Search Results (2,312)

Due to their potential to reduce occupational physical strain and enhance human performance, the development of exoskeletons has gained significant attention. This study presents a musculoskeletal simulation pipeline designed to evaluate the biomechanical effects of shoulder-supporting exoskeletons. The focus of the investigation is on the biomechanical tools obtained from musculoskeletal simulations for the evaluation of exoskeletons. Such tools result in many biomechanical values, such as joint kinematics, external joint torques, muscle activation and joint reaction forces. The pipeline was applied to a use case, where electromyography (EMG) signals were collected and compared with simulated muscle activations for validation. The simulated muscle activations had a relative root mean square error (RMSE) of 37% in the area under the curve (AUC) compared to the EMG muscle activation. Joint reaction force analysis revealed altered magnitude and direction of the tangential JRF in the glenohumeral joint during exoskeleton support. This work raises the question of whether the focus in the development of shoulder exoskeletons should be on reducing the load on the subacromial space. By analyzing joint reaction forces and muscle activations, the pipeline can help to identify design parameters that reduce the load on the rotator cuff in the subacromial space. Full article

Background: Lumbar spondylosis is a frequent cause of chronic low back pain, often associated with radiculopathy. Although imaging evaluation is widely used, it does not always reflect the degree of functional impairment of the nerve roots. Electrophysiological assessments, such as nerve conduction studies (NCS) and surface electromyography (sEMG), can provide additional information on neuromuscular function under conservative treatment. Methods: This quasi-experimental study included 60 patients with lumbar spondylosis and 25 healthy subjects, who underwent clinical, imaging, and electrophysiological assessments. NCS and sEMG parameters were assessed in the patient group before and six months after rehabilitation treatment. The control group was assessed only once, at baseline. We analyzed the nerve conduction velocity of the tibial and peroneal nerves and the sEMG activity of the tibialis anterior muscle bilaterally. Statistical analysis used nonparametric tests, Spearman’s coefficient, and Hodges–Lehmann estimates. Results: Compared to the control group, patients presented increased residual latencies and reduced CMAP amplitude and motor conduction velocity values (p < 0.001). After rehabilitation treatment, significant improvements in NCS parameters were observed, with decreased latencies and increased CMAP amplitude and motor conduction velocity bilaterally (p < 0.001). Also, sEMG amplitude and recruitment pattern scores increased significantly at the 6-month follow-up (p ≤ 0.004). Correlations between electrophysiological parameters and the severity of imaging changes were limited, with modest associations for left tibial latencies (ρ = 0.401–0.467; p < 0.050). Conclusions: In patients with lumbar spondylosis, rehabilitation treatment was associated with functional improvements in nerve conduction velocity parameters and muscle activity. Full article

Passive arm support exoskeletons (ASEs) have attracted interest with the prospect of reducing shoulder musculoskeletal injuries. The objective of this study was to assess the impact of passive ASEs on electrical activation of shoulder and torso muscles while performing simulated vertical and horizontal drilling exertions by 17 experienced aircraft workers. The tasks included three vertical drilling heights (chin, head, overhead levels) and two horizontal drilling heights (eye, overhead levels), where participants performed five two-second exertions with one-second no-exertion times between successive drilling exertions. Electromyographic signals from the anterior and medial deltoids, trapezius, latissimus dorsi, erector spinae, biceps and triceps were captured. During vertical drilling exertions, ASEs significantly reduced dominant and non-dominant medial deltoid muscle activity, as well as activity in the non-dominant anterior deltoid, but not the dominant anterior deltoid. During horizontal drilling exertions, ASEs significantly decreased dominant and non-dominant anterior and medial deltoid muscle activity. ASEs significantly reduced non-dominant and dominant anterior and medial deltoid muscle activity during the time between drilling exertions in both the vertical and horizontal drilling directions. These results are encouraging in suggesting that ASEs reduce muscular exertion during drilling tasks commonly found in aircraft manufacturing. However, ASEs must be evaluated in worksite studies to better assess their efficacy. Full article

Background: Existing evidence suggests an association between temporomandibular disorders (TMDs) and alterations in body posture and balance; however, the mechanism underlying this relationship remains unknown. The present study aimed to investigate the associations between specific TMD subtypes, indices of bioelectrical activity of the masticatory muscles, and parameters of body posture and balance. Methods: The study followed a case–control study design. A total of 81 participants were enrolled, including 33 controls and 48 individuals with TMD, classified into myofascial (n = 14), articular (n = 17), and mixed (n = 17) subtypes. Diagnosis of temporomandibular disorders was carried out by prosthodontic specialists using the Polish adaptation of the Diagnostic Criteria for Temporomandibular Disorders. Masticatory muscle bioelectrical activity was assessed by surface electromyography. For statistical analysis, the Asymmetry Index and Functional Clenching Activity Indices were used. Static balance was evaluated with a pedobarographic platform. The sway area, velocity, and length of the Center of Pressure, as well as the foot contact area, were recorded and automatically calculated by the system. Measurements were performed under different mandibular conditions, with both eyes open and eyes closed. Correlation analyses were performed using Spearman Rank Order Correlation. Pearson’s Chi-squared test was used for the analysis of categorical variables. Results: Weak to moderate negative correlations were primarily observed, indicating that higher indices of masticatory muscle bioelectrical activity were associated with better postural balance, with distinct correlation patterns identified across different TMD subtypes. Conclusions: This exploratory study identified multiple correlations between masticatory muscle activity and postural or balance parameters, suggesting possible subtype-specific patterns in TMDs. However, the evidence remains preliminary and should be interpreted with caution, warranting further confirmatory and longitudinal research. Full article

This systematic review examined the influence of menstrual cycle phases on lower-limb muscle activation patterns in eumenorrheic women. Following the PRISMA guidelines, a comprehensive search was conducted in PubMed, Web of Science, and SPORTDiscus using the keywords: (menstrual cycle OR menstrual phase* OR menstruation) AND (neuromuscular activation OR muscle activation OR muscle activity OR neuromuscular control patterns) AND (electromyography OR EMG). Inclusion criteria required participants to be eumenorrheic women with regular menstrual cycles, verified through blood analysis and other physiological confirmation methods, and without menstrual disorders or hormonal contraceptive use. Additionally, eligible studies had to assess lower-limb muscle activation using electromyography. Seven studies met the criteria, comprising a total of 116 eumenorrheic women. Most studies reported no statistically significant differences in muscle activation patterns across menstrual cycle phases. Overall, hormonal fluctuations may influence muscle activation depending on the nature of the task performed (dynamic vs. static; fatiguing vs. non-fatiguing). Future research should incorporate larger sample sizes, longer monitoring periods, and more standardized methodological approaches. Full article

Background/Objectives: Diabetic neuropathy (DN), a common complication of type 2 diabetes mellitus, manifests as peripheral nerve dysfunction with symptoms such as fatigue. Although exercise effectively reduces fatigue in neuropathy patients, precise detection methods are crucial to elucidate the role of rehabilitation. Accordingly, this study aimed to evaluate fatigue in DN patients using a multimodal approach (clinical and instrumental) and to compare the efficacy of aerobic versus resistance training on fatigue parameters. Methods: Eligible DN inpatients admitted for rehabilitation at the Neuromotor Rehabilitation Unit of the IRCCS ICS Maugeri Institute of Montescano (PV) were enrolled. Inclusion criteria included age between 65 and 85 years and confirmation via the Michigan Neuropathy Screening Instrument (anamnestic section: ≥7; clinical section: ≥2.5). Patients with confounding orthopedic, neurologic, or unstable cardiopulmonary/diabetic conditions were excluded. Overall, 36 participants were randomized into two groups: 17 underwent aerobic training (treadmill), while 19 received resistance training (elastic bands), both as supplements to a standard rehabilitation program. Assessments at baseline and post-training comprised clinical measures (Borg CR10 scale, Functional Independence Measure (FIM) total and subitems, Six-Minute Walk Test (6MWT), fasting blood glucose) and instrumental evaluations (sEMG of the tibialis anterior muscle to analyze conduction velocity intercept, slope, and changes). Results: All patients completed the protocol without dropout or adverse events. Both groups demonstrated significant improvements in FIM scores and post-exercise perceived exertion over time. Instrumental sEMG analysis confirmed a physiological fatigue trend manifested as conduction velocity reduction, yet revealed no significant differences between groups. Conclusions: Multimodal assessment provides an effective means to characterize fatigue in DN patients. Both aerobic and resistance modalities enhance functional independence and fatigue perception. Its early identification enables clinicians to tailor rehabilitation strategies to overcome exercise barriers. Full article

Time–frequency (TF) characterization of electromyographic (EMG) bursts is essential for accurately assessing muscle function, particularly when the signals exhibit a high degree of nonstationarity. In this exploratory study, we investigated the temporal dynamics of the spectral components associated with short-latency EMG bursts using several TF analysis techniques. Specifically, we compared the performance and interpretability of spectrograms obtained via the short-time Fourier transform (STFT), the continuous wavelet transform (CWT), and noise-assisted multivariate empirical mode decomposition (NA-MEMD), applied to EMG signals recorded from the biceps femoris muscle of freely moving rats in an animal model of Parkinson’s disease, acquired using chronically implanted bipolar electrodes during treadmill locomotion. For each method, we evaluated its effectiveness in capturing transient variations in frequency content, the stability of extracted features across bursts, and the extent to which these features reflect physiologically meaningful aspects of muscle activation. The results show that TF approaches reveal complementary information about burst structure; NA-MEMD provides greater adaptability to nonlinear and nonstationary components, whereas STFT- and CWT-based representations offer more controlled and comparable analyses. Overall, these findings highlight the value of TF analysis as a methodological tool for evaluating muscle function and provide a solid foundation for selecting analytical strategies in studies where EMG bursts exhibit complex and highly variable spectral profiles. Full article

Background: Age-related differences in neuromuscular coordination during multi-joint tasks are reported, but phase-specific evidence during maximal sprinting is limited. Aim: The aim of this study was to investigate phase-specific age differences in agonist–antagonist coordination of the biarticular thigh muscles during 50 m sprinting. Methods: Thirty-eight healthy trained track athletes (Adults: n = 21, age = 23.32 ± 2.98 years; Adolescents: n = 17, age = 13.65 ± 0.76 years) performed maximal 50 m sprints over force plates. Bilateral rectus femoris (RF) and biceps femoris (BF) sEMG and ground reaction forces were recorded; each stride was segmented into seven phases, and an RF–BF co-contraction index (CCI) was calculated per phase. Between-group differences in phase mean CCI were tested (α = 0.05) and quantified with Hedges’ g. Speed- and frequency-dependent modulation of CCI was evaluated using linear mixed-effects models (LME; random intercepts for participant) with Frequency × Group and Speed × Group interaction terms; ordinary least squares (OLS) fits on stride cycle-level group means were descriptive. Linear and single-breakpoint segmented models were compared using the corrected Akaike information criterion (AICc) and Akaike weights. Results: Adolescents showed higher CCI in contact (right: Adults 0.09 ± 0.05 vs. Adolescents 0.13 ± 0.07, g = 0.68; left: Adults 0.08 ± 0.04 vs. Adolescents 0.12 ± 0.06, g = 0.84) and propulsive phases (right: Adults 0.08 ± 0.05 vs. Adolescents 0.13 ± 0.08, g = 0.68; left: Adults 0.07 ± 0.04 vs. Adolescents 0.12 ± 0.07, g = 0.84; p < 0.05 for both legs in both phases). LME identified Frequency × Group interactions in the stride cycle (ΔSlope = 0.10, p < 0.001) and late swing (ΔSlope = 0.12, p < 0.05) and a Speed × Group interaction in mid swing (ΔSlope = 0.01, p < 0.05). Mid swing showed a positive CCI–speed/frequency relationship in both groups, whereas across most other phases Adults downregulated CCI as speed/frequency increased while Adolescents tended to increase CCI. Model selection supported phase-dependent single-breakpoint patterns, with breakpoints around 2.19–2.21 Hz and 6.11–9.51 m·s⁻¹ in Adults and around 2.11 Hz and 7.13–7.59 m·s⁻¹ in Adolescents. Conclusions: Maximal sprinting revealed phase-specific age differences in BF–RF co-contraction and its scaling with speed/frequency, which may help guide age-informed monitoring and training considerations in developing athletes. Full article

Intensive Care Unit Acquired Weakness (ICUAW) is a highly prevalent neuromuscular complication affecting around 40% of critically ill patients, rising to over 80% in high-risk cohorts. It is independently associated with prolonged mechanical ventilation, increased intensive care unit (ICU) and hospital length of stay, elevated mortality (in-hospital, 1-year, and 5-year), higher healthcare costs, and long-term functional impairment. ICUAW is clinically defined by symmetric flaccid tetraparesis, frequently involving respiratory muscles, and exhibits significant pathobiological heterogeneity. Further subclassification is based on neurotopographic patterns: Critical Illness Polyneuropathy (CIP), Myopathy (CIM), and Polyneuromyopathy (CIPNM). Diagnosis typically relies on the Medical Research Council (MRC) Sum Score, with a threshold of <48 indicating clinically relevant weakness. While adjunct modalities such as electromyography/nerve conduction studies support assessment, their utility may be limited by patient cooperation and availability. Preventive strategies center on modifiable metabolic factors. Caloric and protein deficits exacerbate catabolism, while overfeeding—linked to anabolic resistance and stress hyperglycemia—also impairs recovery. To date, pharmacologic interventions remain inconclusive. However, early mobilization and neuromuscular electrical stimulation are promising non-pharmacologic strategies. The multifactorial and heterogeneous pathophysiology of ICUAW highlights the need for a biologically refined definition that can guide future targeted therapeutic interventions. Comprehensive multimodal strategies, together with structured long-term follow-up in Post-Intensive Care Syndrome (PICS) clinics, are essential for improving outcomes in this prevalent complication of critical care. Full article

Background: Sudden unexpected death in epilepsy (SUDEP) causes significant mortality, affecting approximately 1 in 1000 people with epilepsy. Clinical and preclinical studies have identified severe seizures, bradycardia, apnea, severe postictal hypoxia, and sleep deficiency that emerge prior to SUDEP and thus may represent temporal biomarkers. The metabolic ketogenic diet (KD) therapy increases longevity in preclinical SUDEP models. Here, the hypothesis that KD therapy would determine whether the emergent sleep deficiency, bradycardia, apnea and/or hypoxemia persist as temporal biomarkers in preclinical SUDEP was tested. Methods: Kv1.1 knockout (KO) mice, a preclinical SUDEP model, and wild-type littermates were weaned onto a standard diet (SD) or treated with KD. In separate cohorts, approximately every 10 days, seizures and sleep architecture were recorded with electroencephalography–electromyography (EEG-EMG), heart rate was measured with noninvasive ECGenie, apnea was assessed with noninvasive airway mechanics, and blood O₂ saturation was measured with pulse oximetry. Data were aligned from the day of sudden death and analyzed retrospectively. Results: KD treatment significantly increased longevity and reduced seizures, reproducing previous studies. Using retrospective analyses from the day of death, KD treatment attenuated the emergence of (i) interictal intermittent bradycardia in the last 20 days of life, (ii) apnea, and (iii) intermittent hypoxemia in the last 10 days of life. In contrast, (iv) KD treatment did not rescue REM and NREM sleep deficiencies during the last 10 days of life. Conclusions: Our findings provide novel preclinical support for KD as a candidate therapy to attenuate seizure frequency and burden, bradycardia, apnea, and hypoxemia in SUDEP. In addition, sleep deficiency persisted as a potential temporal biomarker of preclinical SUDEP; however, causality will need to be tested in future studies. Full article

This study identifies electromyography (EMG) features as an alternative to metabolic cost for distinguishing varying levels of movement effort. Data from two experiments was used to analyze the performance of 50 EMG-based features. The first experiment, the Load experiment, involved participants walking with and without carrying loads of 2, 4, and 8 kg, and the second, the Exo experiment, had participants walking with and without varying levels of hip exoskeleton assistance. In the Load experiment, amplitude-based features generally performed well, with Waveform Length (WL) emerging as the top-performing feature achieving a detection rate of 77% when distinguishing between loaded and unloaded conditions in the most challenging 2 kg condition. In contrast, in the Exo experiment, where both increases and decreases in EMG were observed throughout the stride, it failed and mean-based as well as variance-based features performed best and effectively captured fluctuations in muscle activation with a detection rate of up to 71%. This study underscores the importance of selecting EMG features tailored to specific movement tasks and highlights the potential benefits of noise management strategies to improve detection performance for varying levels of movement effort, providing a foundation for EMG-based human-in-the-loop optimization of lower limb exoskeletons. Full article

This systematic review focuses on the effect of concurrent high-intensity interval training (HIIT) and resistance training on musculoskeletal function in adult individuals. Four electronic databases (PubMed, Web of Science Core Collection, Scopus, and PsycINFO) were searched for controlled trials in older or middle-aged adults, in recreationally exercising adults, and in athletic or tactical populations, which completed parallel HIIT and resistance training and described musculoskeletal responses to the intervention up to 30 November 2025. A total of 18 trials fulfilled the eligibility criterion and were synthesized narratively across the domains of maximal strength, explosive performance, neuromuscular activity, muscle morphology and architecture, tendon-related outcomes, and adherence and safety. Most 8- to 12-week interventions maintained two to three weekly resistance sessions and were designed in time-effective HIIT formats, increasing or preserving maximal strength in older subjects as well as younger ones that were trained. Explosive performance metrics, including both jump and sprint tasks, were usually preserved or even improved by the maintenance of the power-oriented component in resistance-based exercise sessions. The limited electromyography data indicated improved neuromuscular activation during submaximal tasks, particularly in older subjects, whereas some studies reported subtle increases or maintenance of muscle size and selective architectural patterns during application of progressive loading. Tendon-specific adaptations are difficult to measure, as imaging was seldom available, but functional tasks influenced by the muscle–tendon unit have been studied in multiple studies. Adherence was good, and adverse events were rare in all studies. Overall, the evidence suggests that well-designed concurrent HIIT and resistance training programs can improve or maintain musculoskeletal performance, although the magnitude and expression of these adaptations vary according to population characteristics and intervention design. Importantly, by integrating neuromuscular, morphological, and performance-related outcomes across diverse adult populations, this review provides a musculoskeletal-centered synthesis that extends prior concurrent training reviews beyond cardiorespiratory or interference-focused perspectives. Full article

Background/Objectives: Accurate assessment of neuromuscular reflexes, such as the Hoffmann reflex (H-reflex), plays a critical role in sports science, rehabilitation, and clinical neurology. Conventional interpretation of H-reflex electromyography (EMG) waveforms is subject to inter-rater variability and interpretive bias, limiting reliability and standardization. This study aims to develop an automated, interpretable, and robust agentic AI–driven framework for H-reflex waveform analysis. Methods: We propose a fine-tuned Vision–Language Model (VLM) consortium combined with a reasoning Large Language Model (LLM)–enabled decision support system for automated H-reflex interpretation. Multiple VLMs were fine-tuned on curated datasets of H-reflex EMG waveform images annotated with expert clinical observations, recovery timelines, and athlete metadata. The VLM outputs were aggregated using a consensus-based strategy and further refined by a specialized reasoning LLM to ensure coherent, transparent, and explainable diagnostic assessments. Model fine-tuning employed Low-Rank Adaptation (LoRA) and 4-bit quantization to enable efficient deployment on consumer-grade hardware. Results: Experimental evaluation demonstrated that the proposed hybrid system delivers accurate, consistent, and clinically interpretable assessments of neuromuscular states, including fatigue, injury, and recovery, directly from EMG waveform images and contextual metadata. Compared with baseline models, the fine-tuned VLM consortium exhibited substantially improved precision, consistency, and contextual awareness, while the reasoning LLM enhanced diagnostic coherence through cross-model consensus and structured reasoning, thereby supporting responsible and explainable AI-driven decision making. Conclusions: This work presents, to the authors’ knowledge, the first integration of a responsible and explainable AI-driven decision support system for H-reflex analysis. The proposed framework advances the automation and standardization of neuromuscular diagnostics and establishes a foundation for next-generation AI-assisted decision support systems in sports performance monitoring, rehabilitation, and clinical neurophysiology. Full article

Introduction: Idiopathic adolescent scoliosis (IAS) is commonly managed non-surgically; however, patients with a Cobb angle >45° before skeletal maturity often require posterior spinal fusion. Because this procedure carries a risk of neurological complications, intraoperative neurophysiological monitoring (IONM) is essential for early detection of spinal cord compromise. Case report: We present a 13-year-old girl with rapidly progressing scoliosis (Cobb angle 78°) who developed intraoperative changes in motor evoked potentials (MEPs) during posterior fusion from L4 to Th2. Total intravenous anesthesia without muscle relaxants was used, and standard multimodal IONM with somatosensory evoked potentials (SSEPs), MEPs, and spontaneous/triggered electromyography was applied. After induction of general anesthesia and surgical exposure, pedicle preparation at Th8–Th9 was followed by increased bleeding from the vertebral bodies and an abrupt loss of MEPs in both lower limbs, most prominently in the tibialis anterior muscles, whilst SSEPs remained unchanged. Intraoperative radiography confirmed correct screw placement, and anesthetic variables were reassessed with no reversible cause identified. Because MEPs remained absent, a wake-up test was performed and demonstrated intact voluntary movement, allowing the surgery to continue. By the end of the procedure, MEPs recovered fully on the left side and partially on the right. The patient awoke without any postoperative motor deficit. Conclusion: It is well known that motor responses can show variability during surgery, including a gradual decrease due to prolonged anesthesia. After excluding anesthetic and mechanical factors, one of the hypothetical explanations for the transient MEP loss was temporary venous congestion and retrograde flow within the intravertebral and epidural/intraspinal venous networks, resulting in reversible spinal cord drainage impairment. Another hypothetical possibility was transient vasospasm from surgical manipulation without direct neural or vascular injury. This case highlights the critical role of continuous multimodal neuromonitoring in detecting reversible spinal cord dysfunction and guiding safe decision-making during complex scoliosis surgery. Full article

A 79-year-old former marathoner, with memory impairment since age 78, developed increasing stumbling and progressively worsening waddling gait. Three months after gait disturbance onset, she noted mild dysphagia. With declining walking distance and endurance, she presented to our hospital six months after onset, exhibiting frontal signs, Parkinsonism with marked trunk rigidity, and hyperreflexia of the jaw and limbs. L-dopa challenge tests showed no improvement. At seven months post-onset, she had difficulty rising. By nine months, she relied on a walker, and speech disturbance appeared. At 10–11 months, both dysarthria and dysphagia rapidly worsened, she became bed-ridden, and upper limb weakness developed (though she could still use chopsticks). Neurological examination at one year revealed severe dysarthria/dysphagia, four extremity fasciculations and muscle weakness (grade 2 in upper limbs, grade 1 in lower limbs), trunk-dominant rigidity, and hyperreflexia in the jaw and limbs. Brain MRI, specifically susceptibility-weighted imaging, revealed motor band signs. Cerebrospinal fluid study revealed albuminocytological dissociation. Needle electromyography revealed acute denervation and chronic reinnervation in the cranial nerve, cervical, and lumbar areas, which was suggestive of motor neuron disease (MND). Serum anti-GQ1b antibodies were detected. Immunotherapy was followed by mild improvement, which might suggest a reversible component, although definitive pathological overlap remains unconfirmed. This case highlights a diagnostic challenge where an acute immune-mediated neuropathy could potentially be superimposed on a chronic neurodegenerative process. Anti-GQ1b antibodies should be interpreted with caution, as they may reflect either a true clinicopathological overlap with Guillain-Barré syndrome or a secondary phenomenon (epiphenomenon) related to the primary neurodegenerative process. Full article