Evaluation Of Muscle Function Research Articles

A patterned mechanical–electrical coupled sensing patch for multimodal muscle function evaluation

A patterned mechanical–electrical coupled sensing patch for multimodal muscle function evaluation

The Association between Anthropometric Measurements and Body Composition with Hand Grip Strength among the Elderly Population in Indonesia.

Background/Objectives: Hand grip strength (HGS) is a crucial measure for evaluating muscle function and general physical ability, and it may be associated with several diseases. Previous studies have demonstrated inconsistent associations between anthropometric measurement and body composition with HGS. This study aims to investigate the association between anthropometric measurement and body composition with HGS in the elderly population residing in Indonesia. Methods: This is a cross-sectional study on older adults aged between 60 and 82 years who live in the community. Anthropometric parameters assessed in this study comprised the body mass index (BMI), mid-upper arm circumference (MUAC), calf circumference (CC), and waist circumference (WC). Subsequently, body composition measurements, including fat mass (FM), fat-free mass (FFM), muscle mass (MM), skeletal muscle mass (SMM), and the appendicular skeletal mass index (ASMI), were assessed using a body composition analyzer. Last, the measurement of HGS was conducted using a hand dynamometer. Results: A total of 109 participants were involved in this study. Our study demonstrates a significant association between anthropometric parameters, namely CC and HGS. Subsequently, several body composition parameters, including FFM, SMM, ASMI, and MM in the four extremities, are also significantly associated with HGS. However, in a multivariate analysis, only CC and FFM were able to significantly predict HGS. Conclusions: Improving CC and maintaining FFM may enhance muscle strength in older adults. This suggests that targeted exercise and nutrition programs could increase muscle mass and strength, thereby mitigating age-related decline and improving quality of life.

Muscle Performance as a Predictor of Bone Health: Among Community-Dwelling Postmenopausal Japanese Women from Setagaya-Aoba Study.

Osteoporosis is a significant health concern for postmenopausal women, necessitating efficient screening methods for bone health. This study explores the potential of muscle function, assessed through the 30-s chair stand test (CS-30), as an indicator for low bone stiffness in this demographic, aiming to establish a practical threshold for large-scale fitness surveillance without the need for specialized tools. We analyzed data from 1055 community-dwelling postmenopausal Japanese women, aged 41-89years, collected between 2016 and 2019. Participants underwent CS-30 to evaluate muscle function alongside quantitative ultrasound (QUS) measurements to assess bone stiffness. The cohort was divided into two groups for the development and validation of a cutoff point for low bone stiffness, defined as a QUS speed of sound less than 1487.3m/s. The CS-30 cutoff was determined using receiver operating characteristic (ROC) curve analysis and validated through logistic regression, accounting for age, body mass index, and smoking status. Among 577 postmenopausal women, 16.0% exhibited low bone stiffness. In the development group (n = 382), ROC analysis identified a CS-30 cutoff of 25 repetitions for detecting low bone stiffness, with an area under the curve of 0.744 (P < 0.001). In the validation group (n = 195), participants performing ≥ 25 repetitions had a higher risk of low bone stiffness compared to those performing ≤ 24 repetitions. The CS-30 test is an effective preliminary screening tool for identifying postmenopausal women at risk of low bone stiffness, with a threshold of 25 repetitions. This method could facilitate early detection of individuals at higher osteoporosis risk, promoting timely intervention.

Diastolic dysfunction in Alzheimer’s disease model mice is associated with Aβ-amyloid aggregate formation and mitochondrial dysfunction

Alzheimer's Disease (AD) is a progressive neurodegenerative disease caused by the deposition of Aβ aggregates or neurofibrillary tangles. AD patients are primarily diagnosed with the concurrent development of several cardiovascular dysfunctions. While few studies have indicated the presence of intramyocardial Aβ aggregates, none of the studies have performed detailed analyses for pathomechanism of cardiac dysfunction in AD patients. This manuscript used aged APPSWE/PS1 Tg and littermate age-matched wildtype (Wt) mice to characterize cardiac dysfunction and analyze associated pathophysiology. Detailed assessment of cardiac functional parameters demonstrated the development of diastolic dysfunction in APPSWE/PS1 Tg hearts compared to Wt hearts. Muscle function evaluation showed functional impairment (decreased exercise tolerance and muscle strength) in APPSWE/PS1 Tg mice. Biochemical and histochemical analysis revealed Aβ aggregate accumulation in APPSWE/PS1 Tg mice myocardium. APPSWE/PS1 Tg mice hearts also demonstrated histopathological remodeling (increased collagen deposition and myocyte cross-sectional area). Additionally, APPSWE/PS1 Tg hearts showed altered mitochondrial dynamics, reduced antioxidant protein levels, and impaired mitochondrial proteostasis compared to Wt mice. APPSWE/PS1 Tg hearts also developed mitochondrial dysfunction with decreased OXPHOS and PDH protein complex expressions, altered ETC complex dynamics, decreased complex activities, and reduced mitochondrial respiration. Our results indicated that Aβ aggregates in APPSWE/PS1 Tg hearts are associated with defects in mitochondrial respiration and complex activities, which may collectively lead to cardiac diastolic dysfunction and myocardial pathological remodeling.

Effects of 3-(4-Hydroxy-3-methoxyphenyl)propionic Acid on Enhancing Grip Strength and Inhibiting Protein Catabolism Induced by Exhaustive Exercise.

3-(4-Hydroxy-3-methoxyphenyl)propionic acid (HMPA), also known as dihydroferulic acid, is a hydroxycinnamic acid derivative that can be derived from the microbial transformation of dietary polyphenols or naturally obtained from fermented foods. Although numerous studies have documented its antioxidant and anti-obesity effects, the effect of HMPA on muscle function remains unknown. This study investigated the effects of HMPA on muscle strength and exercise endurance capacity. Mice were orally administered low and high doses of HMPA for 14 days and subjected to grip force and treadmill exhaustion tests to evaluate muscle function. Our results showed that HMPA-administered groups significantly enhanced absolute grip strength (p = 0.0256) and relative grip strength (p = 0.0209), and low-dose HMPA decreased the plasma level of blood urea nitrogen after exercise (p = 0.0183), but HMPA did not affect endurance performance. Low-dose HMPA administration increased Myf5 expression in sedentary mice (p = 0.0106), suggesting that low-dose HMPA may promote muscle development. Additionally, HMPA improved hepatic glucose and lipid metabolism, and inhibited muscular lipid metabolism and protein catabolism, as indicated by changes in mRNA expression levels of related genes. These findings suggest that HMPA may be a promising dietary supplement for muscle health and performance.

Uncovering sarcopenia and frailty in older adults by using muscle ultrasound-A narrative review.

Muscle ultrasound is a valuable non-invasive and cost-effective method in assessing muscle mass and structure, both of which are significant indicators for the development of sarcopenia and frailty in elderly individuals. Sarcopenia refers to the loss of muscle mass and strength that occurs with age, whereas frailty is a complex geriatric syndrome characterized by reduced physical function and an increased susceptibility to negative health outcomes. Both conditions are prevalent in older adults and are associated with higher risks of falls, disability, and mortality. By measuring muscle size and structure and several other ultrasound parameters, including muscle thickness, cross-sectional area, echogenicity (brightness in the ultrasound image), pennation angle, and fascicle length ultrasound can assist in identifying sarcopenia and frailty in older adults. In addition, ultrasound can be used to evaluate muscle function such as muscle contraction and stiffness, which may also be affected in sarcopenia and frailty. Therefore, muscle ultrasound could lead to better identification and tracking of sarcopenia and frailty. Such advancements could result in the implementation of earlier interventions to prevent or treat these conditions, resulting in an overall improvement in the health and quality of life of the elderly population. This narrative review describes the benefits and challenges when using ultra-sound for the evaluation of frailty and sarcopenia.

Methods for Clinical Monitoring of Neuromuscular Transmission in Anesthesiology - A Review.

The administration of general anesthesia is a crucial aspect of surgery. However, it can pose significant risks to patients, such as respiratory depression and prolonged neuromuscular blockade. To avoid such complications, it is essential to monitor neuromuscular transmission during anesthesia. While clinical tests have been used for decades to evaluate muscle function, they are now known to be unreliable, and relying on them increases the risk of postoperative complications. Thankfully, there are now six methods available for neuromuscular monitoring during anesthesia: mechanomyography, acceleromyography, electromyography, kinemyography, phonomyography, and compressomyography. Each of these methods differs in terms of their approach and methodology, and their importance in clinical practice varies accordingly. Mechanomyography involves measuring the mechanical response of a muscle to nerve stimulation, while acceleromyography measures the acceleration of muscle contraction. Electromyography records the electrical activity of muscles, while kinemyography tracks muscle movement. Phonomyography records the sound waves produced by contracting muscles, and compressomyography involves monitoring the pressure changes in a muscle during contraction. Overall, understanding the differences between these methods and their clinical significance is crucial for anesthesiologists. This review aims to provide an updated understanding of the current methods available for neuromuscular monitoring during anesthesia, so that anesthesiologists can make informed decisions about patient care and reduce the risk of postoperative complications.

Ab. No. 131 Physical Performance and Sarcopenia Among Children and Adolescents With Nephrotic Syndrome: A Cross Sectional Analysis

Introduction: Literature suggests that renal disease &amp; long term steroid therapy are likely to affect muscle function. There are no studies done on children &amp; adolescents with nephrotic syndrome (NS). Hence, this study focuses on assessing sarcipenia &amp; physical performance among children &amp; adolescence with NS. This will help us in understanding structural impairment at muscle level &amp; physical performance. Methods: Participants- Age 5- 18 years of children &amp; adolescents with NS. Following ethical approval, parent consent &amp; assent of participants were taken. Components included in Physical performance were 2minute walk test (2WMT), Hand grip strength (HGS),1 minute sit to stand(IMSTS). Sarcopenia was evaluated using diagnostic ultrasound to measure cross sectional area (CSA) of dominant side rectus femoris (RF) muscle. Descriptive statistics and comparison statistics were performed. Results: 14 participants with mean age, gender &amp; BMI (9.1±3.4 years; 64% boys; BMI: 17.5±3.1kgm-2) were recruited. 2MWT distance (139.8±32.7m), HGS (10.1±2.9kg), 1MSTS (29.2±4.3) &amp; CSA – RF (2.43±0.87cm2). 2MWT distance, HGS &amp; 1MSTS were reduced in compare to normative data (p&lt;0.05, CI 95%). CSA – RF of pediatirc with other chronic condition presented (3.91±1.51cm2) which is aligning with our findings. Conclusion: Physical performance data shows significant reduction in comparison to established norms. CSA of muscle assessed in this study aligns closely with that observed in other chronic conditions within the pediatric population, suggesting presence of sarcopenia. Implications: Timely evaluation and rehabilitation of sarcopenia among children &amp; adolescents with NS is very crucial. Conducting this study on a larger population is essential to establish relationship between physical performance &amp; sarcopenia. This finding will help in developing clinical care pathway in management of children &amp; adolescents with NS &amp; advocating Nephrologists about the significance of muscle function evaluation. Acknowledgement This work was supported by Society of Indian Physiotherapists, Ref No: SIP_2021_SR03

Assessing nutrition status, sarcopenia, and frailty in adult transplant recipients.

The assessment of nutrition status, sarcopenia, and frailty holds significant relevance in the context of adult transplantation, as these factors are associated with an unfavorable prognosis; thus, transplant candidates must undergo a full nutrition assessment. Screening tools may be used to prioritize patients, this can be done using the Nutrition Risk Screening 2002 or Royal Free Hospital-Nutritional Prioritizing Tool. Subsequently, a thorough nutrition-focused physical examination should be conducted to evaluate clinical signs of nutrition deficiencies, fat and muscle loss, and fluid overload; dietary history and current intake must also be assessed. Apart from physical examination, specific testing for sarcopenia and frailty are recommended. For sarcopenia assessment, specifically for muscle quantification, the gold standard is the cross-sectional measurement of the muscle at L3 obtained from a computed tomography scan or magnetic resonance imaging; dual-energy x-ray absorptiometry is also a good tool especially when appendicular skeletal muscle index is calculated. Other more readily available options include phase angle from bioelectrical impedance or bioimpedance spectroscopy. In the sarcopenia assessment, muscle function evaluation is required, handgrip strength stands as the primary test for this purpose; this test is also part of the subjective global assessment and is included in some frailty scores. Finally, for frailty assessment, the Short Physical Performance Battery is useful for evaluating physical frailty, and for a multidimensional evaluation, the Fried frailty phenotype can be used. Specifically for liver transplant candidates, the use of Liver Frailty Index is recommended.

Isometric Shoulder Testing Using a Forcemeter Is a Reliable Method of Strength Evaluation.

Isometric strength testing using a digital dynamometer is reliable for muscle function evaluation. It allows us to objectify manual strength assessment measurement. We tested intra- and inter-observer reliability of a user-friendly efficient digital dynamometer-the Forcemeter-equipped with a computer program to monitor the measurements and to store the data. Abduction, forward flexion, and external and internal rotation of both shoulders were tested three times in 20 healthy volunteers with no record of shoulder trauma. Isometric contracture was recorded in newtons. The first and the third test were carried out by Examiner A (intra-rater reliability); the second test, by Examiner B (inter-rater reliability). Good reliability was shown for intra-class correlation coefficient (ICC) values which mean moderate to high correlations (r = 0.66-0.93) for both examiners. Moderate to high correlations (r = 0.72-0.91) were found for comparisons between the results obtained by Examiner A.

The Importance of Rebalancing Foot Biomechanics by Computerized Podoscopic Assessment - Study in Charcot Marie Tooth Syndroms

Abstract Charcot–Marie–Tooth disease (CMT) is one of the hereditary motor and sensory neuropathies, a group of varied inherited disorders of the peripheral nervous system characterized by progressive loss of muscle tissue and touch sensation across various parts of the body. Currently incurable, this disease is the most commonly inherited neurological disorder, and affects about one in 2,500 people. A CMT diagnosis involves clinical evaluation of muscle function and atrophy, testing of sensory responses, and electromyography and nerve conduction studies. Often, the most important goal for patients with CMT is to maintain movement, muscle strength, and flexibility. Therefore, an interprofessional team approach with occupational therapy, physical therapy, orthotics, podiatrist, and orthopedic surgeon is recommended. Physical therapy should be involved in designing an exercise program that fits a person’s personal strengths and flexibility, but also in a god evaluation podoscopic assessment. Due to the lack of good sensory reception in the feet, CMT patients need to see a physical therapist in order to stabilize their feet or correct progressive problems by rebalancing the biomechanics of the foot. The procedure involves a computerized assessment, the realization of the plant footprint in the foam and the creation of plantatory therapeutics on the mold. These plantar orthoses help control foot drop and ankle instability and often provide a better sense of balance for patient. Appropriate footwear is also very important for CMT case, but often with difficulty finding well-fitting shoes because of their high arched feet and hammer toes. The patient will use these plantatory proponents in the right shoes in order to: increase of planting support surface, reduction of varus, slowing down the retraction tendency of plant aponeurosis

Using represented bodies in Renaissance artworks to teach musculoskeletal and surface anatomy.

Surface anatomy is an important skill for students in preparation for patient care, and peer examination is often used to teach musculoskeletal and surface anatomy. An alternative pedagogical approach is to use bodies represented in artworks. Represented bodies display fictive anatomy, providing students with the opportunity to apply their musculoskeletal knowledge and to think critically when evaluating the anatomical fidelity of a represented body. An elective course at the University of Michigan enabled undergraduate students to analyze the musculoskeletal and surface anatomy depicted in Renaissance artworks. Students traveled to Italy in 2018 (n = 14) and 2022 (n = 15) to analyze the fictive anatomy portrayed in artistic sculptures and musculoskeletal structures depicted in wax anatomy models and sculpted skeletons. In assignments, students were asked to identify musculoskeletal structures as portrayed in the context of represented anatomy created by Italian Renaissance artists and to assess the fidelity of the depicted anatomy. The students also applied their knowledge of musculoskeletal anatomy to describe body position and evaluate muscle function in their assessments of the accuracy or inaccuracy of the fictive anatomy. The students reported that evaluating the anatomical fidelity of represented bodies in artworks supported their learning of musculoskeletal and surface anatomy, and that their critical thinking skills improved in the course. Evaluation of the anatomical fidelity of represented bodies in artworks is an effective pedagogical approach that can be implemented in art museums as an adjunctive learning experience to deepen students' musculoskeletal and surface anatomy knowledge and further develop their critical thinking skills.

Factors affecting real‐time evaluation of muscle function in smart rehab systems

AbstractAdvancements in remote medical technologies and smart devices have led to expectations of contactless rehabilitation. Conventionally, rehabilitation requires clinicians to perform routine muscle function assessments with patients. However, assessment results are difficult to cross‐reference owing to the lack of a gold standard. Thus, the application of remote smart rehabilitation systems is significantly hindered. This study analyzes the factors affecting the real‐time evaluation of muscle function based on biometric sensor data so that we can provide a basis for a remote system. We acquired real clinical stroke patient data to identify the meaningful features associated with normal and abnormal musculature. We provide a system based on these emerging features that assesses muscle functionality in real time via streamed biometric signal data. A system view based on the amount of data, data processing speed, and feature proportions is provided to support the production of a rudimentary remote smart rehabilitation system.

Handgrip Strength Is Positively Associated with 24-hour Urine Creatine Concentration

Muscle mass evaluation methods are often expensive and therefore limited in their daily use in clinical practice. In this study, we investigated the relationship between hand grip strength (HGS) and other parameters of body measurements with urine creatinine, especially to investigate whether HGS measurement is an indicator of muscle metabolism. In total, 310 relatively healthy people (mean age 47.8 + 9.6; 161 people or 51.9% of the total population were men) who were undergoing preventive examinations were included in this study and given a container to collect 24-h urine, and the amount of creatinine in the urine was determined by a kinetic test without deproteinization according to the Jaffe method. A digital dynamometer (Takei Hand Grip Dynamometer, Japan) was used in the measurement of HGS. There was a significant difference in 24-h urine creatinine (24 hCER) between the sexes, with a mean of 1382.9 mg/24 h in men and 960.3 mg/24 h in women. According to the correlation analysis, the amount of urine creatinine was related to age (r = -0.307, p < 0.001 in men, r = -0.309, p < 0.001 in women), and HGS (r = 0.207, p = 0.011 in men, r = 0.273, p = 0.002 in women) was significant for either sex. However, other parameters of body measurements, such as girth, forearm circumference, and muscle mass measured by bioelectrical impedance, were not related to urine 24 hCER. A correlation between HGS and 24 hCER was observed in age groups. We found that HGS is a potential marker in muscle metabolism assessment that is proven through 24 hCER. In addition, therefore, we suggest using the HGS measure in clinical practice to evaluate muscle function and well-being.

The protective effect of IL-12/23 neutralizing antibody in sarcopenia associated with dextran sulfate sodium-induced experimental colitis.

The improvement of colitis symptoms by treatment with IL-12/23 p40 neutralizing antibody should increase the muscle mass and the function of the sarcopenia phenotype. An experimental colitis model was induced by oral administration of 2% dextran sulfate sodium (DSS) for 7days. During induction of colitis, IL-12/23 p40 neutralizing antibody was injected twice on Days 3 and 5. The total body mass index was measured by dual-energy X-ray absorptiometry. The muscle function was measured by forelimb grip strength and fatigue running distance. The muscle fibre cross-sectional area (CSA) was calculated after the transverse section and haematoxylin and eosin staining, and gene expression was confirmed by RT-qPCR. Differentiated C2C12 cells were used as in vitro models and treated with recombinant IL12/23 proteins to mimic the enhanced cytokines in colitis. The symptoms of colitis were alleviated by injection of IL-12/23 p40 neutralizing antibody compared with phosphate-buffered saline (PBS), and the disease activity index score was significantly lower on Day 8 (0.0±0.00 of cont. vs. 11.3±0.9 of DSS+PBS, P<0.0001; DSS+PBS vs. 7.7±1.25 of DSS+p40Ab, P<0.0001). The CSA of the gastrocnemius and tibialis anterior muscle fibres decreased in mice with DSS-induced colitis (gastrocnemius, 1258.2 μm2 ± 176.45 of cont. vs. 640.1 μm2 ± 59.83 of DSS + PBS, P < 0.0001; tibialis anterior, 1251.8 μm2 ± 331.48 of cont. vs. 678.9 μm2 ± 67.59 of DSS + PBS, P < 0.0001), and the treatment of IL-12/23 p40 neutralizing antibody partially restored CSA of the gastrocnemius (640.1 μm2 ± 59.83 of DSS + PBS vs. 1062.0 μm2 ± 83.41 of DSS + p40Ab, P < 0.0001) and tibialis anterior (678.9 μm2 ± 67.59 of DSS + PBS vs. 1105.3 μm2 ± 143.15 of DSS + p40Ab, P = 0.0003).vs. 640.1μm2 ±59.83 of DSS+PBS, P<0.0001) and tibialis anterior (1251.8μm2 ±331.48 of cont. vs. 678.9μm2 ±67.59 of DSS+PBS, P<0.0001), and the treatment of IL-12/23 p40 neutralizing antibody partially restored CSA of the gastrocnemius (640.1μm2 ±59.83 of DSS+PBS vs. 1062.0μm2 ±83.41 of DSS+p40Ab, P<0.0001) and tibialis anterior (678.9μm2 ±67.59 of DSS+PBS vs. 1105.3μm2 ±143.15 of DSS+p40Ab, P=0.0003). In the evaluation of muscle function, grip strength and fatigue distance decreased by colitis were partially restored (grip strength: 139.9g±5.38 of cont. vs. 83.9g±5.48 of DSS+PBS, P<0.0001; DSS+PBS vs. 118.6g±4.05 of DSS+p40Ab, P<0.0001; fatigue distance: 872.5m±104.01 of cont. vs. 58.2m±107.72 of DSS+PBS, P<0.0001; DSS+PBS vs. 328.0m±109.71 of DSS+p40Ab, P=0.0015) by injection of IL-12/23 p40 neutralizing antibody. Our study demonstrates that Il-12/23 acts directly on muscle to induce atrophy, and the IL-12/23 p40 neutralizing antibody is effective not only in suppressing colitis but also in maintaining muscle mass and improving muscle function in an experimental colitis model.

Using T1 mapping indices to evaluate muscle function and predict conservative treatment outcomes in diabetic patients with peripheral arterial disease.

To investigate interstitial muscle fibrosis via T1 mapping indices and its relationships with muscle function and conservative treatment outcomes. A total of 49 DM patients with PAD were prospectively recruited from 2016 to 2017. All PAD patients underwent pre-treatment MRI with conservative treatment via a rehabilitation program and antiplatelet therapy. The need to require percutaneous transluminal angioplasty intervention was recorded as intolerance to conservative treatment outcomes. We quantified calf interstitial muscle fibrosis using T1 mapping indices (native T1, post-contrast T1, and the extracellular volume fraction [ECV]). Muscle function was evaluated using a 6-min walking test (6MWT) and a 3-min stepping test (3MST). PAD patients were divided into two groups according to their tolerance or intolerance of the conservative treatment. Pearson's correlation, reproducibility, and multivariable Cox hazard analyses were performed with p < 0.05 indicating statistical significance. Among the T1 mapping indices in the posterior compartment of the calf in PAD patients, the native T1 value was significantly correlated with 6MWT (r = -0.422, p = 0.010) and 3MST (r = -0.427, p = 0.009). All T1 mapping indices showed excellent intra-observer and inter-observer correlations. ECV was an independent predictor of conservative treatment intolerance (average ECV, hazard ratio: 1.045, 95% confidence interval: 1.011-1.079, p = 0.009). T1 mapping measurements are reproducible with excellent intra-observer and inter-observer correlations. T1 mapping indices may be predictive of treatment and functional outcomes and carry promise in patient evaluation. Clinical Trials Identifier: NCT02850432 . • T1 mapping measurements of the calf muscles are reproducible with excellent intra-observer and inter-observer correlations (0.98 and 0.95 for anterior and posterior compartment muscle extracellular volume matrix [ECV] measurements, respectively). • ECV is shown to independently predict conservative treatment intolerance. • T1 mapping indices may be predictive of treatment and functional outcomes and carry promise in patient evaluation.

Clinical evaluation of muscle functions in neurofibromatosis type 1.

Muscle weakness, fatigue and speech problems can occur in neurofibromatosis type 1 (NF1). The pathogenesis of these symptoms is unclear, likely multifactorial. We examined motor function in limb and speech muscles in NF1 patients. We evaluated NF1 and control groups aged 4-18 years for muscle strength, tone and mobility using standard manual testing, joint motion and Beighton score measurements. Speech and language functions were assessed by speech articulation and resonance. As a marker of muscle tissue turnover, we determined collagen degradation products in urine before and after submaximal exercise. NF1 patients had reduced strength in proximal limb muscles compared to control subjects. Speech articulation problems and hypernasality were more common in NF1 (47% and 38%, respectively). Collagen products excreted in urine correlated with gluteal and biceps muscle strength. Muscle dysfunction can be detected in some children with NF1 and may explain certain clinical features including fatigue, speech and articulation problems. If confirmed by further research, these findings may be relevant to the management of this condition.

Stretchable electronic skin patch with strain isolation for the simultaneous measurements of surface electromyography and temperature

Stretchable electronic skin patches have continuously attracted the attention of researchers and clinicians due to their potentials in medical applications. Despite the remarkable progress of electronic skin patches with diverse sensor modalities for regions undergoing small deformations, the electronic skin patch in a stretchable format for regions requiring large strain accommodations has far less been explored. Here, we report a stretchable electronic skin patch with strain isolation for the simultaneous measurement of surface electromyography (sEMG) and temperature. The electronic skin patch consists of two mesh-like sEMG electrodes and one resistance temperature sensor on a compliant substrate with programmable stiffness induced by the spatioselective ultraviolet exposure. This construct allows for mechanical softness of electrodes for an intimate attachment to skin and isolation of deformation-induced disturbances and damages to the temperature sensor. Experimental and numerical studies reveal the design, fabrication and operation of the skin patch. Demonstration of the skin patch with strain isolation on the lumbar muscle groups during the trunk flexion, which may introduce a 20% strain level, illustrates its robust capabilities for the comprehensive assessment of muscle activities with possibilities to study the temperature effect on sEMG signals. The results reported here provide important inspiration for constructing multifunctional electronic skin patches with a wide range of applications such as health-monitoring devices, wearable human-machine interface and clinical muscle function evaluation.

Verification of Shoulder External Rotators Strength Measurement Using a Suspension Scale.

BackgroundOf the shoulder external rotators, the infraspinatus and teres minor are the key muscles that contribute to the dynamic stability of the shoulder. It is crucial to properly measure the strength values to evaluate muscle function and training load for shoulder external rotators. A suspension scale (SPS) can measure the mass of the suspended object, and it may be possible to apply it to measure strength. However, the utility of strength measurements using an SPS has not been clarified in previous studies. In this study, we aimed to investigate the intra-rater reliability of measuring the strength of shoulder external rotators using an SPS and the relationship between strength measurement using an SPS and a handheld dynamometer (HHD).MethodologyThe participants were 10 healthy males with 20 shoulders (24.5 ± 2.5 years old; height = 172.8 ± 5.4 cm; weight = 69.6 ± 8.1 kg). Upper extremity strength was measured at 90° shoulder abduction, 90° external rotation, 0° horizontal adduction/abduction, 90° elbow flexion, and 0° forearm pronation/supination in the prone position. The isometric strength of shoulder external rotation was measured with the SPS and HHD, and one examiner measured the maximum strength value. The intra-rater reliability of the two methods using SPS and HHD was evaluated using the intraclass correlation coefficient (ICC1,2), standard error of measurement (SEM), minimum detectable change (MDC), and Bland-Altman analysis. The relationship between the SPS and HHD was calculated as the correlation coefficient between the strength values of SPS and HHD.ResultsThe intra-rater reliability of the strength measurement of shoulder external rotators using SPS was ICC1,2 0.98 (95% confidence interval = 0.95-0.99), and SEM and MDC were 0.3 and 0.9, respectively. The measurements using SPS had no fixed and proportional biases. A significant positive correlation was observed between SPS and HHD (r = 0.94, p < 0.01).ConclusionsThe SPS is an alternative to the HHD for measuring the strength of shoulder external rotators. Thus, measuring the strength of shoulder external rotators using an SPS may be applied as a cost-effective and portable assessment method for shoulder function.

Contributions of individual muscle forces to hip, knee, and ankle contact forces during the stance phase of running: a model-based study.

Knowledge of muscle forces' contributions to the joint contact forces can assist in the evaluation of muscle function, joint injury prevention, treatment of gait disorders, and arthroplasty planning. This study's objective was to evaluate the contributions of human lower limb muscles to the hip, knee, and ankle joint contact forces during the stance phase of running. A total of 25 muscles (or groups) were investigated based on the OpenSim framework along the anterior-posterior, superoinferior, and mediolateral components of each joint coordinate system. It was revealed that, during the running stance phase, the gluteus medius, gluteus maximus, and iliopsoas mainly contributed to the hip contact force. The soleus, vastus group, and rectus femoris primarily contributed to the knee contact force, while the peroneus, soleus, gluteus medius, and gastrocnemius mainly contributed to the ankle joint force; some muscles simultaneously offloaded the joints during the stance phase. The distributivepattern of the individual muscle functions contributing to the joint load may substantially differ during the running and walking stance phases. This study's findings may further provide suggestive information for the design of lower limb joint prosthesis, the study of the biomechanics of pathologic walking and running, and the progression of joint osteoarthritis.