Search Results (72)

Plasmodium falciparum malaria remains a major cause of morbidity and mortality, particularly in endemic regions. We report the case of a 21-year-old male with recent travel to an endemic area (Guapi, Colombia), who presented with febrile symptoms, severe respiratory distress, and oxygen saturation below 75%, necessitating orotracheal intubation. During the procedure, he developed pulseless electrical activity cardiac arrest, achieving return of spontaneous circulation after advanced resuscitation. Diagnosis was confirmed by thick blood smear, demonstrating P. falciparum infection. The patient progressed to multiorgan failure, including acute respiratory distress syndrome with capillary leak pulmonary edema, refractory distributive shock, acute kidney injury with severe hyperkalemia, and consumptive thrombocytopenia. Management included invasive mechanical ventilation, vasopressor support, sedation-analgesia, neuromuscular blockade, methylene blue, unsuccessful hemodialysis due to hemorrhagic complications, and platelet transfusions. Despite these interventions, the patient experienced a second cardiac arrest and died. This case highlights the severity and rapid progression of severe malaria with multisystem involvement, underscoring the critical importance of early diagnosis and intensive multidisciplinary management. It also emphasizes the need for preventive strategies for travelers to endemic areas and the development of clinical protocols to improve outcomes in complicated malaria. Full article

Whether pattern or amount of daily activity determines neuromuscular properties is the focus of this review. The fast-to-slow conversion of many properties of fast-twitch muscles, by stimulating their nerves electrically with the continuous low-frequency pattern typical of slow motoneurons, argued that muscle properties are determined by their pattern of activity. However, the composition of the motor units (MUs) in almost all muscles is heterogeneous, with the MUs grouped into slow, fast-fatigue-resistant and fast-fatigable types that match corresponding histochemical fiber types. Nonetheless, their contractile forces lie on a continuum, with MUs recruited into activity in order of their size. This ‘size principle’ of MU organization and function applies in normally innervated and reinnervated muscles and, importantly, begs the question of whether it is the amount rather than the pattern of the MU activation that determines their properties. Experimental evidence that uniform daily amounts of ~<0.5, 5%, and 50% ES, converted motoneuron, nerve, and muscle properties to one physiological and histochemical type, argued in favor of the amount of activity determining MU properties. Yet, that the properties were not confined to the expected narrow range argued that factors other than the pattern and/or amount of neuromuscular activity must be considered. These include the progressive increase in the synaptic inputs onto motoneurons. The range of the effects of endurance and intermittent exercise programs on healthy subjects and those suffering nerve injuries and disease is also consistent with the argument that factors other than pattern or amount of neuromuscular activity should be investigated. Full article

This study aimed to (1) determine and compare the magnitude and direction of asymmetry in lower limbs neuromuscular properties, range of motion, strength and muscle electrical activity (EMG) in well-trained male road cyclist across categories (elite, under-23 and junior); (2) establish test- and age-specific asymmetry thresholds for these variables to enable individualized classification; and (3) examine the relationship between these lateral asymmetries and performance in a maximal incremental cycle ergometer test. Fifty-five well-trained road cyclists were assessed through tensiomyography (TMG), active knee extension test (AKE), leg press and EMG of vastus lateralis (VL-EMG) during a maximal incremental cycling test. Junior cyclists showed lower asymmetry in VM than elite cyclists, but greater asymmetry in AKE. No significant differences were found in strength or VL-EMG during the maximal incremental cycle ergometer test. The magnitude and direction of lateral asymmetry differs between tests (TMG: 11.3–21.3%; AKE: 2.3%; leg-press: 9.8–31.9%; VL-EMG: 20.8–22.7%). Multiple linear regression revealed a significant predictive model for maximal incremental cycling ergometer performance based on lateral asymmetry in AKE, leg press and VL and rectus femoris contraction time (R²_a = 0.23). These reference data can support trainers in monitoring and managing lateral asymmetry throughout the cyclists’ season. Full article

Objectives: A pulsed electromagnetic field (PEMF) induces electric currents in biological tissue, enhancing muscle energy expenditure during heavy constant-load exercises. In this paper, we investigate the PEMF effect on muscular activation in male sedentary people. Methods: The surface electromyographic (EMG) activity of the right leg’s vastus medialis (RVM) and biceps femoris (RBF) muscles was recorded and analyzed. The root mean square values were normalized to the peak amplitude observed during maximal voluntary contraction. Measurements were taken at baseline (stationary seated position), during warm-up (unloaded cycling), and throughout 15 min of constant-load exercise performed at moderate intensity. Subjects performed two experimental conditions, when PEMF was turned ON versus OFF. Results: No significant difference was found during the baseline. The analysis during warm-up showed significant differences between conditions (ON vs. OFF) for both muscles (RVM p = 0.019; RBF p < 0.001). The analysis during constant-load exercise showed significant differences between conditions (ON vs. OFF) for RVM only (p = 0.002). Conclusions: This study provides evidence that PEMF stimulation acutely enhances muscle activation, primarily in the vastus medialis, with a comparatively smaller effect on the biceps femoris during moderate-intensity cycling in sedentary young men. The observed increase in EMG activity suggests that PEMF may facilitate neuromuscular excitability and muscle recruitment, potentially through mechanisms related to calcium signaling and enhanced muscle perfusion. Full article

Background: Falls among the elderly are a major public health concern, leading to increased disability and mortality. Traditional protective measures are important, but early detection and prevention are equally critical. Surface electromyography (sEMG) signals, which assess muscle electrical activity, can indicate a fall risk by detecting muscle weakness or instability. Objective: This narrative review synthesizes the research progress of sEMG in predicting neuromuscular falls among the elderly. Our goal is to explore the innovative application and development potential of the integration of sEMG and artificial intelligence (AI) in fall prevention among the elderly. Methods: A systematic search of PubMed, IEEE Xplore, and Web of Science (2013–2023) was conducted using the following keywords: artificial intelligence, wearable, sEMG, neuromuscular, and fall prediction. The inclusion criteria prioritized studies integrating sEMG with AI for elderly fall risk assessments, while non-empirical or non-English studies were excluded. Results: AI algorithms hold significant potential in medical applications, and studies on predicting neuromuscular falls in the elderly using sEMG signals have made notable progress. However, limitations include a reliance on simulated data, a lack of standardized models, sensor inaccuracies, and a focus on prediction rather than prevention. To address these challenges, this study proposes collecting authentic sEMG signals from elderly individuals with fall histories and healthy controls. By leveraging AI to develop predictive models and designing a portable sEMG acquisition and analysis system tailored for elderly communities, real-time fall risk predictions and early warnings can be achieved, thereby reducing fall incidences among the elderly. Conclusions: The combination of sEMG and AI presents a substantial promise for predicting neuromuscular falls in the elderly. Future research should prioritize validating models in real-world settings, refining sensor technology and signal processing techniques, and shifting focus toward comprehensive preventive strategies rather than mere prediction. These advancements could significantly enhance the quality of life and health outcomes of the elderly, while alleviating burdens on families and healthcare systems. Full article

Objective: This study aimed to investigate the effects of neuromuscular electrical stimulation (NMES) on lower limb muscle synergies during the single-leg hop test in martial artists after anterior cruciate ligament (ACL) reconstruction. Methods: Twenty-four martial artists who underwent ACL reconstruction were recruited and performed a single-leg hop test under two conditions: with NMES (ES) and without NMES (CON). The ES condition involved using Compex SP 8.0 to deliver biphasic symmetrical wave stimulation. Jump performance metrics and electromyographic (EMG) signals were recorded. Muscle synergies of the lower limbs were extracted using non-negative matrix factorization (NMF) to analyze patterns of muscle coordination. Results: Compared with the CON condition, the ES condition significantly reduced the jump time (0.13 ± 0.05 vs. 0.18 ± 0.09; F = 5.660; p = 0.022) and significantly increased the contact time (0.53 ± 0.12 vs. 0.43 ± 0.21; F = 4.013; p = 0.049). Muscle synergy analysis revealed three distinct synergy patterns under both conditions. For synergy pattern 1, compared with the CON condition, the muscle weightings of the rectus femoris and tibialis anterior muscles were significantly increased under the ES condition (p < 0.001). For synergy pattern 2, compared with the CON condition, the muscle weighting of the lateral gastrocnemius muscle was significantly increased under the ES condition (p < 0.001). Additionally, the activation timing of synergy pattern 2 was significantly reduced under the ES condition (p = 0.001). Conclusion: Neuromuscular electrical stimulation enhances jump performance and alters muscle synergy patterns in martial artists after ACL reconstruction. The findings suggest that NMES can promote better lower limb muscle coordination during jumping tasks, potentially aiding in postoperative rehabilitation and performance optimization. Full article

The Pilates breathing technique is theorized to improve neuromuscular efficiency, but its specific effects on peripheral muscles have not been thoroughly investigated. This study evaluated how Pilates breathing influenced the neuromuscular efficiency of the biceps brachii muscle during submaximal elbow flexion in comparison to regular breathing. Fifty-eight healthy adults without prior experience with the Pilates method of exercise performed concentric and eccentric elbow contractions at 20%, 40%, and 60% of their maximal voluntary isometric contraction under two breathing conditions: the specialized Pilates breathing pattern (executing movements exclusively during expiration) and normal breathing patterns. Muscle activity was measured using surface electromyography, with neuromuscular efficiency quantified as the relationship between muscle electrical activity and force production. The results revealed significantly improved neuromuscular efficiency during Pilates breathing at all tested intensity levels, with the most substantial enhancement observed at 60% of maximal effort. The eccentric phase of movement demonstrated greater efficiency gains compared to the concentric phase. These findings indicate that the distinct breathing pattern used in Pilates can independently enhance neuromuscular performance in the biceps brachii. This study suggests that incorporating Pilates breathing techniques could be beneficial in rehabilitation programs and strength training regimens to optimize both muscle function and movement efficiency. Additional research is recommended to examine the long-term effects and practical applications in clinical and athletic settings. Full article

Surface electromyography (sEMG) is a critical tool for quantifying muscle activity and inferring biomechanical function, enabling the detection of neuromuscular deficits through the analysis of electrical potential propagation. However, the inherent variability in sEMG signal amplitude, influenced by factors such as electrode placement, equipment characteristics, and individual physiology, necessitates robust normalization techniques for accurate comparative analysis. This study investigates the reliability and effectiveness of several normalization methods in the context of bicep and tricep muscle activation during dynamic and isometric exercises: maximum voluntary contraction (MVC), submaximal voluntary contraction (SMVC), remote voluntary contraction (RVC), mean, and peak normalization. We conducted a comprehensive experimental protocol involving healthy volunteers, capturing sEMG signals during controlled bicep curls, tricep extensions, and isometric contractions. The efficacy of each normalization method was evaluated based on its ability to minimize inter-subject variability and enhance signal consistency. Specifically, while SMVC, MVC, and RVC methods exhibited generally superior performance in normalizing bicep and tricep signals, the optimal method varied depending on the task and muscle, providing consistent and reliable data for biomechanical analysis. These results underscore the importance of selecting appropriate normalization techniques to improve the accuracy of sEMG-based assessments in clinical and sports biomechanics, contributing to the development of more effective rehabilitation protocols and performance enhancement strategies. Full article

This study explored the impact of a four-week Neuromuscular Electrical Stimulation (NMES)-induced eccentric contraction training on single-leg standing balance and muscle strength in 17 healthy adults. The unique training approach involved active antagonist muscle contraction during NMES. Post-training results revealed significant improvements in balance, with notable reductions in Center of Pressure (CoP) trajectory velocity (mean reduction: 0.07 ± 0.01 cm/s, p < 0.05) and range (mean reduction: 2.98 ± 0.53 cm, p < 0.05) on a firm surface. While increases in dorsiflexion force (mean increase: 21.43 ± 0.79 N, p < 0.05) and muscle activation were observed, these were not statistically significant. Changes in muscle pennation angles were also not significant (mean change: 0.43 ± 0.06 degrees, p > 0.05), underscoring the complexity of muscle adaptation processes. This study highlights NMES’s potential in enhancing balance and proprioceptive sensing, suggesting its promising applications in neuromuscular rehabilitation. However, further research is needed to fully understand its impact. Full article

Background: Adequate hamstring flexibility is crucial for musculoskeletal health as increased muscle tone can lead to stretch-type injuries, muscle weakness, dysfunctional neuromuscular control, postural changes, and lower back pain. The aim was to compare the effectiveness of a program based on Electrical Muscle Elongation (EME), Proprioceptive Neuromuscular Facilitation (PNF), and no intervention in improving flexibility and viscoelastic properties of hamstring and quadriceps muscles in active young adults with functional hamstring disorder (type 2B according to the Munich Consensus). Methods: Sixty-five participants (45 male, 20 female) were randomly assigned to three groups: the EME group (n = 21) received a simultaneous combination of interferential current and stretching, the PNF group (n = 22) underwent active stretching, and the Control group (n = 22) received no intervention. Hamstring and quadricep flexibility and muscle stiffness were measured in both limbs at baseline, post-intervention, and at the 4-week follow-up. Results: The EME group showed significant improvements in hamstring flexibility in the left limb compared to the Control group and in some myotonometric variables of the quadriceps muscle compared to the PNF and Control groups (p < 0.05). Within-groups differences indicated higher improvements in the EME group. Conclusions: This study suggests that EME may offer greater benefits than PNF stretching in young adults with functional hamstring disorder. Full article

Electromyography (EMG) signals are fundamental in neurorehabilitation as they provide a non-invasive means of capturing the electrical activity of muscles, enabling precise detection of motor intentions. This capability is essential for controlling assistive devices, such as therapeutic exoskeletons, that aim to restore mobility and improve motor function in patients with neuromuscular impairments. The integration of EMG into neurorehabilitation systems allows for adaptive and patient-specific interventions, addressing the variability in motor recovery needs. However, achieving the high fidelity, low latency, and robustness required for real-time control of these devices remains a significant challenge. This paper introduces a novel multi-channel electromyography (EMG) acquisition system implemented on a System-on-Chip (SoC) architecture for robotic neurorehabilitation. The system employs the Zynq-7000 SoC, which integrates an Advanced RISC Machine (ARM) processor, for high-level control and an FPGA for real-time signal processing. The architecture enables precise synchronization of up to eight EMG channels, leveraging high-speed analog-to-digital conversion and advanced filtering techniques implemented directly at the measurement site. By performing filtering and initial signal processing locally, prior to transmission to other subsystems, the system minimizes noise both through optimized processing and by reducing the distance to the muscle, thereby significantly enhancing the signal-to-noise ratio (SNR). A dedicated communication interface ensures low-latency data transfer to external controllers, crucial for adaptive control loops in exoskeletal applications. Experimental results validate the system’s capability to deliver high signal fidelity and low processing delays, outperforming commercial alternatives in terms of flexibility and scalability. This implementation provides a robust foundation for real-time bio-signal processing, advancing the integration of EMG-based control in neurorehabilitation devices. Full article

Background/Objective: Maintaining sufficient ankle joint range of motion (ROM) contributes to efficient movement in sports and daily activities. Static stretching (SS), while effective, demands significant time, highlighting the need for alternative, time-efficient approaches to improve ROM. Therefore, this study aimed to evaluate the effectiveness of combined intervention (CI) using neuromuscular electrical stimulation (NMES) and elastic tape versus SS. Methods: This randomized crossover trial was conducted in healthy university students. They underwent both interventions with a 1-week washout period. The CI entailed the application of elastic tape to the plantar surface of the foot coupled with NMES targeting the posterior lower leg muscles for 1 min. SS was administered for 5 min using a tilt table. Outcome measures included the dorsiflexion angle (DFA), finger-floor distance (FFD), straight leg raise (SLR) angle, plantar flexor strength (PFS), and knee flexor strength (KFS), assessed pre- and post-intervention. DFA was analyzed using equivalence testing with a predefined margin. Results: Both interventions yielded significant improvements in DFA, FFD, and SLR. The combination of NMES and elastic tape demonstrated equivalence to 5 min of SS in enhancing DFA. Neither intervention resulted in a significant reduction in PFS or KFS. Conclusions: The CI of NMES and elastic tape effectively and safely improves flexibility in a short time. Its time efficiency makes it a promising alternative to SS, especially for brief warm-ups or limited rehabilitation time. Further research should explore its long-term effects and broader applicability. Full article

Background: Malnutrition and muscle weakness are highly prevalent in critically admitted patients. To overcome sarcopenia and muscle weakness, physical activity and neuromuscular electric stimulation have been introduced with limited efficacy. Thus, several anabolic remedies have been introduced. An adequate increase in protein support according to indirect calorimetry and body composition and methyl hydroxybutyrate (HMB) is emerging. Therefore, we wanted to investigate the impact of HMB-enriched whey formula on the nutritional status, muscle weakness, and clinical course of critically ill patients undergoing nutritional status multimodal assessment and physical rehabilitation. Methods: We consecutively enrolled critically ill adult patients admitted to the intensive care unit (ICU) of “Santa Maria Hospital”, Terni, Italy. All patients underwent preliminary anthropometric, laboratory tests, nutritional (bioimpedance vector analysis and indirect calorimetry), and ultrasound muscle assessment at admission (T0). Laboratory tests monitoring continued throughout the ICU stay. Nutritional and muscle strength assessment was taken weekly throughout the patient’s ICU stay. All patients were enterally administered with a whey protein-enriched formula. Ten days after admission (during the physical rehabilitation period), patients were randomly administered a mixture of essential amino acids and methyl hydroxybutyrate (HMB). Results: We consecutively enrolled 54 ICU patients. At the baseline, survivors (n = 46) were significantly younger than non-survivors. The latter had a worse SAPS II score, nutritional status, and risk, with no significant difference in basal metabolism. Prealbumin values significantly correlated with improved nutritional status and metabolism. Starting from 10 days upon ICU admission, the pennation angle (used as a measure of muscle strength) significantly correlated with the improvement in nutritional status. Whey proteins were well tolerated. Its administration showed a tendency to improve the pennation angle. No specific effect of the mixture containing essential amino acids and methyl hydroxybutyrate was observed. Nutritional status improvement and the rise of basal metabolism were significantly correlated with the extubation time. On the other hand, the reduction in muscle weakness was not significantly correlated with the timing of extubation. Conclusions: Whey protein formula administration can significantly improve nutritional status and basal metabolism in ICU patients. This is reflected in improved muscle strength. Whey protein administration shows a tendency toward a rise in pennation angle. A similar and non-specific trend was observed upon HMB mixture add-one. Further prospective large-scale controlled studies are needed to confirm these promising results. Full article

Background: Falls and fall consequences in older adults are global health issues. Previous studies have compared postural sways or stepping strategies between older adults with and without fall histories to identify factors associated with falls. However, more in-depth neuromuscular/kinematic mechanisms have remained unclear. This study aimed to comprehensively investigate muscle activities and joint kinematics during reactive balance control in older adults with different fall histories. Methods: This pilot observational study recruited six community-dwelling older fallers (≥1 fall in past one year) and six older non-fallers, who received unpredictable translational balance perturbations in randomized directions and intensities during standing. The whole-body center-of-mass (COM) displacements, eight dominant-leg joint motions and muscle electrical activities were collected, and analyzed using the temporal and amplitude parameters. Results: Compared to non-fallers, fallers had significantly: (a) smaller activation rate of the ankle dorsiflexor, delayed activation of the hip flexor/extensor, larger activation rate of the knee flexor, and smaller agonist-antagonist co-contraction in lower-limb muscles; (b) larger knee/hip flexion angles, longer ankle dorsiflexion duration, and delayed timing of recovery in joint motions; and (c) earlier downward COM displacements and larger anteroposterior overshooting COM displacements following unpredictable perturbations (p < 0.05). Conclusions: Compared to non-fallers, fallers used more suspensory strategies for reactive standing balance, which compensated for inadequate ankle/hip strategies but resulted in prolonged recovery. A further longitudinal study with a larger sample is still needed to examine the diagnostic accuracies and training values of these identified neuromuscular/kinematic factors in differentiating fall risks and preventing future falls of older people, respectively. Full article

This pilot study explored how muscle activation influences the pattern recognition of tactile cues delivered using electrical stimulation (ES) during each 10% window interval of the normal walking gait cycle (GC). Three healthy adults participated in the experiment. After identifying the appropriate threshold, ES as the haptic cue was applied to the gastrocnemius lateralis (GL) and biceps brachii (BB) of participants walking on a treadmill. Findings revealed variable recognition patterns across participants, with the BB showing more variability during walking due to its minimal activity compared to the actively engaged GL. Dynamic time warping (DTW) was used to assess the similarity between muscle activation and electro-stimulated haptic perception. The DTW distance between electromyography (EMG) signals and muscle recognition patterns was significantly smaller for the GL (4.87 ± 0.21, mean ± SD) than the BB (8.65 ± 1.36, mean ± SD), showing a 78.6% relative difference, indicating that higher muscle activation was generally associated with more consistent haptic perception. However, individual differences and variations in recognition patterns were observed, suggesting personal variability influenced the perception outcomes. The study underscores the complexity of human neuromuscular responses to artificial sensory stimuli and suggests a potential link between muscle activity and haptic perception. Full article