Muscle Responses Research Articles

Hemifacial Spasm Associated With the Specific Offending Vein.

Hemifacial spasm (HFS) caused by venous compression is a rare occurrence. Currently, there is no relevant research on the venous characteristics and potential pathogenic mechanisms causing venous HFS. Exploring the venous characteristics in venous-type HFS may reduce the likelihood of repeated surgery. The authors presented 4 cases of HFS caused by veins of middle cerebellar peduncle (V. of Mid.Cer.Ped) successfully treated with microvascular decompression. Based on intraoperative observations and abnormal muscle response (AMR) monitoring, it was determined that V. of Mid.Cer.Ped were offending vessels in these patients. Moreover, veins crossed between the facial and vestibulocochlear nerves, and then surrounded the ventral aspect of the facial nerve root. Microvascular decompression for the offending vessel was successfully performed, and AMR disappeared for each patient. These patients were discharged without any complications and involuntary contractions or twitching of facial muscles. The study demonstrated that veins can indeed induce HFS. The characteristic of the V. of Mid.Cer.Ped that leads to HFS is that these veins traverse between the facial nerve and the vestibulocochlear nerve, and then surround the ventral aspect of the facial nerve root. The dynamic influence of cerebrospinal fluid leads to pulsatile impingement of the facial nerve on the vein, resulting in facial nerve bending and deformation at the location of the vein. Significantly, in the context of surgery, if it is noticed that the V. of Mid.Cer.Ped surrounds the ventral aspect of the facial nerve root and the facial nerve is compressed and deformed, when AMR disappears after decompression of the artery, it may be necessary to perform vein decompression.

Transcriptomic and Epigenomic Responses to Cortisol-Mediated Stress in Rainbow Trout (Oncorhynchus mykiss) Skeletal Muscle.

The production and release of cortisol during stress responses are key regulators of growth in teleosts. Understanding the molecular responses to cortisol is crucial for the sustainable farming of rainbow trout (Oncorhynchus mykiss) and other salmonid species. While several studies have explored the genomic and non-genomic impacts of cortisol on fish growth and skeletal muscle development, the long-term effects driven by epigenetic mechanisms, such as cortisol-induced DNA methylation, remain unexplored. In this study, we analyzed the transcriptome and genome-wide DNA methylation in the skeletal muscle of rainbow trout seven days after cortisol administration. We identified 550 differentially expressed genes (DEGs) by RNA-seq and 9059 differentially methylated genes (DMGs) via whole-genome bisulfite sequencing (WGBS) analysis. KEGG enrichment analysis showed that cortisol modulates the differential expression of genes associated with nucleotide metabolism, ECM-receptor interaction, and the regulation of actin cytoskeleton pathways. Similarly, cortisol induced the differential methylation of genes associated with focal adhesion, adrenergic signaling in cardiomyocytes, and Wnt signaling. Through integrative analyses, we determined that 126 genes showed a negative correlation between up-regulated expression and down-regulated methylation. KEGG enrichment analysis of these genes indicated participation in ECM-receptor interaction, regulation of actin cytoskeleton, and focal adhesion. Using RT-qPCR, we confirmed the differential expression of lamb3, itga6, limk2, itgb4, capn2, and thbs1. This study revealed for the first time the molecular responses of skeletal muscle to cortisol at the transcriptomic and whole-genome DNA methylation levels in rainbow trout.

Prediction of isometric forces from combined epidural spinal cord and neuromuscular electrical stimulation in the rat lower limb

Although epidural spinal cord and muscle stimulation have each been separately used for restoration of movement after spinal cord injury, their combined use has not been widely explored. Using both approaches in combination could provide more flexible control compared to using either approach alone, but whether responses evoked from such combined stimulation can be easily predicted is unknown. We evaluate whether responses evoked by combined spinal and muscle stimulation can be predicted simply, as the linear summation of responses produced by each type of stimulation individually. Should this be true, it would simplify the prediction of co-stimulation responses and the development of control schemes for spinal cord injury rehabilitation. In healthy anesthetized rats, we measured hindlimb isometric forces in response to spinal and muscle stimulation. Force prediction errors were calculated as the difference between predicted and observed co-stimulation forces. We found that spinal and muscle co-stimulation could be closely predicted as the linear summation of the individual spinal and muscle responses and that the errors were relatively low. We discuss the implications of these results to the use of combined muscle and spinal stimulation for the restoration of movement following spinal cord injury.

Changes in contractile characteristics of rat skeletal muscles associated with P2-receptor activation after spinal cord transection

Introduction. Traumatic spinal cord and peripheral-nerve injury is associated with release of proinflammatory cytokines and chemokines, which may stimulate neuronal activity. Adenosine triphosphoric acid (ATP) is an important pain mediator involved in the acute and chronic neuropathic pain development. Its excessive release from primary injured tissue leads to activation of P2-receptors, which may further start secondary injury mechanisms. Although the effects of ATP on the peripheral nervous system are relatively well studied, the pathophysiological role of purinergic signaling after spinalization remains unclear. The study was aimed at assessing the post-spinalization effects of P2-receptors on the contractile characteristics of rat skeleton muscles. Materials and methods. The objects of the study were the soleus muscle, the extensor digitorum longus (EDL) muscle, and diaphragm in intact rats and spinalized rats. Seven days after laminectomy followed by spinal cord transection, animals were anesthetized, exsanguinated, and their muscles with nerve stumps were isolated. Contractile response parameters were recorded using mechanomyography (MMG). To study effects of ATP on ligand binding, ATP was added to a bath and mechanical responses in the rat muscles were assessed 7 min after. After washing with Krebs–Henseleit solution, the preparations were incubated with suramin solution for 20 min with subsequent ATP application. Then the mechanical responses in the muscles were again recorded. Statistical significance was assessed using Student's t-test for independent (unpaired) and paired samples. Results. We found a significant (p 0.05) decrease in the modulating activity of ATP, as the main endogenous signaling agent, in the cholinergic synapse of the soleus muscle from 32.4 to 5.8% and from 13.7 to 5.6% for the EDL muscle after the spinalization (spinal cord injury at the Th6–Th7 level) compared with intact animals. No such dramatic changes were observed in the diaphragm. Conclusions. Abnormal ATP-mediated modulation of neuromuscular transmission demonstrated in this study supports the involvement of purinergic signaling in the neurotrophic control and functioning of various motor units.

The breath shape controls intonation of mouse vocalizations.

Intonation in speech is the control of vocal pitch to layer expressive meaning to communication, like increasing pitch to indicate a question. Also, stereotyped patterns of pitch are used to create distinct sounds with different denotations, like in tonal languages and, perhaps, the 10 sounds in the murine lexicon. A basic tone is created by exhalation through a constricted laryngeal voice box, and it is thought that more complex utterances are produced solely by dynamic changes in laryngeal tension. But perhaps, the shifting pitch also results from altering the swiftness of exhalation. Consistent with the latter model, we describe that intonation in most vocalization types follows deviations in exhalation that appear to be generated by the re-activation of the cardinal breathing muscle for inspiration. We also show that the brainstem vocalization central pattern generator, the iRO, can create this breath pattern. Consequently, ectopic activation of the iRO not only induces phonation, but also the pitch patterns that compose most of the vocalizations in the murine lexicon. These results reveal a novel brainstem mechanism for intonation.

F wave analysis based on the compound muscle action potential scan.

Conventional F wave analysis involves a relatively uniform physiological environment induced by supramaximal stimulations. The F wave characteristics in a dynamic physiological condition, however, are rarely investigated. This study aimed to improve understanding of F wave properties in the more dynamic process by introducing a novel method to analyze F waves based on the compound muscle action potential (CMAP) scan technique. Twenty four healthy subjects participated in the study. The CMAP scan was applied to record muscle responses in the abductor pollicis brevis (APB) and abductor digiti minimi (ADM) muscles, respectively. F wave characteristics including mean F wave amplitude and latency (F-M latency), persistence and activating threshold were quantified. An average of 200 F waves per muscle were obtained from the CMAP scan recording. Weak to moderate correlations between F wave amplitude and stimulating intensity were observed in most of the APB (19 muscles; r = 0.33 ± 0.14, all p < .05) and ADM (23 muscles, r = 0.46 ± 0.16, all p < .05) muscles. Significantly longer mean F latency and lower activating F-threshold were found in the ADM muscles (F-M latency: APB: 25.43 ± 2.39 ms, ADM: 26.15 ± 2.32 ms, p < .05; F-threshold: APB: 7.68 ± 8.96% CMAP, ADM: 2.35 ± 2.42% CMAP, p < .05). This study introduces new features of F waves using the CMAP scan technique and identifies differences of F wave characteristics between the hand muscles. The CMAP scan based F waves analysis can be combined with the motor unit number estimation to assess functional alterations in motor neurons in neurological disorders.

The Role of Cardiopulmonary Exercise Testing in Assessment of Patients with Interstitial Lung Disease

Abstract Background Cardiopulmonary exercise testing (CPET) is considered as the gold standard for evaluating the causes of exercise intolerance in patients with pulmonary and cardiac disease, and is based on the principle that system failure typically occurs while the system (e.g muscle-energetic, cardiovascular or pulmonary) is under stress. Objective To evaluate the role of cardiopulmonary exercise test in assessment of patients with interstitial lung disease. Patients and Methods This is observational study included 30 consecutive examined with the diagnosis of ILDs in Kobry El Kopa military hospital. The study was carried out over the period from February 2016 to August 2019. All patients with dyspnea to be investigated and ILDs diagnosed and assessed in rehabilitation department who undergo cardio pulmonary exercise test. Results Reduction on the compliance of the lung and/ or chest wall cause change in lung volumes and tachypnea during exercise. Also agreed with harris EzeAo Who showed that alterations on breathing pattern such as lower Vt, increased respiratory effort, rapid shallow breathing were reported in individual with interstitial lung diseases. Conclusion The pathophysiology of ILD has a negative impact on the ventilatory, cardiovascular, and skeletal muscle responses to exercise, thereby leading to exertional dyspnea and reduced exercise capacity. CPET is an excellent tool for assessing the severity of exertional dyspnea and mechanisms of exercise limitation in patients with various forms of cardiorespiratory disease; however, its application in ILD has remained limited. A growing body of evidence supports the use of CPET in patients with ILD. CPET is currently used to assess functional capacity, to inform exercise prescription, and to evaluate the effects of various interventions. Recent findings highlight that, in addition to its current uses, CPET-derived measures may help improve the management of patients with ILD. Despite these recent advances, additional research is required in order to confirm the utility of CPET in this population.

Proteomic and transcriptomic response of human skeletal muscle to 12-week resistance training

BACKGROUND: Decreased skeletal muscle mass and properties lead to the development of various pathologies and increased risk for injuries. Studies of the molecular mechanisms of skeletal muscle adaptation to resistance training to increase muscle mass and strength appear imperative for medicine and sports. AIM: To assess changes in the proteomic profile (quantitative panoramic mass spectrometric analysis) of skeletal muscles and the correlation of these changes with the expression of the corresponding mRNAs (RNA-sequencing) before and after 12 weeks of strength training and changes in the transcriptome 8 and 24 h after an acute resistance exercise with one leg. METHODS: Ten untrained men (aged 23 [20.8–25.9] years; body mass index, 22 [20.9–25.1] kg/m2) performed a two-legged seated platform press for 12 weeks (3 times/week, 50–75% of maximum voluntary contraction [MVC]). After training, the volunteers performed an acute strength exercise with one leg. Before and after 12 weeks of training, the MVC and volume of the quadriceps femoris muscle were assessed. Before and after training, as well as 8 and 24 h after the acute resistance exercise, a biopsy of the vastus lateralis muscle was performed from the loaded and contralateral limbs for immunohistochemical, proteomic (high-performance liquid chromatography-tandem mass spectrometry), and transcriptomic (RNA-sequencing) analyses. RESULTS: The 12-week strength training increased the MVC by 19%, quadriceps femoris volume by 12%, cross-sectional area of type 2 (fast) fibers by 29%, minimum Feret diameter of type 2 fibers by 10%, and type 1 (slow) fibers by 13%. Of the 1174 detected proteins, 24 increased, and 83 decreased in content. Strength training resulted in an increase in the expression levels of 142 and a decrease in 65 of the 12,112 mRNAs detected, with enrichment for the functional terms of the extracellular environment, matrix, basement membrane, etc. Changes in the contents of 433 mRNAs after 8 h and 639 mRNAs after 24 h were found when comparing the once-loaded muscle with the contralateral one (genes associated with contractile activity). Changes in the content of only a small part of proteins (5–9 out of 107) correlated with the changes in the corresponding mRNAs. CONCLUSION: Proteomic analysis showed that the 12-week resistance training had little effect on the relative abundance of high-abundance proteins in muscles. The increase in muscle mass induced by training appears to be explained by a similar change in the synthesis/degradation rates of the detected proteins. In the comparison of proteomic data with changes in mRNA expression after 12 weeks of training and 8 and 24 h after a single load (gene response specific to contractile activity), changes in protein contents caused by strength training were regulated mainly at the post-transcriptional level.

Electrophysiological Insights: Using Repetitive Nerve Stimulation to Monitor Clinical Status and Remission in Myasthenia Gravis

ABSTRACT Objective: Myasthenia gravis (MG) is a chronic autoimmune neuromuscular disorder with a variable course that complicates the prediction of remission. This study aimed to evaluate the utility of repetitive nerve stimulation (RNS) in monitoring clinical status through the assessment of decremental response rates in the nasalis and trapezius muscles during treatment. Subjects and Methods: A prospective study was conducted with 52 patients diagnosed with generalized MG. Patients underwent clinical assessments, including tests for anti-acetylcholine receptor and anti-muscle-specific kinase antibodies, and were classified according to the Myasthenia Gravis Foundation of America classification. Electrophysiological testing through RNS and single-fiber electromyography was performed. Data analysis involved comparing the RNS decrement rates with clinical and demographic variables. Follow-up for assessing remission spans 2 years. Results: Among the 52 patients, 53.8% achieved clinical remission. In the remission group, 14.3% of the patients exhibited a decremental response compared with 70.8% in the nonremission group, particularly in the nasalis and trapezius muscles, in the follow-up RNS conducted 2 years after the initial assessment (P &lt; 0.05). The remission group presented significantly lower rates of antibody positivity and less bulbar involvement. Interestingly, initial clinical severity did not correlate significantly with remission. Conclusion: This study demonstrated the usefulness of RNS in assessing the clinical status of MG patients and evaluating the effectiveness of current therapeutic strategies. These findings suggest that focusing on specific muscle responses in RNS can provide valuable information for patient management.

Skeletal muscle BMAL1 is necessary for transcriptional adaptation of local and peripheral tissues in response to endurance exercise training

ObjectiveIn this investigation, we addressed the contribution of the core circadian clock factor, BMAL1, in skeletal muscle to both acute transcriptional responses to exercise and transcriptional remodeling in response to exercise training. Additionally, we adopted a systems biology approach to investigate how loss of skeletal muscle BMAL1 altered peripheral tissue homeostasis as well as exercise training adaptations in iWAT, liver, heart, and lung of male mice. MethodsCombining inducible skeletal muscle specific BMAL1 knockout mice, physiological testing and standardized exercise protocols, we performed a multi-omic analysis (transcriptomics, chromatin accessibility and metabolomics) to explore loss of muscle BMAL1 on muscle and peripheral tissue responses to exercise. ResultsMuscle-specific BMAL1 knockout mice demonstrated a blunted transcriptional response to acute exercise, characterized by the lack of upregulation of well-established exercise responsive transcription factors including Nr4a3 and Ppargc1a. Six weeks of exercise training in muscle-specific BMAL1 knockout mice induced significantly greater and divergent transcriptomic and metabolomic changes in muscle. Surprisingly, liver, lung, inguinal white adipose and heart showed divergent exercise training transcriptomes with less than 5% of ‘exercise-training’ responsive genes shared for each tissue between genotypes. ConclusionsOur investigation has uncovered the critical role that BMAL1 plays in skeletal muscle as a key regulator of gene expression programs for both acute exercise and training adaptations. In addition, our work has uncovered the significant impact that altered exercise response in muscle and its likely impact on the system plays in the peripheral tissue adaptations to exercise training. Our work also demonstrates that if the muscle adaptations diverge to a more maladaptive state this is linked to increased gene expression signatures of inflammation across many tissues. Understanding the molecular targets and pathways contributing to health vs. maladaptive exercise adaptations will be critical for the next stage of therapeutic design for exercise mimetics.

Respiratory SARS-CoV-2 Infection Causes Skeletal Muscle Atrophy and Long-Lasting Energy Metabolism Suppression.

Muscle fatigue represents the most prevalent symptom of long-term COVID, with elusive pathogenic mechanisms. We performed a longitudinal study to characterize histopathological and transcriptional changes in skeletal muscle in a hamster model of respiratory SARS-CoV-2 infection and compared them with influenza A virus (IAV) and mock infections. Histopathological and bulk RNA sequencing analyses of leg muscles derived from infected animals at days 3, 30, and 60 post-infection showed no direct viral invasion but myofiber atrophy in the SARS-CoV-2 group, which was accompanied by persistent downregulation of the genes related to myofibers, ribosomal proteins, fatty acid β-oxidation, tricarboxylic acid cycle, and mitochondrial oxidative phosphorylation complexes. While both SARS-CoV-2 and IAV infections induced acute and transient type I and II interferon responses in muscle, only the SARS-CoV-2 infection upregulated TNF-α/NF-κB but not IL-6 signaling in muscle. Treatment of C2C12 myotubes, a skeletal muscle cell line, with combined IFN-γ and TNF-α but not with IFN-γ or TNF-α alone markedly impaired mitochondrial function. We conclude that a respiratory SARS-CoV-2 infection can cause myofiber atrophy and persistent energy metabolism suppression without direct viral invasion. The effects may be induced by the combined systemic interferon and TNF-α responses at the acute phase and may contribute to post-COVID-19 persistent muscle fatigue.

The Influence of Aging on the Unfolded Protein Response in Human Skeletal Muscle at Rest and after Acute Exercise.

The unfolded protein response (UPR) is a proteostatic process that is activated in response to endoplasmic reticulum stress. It is currently unclear how aging influences the chronic and adaptive UPR in human skeletal muscle. Here we determined the effect of aging on UPR activation at rest, in response to exercise, and the associations with muscle function. Thirty young (20-35 yr) and 50 older (65-85 yr) individuals were enrolled. Vastus lateralis biopsies were performed at rest and 3 and 48 h after a single bout of resistance exercise. The abundance of UPR-related transcripts and proteins was measured by RNA sequencing and Western blotting, respectively. Fractional synthetic rates of muscle protein were determined by mass spectrometry after intravenous infusion of 13 C 6 phenylalanine. Older adults demonstrated elevated transcriptional and proteomic markers of UPR activation in resting muscle. Resting UPR gene expression was negatively associated with muscle strength and power in older adults. The UPR is similarly activated by acute resistance exercise in young and older adults and positively associated with muscle function but not the anabolic response to exercise. Skeletal muscle from older adults exhibits chronically activated UPR, which accompanies functional decline. The adaptive UPR is a proteostatic mechanism that is upregulated in response to exercise in young and older adults and positively associated with muscle function.

Transcutaneous Electrical Spinal Cord Stimulation Increased Target-Specific Muscle Strength and Locomotion in Chronic Spinal Cord Injury.

The recovery of locomotion is greatly prioritized, and neuromodulation has been emerging as a promising approach in recent times. Single-subject research design. A laboratory at The Hong Kong Polytechnic University. To investigate the effects of augmenting activity-based therapy (ABT) to transcutaneous electrical spinal cord stimulation (TSCS) on enhancing specific lower limb muscle strength and improving locomotor ability in an individual with chronic incomplete spinal cord injury (iSCI). An individual with iSCI underwent two phases of treatment, ABT alone followed by combined ABT+TSCS, each for a period of 10 weeks. The TSCS stimulated T10-T11 and T12-L1 segments with a frequency of 30 Hz at an intensity between 105 mA and 130 mA. Manual muscle testing, 6 min walk test (6MWT), and surface electromyography (EMG) responses of specific lower limb muscles were measured. Additionally, spasticity and sensorimotor examinations were conducted every two weeks, while pain tolerance was recorded after each treatment session. After the ABT+TSCS treatment, there was an increase in overall muscle strength grading (from 1.8 ± 0.3 to 2.2 ± 0.6 out of 5.0). The 6MWT showed a greater increase in walking distance (3.5 m to 10 m) after combined treatment than ABT alone. In addition, the EMG response of the anterior rectus femoris, biceps femoris, medial gastrocnemius, and tibialis anterior after ABT+TSCS increased more than after ABT alone. The spasticity grade was reduced (from 0.8 ± 0.7 to 0.5 ± 0.6) whereas the average lower limb motor score increased from 17 to 23 points. No adverse effects were reported. ABT+TSCS increased the target-specific lower limb muscle strength and walking ability more than ABT alone in an individual with chronic iSCI.

Effects of Whole-Body Vibration Exercises on Muscle Responses and on Risk of Falls in Elderly Individuals: A Systematic Review

Background: This systematic review was conducted to assess the effects of whole-body vibration (WBV) exercises on muscles responses and on risk of falls in elderly individuals. Methods: Searches were conducted in MEDLINE/PubMed, Physiotherapy Evidence Database (PEDro), Web of Science, CINAHL and Scopus databases in Feb 2023 to identify studies with the potential to be included according to the eligibility criteria. Relevant data from included studies were extracted. The methodological quality was evaluated for each study included by PEDro scale, risk of bias (Cochrane Collaboration’s tool), and the level of evidence by National Health and Medical Research Council (NHMRC). Results: Six randomized clinical trial (RCT) were included. In respect of the level of evidence, all studies were classified as Level II (NHMRC) and regarding to the methodological quality (PEDro scale), four studies were considered ‘high’ and two were ‘fair’. Two publications presented low risk of bias, three with high risk of bias and one unclear. All the selected studies reported positive effects and improvements on risk of falls and muscle response after WBV exercise. Conclusion: WBV exercise may contribute to reduce the risk of falls and improve muscle responses in the elderly individuals.

Unraveling radiation-induced skeletal muscle damage: Insights from a 3D human skeletal muscle organoid model

BackgroundThree-dimensional (3D) organoids derived from human pluripotent stem cells (hPSCs) have revolutionized in vitro tissue modeling, offering a unique opportunity to replicate physiological tissue organization and functionality. This study investigates the impact of radiation on skeletal muscle response using an innovative in vitro human 3D skeletal muscle organoids (hSMOs) model derived from hPSCs. MethodsThe hSMOs model was established through a differentiation protocol faithfully recapitulating embryonic myogenesis and maturation via paraxial mesodermal differentiation of hPSCs. Key skeletal muscle characteristics were confirmed using immunofluorescent staining and RT-qPCR. Subsequently, the hSMOs were exposed to a clinically relevant dose of 2 Gy of radiation, and their response was analyzed using immunofluorescent staining and RNA-seq. ResultsThe hSMO model faithfully recapitulated embryonic myogenesis and maturation, maintaining key skeletal muscle characteristics. Following exposure to 2 Gy of radiation, histopathological analysis revealed deficits in hSMOs expansion, differentiation, and repair response across various cell types at early (30 min) and intermediate (18 h) time points post-radiation. Immunofluorescent staining targeting γH2AX and 53BP1 demonstrated elevated levels of foci per cell, particularly in PAX7+ cells, during early and intermediate time points, with a distinct kinetic pattern showing a decrease at 72 h. RNA-seq data provided comprehensive insights into the DNA damage response within the hSMOs. ConclusionsOur findings highlight deficits in expansion, differentiation, and repair response in hSMOs following radiation exposure, enhancing our understanding of radiation effects on skeletal muscle and contributing to strategies for mitigating radiation-induced damage in this context.

Effects of Acute Piano Performance With Blood Flow Restriction on Upper Limb Muscle and Perceptual Response in Pianists.

Long-term and prolonged piano performance does not provide essential skeletal muscle training benefits while increasing the risk of injury to the upper extremities. Unlike high-intensity exercise training, moderate blood flow restriction (BFR) training has been found to improve neuromuscular mechanisms with a variety of physical exercises (machine, elastic band, walking, electrical stimulation, and body weight). We investigated the physiological and perceptual responses related to piano performance with or without BFRbased on acute responses of neuromuscular mechanisms.Student or professional pianists (n=7) performed the "Revolutionary Etude" on the piano with (Piano-BFR) and without (Piano-Ctrl) BFR. During the Piano-BFR performance, 150-180 mmHg of cuff pressure was applied around the most proximal region of both arms as a moderate BFR. Changes in upper limb girth, muscle thickness, and hand grip strength were measured before and immediately after the performance. After the performance, perceptual and other responses were recorded.Immediately after the performance, the Piano-BFR condition induced greater changes in girth (forearm and upper arm), muscle thickness (forearm), and handgrip strength than the Piano-Ctrl condition.Piano-BFRwas (p<0.01) higher than Piano-Ctrl on eight questions regarding perceptual response (upper arm fatigue and difficulty playing the piano). Piano performance with BFR was revealed to increase upper extremity muscle size and fatigue in pianists after playing. Piano performance with BFR was revealed to increase upper extremity muscle size and fatigue in pianists after playing. The effect of BFR on neuromuscular mechanisms on piano performance was greater in the forearm than in the upper arm.

Skeletal Muscle Proteome Modifications following Antibiotic-Induced Microbial Disturbances in Cancer Cachexia.

Cancer cachexia is an involuntary loss of body weight, mostly of skeletal muscle. Previous research favors the existence of a microbiota-muscle crosstalk, so the aim of the study was to evaluate the impact of microbiota alterations induced by antibiotics on skeletal muscle proteins expression. Skeletal muscle proteome changes were investigated in control (CT) or C26 cachectic mice (C26) with or without antibiotic treatment (CT-ATB or C26-ATB, n = 8 per group). Muscle protein extracts were divided into a sarcoplasmic and myofibrillar fraction and then underwent label-free liquid chromatography separation, mass spectrometry analysis, Mascot protein identification, and METASCAPE platform data analysis. In C26 mice, the atrogen mafbx expression was 353% higher than CT mice and 42.3% higher than C26-ATB mice. No effect on the muscle protein synthesis was observed. Proteomic analyses revealed a strong effect of antibiotics on skeletal muscle proteome outside of cachexia, with adaptative processes involved in protein folding, growth, energy metabolism, and muscle contraction. In C26-ATB mice, proteome adaptations observed in CT-ATB mice were blunted. Differentially expressed proteins were involved in other processes like glucose metabolism, oxidative stress response, and proteolysis. This study confirms the existence of a microbiota-muscle axis, with a muscle response after antibiotics that varies depending on whether cachexia is present.

Virtual reality and functional training effect on contractile properties of lower leg muscles and postural stability

Purpose. Tensiomyography is a noninvasive and reliable method to identify the differences in skeletal muscle responses. Poor lower leg muscles cause poor postural stability, leading to the risk of injury in athletes. The study aims to investigate the aftereffect of a six-week virtual reality environment and functional training program on the contractile properties of lower-leg muscles and postural stability index. Material and methods. A comparative pre-test and post-test study design was selected for this study. Twenty-four male athletes were taken part in the study. The participants were randomly divided into a virtual reality intervention-training group (n=12) or a functional training group (n=12). The virtual reality environment training was provided using the CAREN integrated virtual reality system with a D-flow application from Motek. Functional training for static and dynamic postural stability was performed with various open and closed-eye exercises in the physical therapy lab. The contractile properties of lower-leg muscles were measured using tensiomyography. The postural stability index was assessed using a stadiometer. The assessments were performed before and after six weeks of training. A paired sample t-test was used to determine differences between pretest and posttest intervention outcome measures, and sample t-test was also applied to determine differences between groups after six weeks of training. Results. Results indicated significant differences between pretest and posttest measurement in virtual reality training group for displacement (t=2.81, p=.043), (t=-6.92, p=&lt;.001) in gastrocnemius lateral and medial muscle respectively, and sustain time (t=2.29, p=.042) in souls muscle. The postural stability with close eye was significant (t=2.61, p=.024). The functional training group showed significant differences for sustain time (t=-18.86, p=&lt;.001) in gastrocnemius lateral, and relaxation time (=3.24, p=.008), delay time (t=3.07, p=.011), and sustain time (t=-19.74, p=&lt;.001) in gastrocnemius medial, and sustain time (t=3.17, p=.009) in souls muscle. The postural stability was having insignificant differences. Conclusion. The virtual reality environment and functional training, help to improve performance, and tensiomyography could be used to assess and evaluate the parameters that could be helpful for optimizing training load in the performance enhancement process of athletes.

MES-FES Interface Enhances Quadriceps Muscle Response in Sitting Position in Incomplete Spinal Cord Injury: Pilot Study

Purpose: In incomplete spinal cord injury (SCI), there is a partial decrease in motor or sensory or autonomic function. Mainly due to the motor impairment in SCI, a muscle–machine interface is a tool that can bring functional benefits to this population. Objective: To investigate the feasibility of the non-invasive myoelectric signal–functional electrical stimulation (MES-FES) interface on the response of the quadriceps muscle in an individual with incomplete SCI. Methods: This is a quasi-experimental, uncontrolled, longitudinal case report study carried out with an individual with incomplete SCI in the chronic phase. The assessments performed before (pre) and after eight (post8) interventions were neuromuscular assessment (surface electromyography (EMG) in rectus femoris (RF) and vastus lateralis (VL) muscles); muscle strength (load cell); knee extension range of motion (goniometry); spasticity (Modified Ashworth Scale); and quality of life (Spinal Cord Injury Quality-of-Life Questionnaire (SCI-QoL.Br)). The MES-FES interface was associated with physical therapy exercises on the extension knee joint muscle group. Results: Improvement in neuromuscular activation (normalized increase in EMGRMS of 2% (RF) and 3.3% (VL)) and synchronism of the motor units (normalized reduction in EMGMDF of 22.8% (RF) and 5.9% (VL)); 1.4 kgf increase in quadriceps strength; 10.6° increase in knee joint extension amplitude; 1 point spasticity reduction; improved quality of life, confirmed by a 12-point reduction in the SCI-QoL.Br score. Moreover, along with interventions, the participant increased the correct FES activation rate, indicating a user learning curve (ρ = 0.78, p-value = 0.04). Conclusions: The MES-FES interface associated with physical therapy promotes neuromuscular and quality of life improvements in the SCI participant.

Reflex Responses in Muscles of the Lower Extremities Elicited by Transcutaneous Stimulation of Cauda Equina: Part 1. Methodology and Normative Data

Introduction: Transcutaneous electrical stimulation is used to stimulate the dorsal roots of the cauda equina. Multiple elicited responses recorded in the lower extremity muscles are called posterior root muscle reflexes (PRMRs). Normal PRMR values in the muscles of healthy lower extremities have yet to be determined. Methods: Thirty subjects without known lumbosacral spinal root illness were included in this study. Subsequently, they were subjected to transcutaneous electrical stimulation of the cauda equina. Posterior root muscle reflex was recorded in the four muscle groups of both lower extremities. We elicited multiple PRMR and examined their characteristics in order to establish normal electrophysiological parameter values. Results: Posterior root muscle reflex was successfully elicited in the tibialis anterior (96.7%), gastrocnemius (100%), quadriceps femoris (93.3%), and hamstring (96.7%). No statistically significant differences were found in the intensity of stimulation, latencies, or area under the PRMR between the right and left leg muscles. The area under PRMR varied significantly among the participants. Higher body weight and abdominal girth showed a significant positive correlation with stimulation intensity for eliciting PRMR, and a significant negative correlation with the area under PRMR. Older age showed a significant negative correlation with the success of eliciting PRMR and the area under the PRMR. Conclusions: Posterior root muscle reflex is a noninvasive and successful method for eliciting selective reflex responses of cauda equina posterior roots. Obtained values could be used in future studies to evaluate the utility of this methodology in clinical practice. This methodology could improve testing of the proximal lumbosacral nervous system functional integrity.