with medial knee OA and obesity.

Methods

To compare the efficacy of two different exercise programs (weight bearing functional exercise and non-weight bearing quadriceps strengthening) on pain and physical function for people ≥50 years with painful medial knee OA and obesity (body mass index ≥30 kg/m²) 128 people in Melbourne, Australia will be recruited for a two group parallel-design, assessor- and participant-blinded randomised controlled trial. Participants will be randomly allocated to undertake a program of either weight bearing functional exercise or non-weight bearing quadriceps strengthening exercise. Both groups will attend five individual sessions with a physiotherapist who will teach, monitor and progress the exercise program. Participants will be asked to perform the exercises at home four times per week for 12 weeks. Outcomes will be measured at baseline and 12 weeks. Primary outcomes are self-reported knee pain and physical function. Secondary outcomes include other measures of knee pain, physical function, quality-of-life, participant-perceived global change, physical performance, and lower limb muscle strength.

Discussion

This study will compare the efficacy of two different 12-week physiotherapist-prescribed, home-based exercise programs for people with medial knee OA and obesity. Findings will provide valuable information to help inform exercise prescription in this common OA patient subgroup.

Trial registration

Australian New Zealand Clinical Trials Registry reference: ACTRN12617001013358, 14/7/2017

Electronic supplementary material

The online version of this article (10.1186/s12891-019-2662-5) contains supplementary material, which is available to authorized users.

Cervical Rotator Muscle Activity With Eye Movement at Different Speeds is Distorted in Whiplash

BACKGROUND

People with whiplash-associated disorders (WADs) report difficulty with quick head movements and cervicoocular dysfunction. Changes in coordination between eye movement and neck muscle activity may be involved.

OBJECTIVE

To examine whether activity of superficial and deep neck muscles increases with eye movement when the head is held in a fixed position, whether this differs between directions and speed of eye movement, and whether this is modified in WAD.

DESIGN

Convenience case series with unmatched controls.

SETTING

Research laboratory.

PARTICIPANTS

Nine individuals with chronic WAD grade II and 11 pain-free controls.

METHODS

Electromyography (EMG) was recorded from muscles that could act to rotate the neck to the right (right obliquus capitis inferior [OI], multifidus [MF], splenius capitis [SC], and left sternocleidomastoid [SCM]) with intramuscular or surface electrodes in 9 WAD participants and 11 pain-free controls. Eyes were rotated without head movement to track slow and medium-speed targets to the right or left, and as fast as possible (FP).

MAIN OUTCOME MEASUREMENTS

Amplitude of EMG.

RESULTS

In controls, SCM and SC EMG increased with right gaze (all P's < .03). EMG of the deep OI muscle increased in both directions (P < .001). WAD involved counterintuitive greater activity of SCM with left rotation across speeds of eye movement (SC with slow movement, P < .036), decreased OI EMG with gaze left (P < .019), and no change in MF EMG (P < .6) in either gaze direction. For FP tasks, EMG of all muscles was greater than slower speeds in controls (all P's < .0001), but not WAD (all P's > .33).

CONCLUSIONS

Coordination between neck muscle activity and eye movements with increasing speed is modified in WAD. Contrasting changes are present in deep and superficial neck muscles with implications for neck function that may explain some common WAD symptoms.

LEVEL OF EVIDENCE

IV.

Can Biomechanics Research Lead to More Effective Treatment of Low Back Pain? A Point-Counterpoint Debate

SYNOPSIS

Although biomechanics plays a role in the development and perhaps the persistent or recurrent nature of low back pain (LBP), whether biomechanics alone can provide the basis for intervention is debated. Biomechanics, which refers to the mechanics of the body, including its neuromuscular control, has been studied extensively in LBP. But, can gains be made in understanding LBP by research focused on this component of biology in the multifactorial biopsychosocial problem of LBP? This commentary considers whether biomechanics research has the potential to advance treatment of LBP, and how likely it is that this research will lead to better treatment strategies. A point-counterpoint format is taken to present both sides of the argument. First, the challenges faced by an approach that considers biomechanics in isolation are presented. Next, we describe 3 models that place substantial emphasis on biomechanical factors. Finally, reactions to each point are presented as a foundation for further research and clinical practice to progress understanding of the place for biomechanics in guiding treatment of LBP. J Orthop Sports Phys Ther 2019;49(6):425-436. Epub 15 May 2019. doi:10.2519/jospt.2019.8825.

Development of a collaborative model of low back pain: report from the 2017 NASS consensus meeting

BACKGROUND CONTEXT

Low back pain (LBP) is a multifactorial problem with complex interactions among many biological, psychological and social factors. It is difficult to fully appreciate this complexity because the knowledge necessary to do so is distributed over many areas of expertise that span the biopsychosocial domains.

PURPOSE

This study describes the collaborative modeling process, undertaken among a group of participants with diverse expertise in LBP, to build a model to enhance understanding and communicate the complexity of the LBP problem.

STUDY DESIGN

The study involved generating individual models that represented participants' understanding of the LBP problem using fuzzy cognitive mapping (FCM), and 4 subsequent phases of consultation and consensus with the participants to characterize and refine the interpretation of the FCMs.

METHODS

The phases consisted of: proposal of Categories for clustering of model Components; preliminary evaluation of structure, composition and focal areas of participant's FCMs; refinement of Categories and Components with consensus meeting; generation of final structure and composition of individual participant's FCMs. Descriptive statistics were applied to the structural and composition metrics of individual FCMs to aid interpretation.

RESULTS

From 38 invited contributors, 29 (76%) agreed to participate. They represented 9 disciplines and 8 countries. Participants' models included 729 Components, with an average of 25 (SD = 7) per model. After the final FCM refinement process (Components from separate FCMs that used similar terms were combined, and Components from an FCM that included multiple terms were separated), there were 147 Components allocated to ten Categories. Although individual models varied in their structure and composition, a common opinion emerged that psychological factors are particularly important in the presentation of LBP. Collectively, Components allocated to the "Psychology" Category were the most central in almost half (14/29) of the individual models.

CONCLUSIONS

The collaborative modeling process outlined in this paper provides a foundation upon which to build a greater understanding and to communicate the complexity of the LBP problem. The next step is to aggregate individual FCMs into a metamodel and begin disentangling the interactions among its Components. This will lead to an improved understanding of the complexity of LBP, and hopefully to improved outcomes for those suffering from this condition.

Do sensorimotor cortex activity, an individual's capacity for neuroplasticity, and psychological features during an episode of acute low back pain predict outcome at 6 months: a protocol for an Australian, multisite prospective, longitudinal cohort study

INTRODUCTION

Low back pain (LBP) is the leading cause of disability worldwide, with prevalence doubling in the past 14 years. To date, prognostic screening tools display poor discrimination and offer no net benefit of screening over and above a 'treat all' approach. Characteristics of the primary sensory (S1) and motor (M1) cortices may predict the development of chronic LBP, yet the prognostic potential of these variables remains unknown. The Understanding persistent Pain Where it ResiDes (UPWaRD) study aims to determine whether sensorimotor cortex activity, an individual's capacity for plasticity and psychosocial factors in the acute stage of pain, predict LBP outcome at 6 months. This paper describes the methods and analysis plan for the development of the prediction model.

METHODS AND ANALYSIS

The study uses a multicentre prospective longitudinal cohort design with 6-month follow-up. 120 participants, aged 18 years or older, experiencing an acute episode of LBP (less than 6 weeks duration) will be included. Primary outcomes are pain and disability.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from Western Sydney University Human Research Ethics Committee (H10465) and from Neuroscience Research Australia (SSA: 16/002). Dissemination will occur through presentations at national and international conferences and publications in international peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ACTRN12619000002189; Pre-results.

Task-specific differences in respiration-related activation of deep and superficial pelvic floor muscles

The female pelvic floor muscles (PFM) are arranged in distinct superficial and deep layers that function to support the pelvic/abdominal organs and maintain continence, but with some potential differences in function. Although general recordings of PFM activity show amplitude modulation in conjunction with fluctuation in intra-abdominal pressure such as that associated with respiration, it is unclear whether the activities of the two PFM layers modulate in a similar manner. This study aimed to investigate the activation of the deep and superficial PFM during a range of respiratory tasks in different postures. Twelve women without pelvic floor dysfunction participated. A custom-built surface electromyography (EMG) electrode was used to record the activation of the superficial and deep PFM during quiet breathing, breathing with increased dead space, coughing, and maximal and submaximal inspiratory and expiratory efforts. As breathing demand increased, the deep PFM layer EMG had greater coherence with respiratory airflow at the frequency of respiration than the superficial PFM (P = 0.038). During cough, the superficial PFM activated earlier than the deep PFM in the sitting position (P = 0.043). In contrast, during maximal and submaximal inspiratory and expiratory efforts, the superficial PFM EMG was greater than that for the deep PFM (P = 0.011). These data show that both layers of PFM are activated during both inspiration and expiration, but with a bias to greater activation in expiratory tasks/phases. Activation of the deep and superficial PFM layers differed in most of the respiratory tasks, but there was no consistent bias to one muscle layer. NEW & NOTEWORTHY Although pelvic floor muscles are generally considered as a single entity, deep and superficial layers have different anatomies and biomechanics. Here we show task-specific differences in recruitment between layers during respiratory tasks in women. The deep layer was more tightly modulated with respiration than the superficial layer, but activation of the superficial layer was greater during maximal/submaximal occluded respiratory efforts and earlier during cough. These data highlight tightly coordinated recruitment of discrete pelvic floor muscles for respiration.

What decreases low back pain? A qualitative study of patient perspectives

Background and aims

This study aimed to determine, from the perspective of individuals living with the condition, what decreases their low back pain (LBP). LBP affects most people at some point during their life. The condition has a meaningful effect on people’s lives including pain, reduced physical and social function, mood fluctuations, and a reduced ability to work. Despite a considerable amount of research on the topic, few strategies to reduce LBP are considered successful, and there has been little investigation into what individuals with the condition believe reduce it. This study aimed to address this gap in the literature by investigating what individuals with the condition believe reduces their LBP.

Methods

We employed a descriptive qualitative design using a custom-built online survey. Participants were 130 adults in Australia who self-identified as having current or having had previous LBP with or without co-morbidities. Data from the survey responses were analysed using content analysis to determine which management approaches participants considered to be effective in reducing their LBP.

Results

Participants most commonly said that they believed their LBP was reduced by: heat/cold (86, 66%), medication (84, 64.1%), and rest (78, 60%). Next most common was activity/exercise (73, 55.7%). Other factors such as consulting a health professional (52, 39.7%), stretching/therapeutic exercise (50, 38.1%), resting from aggravating activities (45, 34.3%), and psychological changes (41, 31.3%) were mentioned, but considerably less often.

Conclusions

Current literature points to the inefficacy of many of the factors participants reported as helping to reduce the effects of their condition, including the treatments that were most commonly listed by the participants in this study, namely: heat/cold, medication and rest. A possible cause of this discrepancy might be that individuals with LBP consider temporary relief (on a scale of hours) to be an acceptable outcome, whereas clinical trials tend to consider efficacy by long term outcomes (on a scale of weeks, months or years).

Implications

There are several implications of this research. From one perspective, there is the implication that public education about efficacious treatments may need to be enhanced as there is a discrepancy between research findings and the perspectives of individuals living with LBP. On the other hand, these findings also suggest that it is timely to re-examine the focus of LBP research to consider outcomes that are valuable to people living with the condition, which this study implies should include short term or temporary effects. The findings may also help clinicians tailor management to suit the individual patients by increasing the awareness that patient and research perspectives may at times diverge.

Activity of Deep and Superficial Pelvic Floor Muscles in Women in Response to Different Verbal Instructions: A Preliminary Investigation Using a Novel Electromyography Electrode

INTRODUCTION

Verbal instructions are used clinically to encourage activation of the pelvic floor muscles (PFM). Whether separate layers of PFM activate differently in response to instructions remains unknown.

AIM

To test the hypotheses that (i) instructions that aimed to bias activity of a specific muscle layer would increase activation of the targeted layer to a greater extent than the other layer, (ii) activity of individual PFM layers would differ between instructions, and (iii) PFM activity would be symmetrical for all instructions.

METHOD

PFM electromyography (EMG) was recorded using custom-designed surface electrodes in 12 women without PFM dysfunction. The electrode included 4 pairs of recording surfaces orientated to measure EMG from deep and superficial PFM on each side. 3 submaximal contractions were performed for 5 seconds in response to 7 verbal instructions. Root-mean-squared EMG amplitude was calculated for 1 second during the period when participants most closely matched the target activation level. A repeated-measures anova was used to test whether PFM EMG differed between instructions and between regions. The EMG increase of individual muscles relative to that of the reference muscle [deep/right PFM] was compared to no change with t-tests for single samples.

MAIN OUTCOME MEASURE

PFM EMG amplitude.

RESULTS

Superficial PFM EMG was greater than deep PFM for all instructions (P = .039). 2 instructions induced the greatest amplitude of EMG for the superficial PFM: "squeeze the muscles around the vaginal opening as if to purse lips of your mouth" and "draw the clitoris in a posterior direction" (P = .036). Asymmetry was found in the deeper PFM in 3 instructions designed to bias the superficial PFM.

STRENGTH & LIMITATIONS

This preliminary study recorded activation of deep and superficial PFM layers in females with a custom-designed novel electrode. Some cross-talk of recording between muscle layers is possible but unlikely to impact the major findings.

CONCLUSION

Verbal instructions used to teach PFM contractions can influence their pattern of activity. This study provides preliminary evidence that, in a selection of verbal instructions, the superficial PFM activates more than the deep PFM, and that the deep PFM can have asymmetrical activation. Aljuraifani R, Stafford RE, Hall LM, et al. Activity of Deep and Superficial Pelvic Floor Muscles in Women in Response to Different Verbal Instructions: A Preliminary Investigation Using a Novel Electromyography Electrode J Sex Med 2019;16:673-679.

A Definition of "Flare" in Low Back Pain: A Multiphase Process Involving Perspectives of Individuals With Low Back Pain and Expert Consensus

Low back pain (LBP) varies over time. Consumers, clinicians, and researchers use various terms to describe LBP fluctuations, such as episodes, recurrences and flares. Although "flare" is use commonly, there is no consensus on how it is defined. This study aimed to obtain consensus for a LBP flare definition using a mixed-method approach. Step 1 involved the derivation of a preliminary candidate flare definition based on thematic analysis of views of 130 consumers in consultation with an expert consumer writer. In step 2, a workshop was conducted to incorporate perspectives of 19 LBP experts into the preliminary flare definition, which resulted in 2 alternative LBP flare definitions. Step 3 refined the definition using a 2-round Delphi consensus with 50 experts in musculoskeletal conditions. The definition favored by experts was further tested with 16 individuals with LBP in step 4, using the definition in three scenarios. This multiphase study produced a definition of LBP flare that distinguishes it from other LBP fluctuations, represents consumers' views, involves expert consensus, and is understandable by consumers in clinical and research contexts: "A flare-up is a worsening of your condition that lasts from hours to weeks that is difficult to tolerate and generally impacts your usual activities and/or emotions." Perspective: A multiphase process, incorporating consumers' views and expert consensus, produced a definition of LBP flare that distinguishes it from other LBP fluctuations.

The nociceptive withdrawal reflex of the trunk is organized with unique muscle receptive fields and motor strategies

Noxious stimuli induce a nociceptive withdrawal reflex (NWR) to protect the tissue from injury. Although the NWR was once considered as a stereotyped response, previous studies report distinct responses depending on the stimulation site and context for limbs. We aimed to determine whether noxious stimuli over the trunk produced adaptable complex NWR. We hypothesized that organization of the NWR of the trunk muscle would vary with the site of noxious input and would differ between body and spine postures, which modify the potential for specific muscles to remove threat. Fourteen participants were tested in sitting and three lumbar spine postures in side lying (neutral, flexion and extension). Noxious electrical stimuli were applied over the sacrum, spinous process of L3 and T12, lateral side of the 8th rib and anterior midline. NWR latency and amplitude were recorded with surface electromyography (EMG) electrodes over different trunk muscles. Distinct patterns of muscle activation depended on the stimulation site and were consistent with motor strategies needed to withdraw from the noxious stimuli. The NWR pattern differed between body positions, with less modulation observed in sitting than side lying. Spine posture did not affect the NWR organisation. Our results suggest the circuits controlling trunk muscle NWR presents with adaptability as a function of stimulation site and body position by utilizing the great complexity of the trunk muscle system to produce an efficient protective response. This suggests that the central nervous system (CNS) uses multiple adaptable strategies that are unique depending on which context the noxious stimuli are applied.