Strength Measurements Research Articles

Method for improving accurate measurement of the magnetic field of wireless passive micro-magnetic stimulator micro-coil

In recent years, the wireless passive micro-magnetic stimulator (WP-μMS) has emerged as a focal for implantable neuromagnetism modulation research. However, accurately measuring the magnetic field strength of the micro-coil presents a significant challenge due to its small size and low mutual inductance (M). Firstly, this paper establishes a theoretical model of magnetic coupling with a three-stage structure of transmitting coil-micro-coil-detecting coil. The calculation method of detecting the coil to measure the magnetic field is determined by calculating the M between each pair of coils. Secondly, the magnetic coupling resonance method enhances the measured value M to the nH-scale. This approach also eliminates the influence of the M between the transmitting coil-detecting coil on the measurement of the transmitting coil-micro-coil M, thereby achieving accurate measurement of the mT-scale magnetic field strength of the WP-μMS micro-coil. Finally, the effectiveness of the measured mT-scale magnitude magnetic stimulation is validated biologically.

Challenges in the measurement of cross-shore geotechnical characteristics of sandy beach surface sediments

Geotechnical properties of surficial beach sediments affect beach erosion and shoreline changes. This study sets out to measure relative density, moisture content, friction angle, and shear strength of sandy beach surface sediments from dune to swash zone towards the goal of assessing their importance in sandy beach morphodynamics. Methods of sediment sampling, a conductivity based moisture probe, field penetrometers, and a field vane shear were deployed to collect data at the sandy Atlantic-side beach in Duck, North Carolina. The tools used were assessed based on their operability in the beach environment and data quality, and results are discussed in the context of beach morphodynamics. A digital field vane shear provided an efficient and direct method of measuring shear strength, but the difficulty of computing stresses on the failure plane, which is necessary to validate the results, ultimately reduced the usability of this instrument. The results from three penetrometers were compared to a partially-saturated bearing capacity model, where a portable free-fall penetrometer yielded the best fit. However, a modified velocity-dependent strain rate correction factor (K=0.31vi) was required to convert dynamic sediment resistance to a quasi-static resistance for the partially saturated sands. A small-scale digital push in penetrometer also achieved a positive correlation when compared to moisture content, but the small tip diameter (5 mm) coupled with the grain size at the beach (0.35 mm) raised concerns about the ability to derive an accurate measure of strength. It was determined that estimating strength parameter using a partially saturated bearing capacity model was appropriate for water contents less than 25% by volume, or anywhere in the crosshore above the swash to the dune. Relative density and moisture content were found to be closely linked, with partial saturation resulting in samples that featured negative relative densities up to −40%.

Investigating the effects of synbiotic supplementation on functional movement, strength and muscle health in older Australians: a study protocol for a double-blind, randomized, placebo-controlled trial

BackgroundAging has been associated with a progressive loss of skeletal muscle quality, quantity and strength, which may result in a condition known as sarcopenia, leading to a decline in physical performance, loss of independence and reduced quality of life. While the cause of impaired physical functioning observed in elderly populations appears to be multifactorial, recent evidence suggests that age-associated alterations in gut microbiota could be a contributing factor. The primary objective will be to assess the effects of a dietary synbiotic formulation on sarcopenia-related functional outcomes such as handgrip strength, gait speed and physical performance within older individuals living independently. The secondary objective will be to examine associations between changes in gut microbiota composition, functional performance and lean muscle mass.MethodsSeventy-four elderly (60–85 years) participants will be randomized in a double-blind, placebo-controlled fashion to either an intervention or control group. The intervention group (n = 37) will receive oral synbiotic formulation daily for 16 weeks. The control group (n = 37) will receive placebo. Assessments of physical performance (including Short Physical Performance Battery, handgrip strength and timed up-and-go tests) and muscle ultrasonography will be performed at 4 time points (baseline and weeks 8, 16 and 20). Likewise, body composition via bioelectric impedance analysis and blood and stool samples will be collected at each time point. Dual-energy X-ray absorptiometry will be performed at baseline and week 16. The primary outcomes will be between-group changes in physical performance from baseline to 16 weeks. Secondary outcomes include changes in body composition, muscle mass and architecture, fecal microbiota composition and diversity, and fecal and plasma metabolomics.DiscussionGut-modulating supplements appear to be effective in modifying gut microbiota composition in healthy older adults. However, it is unclear whether these changes translate into functional and/or health improvements. In the present study, we will investigate the effects of a synbiotic formulation on measures of physical performance, strength and muscle health in healthy older populations.Trial registrationThis study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12622000652774) in May 2022.

Improving the identification of bone-specific physical activity using wrist-worn accelerometry: A cross-sectional study in 11-12-year-old Australian children.

Physical activity (PA) during childhood and adolescence is important for the accrual of maximal peak bone mass. The precise dose that benefits bone remains unclear as methods commonly used to analyze PA data are unsuitable for measuring bone-relevant PA. Using improved accelerometry methods, this study identified the amount and intensity of PA most strongly associated with bone outcomes in 11-12-year-olds. Participants (n=770; 382 boys) underwent tibial peripheral quantitative computed tomography to assess trabecular and cortical density, endosteal and periosteal circumference and polar stress-strain index. Seven-day wrist-worn raw acceleration data averaged over 1-s epochs was used to estimate time accumulated above incremental PA intensities (50 milli-gravitational unit (mg) increments from 200 to 3000mg). Associations between time spent above each 50mg increment and bone outcomes were assessed using multiple linear regression, adjusted for age, sex, height, weight, maturity, socioeconomic position, muscle cross-sectional area and PA below the intensity of interest. There was a gradual increase in mean R2 change across all bone-related outcomes as the intensity increased in 50mg increments from >200 to >700mg. All outcomes became significant at >700mg (R2 change=0.6%-1.3% and p=0.001-0.02). Any further increases in intensity led to a reduction in mean R2 change and associations became non-significant for all outcomes >1500mg. Using more appropriate accelerometry methods (1-s epochs; no a priori application of traditional cut-points) enabled us to identify that ∼10min/day of PA >700mg (equivalent to running ∼10km/h) was positively associated with pQCT-derived measures of bone density, geometry and strength in 11-12-year-olds.

Consideration of the Accuracy of Empirical and Indirect Laboratory Methods for the Characterisation of Tension Strength

This research explores the results of the most common laboratory based indirect tension strength methods over the range of UCS strengths 0.1 MPa (cemented paste backfill) to 100 MPa (concrete). The accuracy of each of the methods is considered through a comparison with direct strength measurements completed on the same material. The results of 241 individual tests suggest that the use of indirect tension methods to determine tension strength for all geo-material strength ranges may provide misleading results unless a correction-factor is applied. Correction factors that relate splitting and flexure results to direct tension results are provided. The correction factors are based on the characteristic UCS of the material. A comparison of the traditional empirical relationship to derive tension from UCS is presented and an updated relationship is proposed that is relevant over the UCS strength range 0.1–100 MPa.

In-situ and label-free measurement of cytochrome C concentration with a Ti2C-MXene sensitized fiber-optic MZI sensor

BackgroundThe concentration of cytochrome C is demonstrated to be an effective indicator of the microbial corrosion strength of metals. Traditional cytochrome C sensor can detect cytochrome C with a low detection limit, but their use is limited by their high cost, cumbersome operation, and susceptibility to malignant environments. In addition, studies on the monitoring of cytochrome C in the field of microbial corrosion has still not been carried out. Therefore, there is a need for a highly sensitive, selective, low-cost, anti-interference, and stable cytochrome C sensor with online monitoring and remote sensing capabilities for in-situ measurement of microbial corrosion strength. ResultsThis paper proposed a highly sensitive label-free fiber-optic sensor based on Mach-Zehnder interferometer (MZI) for in-situ measurement of the microbial corrosion marker cytochrome C. Two-dimensional Ti2C-MXene material is uniformly immobilized onto the surface of the sensing area to improve the sensitivity, hydrophilicity, and specific surface area of the sensing area, as well as to facilitate the immobilization of specific sensitive materials. The cytochrome C antibody is modified on the surface of Ti2C-MXene to specifically recognize cytochrome C, whose concentration variation can be measured by monitoring the spectral shift of MZI sensor. Results demonstrate a measurement sensitivity of 1.428 nm/μM for cytochrome C concentrations ranging from 0 to 7.04 μM. The detection limit of the sensor is calculated to be 0.392 μM with remarkable performance, including selectivity, stability, and reliability. Besides, the measurement result of the proposed sensor in real microbial corrosive environment is consistent with that of the ideal environment. Significance and noveltyThis is the first instance of achieving in-situ and label-free measurement of cytochrome C by using a fiber-optic MZI sensor, which undoubtedly provides a feasible solution for the effective monitoring of microbial metal corrosion in the environment.

The reliability, variability and minimal detectable change of multiplanar isometric trunk strength testing using a fixed digital dynamometer

ABSTRACT Trunk strength plays a vital role in athletic performance, rehabilitation and general health, however, current assessment methods are expensive, non-portable or unreliable. This study aimed to investigate the within- and between-session reliability, variability, standard error of measurement and minimal detectable change (MDC) of trunk strength in the sagittal (flexion and extension) and frontal planes (left and right lateral flexion) using a fixed digital dynamometer. Eighteen participants (ten men and eight women) attended two sessions separated by 7 days. Participants were fitted with a trunk harness which was secured to an immovable base via a digital dynamometer. Three maximal voluntary isometric contractions were completed across four positions (prone, supine, left-side recumbent and right-side recumbent, respectively) on a glute-hamstring raise machine. All positions demonstrated excellent reliability and low variability within session (ICC: 0.95–0.98; CV: 5–7%) and between sessions (ICC: 0.98–0.99; CV: 4–6%), across all positions. The between-session MDC ranged from 8% (prone) to 13% (right-side recumbent), translating to absolute values between 2.9 and 3.2 kg across all positions. Maximal isometric force testing using a fixed digital dynamometer provides reliable measurements of multiplanar trunk strength, providing a practical method for use in clinical practice.

Measuring Body Composition and Functional Strength: Implications for the Clinical Assessment of Skeletal Muscle

Skeletal muscle represents the largest single component of the body, comprising up to 50% of total mass in healthy individuals. Body composition assessment has largely focused on overweight and obese individuals, but healthy skeletal muscle is also an important indicator of health and wellbeing. We hypothesized that estimates of lean body mass and empirical measures of functional strength should be directly correlated with one another. In the current study, we estimated body composition using two different field methods. Bioimpedance spectroscopy (BIS) employs 256 frequencies of low energy electrical current to estimate body composition. We used BIS (Impedimed SFB7) to determine percent body fat and fat free mass in physically active volunteers, ranging in age from 18 – 62 years. In addition, we used the Jackson and Pollock 3-site skin fold method to estimate these parameters from the same individuals. We also measured functional strength with a whole body dynamometer to determine mid-thigh pull strength, and a grip dynamometer to assess grip strength (Baseline Evaluation Instruments). Data collected from more than 75 men and women revealed significant correlations between fat-free mass (FFM) and both measures of functional strength. Interestingly, men and women fell along the same trend line, with women exhibiting similar strength for a given FFM. Moreover, functional strength standardized to FFM provides an objective measure of relative strength that was not different between men and women. The American Medical Association released a new policy statement about body mass index (BMI) in June of 2023, highlighting that BMI is an imprecise measure of body composition and recommending that alternative measures, such as more precise measurement of body composition, also be used. Indeed, we found that for individuals with a BMI of less than 30, there was direct relationship between FFM and functional strength. By contrast, percent body fat was not correlated with BMI within this range. We suggest that FFM and functional strength could be used to assess healthy weight, in conjunction with BMI. These measures could also be used to screen for sarcopenia, cachexia, and other conditions associated with significant muscle loss. Skeletal muscle represents an often underappreciated component of health and a more precise assessment of muscle mass and strength should be used as a measure of overall health. This work was supported by a Keenan Award at St. Bonaventure University. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Limited preoperative forward flexion does not impact outcomes between anatomic or reverse shoulder arthroplasty for primary glenohumeral arthritis

BackgroundAnatomic total shoulder arthroplasty (TSA) remains the treatment of choice for primary glenohumeral osteoarthritis with an intact rotator cuff (PGHOA). However, reverse total shoulder arthroplasty (RSA) has gained popularity as a primary procedure in selected patients who may be at risk for postoperative rotator cuff dysfunction or glenoid loosening. The purpose of this study was to compare short-term outcomes between TSA and RSA in patients with PGHOA and limited preoperative forward flexion (FF). MethodsA retrospective review was performed on a multi-institutional registry of patients to identify patients aged less than 80 years undergoing TSA or RSA for PGHOA with preoperative FF ≤ 90°. Forty-five TSAs were identified and matched by age and sex to 45 patients undergoing RSA. A subset of 22 TSAs and 24 RSAs with severely limited preoperative FF of ≤ 70° was also analyzed. Range of motion including FF, external rotation and internal rotation, strength, and patient-reported outcomes including visual analog scale pain score, Western Ontario Osteoarthritis of the Shoulder index score, Veterans RAND 12 mental score, American Shoulder and Elbow Surgeons score, and Constant-Murley score were evaluated at a minimum of 2 years postoperative. ResultsNo significant differences were observed in postoperative FF, external rotation, or strength measurements between groups. The limited FF TSA group achieved significantly improved internal rotation compared to the RSA group (L2 vs. L4, P < .002). No significant differences were observed between TSA and RSA in American Shoulder and Elbow Surgeons, visual analog scale, Constant, or Single Assessment Numeric Evaluation scores (P > .05) for both the overall comparison and subset of patients with FF of ≤ 70°. However, patients in the RSA cohort showed a significantly higher return to normal sporting activities than the TSA group. ConclusionPatients aged less than 80 years with PGHOA and limited preoperative FF achieve similar postoperative range of motion and patient-reported outcomes whether treated with TSA or RSA. Therefore, limited preoperative FF does not appear to be a major determinant of outcomes for PGHOA.

Staged bilateral total shoulder arthroplasty: a single institutional experience with mid-term follow-up

BackgroundThe preferred surgical approach for surgical treatment of advanced glenohumeral arthritis is shoulder arthroplasty (SA). Considering the growing volume and success of SA, patients with bilateral shoulder disease are likely to undergo surgery on both shoulders. There are numerous studies evaluating the outcomes of bilateral hip and knee arthroplasty, but a paucity of information examining bilateral SA. This study intends to evaluate the clinical outcomes of patients undergoing staged bilateral anatomic total shoulder arthroplasty (aTSA) or reverse total shoulder arthroplasty (rTSA). MethodsInstitutional records were queried for patients who underwent staged bilateral aTSA or rTSA from 2009 to 2020. Patient records were retrospectively reviewed to assess preoperative and postoperative range of motion (ROM) and strength measurements, demographic information, and complications. Mean ± standard deviation was reported for all continuous variables. Mean functional measurements were compared using a 2-Sample t-Test, ordinal variables via Wilcoxon-Mann Whitney test, and categorical variables via Chi-squared test. Patients were included in the outcome analysis if they had a bilateral TSA with the same procedure (i.e. aTSA on both sides, or rTSA on both sides). Results43 patients (15 male, 28 female) were included. There was an average time of 1.8 years between surgeries. Of the 43 patients, 26 patients had staged bilateral aTSAs and 14 had staged bilateral rTSAs with three patients who had different surgeries on each shoulder. The three patients with different surgeries on each shoulder were excluded from outcome analysis. Patients who had staged aTSA operations demonstrated significant improvement in external rotation (P = .0191, P < .001), forward elevation (FE) (P = .0004, P < .001), and internal rotation (IR) (P = .0183, P = .0166) after the first and second surgeries. Staged rTSA patients showed significant improvement in FE after the first (P = .0043) and second surgeries (P = .016). Patients demonstrated significant increase in strength of external rotation (P = .0136), FE (P = .0088), and IR (P = .0206) after the first rTSA. There was no corresponding increase in strength testing after the second bilateral rTSA surgery. The average Single Assessment Numeric Evaluation, Contralateral Single Assessment Numeric Evaluation, American Shoulder and Elbow Surgeons, and Simple Shoulder Test scores for all surgeries were 84 ± 10, 83 ± 13, 75 ± 20, and 9 ± 2, respectively for the first surgery and 82 ± 13, 83 ± 13, 71 ± 21, and 8 ± 3 for the second surgery. ConclusionIndividuals that undergo staged aTSA procedures gain a better ROM and IR strength after both operations. However, individuals that undergo staged rTSA procedures have an improved ROM and strength after the first surgery but limited improvement after the second.

HDAC4 Genomic Methylation and Subsequent DNA Binding Following Joint Injury Confers a Sustained Epigenetic Memory of Disrupted Muscle Plasticity

Joint injury is associated with protracted atrophy and weakness that poorly recovers; our objective was to define molecular effectors of lost muscle size, strength, and plasticity following joint injury. We hypothesized that epigenetic imprinting of joint injury in muscle impairs muscle plasticity and contributes to poor functional recovery following surgical repair. We recruited a total of sixteen ACL-injured participants from whom we obtained vastus lateralis muscle biopsies Pre-, 7-days post-, and 4-months post- reconstruction surgery (Sx) and strength measures up to 6-months post-Sx. We performed immunohistochemistry, RNA-seq, reduced representation bisulfite sequencing (RRBS), and HDAC4 chromatin immunoprecipitation sequencing (HDAC4 ChIP-seq) to determine the impact of epigenetics and gene expression on histological profiles, muscle size and muscle strength following injury. Binding and Expression Target Analysis (BETA) of DNA methylation revealed a conserved 985bp regulatory genomic region that was differentially methylated upstream of the HDAC4 promoter. We observed 108 (Pre-Sx), 111 (7d post-Sx), and 110 (4-months post-Sx) differentially methylated promoter sites of which 95 sites were common across all timepoints in the injured limb. Additionally, we observed 1293 differentially methylated intragenic sites within the HDAC4 locus that were also common across all timepoints following injury. Altered HDAC4 methylation was associated with a 2.2 and 4.3 fold change in HDAC4 transcript abundance Pre-Sx and 7d post-Sx, respectively (FDR &lt; 0.05). Notably, HDAC4 binding to critical contractile genes coincided with their downregulation 7d post-Sx (Log2 fold change: ACTA1: -2.02; CKM: -0.97; ATP2A1: -2.34; HOMER2: -1.09; all FDR&lt;0.05). Altered transcript abundance of these genes coincided with lower mean muscle fiber cross-sectional area in the injured limb compared to Healthy (Healthy: 4845 ± 213.4μm2; pre-Sx: 4313 ± 190.6μm2, p&lt;0.05; 7d post-Sx: 3685 ± 228.1μm2, p&lt;0.05; 4-months post-Sx: 3422 ± 142.8μm2, p&lt;0.05) and lower peak torque compared to Healthy (Healthy: 174.8 ± 10.72nm; pre-Sx: 135.2 ± 10.19nm, p&lt;0.05; 4-months post-Sx: 82.64 ± 6.80nm, p&lt;0.05; 6-months post-Sx: 105.9 ± 8.26nm, p&lt;0.05) that was sustained throughout follow-up. Our results suggest that joint injury confers HDAC4 promoter-proximal and intragenic epigenetic imprinting by DNA methylation that increases HDAC4 transcript abundance and HDAC4-DNA binding to represses expression of genes regulating muscle contractile function. This HDAC4 gene regulatory program likely contributes to prolonged deficits in muscle size and strength following joint injury. This work was supported by NIH-NIAMS R01 AR072061. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

WALKING WITH BLOOD FLOW RESTRICTION: A NOVEL METHOD TO IMPROVE PHYSICAL FITNESS IN OLDER ADULTS?

INTRODUCTION AND AIMS Alternative physical activity modalities and methods are needed to combat low adherence among older populations. Therefore, we are investigating whether blood flow restricted (BFR) walking improves measures of lower limb strength, and functional performance, compared to traditional walking in older adults. METHODS Healthy adults ≥60 years were randomised into BFR (n=5) or non-BFR (n=4) walking groups. Both groups walked outdoors, 3 days/week for 12 weeks starting at 4km/h and increasing walking speed by 0.5km/h every 4 weeks. The BFR group walked for 25min with BFR applied (60% arterial occlusion pressure) to the lower limbs in 2x 10mins bouts (separated by 5mins walking without occlusion). The non-BFR group walked for 50mins without occlusion, matching current best practice for low-moderate intensity physical activity. Participants were assessed at baseline and post-intervention (12 weeks) for knee extension maximal voluntary torque (MVTpeak) and functional capacity (four square step test [4SST], 5x sit-to-stand [STS], timed up and go [TUG], gait speed, and 6-minute walk test [6mWT]). RESULTS There were no differences at baseline between groups (p&amp;gt;0.05). Both groups improved across all measures from baseline to post-intervention, with significant effects for time observed for: 4SST (7.92±1.2s – 6.83±1.39s; p=0.035), TUG (6.16±0.81s – 5.58±0.9s; p=0.04), STS (11.30±1.70s – 10.14±1.7s; p=0.032), but not for gait speed (3.98±0.69s – 3.71±0.69s; p=0.456), 6mWT (564.72±72.13m – 601.27±64.2m; p=0.129) and MVTpeak (112.33±25.8Nm – 120.55±23.5Nm; p=0.995). No group x time effect was observed from baseline to 12 weeks (p&amp;gt;0.05). SUMMARY The current results demonstrate significant improvements in functional measures (4SST, TUG, STS) from baseline to post-intervention, with no differences observed between groups. This indicates that low-intensity BFR walking may provide comparable physical fitness improvements to non-BFR walking while completing only 50% of the volume.

Sarcopenia prevalence using handgrip strength or chair stand performance in adults living with type 2 diabetes mellitus.

The updated European Working Group on Sarcopenia in Older People (EWGSOP2) recommends handgrip strength (HGS) and the chair stand test (CST) to assess muscle strength, with the CST being a convenient proxy for lower limb strength. However, adiposity may differentially influence these strength criteria and produce discrepant sarcopenia prevalence. To determine the prevalence of sarcopenia using HGS or the CST, and to investigate the associations between these strength criteria and adiposity in adults with type 2 diabetes mellitus. The EWGSOP2 definition was used to assess the prevalence of probable (low muscle strength), confirmed (plus low muscle mass) and severe (plus poor physical performance) sarcopenia. Linear regression models were used to study the association between different measures of muscle strength and adiposity. We used data from 732 adults with type 2 diabetes mellitus (35.7% female, aged 64 ± 8years, body mass index 30.7 ± 5.0kg/m2). Using the CST compared with HGS produced a higher prevalence of probable (31.7% vs. 7.1%), confirmed (5.6% vs. 1.6%) and severe (1.0% vs. 0.3%) sarcopenia, with poor agreement between strength criteria to identify probable sarcopenia. CST performance, but not HGS, was significantly associated with all measures of adiposity in unadjusted and adjusted models. Higher levels of adiposity may impact CST performance, but not HGS, resulting in a higher prevalence of sarcopenia in adults with type 2 diabetes mellitus. Consideration should be paid to the most appropriate measure of muscle function in this population.

Preparation For Flight: The Physical Profile of Pre-Professional and Professional Circus Artists in the United States.

Established norms for fitness and performance measures are lacking in circus arts. These would assist healthcare professionals and coaches to screen for readiness to participate in training or performance, determine post-injury return to performance, and develop targeted conditioning programs. The purpose of this research was to establish norms for trunk and extremity physical exam and performance measures in circus artists by professional status, assigned sex at birth (ASAB), and age. Descriptive laboratory study. Circus artists (n=201; ages 13-69y; 172 females ASAB, 29 males ASAB) from 10 cities across the United States underwent a baseline physical examination including shoulder, hip and trunk measures of passive (PROM) and active (AROM) range of motion, measures of flexibility (shoulder and hip), strength (manual muscle tests, grip strength), cardiovascular fitness (3 minute-step test), balance (single limb and handstand), and performance, (pull-ups, and the closed kinetic chain upper extremity stability test [CKCUEST]). ANOVAs were used to determine between group differences by age and T-tests to discern differences by ASAB or professional status. Differences existed by professional status for shoulder external rotation PROM, hip PROM, hip flexibility, shoulder and abdominal strength, and cardiovascular fitness. Sex differences were seen in active scapular upward rotation, hip and shoulder PROM and flexibility, hip and grip strength, and for functional performance measures (pull-ups, CKCUEST). Differences by age were limited to active scapular upward rotation, shoulder PROM, flexibility and strength, cardiovascular fitness, and balance. Overall, professionals outperformed pre-professionals for lower abdominal strength, pull-ups, handstand balance, cardiovascular fitness, hamstring, and straddle flexibility. Generally, males ASAB demonstrated greater shoulder flexibility and upper body functional strength while females ASAB had greater hip and lumbar flexibility and hip strength. No measures showed consistent declines with increasing age, though some showed differences between adolescents and adults. These normative values for physical characteristics and functional performance in pre-professional and professional circus artists may be used to guide screening for readiness to participate in advanced training or performance, return to performance after injury, and the development of targeted strength and conditioning programs. 3.

The glucocorticoid receptor acts locally to protect dystrophic muscle and heart during disease.

Absence of dystrophin results in muscular weakness, chronic inflammation and cardiomyopathy in Duchenne muscular dystrophy (DMD). Pharmacological corticosteroids are the DMD standard of care; however, they have harsh side effects and unclear molecular benefits. It is uncertain whether signaling by physiological corticosteroids and their receptors plays a modifying role in the natural etiology of DMD. Here, we knocked out the glucocorticoid receptor (GR, encoded by Nr3c1) specifically in myofibers and cardiomyocytes within wild-type and mdx52 mice to dissect its role in muscular dystrophy. Double-knockout mice showed significantly worse phenotypes than mdx52 littermate controls in measures of grip strength, hang time, inflammatory pathology and gene expression. In the heart, GR deletion acted additively with dystrophin loss to exacerbate cardiomyopathy, resulting in enlarged hearts, pathological gene expression and systolic dysfunction, consistent with imbalanced mineralocorticoid signaling. The results show that physiological GR functions provide a protective role during muscular dystrophy, directly contrasting its degenerative role in other disease states. These data provide new insights into corticosteroids in disease pathophysiology and establish a new model to investigate cell-autonomous roles of nuclear receptors and mechanisms of pharmacological corticosteroids.

PREHABILITATION AND SUPPORTIVE CARE IN ONCOLOGY TREATMENT OF BREAST CANCER: PROACTIVE-B

INTRODUCTION &amp; AIMS Neoadjuvant therapy has become standard treatment for patients with Stage II/III HER2 positive and triple negative breast cancer and in selected patients with locally advanced and borderline resectable high risk, luminal B breast cancer (1). Side effects such as fatigue, cardiotoxicity, neurotoxicity, anxiety, insomnia, vasomotor symptoms, gastrointestinal disturbance as well as a raft of immune-related adverse events, impact treatment tolerance, long term outcomes and quality of life. Post-treatment, many women increase body fat and decrease lean mass and develop metabolic syndrome (2) and accelerated cardiac aging (3). All of these are modifiable targets of exercise. The aim of this study was to determine if an early multi-modal supportive care program, designed through a qualitative study from consumers and healthcare professionals, can mitigate these side effects and improve chemotherapy completion, cardiometabolic, residual cancer burden (pCR) and surgical outcomes. METHODS This was a prospective, mixed-method, feasibility study that recruited 23 women receiving neoadjuvant therapy for breast cancer, combining qualitative and quantitative data collection and analysis. The supervised exercise intervention was designed to include aerobic interval, resistance and balance training twice/week, adapted for symptom burden in each session with relative training dose intensity calculated. An optional home program as also provided with therabands. Body composition, upper and lower body strength and cardiometabolic outcome measures were collected at baseline, end of first and second line of treatment and then 6 months post-surgery. RESULTS Full data will be completed in March 2024 to be presented. There was a high rate of complete pathological response (18/22). Currently, 13 participants have completed 6 month post-surgery assessments and preliminary analyses indicate increases in strength and maintenance of muscle mass during and after treatment. The program was found to be acceptable and feasible with high attendance and satisfaction ratings. The additional home program had poor uptake. Of interest to exercise physiologists was participant responses to cluster set training, how poorly rate of perceived exertion reflected training and strength testing loads, heart rate and blood pressure responses and treatment toxicities including cases of immunotherapy induced hepatitis. Many participants were stronger at the end of chemotherapy than before and reported that exercise gave them a sense of control. CONCLUSION Adapting exercise during neoadjuvant chemotherapy with additional supportive therapies for symptom management, improved physical and psychosocial functioning. The program was feasible and acceptable, with high satisfaction reported. Muscle mass can be maintained with supervised exercise training and maintained and 6 months after surgery.

IN-HOME COMMUNITY AGED CARE FALLS PREVENTION TELEHEALTH PILOT

BACKGROUND A small scale pilot was conducted to test the concept of a remotely delivered in-home prescriptive exercise program for older Australians at risk of falling or with a history of falls. There is limited evidence for the efficacy of remotely delivered falls prevention programs within the aged community setting. Most community models are in-person and resource poor. This can result in older Australians living in isolated locations not having access to a service or provision of a service that cannot support the intervention intensity to produce effective functional gains. In the Residential aged care facility setting, the SUNBEAM trial is evidenced to reduce falls prevalence in participating residents. This pilot aimed to discover if exercise prescription modeled on the SUNBEAM trial could be delivered in a remote format to in-home clients and result in improvement in strength, mobility and balance scores associated with a reduced risk of falling. METHOD The pilot commenced in April 2023 and was delivered by an Accredited Exercise Physiologist for a period of 14 weeks, offering a total of 28 hours of exercise to 6 participants with a history of falls. Participants were provided with a home exercise kit for use and all sessions were conducted as individual appointments, using videoconferencing via the telehealth platform, Coviu. A series of strength and balance related outcome measures and assessments were collected using modified methodology for telehealth. RESULTS The individual results of the program demonstrated gains in strength and balance, directly linked to reducing falls risk. Participants reported meaningful impacts on sense of self from the program. CONCLUSION The pilot was successful in proving the concept of a remotely delivered falls prevention exercise-based program can work for the in-home aged care setting. This warrants future efforts to expand on findings to benefit the wider aged care population residing in their own homes.

Comparison of Pain Characteristics, Strength, and Movement Patterns in Adolescents With Juvenile Fibromyalgia and High Versus Low Fear of Movement

Physical activity avoidance and fear of movement (FOM) is often observed in individuals with chronic musculoskeletal pain, along with difficulties coping with pain. There is little research regarding how FOM may also relate to reduced physical strength and altered movement patterns that may perpetuate a cycle of pain, FOM, and disability. The objective of this observational study was to compare how adolescents with juvenile fibromyalgia (JFM) exhibiting high versus low FOM (Tampa Scale of Kinesiophobia-11) differed on patient-reported measures of pain, fatigue, catastrophizing and pain interference, and performance-based measures of strength, postural control, and biomechanical function. Participants were youth with JFM (N = 135, Meanage = 15.6 years, 88.9% female) enrolled in an ongoing clinical trial who completed self-report questionnaires and standardized tests, including knee and hip strength, the Star Excursion Balance Test, and the Drop Vertical Jump (with 3 dimensional motion capture). Participants were categorized into Low, Medium, and High FOM groups based on Tampa Scale of Kinesiophobia-11 tertile scores. Relative to the Low FOM group, the High FOM group reported significantly greater fatigue, pain interference and catastrophizing, as well as reduced dominant leg knee strength. Additionally, those with high FOM showed altered lower-extremity movement patterns. This preliminary study highlights the importance of combining self-reported measures of symptoms and functioning with physical assessments to gain a more comprehensive view of the impact of FOM in patients with chronic musculoskeletal pain. The results could inform the development of more precise interventions to reduce FOM using a combination of behavioral and exercise-based interventions. PerspectiveThe results of this study demonstrate the association between FOM, fatigue and pain interference in adolescents with JFM, as well as preliminary evidence for altered movement patterns in that may predispose them to further pain/injury and activity avoidance. Clinical trials.gov registrationNCT 03268421

Preparation of a nano aluminum phosphate enhanced hydroxyapatite coating for marble conservation

Open-air marble relics in Beijing are experiencing degradation due to sugaring, dissolution and other illnesses. Therefore, it is necessary to apply a protective and reinforcing coating to the weathered surface. Hydroxyapatite (HAP) has significantly lower solubility and dissolution rate compared to calcite. Additionally, HAP has similar lattice parameters with calcite, suggesting that a cohesive layer of HAP can be formed over calcite. In fact, HAP exhibits a lattice mismatch of 5 % with calcite, which might potentially lead to stress if the layer exceeds a few nanometre in thickness. On the other hand, aluminum phosphates (ideally, B-AlPO4) only exhibit a 1 % mismatch with calcite and have a solubility lower than that of calcite. In this study, in order to improve the property of HAP in marble conservation, sol–gel method was employed to synthesize nano AlPO4, which were then incorporated into the phosphate solution to produce protective coating on the stone surface. The coatingʼs morphology and the structure were characterized by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), high capacity 3D X-ray microscopy (XRM), optical microscope, and scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). Moreover, the color, the contact angle, the three-point bending strength measurements, as well as the simulated acid rain test and freeze–thaw treatment were performed to assess the chromatic aberration, hydrophilicity, reliability, and durability of the coating. Results indicated that the nano AlPO4, with its matched lattice parameters and nucleation site provision, facilitated the formation a coherent HAP layer of crystal flakes. Subsequently, the anti‑corrosion property, freeze-thaw resistance and consolidation property of the coating were improved, demonstrating the potential application the hybrid of HAP with nano AlPO4 in the preservation of marble.

PATIENTS WITH FEMOROACETABULAR IMPINGEMENT SYNDROME OBTAIN SIGNIFICANT AND SUSTAINED IMPROVEMENT FOLLOWING A COMBINED HIP INJECTION AND REHABILITATION PROGRAM

INTRODUCTION Initial treatment recommendations for symptomatic femoroacetabular impingement syndrome include non-surgical therapies such as injections and rehabilitation. However, many patients undergo isolated injections or a rudimentary exercise regime. This study investigated the benefit of a combined intra-articular hip injection and structured exercise rehabilitation program in patients with FAIS. METHODS Participants were recruited and underwent a guided intra-articular injection of corticosteroid and local anaesthetic, followed by a 12-week rehabilitation program. Patients were assessed pre-and post-injection(8 weeks, 4, 6, 12 and 24 months) via patient-reported outcome measures including the 33-item International Hip Outcome Tool and Hip Outcome score. Hip ROM and peak isometric hip strength in all planes were assessed, along with single-limb hop capacity. Limb Symmetry Indices were calculated. The percentage of patients transitioning toward surgery over the period was evaluated. RESULTS A total of 44 patients underwent the injection and completed the initial 8-week rehabilitation component. A significant improvement (p&amp;lt;0.05) in all PROMs was observed, with 93% of patients satisfied. A significant increase (p&amp;lt;0.05) in all active hip ROM and isometric strength measures was observed, sustained over the 24-month period. Bilateral improvements in hop capacity were observed, with all hop test LSIs significantly improving (p&amp;lt;0.05). Overall, 14 patients (32%) progressed toward surgical intervention over the 24-month post-injection period. These patients reported significantly worse (p&amp;lt;0.05) PROMs pre-surgery and more pain within the first 4 weeks post-injection. CONCLUSION This is the first study seeking to implement and comprehensively assess a best-practice, multimodal non-operative program consisting of an intra-articular injection and a structured exercise program. Most patients with symptomatic FAIS demonstrated significant improvement in symptoms.