Electromyographic Analysis Research Articles

Electromyographic Activation and Co-contraction of the Thigh Muscles During Pilates Exercises on the Wunda Chair

ObjectiveThe aim of the present study was to investigate whether Pilates exercises on the Wunda chair (Going Up Front and Mountain Climb) activate the muscles rectus femoris (RF) and biceps femoris (BF) in 2 situations (foot on the pedal and foot on the seat). MethodsSixteen young female Pilates practitioners (18-35 years old) participated in this study. The muscles of their right leg were then submitted to electromyography analysis during the exercises. ResultsSignificant differences were found for the RF muscle (maximal voluntary isometric contraction [%MVIC]), which was assessed and compared between the 2 exercises (Going Up Front and Mountain Climb: F = 9.83; P = .03; np2 = 0.14); 2 conditions (foot on the pedal and foot on the seat: F = 40.02; P < .001; np2 = 0.90) and interactions (F = 14.49; P < .001; np2 = 0.20) and for BF muscle (%MVIC) in the comparisons between the 2 conditions (foot on the pedal and foot on the seat: F = 27.5; P < .001; np2 = 0.82) and interactions (F = 12.57; P < .001; np2 = 0.17). The percentage of cocontraction presented the significant difference in the comparisons between the 2 conditions (foot on the pedal and foot on the seat: F = 24.07; P < .001; np2 = 0.286) ConclusionBoth Pilates exercises activated the thigh core muscles in the moderate and high categories. The highest percentage of cocontraction levels were presented when the foot was resting on the pedal.

Activity of deep trunk muscles for postural control to predictable and unpredictable sagittal plane perturbations: Electromyographic analysis.

The activity of deep trunk muscles (psoas major; PM, quadratus lumborum; QL, transverse abdominis; TrA, and lumbar multifidus; MF) in response to external perturbation is not clearly known. This study aimed to record the onset and amount of activity of the deep trunk muscles during sagittal plane perturbations. Fourteen healthy males participated in this study. The activity of the right deep trunk muscles was recorded using wire electrodes. In standing, the participants performed three tasks: a pendulum impacted from anterior with predictable and unpredictable and posterior with unpredictable. In predictable anterior perturbation, the TrA and PM demonstrated feedforward activation, while all deep trunk muscles demonstrated feedback activation in unpredictable anterior and posterior perturbations. In the anticipatory postural adjustment phase, the activity of the TrA was large in predictable anterior perturbation, while that of all deep trunk muscles was slight in other perturbations. In the compensatory postural adjustment phase, the activity of the PM, QL, and TrA in unpredictable anterior perturbation and those of the PM, QL, and MF in unpredictable posterior perturbation were large. These results showed that the onset and magnitude of deep trunk muscle activity changed depending on both predictable or unpredictable perturbation and the direction of perturbation.

Electromyographical Analysis of The Thigh Muscle During Four Yogasana

The goal of the study was to examine the peak EMG at four lower body muscles during four different yoga poses performed by yoga practitioners. Materials and methods: Male Yoga practitioners (n= 11) were assessed for peak electromyography (EMG) of VM-Vastus Medialis, VL- Vastus lateralis, BF- Biceps femoris, ST- Semitendinosus, while performing four Yogasana: UK- Utkatasana, VB- Virabhadrasana II, UPE- Urdhva prasarita ekapadasana six, DOL- Dolasana (pendulum pose). Results: The UK induced the highest EMG for VM (124.5000 ± 25.36088), VL(124.2364 ± 27.35410), ST (106.6091 ± 32.77619),BF (96.6909 ± 29.34824),The VB II induced the highest EMG for the VL (102.0727 ± 32.96262), VM (100.4091± 16.30960), BF (84.5727 ± 28.63844), ST (86.2818 ± 26.07239).The UPE-Six induced the highest EMG for the VM (42.4364 ± 17.09025), BF (45.0636 ± 21.33440),ST (39.3727 ± 17.03315),VL (38.3636 ± 20.73612).The DOL induced the highest EMG for the VM (88.7455 ± 56.13069), BF (65.2545 ± 36.53172), ST (62.6455 ± 19.28302),VL (43.2545 ± 24.14255). However, between Yogasana, only the VM showed a significant (P &lt; .000) * different EMG. Specifically, the UK induced greater VM EMG compared to UPE (82.064, P &lt; .000), VB (57.973, P &lt; .000) * Conclusions: Peak muscular activation in the four lowerbody muscles can change depending on how the yoga players treat the four differences. A declining pattern of peak EMG for the UK &gt; VB II &gt; DOL and UPE six Yogasana, however, indicates that variations between poses appear to be minimal, with the exception of the VM muscle.

Diving into dual functionality: Swim bladder muscles in lionfish for buoyancy and sonic capabilities.

Although the primary function of the swim bladder is buoyancy, it is also involved in hearing, and it can be associated with sonic muscles for voluntary sound production. The use of the swim bladder and associated muscles in sound production could be an exaptation since this is not its first function. We however lack models showing that the same muscles can be used in both movement and sound production. In this study, we investigate the functions of the muscles associated with the swim bladder in different Pteroinae (lionfish) species. Our results indicate that Pterois volitans, P. radiata and Dendrochirus zebra are able to produce long low-frequency hums when disturbed. The deliberate movements of the fin spines during sound production suggest that these sounds may serve as aposematic signals. In P. volitans and P. radiata, hums can be punctuated by intermittent louder pulses called knocks. Analysis of sonic features, morphology, electromyography and histology strongly suggest that these sounds are most likely produced by muscles closely associated with the swim bladder. These muscles originate from the neurocranium and insert on the posterior part of the swim bladder. Additionally, cineradiography supports the hypothesis that these same muscles are involved in altering the swim bladder's length and angle, thereby influencing the pitch of the fish body and participating in manoeuvring and locomotion movements. Fast contraction of the muscle should be related to sound production whereas sustained contractions allows modifications in swim bladder shape and body pitch.

Changes in Electromyographic Activity of the Dominant Arm Muscles during Forehand Stroke Phases in Wheelchair Tennis.

The aim of this study was to determine the muscle activations of the dominant arm during the forehand stroke of wheelchair tennis. Five players participated in the present study (age: 32.6 ± 9.9 years; body mass: 63.8 ± 3.12 kg; height: 164.4 ± 1.7 cm). The electrical muscle activity of six dominant arm muscles was recorded using an sEMG system. A significant effect of the muscle's activity was observed, and it was shown that the muscle activation was significantly higher in the execution phase compared to the preparation phase in the anterior deltoid and biceps brachii (34.98 ± 10.23% and 29.13 ± 8.27%, p < 0.001); the posterior deltoid, triceps brachii, flexor carpi radialis, and extensor carpi radialis were higher in the follow-through phase than in the execution phase (16.43 ± 11.72%, 16.96 ± 12.19%, 36.23 ± 21.47% and 19.13 ± 12.55%, p < 0.01). In conclusion, it was determined that the muscle activations of the dominant arm muscles demonstrate variances throughout the phases of the forehand stroke. Furthermore, the application of electromyographic analysis to the primary arm muscles has been beneficial in understanding the muscular activity of the shoulder, elbow, and wrist throughout the various phases of the forehand stroke in wheelchair tennis.

Influence of Breathing Modes and Facial Growth Patterns on Electromyographic Fatigue of Masticatory Muscles in Children.

Introduction Changes in breathing patterns affect the harmonious development of the structures of the craniofacial system, leading to changes in posture, occlusion, and facial growth patterns. However, little is known about how these changes influence the muscle contraction patterns, either at rest or while functioning, and either in a normal or unbalanced condition. Objective To study the masseter and anterior temporal muscles fatigue during mastication in nasal- and mouth-breathing children, also considering their facial growth patterns. Methods: A total of 70 children aged 6 to 12 years old who met the study criteria were assessed. Speech-language-hearing, otorhinolaryngologic, and cephalometric assessments were performed to divide them into groups. In the electromyographic assessment, the children were asked to chew gum following a metronome until they felt fatigued. The median frequency of the muscles was analyzed at 15, 30, 45, and 60 seconds of mastication. The reported time of fatigue perception was recorded. The data were analyzed with analysis of variance (ANOVA) and the Kruskal-Wallis and the Mann-Whitney U tests. Results There were no median frequency decrease patterns nor differences in the myoelectric manifestations and reported time of fatigue between the groups. Conclusion The masticatory muscles did not reveal fatigue in the electromyographic analysis; however, the fatigue time was reported, despite the absence of physiological fatigue. The breathing mode, the facial growth pattern, and the association between them did not interfere with the behavior of the median frequency of the electromyographic signal and the fatigue time perception.

Abstract PO-049: The neural landscape is associated with functional outcomes for patients with oropharyngeal squamous cell carcinoma

Abstract Despite the excellent prognosis of patients with oropharyngeal squamous cell carcinoma (OPSCC), long-term functional impairment (e.g., dysphagia) is a major burden for many patients. Recent studies have explored the role of pharyngeal constrictors and muscle fibrosis in dysphagia. However, to date, no study has examined the association between the OPSCC neural microenvironment and posttreatment functional impairment. We hypothesized that cancer-related neuronal changes in the OPSCC tumor microenvironment (TME) would affect patients’ prognoses. Therefore, in the present study, we investigated whether cancer-related changes in the tumor neuronal microenvironment influence functional outcomes in patients with OPSCC. Prospectively collected, patient-reported outcomes (i.e., from the MD Anderson Symptom Inventory [MDASI] and the MD Anderson Dysphagia Inventory [MDADI]) and functional outcomes from the Dynamic Imaging Grade of Swallowing Toxicity [DIGEST] for patients with OPSCC were collected (n=29). OPSCC tissue samples were obtained from surgically treated patients, and multiplex/high-plex immunofluorescence and machine learning techniques were used to correlate neuronal changes with prospectively collected patient data. Electromyography was performed to assess the neuronal populations involved in neuropathies after treatment. A murine animal model of dysphagia was also used to correlate the neuronal changes. The results showed that sensory nerves with adrenergic features (CGRP+TH+) were associated with perineural and lymphovascular invasion. In addition, we found that human papillomavirus associated OPSCC was associated with an enrichment of parasympathetic progenitors (VIP+DCX+). Poor MDASI scores were associated with CGRP+, adrenergic (TH+), or CGRP+TH+ innervation, and growing progenitor neurons (GAP43+DCX+) were associated with improved oral symptoms. Swallowing, measured by MDADI scale revealed that patients with tumors enriched with growing (GAP43+), parasympathetic (VIP+), and neuronal progenitor (DCX+) neurons reported poor swallowing perception; subgroup electromyography analysis confirmed our findings. Quantitative swallowing assessment with DIGEST by speech language pathologists revealed that TMEs innervated by CGRP+, TH+, and MBP+ neurons were associated with poor swallowing functions. Finally, using a murine model of dysphagia we confirmed that sensory (CGRP+), myelinated (MBP+), and cholinergic parasympathetic (CHAT+) or progenitor (CHAT+DCX+) enrichment was associated with denervation and downstream dysphagia. In conclusion, our results show that neuronal changes are correlated with clinical features in OPSCC patients. Patients’ functional outcomes after therapy completion are influenced by distinct nerve populations in the TME. These benchmark data should be further evaluated as a potential target for cancer survivors with dysphagia and as a biomarker for patients who might need escalated swallowing rehabilitation during and after treatment for OPSCC. Citation Format: Shajedul Islam, Frederico O. Gleber-Netto, Collin F. Mulcahy, Mica D. E. Glaun, Patrick J. Hunt, Michelle D. Williams, Carly E. Barbon, Weilu Zhao, Adewale Adebayo, Shamima Akhter, Tongxin Xie, Ismail Yaman, Jared K. Burks, Javier Gomez, Karin Woodman, Teresa E. Lever, Katherine A. Hutcheson, Moran Amit. The neural landscape is associated with functional outcomes for patients with oropharyngeal squamous cell carcinoma [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Innovating through Basic, Clinical, and Translational Research; 2023 Jul 7-8; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2023;29(18_Suppl):Abstract nr PO-049.

P2E5-12 A method of simultaneous record and analysis of voice and high-density surface electromyography of laryngeal muscle

P2E5-12 A method of simultaneous record and analysis of voice and high-density surface electromyography of laryngeal muscle

Effects of extracorporeal shock wave therapy combined with isokinetic strength training on spastic calf triceps in patients after a stroke: a double-blinded randomised controlled trial

ABSTRACT Objectives To evaluate the antitetanic effects of extracorporeal shock wave therapy (ESWT) combined with isokinetic strength training (IST) on calf triceps spasm in patients after a stroke. Methods Forty-five patients with hemiplegia after a stroke and lower extremity spasms were randomly assigned into three groups: a control group (n = 15), an ESWT group (n = 15) and an ESWT+IST group (n = 15). All patients agreed to conventional rehabilitation therapy, while the ESWT and ESWT+IST groups received ESWT of 2.0–3.0 bar once a week for four weeks. In addition, the ESWT+IST group underwent four weeks of ankle IST. All groups were assessed using the modified Ashworth scale (MAS) and surface electromyography before and after four weeks of treatment. The ankle passive movement of all groups was measured using the BIODEX isokinetic system at angular velocities of 60°/s, 120°/s, 180°/s and 240°/s. Results After four weeks of treatment, compared with the control group, the ESWT+IST groups showed a significant reduction in MASscores (P = 0.030). The ESWT+IST group had significantly lower MAS scores than the baseline (P = 0.002), while the ESWT group did not show a significant difference (P = 0.072). The average electromyography (AEMG) analysis demonstrated a significant difference among the groups after four weeks (P = 0.001), with the ESWT+IST group having lower AEMG values compared with the control group (P < 0.001) and the ESWT group (P = 0.042). Peak resistive torque significantly decreased in both the ESWT and ESWT+IST groups at all velocities (60°/s: P = 0.030, 120°/s: P = 0.039, 180°/s: P = 0.030 and 240°/s: P = 0.042). Conclusions Extracorporeal shock wave therapy combined with IST can significantly improve calf triceps spasm in patients after a stroke.

Decoding Hip Muscle Activation: A Comparative Electromyographic Analysis of Turn-Out Bent Knee Pulse and Single-Leg Banded Glute Bridge Exercises in Healthy Female Subjects.

Individuals with lower extremity injuries and back pain may exhibit weakness and stiffness in important muscles such as the gluteus maximus and external hip rotators. To aid clinicians in understanding the impact of exercises on factors like stability, endurance, and strength, electromyography (EMG) examination can be employed to monitor muscle activation. In this investigation, the EMG activity of the gluteus maximus and medius were compared between two exercises: the turn-out bent knee pulse and the single-leg banded glute bridge. The study enrolled a group of 64 healthy young women, aged 19 to 24 years. The raw data collected were standardized and represented as a percentage of maximum voluntary isometric contraction (%MVIC). To assess the reliability of the EMG recordings, the test-retest analysis was performed using the intraclass correlation coefficient (ICC3,1). Statistical analysis involved conducting a one-way ANOVA to compare the EMG amplitudes between the two exercises. Remarkably, the results demonstrated a significantly higher EMG signal amplitude during the single-leg banded glute bridge exercise (mean ± SD: 90 ± 28% MVIC) when compared to the turn-out bent knee pulse exercise (mean ± SD: 70 ± 15% MVIC) (F = 16.584, p = 0.001). The study found that the single-leg banded glute bridge exercise had a significantly higher EMG signal amplitude compared to the turn-out bent knee pulse exercise. This suggests that the single-leg banded glute bridge exercise may be more effective in strengthening the gluteus maximus and medius muscles. Overall, this study highlights the importance of targeted muscle training in rehabilitation protocols and the use of EMG examination to monitor muscle activation.

Electromyography (EMG) Analysis of Multi-Regional Lower Extremity and Trunk Musculature During Sidelying Hip Abduction With Frontal Plane Stabilization.

Sidelying hip abduction (SHA) is a common exercise utilized in rehabilitation to strengthen thegluteus medius (GMed). Alterations in the exercise can produce different patterns of muscularactivity. No studies have examined the effect of mechanical pelvic stabilization during SHA.This study enrolled 19 participants (male = 11, female = 8) who performed the same SHA exercise under two randomized conditions: standard and with a mechanical block to prevent frontal-plane movement. Electromyographic amplitudes during exercise were obtained through surface electrodes and compared against maximum voluntary isometric contraction (MVIC) testing: GMed, gluteus maximus, biceps femoris, tensor fascia latae, quadratus lumborum, and vastus lateralis. While no significant differences were found in GMedactivity during SHA with or without pelvic stabilization, reduced concomitant activation of other musculature was observed, potentially producing a more isolated exercise for the GMed with lesscompensatory activity.

Toddlers’ affective responses to sociomoral scenes: Insights from physiological measures

A growing literature suggests that preverbal infants are sensitive to sociomoral scenes and prefer prosocial agents over antisocial agents. It remains unclear, however, whether and how emotional processes are implicated in infants’ responses to prosocial/antisocial actions. Although a recent study found that infants and toddlers showed more positive facial expressions after viewing helping (vs. hindering) events, these findings were based on naïve coder ratings of facial activity; furthermore, effect sizes were small. The current studies examined 18- and 24-month-old toddlers’ real-time reactivity to helping and hindering interactions using three physiological measures of emotion-related processes. At 18 months, activity in facial musculature involved in smiling/frowning was explored via facial electromyography (EMG). At 24 months, stress (sweat) was explored via electrodermal activity (EDA). At both ages, arousal was explored via pupillometry. Behaviorally, infants showed no preferences for the helper over the hinderer across age groups. EMG analyses revealed that 18-month-olds showed higher corrugator activity (more frowning) during hindering (vs. helping) actions, followed by lower corrugator activity (less frowning) after hindering (vs. helping) actions finished. These findings suggest that antisocial actions elicited negativity, perhaps followed by brief disengagement. EDA analyses revealed no significant event-related differences. Pupillometry analyses revealed that both 18- and 24-month-olds’ pupils were smaller after viewing hindering (vs. helping), replicating recent evidence with 5-month-olds and suggesting that toddlers also show less arousal following hindering than following helping. Together, these results provide new evidence with respect to whether and how arousal/affective processes are involved when infants process sociomoral scenarios.

Motor unit tracking using blind source separation filters and waveform cross-correlations: reliability under physiological and pharmacological conditions.

Recent advancements in the analysis of high-density surface electromyography (HDsEMG) have enabled the identification, and tracking, of motor units (MUs) to study muscle activation. This study aimed to evaluate the reliability of MU tracking using two common methods: blind source separation filters and two-dimensional waveform cross-correlation. An experiment design was developed to assess physiological reliability, and reliability for a drug intervention known to reduce the firing rate of motoneurones (cyproheptadine). HDsEMG signals were recorded from tibialis anterior during isometric dorsiflexions to 10%, 30%, 50% and 70% of maximal voluntary contraction. MUs were matched within session (2 hr) using the filter method, and between sessions (7 days) via the waveform method. Both tracking methods demonstrated similar reliability during physiological conditions (e.g., MU discharge: filter ICC 10% of MVC = 0.76, to 70% of MVC = 0.86; waveform ICC: 10% of MVC = 0.78, to 70% of MVC = 0.91). Although reliability slightly reduced after the pharmacological intervention, there were no discernible differences in tracking performance (e.g., MU disc filter ICC: 10% of MVC = 0.73, to 70% of MVC = 0.75; DR waveform ICC: 10% of MVC = 0.84, to 70% of MVC = 0.85). The poorest reliability typically occurred at higher contraction intensities, which aligned with the greatest variability in MU characteristics. This study confirms that tracking method may not impact the interpretation of MU data, provided that an appropriate experiment design is employed. However, caution should be used when tracking MUs during higher intensity isometric contractions.

Involvement of Myofascial Spiral Chains of the Lower Limb in Semi-unipodal Balance: A Pilot Study.

Introduction Single-leg stance has been extensively studied for functional evaluation, therapeutic exercise, sports training, and fall prevention. However, the motor strategies of the supporting limb have been investigated only at the ankle level. It is not known, at the hip, how the muscular system reacts to medial and lateral imbalances. We hypothesize, based on a myofascial chain approach, that the balance is managed by the front and back spiral chains. The aim of this work was to perform a preliminary experimental analysis to verify the spiral chain hypothesis, testing a method to investigate the motor strategies underlying equilibrium. Methods Five healthy subjects (i.e. without neurological or orthopedic pathologies affecting the upright position) underwent perturbations of their monopodal balance while a surface electromyographic analysis of gluteus maximus, gluteus medius, adductor longus (ADD), tibialis anterior (TA), and peroneus longus (PL) was executed. The percentage of electrical activation with respect to maximal contraction was calculated for each muscle investigated. The coordination in activation between the hip and ankle muscles was analyzed by the Pearsoncorrelation coefficient. Results Of the studied muscles, TA (43% of maximal contraction) and gluteus medius (28%) had the average highest reaction to lateral imbalance and the highest correlation coefficient (0.89, p-value<0.01); PL (35%) and ADD (16%) were the most relevant in counteracting the medial imbalance (correlation coefficient=0.83, p-value<0.01). Conclusion The study was performed on a few subjects, and the muscles of the lower limb were only partially investigated. However, the consistency of the resultswith former experimental studies provided preliminary evidenceof the adequacy of the method adopted. The correlation of hip and ankle muscle activations was in line with the spiral chain hypothesis.

Cross-day analysis of Multicode Surface Electromyography based Biometrics for Personal Identification.

Recently, surface electromyography (sEMG) has emerged as a novel biometric trait for personal identification, potentially providing a superior spoof-resistant solution over existing traits. The sEMG possesses a unique dual-mode security: they differ between individuals (biometric-mode), and different gestures have different sEMG characteristics (knowledge-mode). To leverage the knowledge-mode facet of the dual-mode security, the previous studies have utilized a multicode framework involving the fusion of codes (gestures), however, the analysis involved data recorded on a single day and from a small subject-pool. In this study, wrist EMG data collected from 43 participants over three different days while performing static hand/wrist gestures was utilized in two cross-day analyses, where the training and testing data were from different days. Three levels of fusion, score, rank, and decision were investigated to determine the optimal fusion scheme. The results showed that the score-level fusion scheme resulted in a median rank-1 accuracy of 77.9% and rank-5 accuracy of 99.6%, all significantly higher (p<0.001) than the respective single-code gesture. Our results showed that the multicode sEMG biometric framework provides superior identification performance in a more realistic cross-day scenario.

Electromyographic signals analysis to assess the response of a proprioceptive neuromuscular facilitation pattern execution.

Proprioceptive Neuromuscular Facilitation is a rehabilitation technique that consists of the stimulation of a healthy muscle in one extremity of the body to produce an activation effect of a damaged muscle in another extremity, laterally or contralaterally. The use of the analysis of the electromyographic response during the process allows us to describe and evaluate if the damaged muscle produces an activation. This paper presents the progress of the results of a clinical protocol where PNF is explored in healthy subjects, manipulating the upper limb, and recording the electromyographic response of the lower limbs in three different muscles in both inferior limbs. Four activation patterns (movement sequence) with three different stages with different intensities of resistance are considered. Lateral plane video recording analysis is performed to extract the trajectory of the manipulated limb and correlate this information with electromyography signals. The electromyography signals are analyzed in their temporal response by integrating the rectified and smoothed signal according to the beginning and end of the trajectory of the manipulated superior limb. Additionally, the spectrogram analysis of the signals is performed. The partial results of the protocol allow us to establish that the response in the most distal muscles to the manipulated upper limb has been non-significant for the subjects, compared to the response of the proximal muscles, where a relationship with activation and trajectory of the arm is observed. particularly in the process with greater resistance. The observed changes in signal frequency across the spectrogram correspond to low-frequency changes in the 15 to 20Hz band.Clinical Relevance- This work presents a strategy to assess the rehabilitation process based on proprioceptive neuromuscular facilitation by analyzing the time and time-frequency response of the electromyographic signal.

Physico-chemical, antioxidant, sensory and electromyographic analyses of shrikhand (flavored strained yoghurt) formulated for dysphagia patients under IDDSI levels 4 and 5

Physico-chemical, antioxidant, sensory and electromyographic analyses of shrikhand (flavored strained yoghurt) formulated for dysphagia patients under IDDSI levels 4 and 5

A Proposal to Analyze Muscle Dynamics Under Fatiguing Contractions Using Surface Electromyography Signals and Fuzzy Recurrence Network Features

The analysis of surface electromyography (sEMG) signals is significant in the detection of muscle fatigue. These signals exhibit a great degree of complexity, nonlinearity, and chaos. Also, presence of high degree of fluctuations in the signal makes its analysis a difficult task. This study aims to analyze the nonlinear dynamics of muscle fatigue conditions using Fuzzy recurrence networks (FRN). Dynamic sEMG signals are measured from biceps brachii muscle of 45 normal subjects referenced to 50% of maximal voluntary contractions (MVC) for this. Recorded signals are then pre-processed and divided into ten equal parts. FRNs are transformed from the signals. The network features, namely average weighted degree (AWD) and Closeness centrality (CC) are extracted to analyze the muscle dynamics during fatiguing conditions. The decrease in these features during fatigue indicates a reduction in signal complexity and an increase in complex network stiffness. Both AWD and CC features are statistically significant with [Formula: see text]. Further, these features are classified using Naïve Bayes (NB), k nearest neighbor (kNN) and random forest (RF) algorithms. Maximum accuracy of 96.90% is achieved using kNN classifier for combined FRN features. Thus, the proposed features provide high-quality inputs to the neural networks that may be helpful in analyzing the complexity and stiffness of neuromuscular system under various myoneural conditions.

Long-Term Bilateral Neuromuscular Function and Knee Osteoarthritis after Anterior Cruciate Ligament Reconstruction.

Neuromuscular function is thought to contribute to posttraumatic osteoarthritis (PTOA) risk in anterior cruciate ligament (ACL)-reconstructed (ACLR) patients, but sensitive and easy-to-use tools are needed to discern whether complex muscle activation strategies are beneficial or maladaptive. Using an electromyography (EMG) signal analysis technique coupled with a machine learning approach, we sought to: (1) identify whether ACLR muscle activity patterns differed from those of healthy controls, and (2) explore which combination of patient outcome measures (thigh muscle girth, knee laxity, hop distance, and activity level) predicted the extent of osteoarthritic changes via magnetic resonance imaging (MRI) in ACLR patients. Eleven ACLR patients 10-15 years post-surgery and 12 healthy controls performed a hop activity while lower limb muscle EMG was recorded bilaterally. Osteoarthritis was evaluated based on MRI. ACLR muscle activity patterns were bilaterally symmetrical and differed from those of healthy controls, suggesting the presence of a global adaptation strategy. Smaller ipsilateral thigh muscle girth was the strongest predictor of inferior MRI scores. The ability of our EMG analysis approach to detect meaningful neuromuscular differences that could ultimately be related to thigh muscle girth provides the foundation to further investigate a direct link between muscle activation patterns and PTOA risk.

Control technologies of lower limb rehabilitation exoskeleton robots based on surface electromyography: A review

The aging population is accompanied by a decline in human body function, leading to an increasing number of people with lower limb dysfunction, which has become a global public health challenge today. The lower limb rehabilitation exoskeleton robot based on surface electromyography is a current research hotspot. It can help people with lower extremity dysfunction perform better rehabilitation training. This review presents the analysis and processing of surface electromyography, feature extraction and recognition, as well as the control methods for lower limb rehabilitation exoskeleton robots.