Muscle Activity Research Articles

Consistent changes in muscle phenotype and mitochondrial abundance underlie dive performance across multiple lineages of diving ducks.

Diving animals must sustain high muscle activity with finite oxygen (O2) to forage underwater. Studies have shown that some diving mammals exhibit changes in the metabolic phenotype of locomotory muscles compared to non-divers, but the pervasiveness of such changes across diving animals is unclear, particularly among diving birds. Here, we examine whether changes in muscle phenotype and mitochondrial abundance are associated with dive capacity across 17 species of ducks from three distinct evolutionary clades (tribes) in the subfamily Anatinae - the longest diving sea ducks, the mid-tier diving pochards, and the non-diving dabblers. In the gastrocnemius (the primary swimming and diving muscle), mitochondrial volume density in both oxidative and glycolytic fiber types were 70% and 30% higher in sea ducks compared to dabblers, respectively. These differences were associated with preferential proliferation of the subsarcolemmal subfraction, the mitochondria adjacent to the cell membrane and nearest to capillaries, relative to the intermyofibrillar subfraction. Capillary density and capillary-to-fiber ratio were positively correlated with mitochondrial volume density, with no variation in the density of oxidative fiber types across tribes. In the pectoralis, sea ducks had greater abundance of oxidative fiber types than dabblers, whereas pochards were intermediate between the two. These data suggest that skeletal muscles of sea ducks have a heightened capacity for aerobic metabolism and an enhanced ability to utilize O2 stores in the blood and muscle while diving.

Influence of restricted mastication on swallowing function.

Oral food processing is an important part of daily food intake. A major part of this process is mastication, which prepares a bolus of food for swallowing by mechanically crushing and grinding ingested food between the teeth using rhythmic movements. Masticatory dysfunction is common in the elderly and in some neurological disorders and can have serious negative health consequences. This study investigated the effect of restricted mastication, achieved by experimentally reducing the duration of mastication, on masticatory patterns and subsequent swallowing function. Thirty healthy men (25 ± 3 years old) were instructed to chew gum jelly with a free mastication duration (G100), a half and a quarter duration of G100. Masseter and digastric electromyographic (EMG) activity was recorded to assess mastication and swallowing activity, respectively. In addition, the acceleration of the thyroid cartilage ridge was measured with an accelerometer. The root mean square (RMS) of muscle EMG activity in the masseter and digastric muscles, the number of masseter EMG bursts, time to peak and total duration of each masseter EMG burst, swallowing duration and laryngeal elevation latency were analysed. Restricting masticatory duration reduced the number of mastication cycles (p < .001), prolonged the time to peak (p < .001) and total duration of masseter EMG bursts (p < .001) and resulted in an overall increased RMS score of masseter muscle activity (p = .017). Furthermore, restricted masticatory duration led to a decrease in both swallowing duration (p = .001) and laryngeal elevation latency (p = .012), with a significant increase in the RMS score of digastric muscle activity (p < .001). Under the experimental conditions of restricted mastication, several adaptation features were observed, including changes in masticatory cycle characteristics and swallowing duration. Thus, although the overall masticatory efficiency was reduced, these adaptations allowed healthy individuals to still swallow safely.

The effect of various dietary MUFA content and n-6/n-3 ratios on rainbow trout (Oncorhynchus mykiss) fed on a whole plant protein based diet: growth performance, digestive enzymes activity, intestinal morphometry and fatty acids profile of muscle and liver.

The effect of diets with various dietary MUFA content and n-6/n-3 ratios, diets 1 (55.33, 1.00), 2 (25.30, 1.00), 3 (55.13, 2.05), 4 (24.92, 2.03), 5 (54.94, 8.06) and 6 (24.91, 8.06) and a control diet with fish oil (FO), diet 7 (33.60, 5.97), was studied on growth and digestive physiology of rainbow trout, Oncorhynchus mykiss. Juveniles, 14.65g ± 0.17, were fed the experimental diets for eight weeks. Those fish fed diet 1 (55.33, 1.00) had the lowest growth and nutritional indices, while fish fed diet 6 (24.91, 8.06) possessed the highest indices. However, fish fed D7 (33.60, 5.97) was intermediate in this regard. Proximate body composition results revealed no significant differences among various experimental groups (P > 0.05). Fish fed on diet 1 possessed the highest alkaline protease activity, while fish raised on diet 2 showed the lowest enzyme activity (P < 0.05). Fish fed on diets 1, 3 and 4 had the highest lipase activity (P > 0.05). Amylase activity and intestinal parameters did not differ among groups (P > 0.05). MUFA contents of liver and muscle reflected the MUFA contents of the diets; however, liver PUFA contents was not affected by dietary PUFA contents (P < 0.05). However, 18:3n-3 contents of liver decreased as dietary n-6/n-3 ratio increased (P < 0.05). Furthermore, the liver 20:4n-6 contents considerably increased as dietary n-6/n-3 increased to 8.06 (P < 0.05). Muscle 22:6n-3 content of groups 1 to 6 was lower than group 7 (P < 0.05). In conclusion, rainbow trout was considerably capable of de novo synthesis of 22:6n-3. Meanwhile, increasing dietary n-6/n-3 ratio to 8.06 decreased the muscle 22:6n-3 content which requires further considerations regarding fish immune competence and nutritional quality for human consumption.

The effect of immediate neuromuscular training on ankle biomechanics in individuals with functional ankle instability

Functional ankle instability arises from recurrent ankle sprains. Neuromuscular training is employed to enhance ankle stability in individuals who experience functional ankle instability. The study involved 24 male university students with functional ankle instability, undergoing ankle neuromuscular training on three surfaces. The OpenSim musculoskeletal model assessed effects on ankle kinematics, kinetics, and muscle activity. Using one-way repeated measures ANOVA and one-dimensional statistical non-parametric mapping to distinguish differences among training surfaces. The study aimed to compare biomechanical characteristics of ankle motion in individuals with functional ankle instability undergoing immediate neuromuscular training on a foam cushion surface versus training on level-ground and artificial turf. Results showed foam cushion training significantly increased tibialis anterior and gastrocnemius medial activation during walking (p &lt; 0.05), with no differences observed in peak ankle plantarflexion, peroneus longus, and gastrocnemius lateral. Foam cushion training further increased activation in four muscles and peak ankle plantarflexion moment during jogging and fast running (p &lt; 0.05). Furthermore, foam cushion training reduced subtalar mobility (p &lt; 0.05) and showed greater dorsiflexion angles during jogging and fast running (p &lt; 0.05). Therefore, immediate ankle neuromuscular training on a foam cushion is more advantageous in enhancing ankle stability among individuals with functional ankle instability, positively impacting functional ankle instability improvement.

Normal values of scapular muscle activity ratio during arm elevation and the relationship to muscle strength and sex difference.

The normal value of the scapular muscle activity ratio during arm elevation is not clear. To obtain normal values of the scapular muscle activity ratio during arm elevation in healthy individuals. This cross-sectional study enrolled 47 healthy people. The participants performed shoulder flexion and lowered task with 90-degree movements every 2 seconds. Muscle activities of scapular muscles were measured. For normalization, the maximum isometric contraction of the shoulder flexion was measured at 90∘ (reference contraction). The integrated electromyographic value (IEMG) obtained during the task was normalized by IEMG during the reference contraction and the relative IEMG value was calculated. Then, the scapular muscle activity ratio was computed. The relationship between muscle strength and other factors was also investigated. The median values for upper trapezius/serratus anterior and upper trapezius/lower trapezius were often approximately 1, and that for upper trapezius/middle trapezius was often between 1 and 2. The shoulder flexion isometric strength and scapular muscle activity ratio showed significant negative correlations in multiple phases. Normal values for upper trapezius/serratus anterior and upper trapezius/lower trapezius during arm elevation and lowering were generally 1. Low muscle strength may contribute to an abnormal scapular muscle activity balance.

Intuitionistic Fuzzy Biofeedback Control of Implanted Dual-Sensor Cardiac Pacemakers

Cardiac pacemakers are used for handling bradycardia, which is a cardiac rhythm of usually less than 60 beats per minute. Therapeutic dual-sensor pacemakers aim to preserve or restore the normal electromechanical activity of the cardiac muscle. In this article, a novel intelligent controller has been developed for implanted dual-sensor cardiac pacemakers. The developed controller is mainly based on intuitionistic fuzzy logic (IFL). The main advantage of the developed IFL controller is its ability to merge the qualitative expert knowledge of cardiologists in the proposed design of controlled pacemakers. Additionally, the implication of non-membership functions with the uncertainty term plays a key role in the developed fuzzy controller for improving the performance of a cardiac pacemaker over other fuzzy control schemes in previous studies. Moreover, the proposed pacemaker control system is efficient for managing all health-status conditions and constraints during the different daily activities of cardiac patients. Consequently, the healthcare of patients with implanted dual-sensor pacemakers can be efficiently improved intuitively.

Work-Related Musculoskeletal Disorders in Endoscopic Sinus and Skull Base Surgery: A Systematic Review With Meta-analysis.

Endoscopic sinus and skull base surgeryhas led to significant improvements in patient outcomes, yet may have come at a cost to surgeons' musculoskeletal(MSK) health. We aimed to determine the prevalence and characteristics of work-related MSK disorders (WRMDs) in endoscopic sinus and skull base surgeons; to investigate contributing factors for WRMD in this population; and to evaluate the effectiveness of ergonomic interventions on the severity or prevalence of WRMD in this population. Medline, Embase, CINAHL, Web of Science, and Scopus from inception to April 2, 2024. A bibliographic examination was performed for further papers. Inclusion criteria included original peer-reviewed papers with work-related MSK outcomes (prevalence, contributing factors, and interventions) relating to endoscopic sinus and/or skull base surgeons in any language. Of 25,772 unique citations, 37 studies met the inclusion criteria. The pooled lifetime, point, and 12-month prevalences of WRMD were 75.9% (95% confidence interval; I2, 67.2%-83.6%, I2 95.6%), 80.8% (77.0%-84.3%, I2 98.0%), and 82.0% (71.8%-90.3%, I2 60.96%) respectively. The neck, lumbar spine, and thoracic spine were the most commonly involved areas. One of 9 studies on contributing factors investigated discomfort as an outcome. The remainder focussed on surrogate outcomes (eg,posture, hand dysfunction). Two of the 13intervention studies investigated pain or fatigue as an outcome. The remainder targeted posture, muscle activity, or workload. WRMDs are highly prevalent in endoscopic sinus and skull base surgeons. Further studies focusing on the direct outcomes of WRMD such as pain are needed.

Have a little heart (or not): highly minimized skeletal muscle regulatory cassettes with low or no activity in heart.

Adeno-associated virus (AAV)-mediated gene therapies for certain muscle disorders require regulatory cassettes that provide high-level, striated muscle-specific activity. However, cardiotoxicity has emerged as a serious concern in clinical trials for Duchenne muscular dystrophy and X-linked myotubular myopathy. While this may be caused by systemic inflammatory effects of the treatment, high transgene expression in the heart may also play a role. Thus, certain muscle disorders may require a modulated level of therapeutic expression in the heart, while others may not require any cardiac expression at all. Additionally, the size of some cargos requires regulatory cassettes to be small enough that large cDNAs and other therapeutic payloads can be accommodated. Thus, we have performed enhancer/promoter optimization to develop highly minimized regulatory cassettes that are active in skeletal muscles, with either low or no detectable activity in cardiac muscle. Our no-heart (NH) cassette is active in most skeletal muscles, but exhibits only very low activity in extensor digitorum longus (EDL), soleus, and diaphragm, and no activity in heart. By contrast, our have-a-little-heart (HLH) cassette displays high activity in most skeletal muscles, comparable to the ~800-bp CK8 cassette, with increased activity in EDL, soleus, and diaphragm, and low activity in heart. Due to their small size, these cassettes can be used in therapeutic strategies with both flexible (e.g., antisense) and stringent (e.g., CRISPR/Cas or bicistronic) size limitations. Thus, our new cassettes may be useful for gene therapies of muscle disorders in which the need for low or almost no expression in cardiac muscle would outweigh the need for high levels of therapeutic product in certain skeletal muscles.

ВЛИЯНИЕ ПРОЦЕССА ЖЕВАНИЯ НА ГЕМОДИНАМИЧЕСКИЕ ПОКАЗАТЕЛИ

Chewing has been shown to have a significant effect on systemic circulation, with circulatory responses appearing to be largely regulated by autonomic nervous activity through a more complex regulatory system than responses to other activities. However, the results of studies on the relationship between masticatory movements and changes in autonomic nervous activity and systemic circulation are still rare and contradictory. We examined changes in systemic circulation during gum chewing. Blood pressure, heart rate, and chewing electromyograms were recorded during continuous gum chewing as indicators of systemic circulation in 27 healthy subjects with normal occlusion. Nonparametric matched-sample analyzes were performed to determine the chronological changes in each variable during gum chewing, and nonparametric Spearman correlations were calculated to assess the relationship between changes in hemodynamic parameters and masticatory muscle activity. Chewing gum increased heart rate and blood pressure, indicating significant changes in sympathetic activity and vagal tone. We have identified a pronounced, statistically significant strong correlation between changes in heart rate and the magnitude of contractions of the masticatory muscles. These results suggest that changes in the activity of parts of the autonomic nervous system may be due to the trigeminal nerve reflex, which explains some of the features of the autonomic nervous regulation of chewing movements.

ВЛИЯНИЕ ПРОЦЕССА ЖЕВАНИЯ НА РЕСПИРАТОРНУЮ СИНУСОВУЮ АРИТМИЮ

Respiratory sinus arrhythmia (RSA) is a clockwise fluctuation in heart rate at the frequency of the respiratory cycle. RSA is an important homeostatic mechanism, the parameters of which change under various conditions - from stress to physical exercise. However, the direct effect of chewing, the most common form of muscle activity, on RSA has not yet been studied. We studied the dynamic evolution of RSA and the associated heart rate and respiratory rate during the transition from rest to chewing gum in 37 students (15 men). The measure of RSA in this study was the spectral power of high-frequency HF oscillations. Chewing was accompanied by a slight increase in respiratory rate (RR) and a significant increase in heart rate (HR), but a statistically insignificant increase in the HR/HR ratio. Although respiration was an important determinant of RSA in this study, we observed a significant decrease in HF in the presence of relatively stable RR and HR/RR levels, indicating that the main driver of the evolution of RSA during mastication is an increase in sympathetic tone due to the trigeminal reflex.

Impact of antiparasitic used in livestock: effects of ivermectin spiked sediment in Prochilodus lineatus, an inland fishery species of South America.

Ivermectin (IVM) is a widely used antiparasitic. Concerns have been raised about its environmental effects in the wetlands of Río de la Plata basin where cattle have been treated with IVM for years. This study investigated the sublethal effects of environmentally relevant IVM concentrations in sediments on the Neotropical fish Prochilodus lineatus. Juvenile P. lineatus were exposed to IVM-spiked sediments (2 and 20µg/Kg) for 14days, alongside a control sediment treatment without IVM. Biochemical and oxidative stress responses were assessed in brain, gills, and liver tissues, including lipid damage, glutathione levels, enzyme activities, and antioxidant competence. Muscle and brain acetylcholinesterase activity (AChE) and stable isotopes of 13C and 15N in muscle were also measured. The lowest IVM treatment resulted in an increase in brain lipid peroxidation, as measured by thiobarbituric acid reactive substances (TBARs), decreased levels of reduced glutathione (GSH) in gills and liver, increased catalase activity (CAT) in the liver, and decreased antioxidant capacity against peroxyl radicals (ACAP) in gills and liver. The highest IVM treatment significantly reduced GSH in the liver. Muscle (AChE) was decreased in both treatments. Multivariate analysis showed significant overall effects in the liver tissue, followed by gills and brain. These findings demonstrate the sublethal effects of IVM in P. lineatus, emphasizing the importance of considering sediment contamination and trophic habits in realistic exposure scenarios.

The effects of exoskeleton use on human response to simulated overhead tasks with vibration

The use of occupational exoskeletons has grown fast in manufacturing industries in recent years. One major scenario of exoskeleton use in manufacturing is to assist overhead, power hand tool operations. This preliminary work aimed to determine the effects of arm-supporting exoskeletons on shoulder muscle activity and human-hand tool coupling in simulated overhead tasks with axially applied vibration. An electromagnetic shaker capable of producing the random vibration spectrum specified in ISO 10819 was hung overhead to deliver vibrations. Two passive, arm-supporting exoskeletons, with one (ExoVest) transferring load to both the shoulder and pelvic region while the second one (ExoStrap) transferring load primarily to the pelvic region, were used in testing. Testing was also done with the shaker placed in front of the body to better understand the posture and exoskeleton engagement effects. The results collected from 6 healthy male subjects demonstrate the dominating effects of the overhead working posture on increased shoulder muscle activities. Vibration led to higher muscle activities in both agonist and antagonist shoulder muscles to a less extent. Exoskeleton use reduced the anterior deltoid and serratus anterior activities by 27% to 43%. However, wearing the ExoStrap increased the upper trapezius activities by 23% to 38% in the overhead posture. Furthermore, an increased human-shaker handle coupling was observed in the OH posture when wearing the ExoVest, indicating a more demanding neuromuscular control.

Evaluation of masticatory muscle function in the treatment dynamics of patients with myofascial pain syndrome

Relevance. Myofascial pain syndrome (MPS) often progresses to a chronic form that is challenging to treat with established methods. This issue is well known to dentists and frequently leads to frustration despite significant efforts to advance knowledge in the fields of etiopathogenesis, diagnosis, and therapy. Most treatment protocols focus on normalizing physiological parameters, such as restoring masticatory function, achieving stable occlusal relationships, alleviating pain, and enhancing the psychological well-being of these patients. Therefore, the need for non-invasive diagnostics to assess functional activity and monitor the condition of masticatory muscles during treatment is crucial. This study aims to address this need.Materials and methods. The examination and treatment of 64 patients with myofascial pain syndrome were conducted in two stages—clinical and electromyographic. During the clinical examination, tenderness of the masticatory muscles during palpation and the degree of mouth opening were assessed. The electromyographic research was also conducted in two stages. The first stage assessed the average amplitude and total biopotential of the masticatory and temporal muscles on both the right and left sides. The second stage evaluated the symmetry index of the masticatory muscles, as well as torsion and masseter indices. The first group received conventional treatment combined with laser therapy, while the second group received ozone therapy and kinesiology taping in addition to the conventional therapy.Results. In the short-term observations over 14 days, both groups achieved positive results. However, patients undergoing ozone therapy and kinesiology taping showed statistically significant improvements in their parameters by the third day of observation compared to their baseline values.Conclusion. For diagnosing this pathology, it is advisable to incorporate electromyography into the examination protocol to allow non-invasive evaluation of the functional activity of the masticatory muscles. For treating myofascial pain syndrome, minimally invasive methods with anti-inflammatory, analgesic, and muscle relaxant effects are recommended. While all treatment methods yielded favorable results, ozone therapy combined with kinesiology taping effectively eliminated both subjective and objective symptoms in this patient category.

Case report: A patient with brachio-cervical inflammatory myopathy was misdiagnosed as flail arm syndrome

Brachio-cervical inflammatory myopathy (BCIM) is a rare inflammatory myopathy characterized by dysphagia, bilateral upper limb atrophy, limb-girdle muscle weakness, and myositis-specific antibody (MSA) negativity. BCIM has a low incidence and is commonly associated with autoimmune diseases. We present a case report of a 55-year-old man with progressive upper limb weakness and atrophy, diagnosed with flail arm syndrome (FAS). The initial electromyography revealed extensive spontaneous muscle activity and increased duration of motor unit potentials (MUPs). During follow-up, evidence of myogenic damage was observed, as indicated by a decreased duration of MUPs in the right biceps muscle. Laboratory and genetic testing ruled out hereditary or acquired diseases. Negative serological antibodies for myasthenia gravis. Hereditary or acquired diseases were ruled out through laboratory and genetic testing. Whole-body muscle magnetic resonance imaging (MRI) showed extensive edema and fat replacement in the bilateral upper limbs, scapular, and central axis muscles, while the lower extremities were relatively mildly affected. Muscle biopsy revealed numerous foci of inflammatory cells distributed throughout the muscle bundle, with predominant CD20, CD138, and CD68 expression, accompanied by a light infiltration of CD3 and CD4 expression. The muscle weakness improved with the combination of oral prednisone (initially 60 mg/day, tapered) and methotrexate (5 mg/week) treatment.

The Warburg Effect Revisited through Blood and Electron Flow

Abstract The Warburg effect describes the propensity of many cancers to consume glucose avidly and convert it to lactate in the presence of oxygen. The benefit of the Warburg effect on cancer cells remains enigmatic, particularly because extracellular disposal of incompletely oxidized lactate is wasteful. However, lactate is not discarded from the body, but rather recycled as pyruvate for metabolism through the tricarboxylic acid cycle in oxidative tissues and cells. Hence, tissue and interorgan metabolism play important roles in tumor metabolism. The production of tumor lactate to be recycled elsewhere parallels the Cori cycle, in which lactate produced by muscle activity is shuttled to the liver, where it is converted to pyruvate and subsequently stored as glucose moieties in glycogen. This perspective will consider this organismal contextwhile discussing how glucose is used in tumors. We highlight several key articles published decades ago in Cancer Research that are foundational to our current understanding of cancer biology and metabolism.

A method for calculating vector forces at human-mattress interface during sleeping positions utilizing image registration

The vector forces at the human-mattress interface are not only crucial for understanding the distribution of vertical and shear forces exerted on the human body during sleep but also serves as a significant input for biomechanical models of sleeping positions, whose accuracy determines the credibility of predicting musculoskeletal system loads. In this study, we introduce a novel method for calculating the interface vector forces. By recording indentations after supine and lateral positions using a vacuum mattress and 3D scanner, we utilize image registration techniques to align body pressure distribution with the mattress deformation scanning images, thereby calculating the vector force values for each unit area (36.25 mm × 36.25 mm). This method was validated through five participants attendance from two perspectives, revealing that (1) the mean summation of the vertical force components is 98.67% ± 7.21% body weight, exhibiting good consistency, and mean ratio of horizontal component force to body weight is 2.18% ± 1.77%. (2) the predicted muscle activity using the vector forces as input to the sleep position model aligns with the measured muscle activity (%MVC), with correlation coefficient over 0.7. The proposed method contributes to the vector force distribution understanding and the analysis of musculoskeletal loads during sleep, providing valuable insights for mattress design and evaluation.

Growth patterns of facial muscles at the angle of the mouth: A histological study using midterm and near-term human fetuses.

At the angle of the mouth, spoke-like muscle bundles converge at the "modiolus," which is believed to appear in utero. The aim of this study was to investigate the growth of the modiolus histologically. We studied frontal histological sections of the face from 12 midterm and six near-term fetuses. At midterm, a convergence of the levator anguli oris (LAOM) and depressor anguli oris (DAOM) was frequently present, and another convergence of the LAOM with the platysma (PM) or orbicularis oris (OOM) was also often evident. At near-term, muscle fiber merging or interdigitation was classified into nine combinations, five of which were frequently seen: LAOM-PM, LAOM-DAOM, zygomaticus major (ZMM)-orbicularis oris (OOM), buccinator (BM)-LAOM, and BM-PM. These combinations existed at slightly different depths and/or sites, thus allowing the angle of the mouth to receive multiple muscles. Notably, tissues interposed between the muscle fibers were limited to a thin epimysium at each crossing or interdigitation. Therefore, the LAOM, DAOM, OOM, BM, and PM appear to form a basic configuration at birth, but the development and growth were much delayed than the classical description. The modiolus is not a specific fibromuscular structure but simply represents a cluster of muscle convergence sites. Even at meeting between an elevator and depressor, a specific fibrous structure seems unlikely to connect the epimysium for the muscle convergence. Instead, the central nervous system appears to regulate the activity of related muscles to minimize tension or friction stress at the meeting site.

Machine Learning-Based Feature Extraction and Classification of EMG Signals for Intuitive Prosthetic Control

Signals play a fundamental role in science, technology, and communication by conveying information through varying patterns, amplitudes, and frequencies. This paper introduces innovative methodologies for processing electromyographic (EMG) signals to develop artificial intelligence systems capable of decoding muscle activity for controlling arm movements. The study investigates advanced signal processing techniques and machine learning classification algorithms using the GRABMyo dataset, aiming to enhance prosthetic control systems and rehabilitation technologies. A comprehensive analysis was conducted on signal processing techniques, including signal filtering and discrete wavelet transform (DWT), alongside a composite feature set comprising Mean Absolute Value (MAV), Waveform Length (WL), Zero Crossing (ZC), Slope Sign Changes (SSC), Root Mean Square (RMS), Enhanced Waveform Length (EWL), and Enhanced Mean Absolute Value (EMAV). These features, refined through Linear Discriminant Analysis (LDA) for dimensionality reduction, were classified using Support Vector Machine (SVM) algorithms. Signal filtering and DWT improved signal quality, facilitating better feature extraction, while the diverse feature set enhanced classification accuracy. LDA further improved accuracy by isolating the most informative features, and the SVM achieved optimal performance in decoding complex EMG patterns. Machine learning models, including K-Nearest Neighbor (KNN), Naïve Bayes (NB), and the SVM, were evaluated, with the SVM outperforming the others. The significance of these results lies in their potential applications in prosthetic control systems and rehabilitation technologies. By accurately decoding muscle activity, the developed systems can facilitate more intuitive and responsive robotic arm movements, contributing to the advancement of innovative solutions for individuals requiring prosthetic devices or undergoing rehabilitation, hence improving the quality of life for users. This research marks a significant step forward in the integration of advanced signal processing and machine learning in the field of EMG analysis.

Upper and Lower Limb Muscle Activation during Green Care: An Electromyographic Analysis

Green care activities are associated with lower intensity and a lower risk of injury than agricultural activities aimed at producing agricultural and livestock products; however, the risk of health problems cannot be completely ruled out. To implement green care interventions to improve physical health, it is essential to identify the green care activity levels and biomechanical characteristics of the movements that are appropriate for each subject’s physical functions and goals. Thus, this study was conducted to determine the muscle activation of the upper and lower limbs during 19 green care farming activities. We used electromyography signals, which are biomedical signals that measure the action potentials generated in the muscles and nervous system when the muscles contract, to evaluate the muscle activation. Twenty adults (aged 29.9 ± 9.6 years) participated in this study. Participants performed 19 green care farming activities, including horticultural activity, animal-mediated, and off-farming activities. The participants performed each activity three times. The electromyography data were assessed using surface electromyography during activities to measure muscle activation. As a result, 16 upper and lower limb muscles were activated during the green care farming activities, which showed significantly different muscle activation by care farming activity. As a result of the comparison of muscle activity according to each muscle, many of the muscles of the upper and lower limbs were most activated during organizing a garden plot, transplanting plants, and collecting natural objects. In conclusion, the electromyography data obtained during this study suggest that green care farming interventions may be effective for training specific muscles of the upper and lower limbs.

Voluntary Contraction of the Abdominal Muscles During Shoulder Exercises Increases Scapular Muscle Activation: A Critically Appraised Topic.

The fascial relationship between scapular muscles and abdominal muscles has been documented from previous studies. However, it is not yet clear whether voluntary abdominal contraction has a beneficial effect on scapular muscle activity during shoulder exercises. Do scapulothoracic muscle activation levels increase if shoulder exercises are performed with voluntary abdominal activation? Summary of Key Finding: After the literature review, 4 cross-sectional studies met the inclusion criteria and were included in this critically appraised topic. There is moderate evidence to support dynamic shoulder exercises with voluntary abdominal contraction can increase trapezius and serratus anterior muscle activation level in asymptomatic shoulders. Strength and Recommendation: Findings from 4 cross-sectional trials indicate that there is moderate evidence supporting that dynamic shoulder exercises performed with voluntary abdominal contraction can increase scapular muscle activity.