An evaluation of the behavioural inhibition system and behavioural activation system (BIS-BAS) model of pain in athletes.

This study examined coping and pain responses using a behavioural inhibition (BIS) - behavioural activation (BAS) framework in 489 student athletes (M(age) = 20, SD = 4; 69% female). Two samples of athletes (226 pain-free athletes and 232 athletes with current pain) completed surveys assessing BIS- and BAS-related cognitions, emotions, and behaviours. Distinct groupings of BAS-related variables were identified in both samples, evidenced by significant positive correlations within BAS-related variables (positive affect, pain openness, approach thoughts and behaviours). Most BIS-related variables (depression, anxiety, harm beliefs, pain catastrophizing and avoidance behaviours) were also correlated in the sample of athletes with pain; however, this was not observed in pain-free athletes. In athletes with pain, BIS-related variables were significantly associated with pain variables, with this association stronger than that found for BAS-related variables. Regression analyses highlighted the pivotal role of pain catastrophizing as a predictor of pain unpleasantness and intensity. Findings shed light on the factors shaping athletes' coping, pain perception and decisions as to whether to pause or push through. Future investigations to explore these dynamics in more depth may aid in the development of targeted interventions that enhance athletes' ability to cope and to manage pain more effectively.

The Biomechanics Research and Innovation Challenge: Development, Implementation, Uptake, and Reflections on the Inaugural Program.

Biomechanics as a discipline is ideally placed to increase awareness and participation of girls and women in science, technology, engineering, and mathematics. A nationwide Biomechanics and Research Innovation Challenge (BRInC) centered on mentoring and role modeling was developed to engage high school girls (mentees) and early-mid-career women (mentors) in the field of biomechanics through the completion of a 100-day research and/or innovation project. This manuscript describes the development, implementation, and uptake of the inaugural BRInC program and synthesizes the research and innovation projects undertaken, providing a framework for adoption of this program within the global biomechanics community. Eighty-seven high school girls in years 9 and 10 (age range: 14-16 y) were mentored in teams (n = 17) by women in biomechanics (n = 24). Using a design thinking approach, teams generated solutions to biomechanics-based problem(s)/research question(s). Eight key reflections on program strengths, as well as areas for improvement and planned changes for future iterations of the BRInC program, are outlined. These key reflections highlight the innovation, impact, and scalability of the program; the importance of a program framework and effective communication tools; and implementation of strategies to sustain the program as well as the importance of diversity and building a sense of community.

Adaptability of the load sharing between the longissimus and components of the multifidus muscle during isometric trunk extension in healthy individuals.

PURPOSE: Redundancy of the musculoskeletal system implies multiple strategies are theoretically available to coordinate back extensor muscles. This study investigated whether coordination between back muscles during a tightly constrained isometric trunk extension task varies within and between individuals, and whether this changes following brief exposure to activation feedback of a muscle. METHODS: Nine healthy participants performed three blocks of two repetitions of ramped isometric trunk extension in side-lying against resistance from 0-30% of maximum voluntary contraction over 30 s (force feedback). Between blocks, participants repeated contractions with visual feedback of electromyography (EMG) from either superficial (SM) or deep multifidus (DM), in two conditions; 'After SM' and 'After DM'. Intramuscular EMG was recorded from SM, DM, and longissimus (LG) simultaneously with shear wave elastography (SWE) from SM or DM. RESULTS: In the 'Natural' condition (force feedback only), group data showed incremental increases in EMG with force, with minor changes in distribution of activation between muscles as force increased. SM was the most active muscle during the 'Natural' condition, but with DM most active in some participants. Individual data showed that coordination between muscles differed substantially between repetitions and individuals. Brief exposure to EMG feedback altered coordination. SWE showed individual variation, but findings differed from EMG. CONCLUSION: This study revealed substantial variation in coordination between back extensor muscles within and between participants, and after exposure to feedback, in a tightly constrained task. Shear modulus revealed similar variation, but with an inconsistent relationship to EMG. These data highlight highly flexible control of back muscles.

Distinct displacement of the superficial and deep fascial layers of the iliotibial band during a weight shift task in runners: An exploratory study.

Motion of the fascial layers of the iliotibial band (ITB), as a reinforcement of the deep fascia lata, is likely to be relevant for its function and mechanical behaviour. This exploratory study aimed to evaluate the ITB fascial layers displacement during a weight shift task. Thirteen pain-free runners performed a 6-second standing weight shift task. B-mode ultrasound imaging using an automated fascicle tracking algorithm was used to measure proximal and distal displacement of superficial and deep ITB layers at the middle region. To study the potential contributors to individual variation of fascial motion, we recorded the activity of five hip/thigh muscles with electromyography (EMG), thigh/pelvis/trunk position with accelerometers, and centre of pressure with a force plate. Linear regressions estimated the relationship between displacement of fascial layers and hip/trunk angles. Independent t-tests or Fisher's exact tests compared EMG and movement-related parameters between participants who demonstrated motion of the fascia in the proximal and distal directions. Thickness of the ITB and the loose connective tissue between its layers were calculated. Proximal displacement was observed in six (-4.1 ± 1.9 mm [superficial]) and two (-6.2 ± 2.0 mm [deep]) participants. Distal displacement was observed for seven participants for each layer (3.1 ± 1.1 mm [superficial]; 3.6 ± 1.3 mm [deep]). Four participants did not show displacement of the deep layer. Trunk lateral flexion and gluteus medius muscle activity were determinants of proximal motion of the superficial layer. Loose connective tissue was thinner in participants without displacement of the deep layer. Displacement of the ITB fascial layers varies between individuals. Variation related to differences in joint movements and muscle activity. This study highlights the complex interaction between fascia and movement.

Trail running injury risk factors: a living systematic review.

OBJECTIVE: To review and frequently update the available evidence on injury risk factors and epidemiology of injury in trail running. DESIGN: Living systematic review. Updated searches will be done every 6 months for a minimum period of 5 years. DATA SOURCES: Eight electronic databases were searched from inception to 18 March 2021. ELIGIBILITY CRITERIA: Studies that investigated injury risk factors and/or reported the epidemiology of injury in trail running. RESULTS: Nineteen eligible studies were included, of which 10 studies investigated injury risk factors among 2 785 participants. Significant intrinsic factors associated with injury are: more running experience, level A runner and higher total propensity to sports accident questionnaire (PAD-22) score. Previous history of cramping and postrace biomarkers of muscle damage is associated with cramping. Younger age and low skin phototypes are associated with sunburn. Significant extrinsic factors associated with injury are neglecting warm-up, no specialised running plan, training on asphalt, double training sessions per day and physical labour occupations. A slower race finishing time is associated with cramping, while more than 3 hours of training per day, shade as the primary mode of sun protection and being single are associated with sunburn. An injury incidence range 0.7-61.2 injuries/1000 hours of running and prevalence range 1.3% to 90% were reported. The lower limb was the most reported region of injury, specifically involving blisters of the foot/toe. CONCLUSION: Limited studies investigated injury risk factors in trail running. Our review found eight intrinsic and nine extrinsic injury risk factors. This review highlighted areas for future research that may aid in designing injury risk management strategies for safer trail running participation.PROSPERO registration numberCRD42021240832.

Implementation of physiotherapy telerehabilitation before and post Covid-19 outbreak: A comparative narrative between South American countries and Australia.

The continuous development in telecommunication tech-nologies has created opportunities for health professionals to optimise healthcare delivery by adopting digital tools into rehabilitation programs (i.e., telerehabilitation). These tech-nological advances, along with the demographic and social characteristics of each country, have made the implementa-tion of telerehabilitation a disparate process across regions. We have gathered the experience of four countries (Australia, Chile, Brazil, and Colombia) in two different regions (Ocea-nia and South America) to recompile the history pre- and post-Covid-19 outbreak until January of 2021, the barriers to, and facilitators of telerehabilitation, and outline the future challenges for these countries.

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.

Exploring the Characteristics and Preferences for Online Support Groups: Mixed Method Study.

BACKGROUND: Osteoarthritis (OA) is a chronic, disabling, and prevalent disorder. As there is no cure for OA, long-term self-management is paramount. Support groups (SGs) can facilitate self-management among people living with OA. Understanding preferences in design and features of SGs, including online SGs (OSGs), among people with OA can inform future development of SG interventions for this condition. OBJECTIVE: The objective of this study was to investigate health care- and health information-seeking behavior, digital literacy, and preferences for the design of SGs in people with OA. The study also explored the perceived barriers and enablers to being involved in OSGs. METHODS: An online survey study was conducted with a mixed method design (quantitative and qualitative). Individuals aged ≥45 years with knee, hip, or back pain for ≥3 months were recruited from an extant patient database of the Institute of Bone and Joint Research via email invitations. Quantitative elements of the survey included questions about sociodemographic background; health care- and health information-seeking behavior; digital literacy; and previous participation in, and preferences for, SGs and OSGs. Respondents were classified into 2 groups (Yes-SG and No-SG) based on previous participation or interest in an SG. Group differences were assessed with Chi-square tests (significance level set at 5%). Responses to free-text questions relating to preferences regarding OSG engagement were analyzed qualitatively using an inductive thematic analysis. RESULTS: A total of 415 people with OA completed the survey (300/415, 72.3% females; 252/415, 61.0% lived in a major city). The Yes-SG group included 307 (307/415, 73.9%) participants. Between the Yes-SG and No-SG groups, there were no differences in sociodemographic characteristics, health care- and health information-seeking behavior, and digital literacy. An online format was preferred by 126/259 (48.7%) of the Yes-SG group. Trained peer facilitators were preferred, and trustworthiness of advice and information were highly prioritized by the respondents. Qualitative analysis for OSG participation revealed 5 main themes. Lack of time and motivation were the main barriers identified. The main enablers were related to accessibility, enjoyment of the experience, and the content of the discussed information. CONCLUSIONS: These findings highlight the preferences in design features and content of SGs and OSGs and may assist in the further development of such groups.

Poor sleep versus exercise: A duel to decide whether pain resolves or persists after injury.

Poor sleep is thought to enhance pain via increasing peripheral and/or central sensitization. Aerobic exercise, conversely, relives pain via reducing sensitization, among other mechanisms. This raises two clinical questions: (1) does poor sleep contribute to the transition from acute-to-persistent pain, and (2) can exercise protect against this transition? This study tested these questions and explored underlying mechanisms in a controlled injury model. Twenty-nine adult female Sprague-Dawley rats performed an intensive lever-pulling task for 4 weeks to induce symptoms consistent with clinical acute-onset overuse injury. Rats were then divided into three groups and exposed for 4 weeks to either: voluntary exercise via access to a running wheel, sleep disturbance, or both. Pain-related behaviours (forepaw mechanical sensitivity, reflexive grip strength), systemic levels of brain derived neurotrophic factor (BDNF), estradiol and corticosterone, and white blood cells (WBC) were assessed pre-injury, post-injury and post-intervention. Mechanical sensitivity increased post-injury and remained elevated with sleep disturbance alone, but decreased to pre-injury levels with exercise both with and without sleep disturbance. Reflexive grip strength decreased post-injury but recovered post-intervention-more with exercise than sleep disturbance. BDNF increased with sleep disturbance alone, remained at pre-injury levels with exercise regardless of sleep, and correlated with mechanical sensitivity. WBCs and estradiol increased with exercise alone and together with sleep disturbance, respectively. Corticosterone was not impacted by injury/intervention. Findings provide preliminary evidence for a role of poor sleep in the transition from acute-to-persistent pain, and the potential for aerobic exercise to counter these effects. BDNF might have a role in these relationships.

Consensus for experimental design in electromyography (CEDE) project: Checklist for reporting and critically appraising studies using EMG (CEDE-Check).

The diversity in electromyography (EMG) techniques and their reporting present significant challenges across multiple disciplines in research and clinical practice, where EMG is commonly used. To address these challenges and augment the reproducibility and interpretation of studies using EMG, the Consensus for Experimental Design in Electromyography (CEDE) project has developed a checklist (CEDE-Check) to assist researchers to thoroughly report their EMG methodologies. Development involved a multi-stage Delphi process with seventeen EMG experts from various disciplines. After two rounds, consensus was achieved. The final CEDE-Check consists of forty items that address four critical areas that demand precise reporting when EMG is employed: the task investigated, electrode placement, recording electrode characteristics, and acquisition and pre-processing of EMG signals. This checklist aims to guide researchers to accurately report and critically appraise EMG studies, thereby promoting a standardised critical evaluation, and greater scientific rigor in research that uses EMG signals. This approach not only aims to facilitate interpretation of study results and comparisons between studies, but it is also expected to contribute to advancing research quality and facilitate clinical and other practical applications of knowledge generated through the use of EMG.

Consensus for experimental design in electromyography (CEDE) project: Single motor unit matrix.

The analysis of single motor unit (SMU) activity provides the foundation from which information about the neural strategies underlying the control of muscle force can be identified, due to the one-to-one association between the action potentials generated by an alpha motor neuron and those received by the innervated muscle fibers. Such a powerful assessment has been conventionally performed with invasive electrodes (i.e., intramuscular electromyography (EMG)), however, recent advances in signal processing techniques have enabled the identification of single motor unit (SMU) activity in high-density surface electromyography (HDsEMG) recordings. This matrix, developed by the Consensus for Experimental Design in Electromyography (CEDE) project, provides recommendations for the recording and analysis of SMU activity with both invasive (needle and fine-wire EMG) and non-invasive (HDsEMG) SMU identification methods, summarizing their advantages and disadvantages when used during different testing conditions. Recommendations for the analysis and reporting of discharge rate and peripheral (i.e., muscle fiber conduction velocity) SMU properties are also provided. The results of the Delphi process to reach consensus are contained in an appendix. This matrix is intended to help researchers to collect, report, and interpret SMU data in the context of both research and clinical applications.

Cross-cultural adaptation and evaluation of the psychometric properties of the University of Wisconsin Running Injury and Recovery Index questionnaire in Spanish (UWRI-S).

OBJECTIVE: To cross-culturally adapt and evaluate the psychometric properties of the University of Wisconsin Running Injury and Recovery Index questionnaire in Spanish (UWRI-S) in Chilean runners with a running-related injury. DESIGN: Cross-cultural adaptation and validation study, following the Consensus-based Standards for selecting health Measurement Instruments (COSMIN) recommendations. SETTING: Outpatient sports medicine clinic and running clubs. PARTICIPANTS: UWRI was forward and backward translated, and culturally adapted. Thirty-one runners participated in the content validity of the UWRI-S; and fifty-seven in the assessment of psychometric properties. MAIN OUTCOME MEASURES: Runners seeking care from a physiotherapist completed the UWRI-S (baseline and after 48-72 h for reliability), Lower Extremity Functional Scale (LEFS), Patient Specific Functional Scale (PSFS), Global Rating of Change scale (GROC), and Numeric Pain Rating Scale (NPRS). RESULTS: Suggestions about accuracy of wording and understanding of items were incorporated. UWRI-S showed a positive moderate correlation with LEFS (r = 0.6; p < 0.05), positive fair with GROC (r = 0.5, p < 0.05), negative fair with NPRS (r = -0.4; p < 0.05) and no correlation with PSFS (r = 0.3; p = 0.1). UWRI-S demonstrated acceptable internal consistency (α = 0.87) and test-retest reliability (ICC = 0.87). CONCLUSION: UWRI-S is a valid and reliable measure to evaluate running ability of Chilean runners during recovery from a running-related injury.

Soleus muscle and Achilles tendon compressive stiffness is related to knee and ankle positioning.

Changes in fascicle length and tension of the soleus (SOL) muscle have been observed in humans using B-mode ultrasound to examine the knee from different angles. An alternative technique of assessing muscle and tendon stiffness is myometry, which is non-invasive, accessible, and easy to use. This study aimed to estimate the compressive stiffness of the distal SOL and Achilles tendon (AT) using myometry in various knee and ankle joint positions. Twenty-six healthy young males were recruited. The Myoton-PRO device was used to measure the compressive stiffness of the distal SOL and AT in the dominant leg. The knee was measured in two positions (90° of flexion and 0° of flexion) and the ankle joint in three positions (10° of dorsiflexion, neutral position, and 30° of plantar flexion) in random order. A three-way repeated-measures ANOVA test was performed. Significant interactions were found for structure × ankle position, structure × knee position, and structure × ankle position × knee position (p < 0.05). The AT and SOL showed significant increases in compressive stiffness with knee extension over knee flexion for all tested ankle positions (p < 0.05). Changes in stiffness relating to knee positioning were larger in the SOL than in the AT (p < 0.05). These results indicate that knee extension increases the compressive stiffness of the distal SOL and AT under various ankle joint positions, with a greater degree of change observed for the SOL. This study highlights the relevance of knee position in passive stiffness of the SOL and AT.

Expert-Moderated Peer-to-Peer Online Support Group for People With Knee Osteoarthritis: Mixed Methods Randomized Controlled Pilot and Feasibility Study.

BACKGROUND: Osteoarthritis (OA) is a major problem globally. First-line management comprises education and self-management strategies. Online support groups may be a low-cost method of facilitating self-management. OBJECTIVE: The aim of this randomized controlled pilot study is to evaluate the feasibility of the study design and implementation of an evidence-informed, expert-moderated, peer-to-peer online support group (My Knee Community) for people with knee OA. The impacts on psychological determinants of self-management, selected self-management behaviors, and health outcomes were secondary investigations. METHODS: This mixed methods study evaluated study feasibility (participant recruitment, retention, and costs), experimental intervention feasibility (acceptability and fidelity to the proposed design, including perceived benefit, satisfaction, and member engagement), psychological determinants (eg, self-efficacy and social support), behavioral measures, health outcomes, and harms. Of a total of 186, 63 (33.9%) participants (41/63, 65% experimental and 22/63, 35% control) with self-reported knee OA were recruited from 186 volunteers. Experimental group participants were provided membership to My Knee Community, which already had existing nonstudy members, and were recommended a web-based education resource (My Joint Pain). The control group received the My Joint Pain website recommendation only. Participants were not blinded to their group allocation or the study interventions. Participant-reported data were collected remotely using web-based questionnaires. A total of 10 experimental group participants also participated in semistructured interviews. The transcribed interview data and all forum posts by the study participants were thematically analyzed. RESULTS: Study feasibility was supported by acceptable levels of retention; however, there were low levels of engagement with the support group by participants: 15% (6/41) of participants did not log in at all; the median number of times visited was 4 times per participant; only 29% (12/41) of participants posted, and there were relatively low levels of activity overall on the forum. This affected the results for satisfaction (overall mean 5.9/10, SD 2.7) and perceived benefit (17/31, 55%: yes). There were no differences among groups for quantitative outcomes. The themes discussed in the interviews were connections and support, information and advice, and barriers and facilitators. Qualitative data suggest that there is potential for people to derive benefit from connecting with others with knee OA by receiving support and assisting with unmet informational needs. CONCLUSIONS: Although a large-scale study is feasible, the intervention implementation was considered unsatisfactory because of low levels of activity and engagement by members. We recommend that expectations about the support group need to be made clear from the outset. Additionally, the platform design needs to be more engaging and rewarding, and membership should only be offered to people willing to share their personal stories and who are interested in learning from the experiences of others. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12619001230145; http://anzctr.org.au/Trial/Registration/TrialReview.aspx?id=377958.

Do the General Public and Health Care Professionals Think That Running Is Bad for the Knees? A Cross-sectional International Multilanguage Online Survey.

Background: Running is a popular sport with widely recognized health benefits. Given the high rates of knee injury in runners and the growing prevalence of knee osteoarthritis (KOA), it may be useful to assess perceptions about running and knee joint health. Purpose: The objectives of this study were to (1) explore and compare the perceptions of the general public (PUB) and health care professionals (HCPs) on the topic of running and knee health and (2) explore recommendations about running and knee health provided by HCPs. Study Design: Cross-sectional study. Methods: We conducted an online survey between June 18 and October 1, 2020. The questionnaire included questions on running and knee health, and HCPs were asked about their typical recommendations and level of confidence in providing recommendations on the topic. Perceptions (proportions) were compared between the PUB and HCPs using the chi-square test. Results: In total, 4521 responses (PUB, n = 2514; HCPs, n = 2007) were analyzed. A greater proportion of HCPs perceived regular running as healthy for knees (86% vs 68%; P < .001). More of the PUB than HCPs (P < .001) believed that running frequently (29% vs 13%), long distances (54% vs 45%), and on hard surfaces (60% vs 36%) increased the risk of developing KOA. Running for those with KOA was perceived by the PUB as posing an increased risk of getting more knee pain (48%) and needing joint replacement surgery (38%), more so than by HCPs (26% and 17%, respectively). The majority of HCPs reported being relatively confident in providing evidence-based recommendations about running and knee health and mostly recommended that runners with KOA modify training parameters instead of quit. Conclusion: More HCPs perceived running as healthy for knees when compared with the PUB. Most HCPs felt confident in providing evidence-based recommendations about running and knee health.

Consensus for experimental design in electromyography (CEDE) project: High-density surface electromyography matrix.

High-density surface electromyography (HDsEMG) can be used to measure the spatial distribution of electrical muscle activity over the skin. As this distribution is associated with the generation and propagation of muscle fiber action potentials, HDsEMG is processed to extract information on regional muscle activation, muscle fiber characteristics and behaviour of individual motor units. This matrix, developed by the Consensus for Experimental Design in Electromyography (CEDE) project, summarizes recommendations on the use of HDsEMG in experimental studies. For each application, recommendations are included regarding electrode montage, electrode type and configuration, electrode location and orientation, data analysis, and interpretation. Cautions and reporting standards are also included. The steps of the Delphi process to reach consensus are contained in an appendix. This matrix is intended to help researchers when collecting, reporting, and interpreting HDsEMG data. It is hoped that this document will be used to generate new empirical evidence to improve how HDsEMG is used in research and in clinical applications.

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.

Shear modulus of multifidus and longissimus muscles measured using shear wave elastography correlates with muscle activity, but depends on image quality.

Shear wave elastography (SWE) estimates shear modulus in muscle. This is interpreted as an index of muscle stiffness, but depends on muscle characteristics. This study evaluated relationship between shear modulus and myoelectric activity of lumbar multifidus and longissimus muscles to assess its validity. Intramuscular electromyography (EMG) of multifidus (deep [DM], superficial [SM] fibres) at L4/5, longissimus [LG] at L2, were recorded in nine healthy participants. Participants performed isometric trunk extension in side-lying from 0 to 30% maximal voluntary contraction (MVC) with EMG amplitude feedback. Using SWE, two regions of interest (ROI) were investigated in each muscle. Generally, shear modulus was moderately correlated with root mean squared (RMS) EMG (r = 0.50-0.78). Univariate and multiple regression analyses showed ultrasound/SWE features of 'B-mode quality' (24.5%), '%Void pixels' (17.9%) and 'Connective tissue' (16.2%) explained most variation in the shear modulus/EMG relationship. Regression prediction scores generated using imaging features were correlated with r-coefficients of shear modulus/EMG relationship. When analysis was restricted to high quality data (i.e., regression prediction score above an a priori defined threshold), the shear modulus/EMG relationship increased to r = 0.70-0.96. Although a linear relationship between shear modulus/EMG was confirmed, supporting validity of SWE measures in anatomically distinct back muscles, this depends on image quality.

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.