Search Results (1,070)

Background: Combat sports require athletes to repeatedly perform explosive actions under conditions of fatigue, demanding high levels of neuromuscular coordination, reactive agility, and intermittent effort capacity. This study examined changes in biomechanical and neuromuscular performance over a 15-week period during which competitive Sambo athletes completed a CrossFit-based functional training program alongside their regular sport-specific training. Methods: Forty male Sambo athletes (22.4 ± 2.6 years) completed a longitudinal repeated-measures intervention consisting of three weekly CrossFit-based sessions integrated into regular sport-specific training. The program was periodized across four progressive mesocycles emphasizing functional strength, explosive power, reactive agility, and fatigue resistance. Pre- and post-intervention assessments included upper- and lower-limb reaction speed, vertical jump height, repeated jump endurance, reactive agility, grip endurance, body-weight squat performance, Romanian deadlift repetitions, and the Special Judo Fitness Test (SJFT). Statistical analyses included paired-samples t-tests or Wilcoxon signed-rank tests with Benjamini–Hochberg false discovery rate correction (α = 0.05). Results: Significant post-intervention improvements were observed in most performance variables. Upper- and lower-limb reaction performance improved by 22.9% and 9.7%, respectively (p < 0.001), while vertical jump height increased by 11.4% and repeated jump endurance by 16.6% (p < 0.001). Reactive agility time decreased by 6.6% (p < 0.001), indicating faster cognitive-motor responsiveness. Functional strength improved substantially, with increases of 43.7% in body-weight squat performance and 71.9% in Romanian deadlift repetitions (p ≤ 0.001). Grip endurance improved by 6.3% (p = 0.007), whereas maximal handgrip strength showed no significant changes. The SJFT index decreased by 5.0% (p < 0.001), reflecting enhanced intermittent effort efficiency and fatigue tolerance. Large effect sizes were identified for upper-limb reaction speed (d = 1.42), explosive endurance (d = 1.46), and reactive agility (d = 0.96). Conclusions: Over the 15-week study period, participation in a CrossFit-based functional training program integrated into regular Sambo practice was associated with improvements in several biomechanical and neuromuscular performance outcomes, including reaction performance, explosive power, agility, muscular endurance, and sport-specific work capacity. However, because the study did not include a control group, these changes cannot be attributed exclusively to the CrossFit-based intervention. Controlled studies are required to distinguish intervention-specific effects from seasonal training adaptations, continued sport-specific practice, and test familiarization. Full article

Background/Objectives: Mechanical power (MP) quantifies the energy delivered to the respiratory system during ventilation and serves as a promising marker for ventilator-induced lung injury (VILI). According to its original definition by Gattinoni, MP reflects the energy transferred from the ventilator to the respiratory system under conditions of deep sedation, passive breathing, neuromuscular blockade, and volume-controlled ventilation. Its role in coronavirus disease 2019 (COVID-19)-associated acute respiratory distress syndrome (ARDS) remains under investigation. This systematic review aimed to synthesize the available evidence on the association between MP and VILI, complications related to mechanical ventilation (MV), and mortality in adult patients with COVID-19 undergoing invasive mechanical ventilation (IMV). Methods: A systematic review was conducted using PubMed-MEDLINE (Medical Literature Analysis and Retrieval System Online) for studies published in recent years, focusing on adult COVID-19 patients undergoing IMV. Inclusion criteria centered on studies reporting MP and its association with VILI, complications, or mortality. Ten studies met eligibility criteria after screening 356 retrieved articles. Results: Most included studies were retrospective and observational, encompassing critically ill COVID-19 patients. Elevated MP was correlated with more severe outcomes, including increased 28-day mortality, prolonged MV, and weaning failure. Franck et al. demonstrated strong correlations between MP and driving pressure, elastance, and positive end-expiratory pressure, emphasizing the importance of calculation methods. González-Castro et al. identified a threshold of 17 J/min, above which mortality risk increased. Stalla et al. highlighted that dynamic MP reductions during prone positioning were associated with survival. Registry-based analyses confirmed that both magnitude and cumulative exposure above 18 J/min increased intensive care unit mortality. Novel indices combining MP with oxygenation parameters improved prognostic accuracy. While absolute MP at initiation provided limited predictive value, temporal trends and individual components were strongly linked to VILI. Conclusions: Higher MP has been associated with adverse clinical outcomes in patients with COVID-19 receiving invasive mechanical ventilation, supporting its potential role as a prognostic indicator. Its dynamic assessment, thresholds, and integration with ventilatory strategies such as prone positioning enhance risk stratification and may guide individualized, lung-protective ventilation. Continuous monitoring and standardized calculation are recommended to optimize clinical decision-making. Full article

Real-time feedback-based training has emerged as a potentially time-efficient approach for enhancing neuromuscular performance, yet evidence in youth basketball athletes remains limited. This study examined the acute and short-term effects of a five-day simulator-based neuromuscular training program incorporating real-time feedback on vertical jump performance and reactive efficiency in youth basketball players. A quasi-experimental, single-group repeated-measures design was employed, with performance assessed at three time points: pre-intervention (T1), post-intervention (T2), and 7-day follow-up (T3). Twenty-one male junior athletes (15.1 ± 0.7 years) completed five consecutive sessions on a condition simulation device (ERGOSIM), designed to enhance force control and neuromuscular coordination through real-time visual feedback. Vertical jump performance was assessed using a 15 s repeated jump test (OptoJump), including bilateral and unilateral conditions. Primary outcomes were jump height (H), mean average power (PU), and contact time (CT), analyzed via the MGM-15 method. Repeated-measures ANOVA revealed significant time effects for bilateral performance: H (F(2,40) = 16.593, p < 0.001, η²_p = 0.453), PU (F(2,40) = 19.281, p < 0.001, η²_p = 0.491), and CT (F(2,40) = 6.009, p = 0.005, η²_p = 0.231). From T1 to T3, bilateral jump height increased by 17.0%, accompanied by a 14.5% increase in average power and a 10.3% reduction in contact time. Unilateral performance improved significantly in both limbs, with progressive reduction in inter-limb asymmetry across the intervention period. Performance gains were largely maintained at T3, indicating short-term retention of neuromuscular adaptations. These findings suggest that simulator-based, feedback-driven neuromuscular training represents a time-efficient strategy for optimizing explosive performance and inter-limb symmetry within competitive microcycles although the single-group design and absence of a control group warrant cautious interpretation. Full article

Background/Objectives: Myasthenia gravis (MG) is an immune-mediated neuromuscular disorder for which antibody-based assays have limited sensitivity, particularly in double-seronegative MG (dsNMG), highlighting the need for complementary biomarkers. Given their roles in immune regulation, membrane integrity, and metabolic stress responses, lipids represent promising candidates for biomarker discovery. Methods: We designed a prospective case–control study and systematically stratified 68 patients with myasthenia gravis (MG) according to clinical classification and autoantibody status. Using LC–MS/MS, we quantified 824 lipids in 136 serum samples collected from these patients and 68 healthy controls. The analyzed subtypes included ocular MG (OMG), generalized MG (GMG), acetylcholine receptor antibody-positive MG (AChR-MG), and dsNMG. Differential lipid analysis, correlation network construction, KEGG pathway enrichment, and multivariable logistic regression were performed. Diagnostic and subtype prediction models were developed using LASSO with 10 × 10 repeated cross-validation and interpreted using Shapley Additive exPlanations (SHAP) analysis. A longitudinal follow-up analysis was conducted to assess dynamic associations between lipid signatures and disease activity. Results: In total, 240 lipids were significantly altered in MG compared with controls. Lipids distinguishing GMG from OMG were enriched in ether lipid metabolism, necroptosis, and sphingolipid signaling pathways. AChR-MG and dsNMG shared lipid networks related to membrane remodeling and signaling regulation, whereas dsNMG exhibited marked elevations in acylcarnitines and bile acid-related metabolites, potentially reflecting a distinct phenotype characterized by altered energy metabolism. The lipid-based model achieved an AUC of 0.917 for distinguishing MG from controls, and AUCs of 0.77 and 0.71 for differentiating AChR-MG from dsNMG and GMG from OMG, respectively. Longitudinal analyses showed that SM(d18:1/23:0) and Cer(d24:1/18:0(2OH)) displayed dynamic changes consistent with disease activity. Conclusions: Serum lipidomics revealed subtype-specific metabolic features of MG, with stable disease-associated remodeling and dynamic sphingolipid changes potentially reflecting disease activity. By integrating systematic clinical and antibody-based subtype stratification with longitudinal follow-up, this study supports lipidomics as a complementary tool for precision diagnosis and disease stratification, particularly in antibody-negative dsNMG. Full article

Introduction: Lateral elbow pain (LEP) is traditionally considered a local tendinopathy; however, emerging evidence suggests that proximal shoulder function and kinetic chain adaptations may contribute to its development in overhead and racquet sport athletes such as padel players. This study compared shoulder strength, neuromuscular activation, elbow tendon morphology, and grip strength between padel players with lateral elbow pain and healthy controls, and between pain and non-pain sides within the symptomatic group. Methods: A pilot study was conducted in padel players with unilateral LEP and matched healthy controls. Assessments included isometric shoulder internal and external rotator (IR/ER) strength, glenohumeral rotational range of motion, electromyographic activity (infraspinatus/deltoid posterior and upper trapezius/lower trapezius ratios), grip strength, and ultrasound evaluation of infraspinatus and common extensor tendon thickness. Results: No significant differences were observed between groups or sides in shoulder strength, IR/ER ratios, electromyographic activity, or grip strength (all p > 0.05). The symptomatic group showed greater infraspinatus muscle thickness than controls. Within the symptomatic group, the pain side demonstrated reduced glenohumeral IR (p = 0.04) and increased common extensor tendon thickness (p = 0.02–0.05). Conclusions: Padel players with LEP demonstrated largely preserved neuromuscular and strength profiles. However, reduced shoulder IR and increased tendon thickness suggest proximal mobility alterations and local tendon adaptations, supporting a kinetic chain interpretation of lateral elbow pain. Full article

Introduction: Exercise programmes effectively prevent sports injuries and enhance neuromuscular parameters, but their impact on futsal performance remains understudied. Objective: The primary objective was to evaluate the effects of exercise-based programmes on injury outcomes in futsal players. The secondary objective was to assess their effects on physical and neuromuscular outcomes potentially associated with injury risk. Material and Methods: A search was carried out in PubMed, Scopus, SPORTDiscus, Web of Science, and PEDro databases. The methodological quality of the included studies was assessed using the PEDro scale, risk of bias using the RoB 2 tool, and certainty of evidence using the GRADE approach. A meta-analysis was performed using the Hedges’ g adjustment. Results: Fifteen reports corresponding to 12 unique studies and 405 randomized participants met the eligibility criteria. Two studies assessed direct injury outcomes. One reported significantly lower exposure-adjusted injury rates following the FIFA 11+ programme, whereas the other reported fewer injury events without a statistically significant between-group difference. Owing to differences in injury definitions and denominators, these findings were synthesized narratively. Random-effects meta-analyses showed significant effects favouring exercise-based programmes for muscle power (Hedges’ g = 0.616; 95% CI, 0.131 to 1.101; p = 0.013), muscle strength (g = 1.972; 95% CI, 0.214 to 3.731; p = 0.028), and flexibility (g = 0.569; 95% CI, 0.029 to 1.108; p = 0.039). The certainty of evidence was very low for injury outcomes and muscle strength and low for muscle power and flexibility. Conclusions: Exercise-based programmes may improve several physical and neuromuscular outcomes in futsal players. However, direct evidence regarding injury prevention is limited to two studies, and improvements in performance-related or biomechanical outcomes should not be interpreted as confirmation of a reduction in injury incidence. Full article

Foam rolling (FR) is widely used to acutely enhance range of motion, yet the influence of different application volumes on neuromuscular, structural, and biochemical responses remains unclear. This study investigated the acute effects of low- and high-volume hamstrings FR interventions. Fifty-seven healthy male participants were randomly assigned to a high-volume FR group (IG10; 10 min per posterior thigh), a low-volume FR group (IG2; 2 min per posterior thigh), or a control group (CG; 20 min rest). Pre- and post-intervention assessments included sit-and-reach (SAR) performance, shoulder circumduction (SC) (mobility), maximal voluntary isometric contraction (MVIC), biceps femoris muscle stiffness (MS), and creatine kinase (CK) levels. Linear mixed-effects models revealed significant Time effects for SAR performance and SC, as well as a Group effect for SC (p < 0.05), whereas no significant Group × Time interactions were observed for any outcome (all p > 0.05). Significant improvements in SC were observed in both intervention groups compared with the CG, whereas no differences were detected between the two intervention durations. In contrast, no differential effects were observed for MS, maximal strength, or CK concentrations between the intervention groups, indicating that extending the FR duration from 2 to 10 min did not provide additional acute benefits. Full article

Background: Tranexamic acid (TXA) is increasingly used to reduce perioperative blood loss during scoliosis surgery; however, its effectiveness in pediatric patients with non-idiopathic scoliosis remains underexplored. Unlike adolescent idiopathic scoliosis, non-idiopathic scoliosis is frequently associated with neuromuscular, syndromic, or other underlying disorders that increase surgical complexity and may limit the generalizability of evidence from idiopathic populations. This systematic review and meta-analysis evaluated the impact of TXA on surgical outcomes in pediatric patients undergoing posterior spinal fusion for non-idiopathic scoliosis. Methods: This analysis encompassed five studies (comprising one randomized controlled trial and four observational studies) involving a total of 230 patients (TXA group: 98; control group: 132). The primary outcomes were estimated blood loss and the volume of packed red blood cells (PRBCs) transfused. Secondary outcomes included total transfusion amount, operation duration, complications, cell salvage application, preoperative hematocrit levels and blood loss percentage. A random-effects model was used. Mean difference (MD) was used for continuous outcomes, and odds ratio (OR) for dichotomous variables, both with 95% confidence intervals (CIs). Results: The use of TXA during posterior fusion surgery showed to be of benefit and was associated with significantly less estimated blood loss (p < 0.0001) and cell salvage volume transfusion (p < 0.0001). The remaining secondary outcomes did not show significant differences when compared with the control. Conclusion: Current evidence suggests that TXA is an effective blood conservation strategy in pediatric patients undergoing posterior spinal fusion for non-idiopathic scoliosis. However, the available evidence remains limited, particularly regarding perioperative complications, and further high-quality prospective studies are required to strengthen the evidence base. Clinical relevance: Exploring the use of TXA in scoliosis surgery has the potential to influence the standard of care, especially if associated with significantly more desirable post-operative and long-term outcomes. Full article

Background/Objectives: Gait impairment and reduced handgrip strength are common in Parkinson’s disease (PD), but their relationship remains unclear. This study examined whether associations between handgrip force and gait reflect PD-specific impairment or broader functional capacity. Methods: In this cross-sectional study, 45 individuals with PD and 51 healthy older adults completed unilateral maximal isometric handgrip testing and overground gait assessment at preferred and maximal speed. Handgrip variables included peak force (PF), rate-of-force development (RFD), and impulse. Gait speed, cadence, and step length were recorded. Results: PF was significantly associated with gait speed and step length in both groups, especially under maximal-speed conditions. RFD and impulse were not significantly associated with gait performance in either group. Compared to controls, participants with PD showed poorer gait performance, with lower preferred walking speed and shorter step length in both gait conditions. Within the PD group, PF was lower on the more-affected side than on the less-affected side, whereas most RFD and impulse variables showed no side differences. Conclusions: Maximal handgrip strength, but not upper-limb RFD or impulse, was associated with key gait outcomes in both PD and healthy older adults. These findings suggest that handgrip strength may reflect general functional capacity rather than a PD-specific neuromuscular mechanism and support its use as a practical clinical indicator of mobility-related function. Full article

Background/Objectives: Subacromial impingement syndrome (SIS) may be associated with altered kinetic-chain mechanics above and below the shoulder. The posterior oblique sling integrates the gluteus maximus and latissimus dorsi through established fascial and neuromuscular connections, yet empirical evidence examining its relevance in SIS remains limited. Therefore, this cross-sectional observational study aimed to investigate the surface electromyographic (sEMG) activity of the latissimus dorsi (LD) and contralateral gluteus maximus (GM) and evaluate their associations with pain, disability, and shoulder range of motion (ROM) in young adults with SIS. Methods: Sixty sedentary young adults with SIS and matched controls were assessed using the Numeric Pain Rating Scale, Arabic QuickDASH, twin-axis electrogoniometer, and sEMG of the gluteus maximus and latissimus dorsi. Results: The SIS group had significantly lower GM activity (23.96 ± 3.54% MVIC for SIS and 34.49 ± 4.16% MVIC for controls) and significantly higher LD activity (118.63 ± 24.87% MVIC for SIS and 75.52 ± 25.93% MVIC for controls) (p = 0.001). In addition to these differences, the SIS group exhibited significantly less ROM in all directions (flexion, extension, abduction, and rotation) and greater disability and pain intensity (both p = 0.001) than controls. Correlations between sEMG activity and clinical outcome measures in the SIS group were weak and not statistically significant. Discriminant logistic regression indicated that both GM and LD sEMG were significant discriminative variables of group membership, with GM underactivity showing the greater discriminative value. Conclusions: These results indicate an altered neuromuscular activation pattern observed in participants with SIS, characterized by decreased GM and increased LD sEMG activity. They may justify further investigation of kinetic-chain-informed rehabilitation, with attention to both hip/lumbopelvic function and shoulder-based treatment. Full article

Age-related sarcopenia involves structural and functional neuromuscular changes. Electrophysiological measures from surface electromyography (sEMG) capture activation dynamics, spectral fatigue indices and motor unit properties that may constitute objective signatures of sarcopenia. The objective of this work is to systematically review sEMG features, fatigability metrics and AI-based classification/regression approaches reported for sarcopenia assessment between 2019 and 2026. PRISMA guidelines were followed, and IEEE Xplore, PubMed and Scopus were searched for open access human studies. Extracted information comprised sample characteristics, muscles and tasks, signal acquisition and preprocessing, extracted time/frequency/time–frequency and motor unit features, fatigue metrics, machine learning pipelines, validation schemes and dataset accessibility. Studies were classified into activation, fatigue, ML, and neural control groups; risk of bias was assessed. A total of 12 studies fulfilled the inclusion criteria. Recurrent electrophysiological signatures included reduced distal activation with compensatory proximal recruitment and higher antagonist co-activation; diminished MF/IMDF fatigue slopes indicative of Type II fiber loss and altered motor unit recruitment; motor unit analyses revealed decreased discharge rates and larger MUAP amplitudes. AI-based models combining multidomain features (time, spectral, CWT/EMD, and motor unit metrics) yielded reasonable screening performance (AUC/accuracy 0.73–0.89) when using robust feature selection and explainability tools. Heterogeneity in acquisition, normalization, small cohorts and sparse data sharing limited comparability and external validity. The findings indicate that sEMG-derived electrophysiological signatures are promising for sarcopenia detection and monitoring. To translate signatures into reliable clinical tools, standardized protocols, larger shared datasets, multimodal features, including motor unit metrics, and rigorous external validation of AI models are required. Full article

Background: The acromiohumeral distance (AHD) is a widely used imaging parameter for evaluating the subacromial region and shoulder function. Traditionally, it has been interpreted as a static anatomical measurement reflecting the available subacromial space and associated with rotator cuff pathology, superior humeral migration, and subacromial impingement. However, inconsistent relationships between AHD, symptoms, and function suggest that purely structural interpretations may be insufficient. Objectives: To propose a systems-based functional morphology framework that reinterprets AHD as an emergent functional state variable reflecting the instantaneous state of the glenohumeral system. Methods: A conceptual synthesis integrated evidence from shoulder biomechanics, functional morphology, movement science, connective tissue research, systems theory, and personalized neuromusculoskeletal modelling. Structural, connective tissue, neuromuscular, and mechanical determinants of AHD were integrated within a multilevel systems perspective. Results: The proposed framework conceptualizes AHD as emerging from the dynamic interaction of four organizational domains: structural constraints, connective tissue properties, neuromuscular regulation, and mechanical context. Rather than representing a fixed anatomical space, AHD is interpreted as a potential systems-level functional biomarker whose value varies according to the functional state of the glenohumeral system. This perspective explains the variability observed across imaging studies and the frequent discordance between structural findings, symptoms, and functional outcomes. Conclusions: Reframing AHD as an emergent functional state variable provides a theoretical basis for integrating anatomy, biomechanics, movement behavior, and neuromuscular control within personalized shoulder assessment. This systems-based perspective may help bridge the traditional gap between structural imaging and clinical presentation while supporting future developments in precision rehabilitation and subject-specific computational modelling. Full article

Electromyography (EMG)-based pattern recognition is a key enabling technology for intuitive upper-limb prosthetic control; however, amputee EMG signals show substantial intersubject variability and nonstationary characteristics, which can limit the effectiveness of conventional fixed feature representations. This study proposes an Adaptive Multi-Representation Fusion Framework that combines an enhanced Adaptive Linear Series Decomposition Learner (Adaptive LSDL) with Time-Domain Power Spectral Descriptors (TDPSD) for amputee movement classification. The proposed Adaptive LSDL extends conventional decomposition by using adaptive threshold-region optimization and multitransform signal analysis, enabling subject-specific identification of the most discriminative decomposition characteristics while preserving low computational complexity. The complementary properties of TDPSD and Adaptive LSDL are then exploited through feature-level fusion, producing a unified representation that captures both local temporal-spectral complexity and adaptive structural signal information. Experimental evaluation was conducted using the Ninapro DB3 dataset, comprising 11 transradial amputees, and a MYO armband amputee dataset, comprising 6 transradial amputees. Subject-specific five-fold cross-validation was performed using a Linear Discriminant Analysis (LDA) classifier. Adaptive LSDL consistently improved performance relative to the original fixed-threshold LSDL representation, while fusion improved classification accuracy for 7 of 11 DB3 amputees and 5 of 6 MYO amputees. The largest fusion gains reached 4.39 and 5.60 percentage points for the DB3 and MYO cohorts, respectively. Furthermore, the proposed framework demonstrated competitive performance relative to a lightweight real-time convolutional neural network benchmark while requiring substantially lower computational complexity. These findings indicate that adaptive decomposition and representation-level information fusion provide an effective approach for exploiting subject-specific neuromuscular information while remaining suitable for computationally efficient prosthetic control applications. Full article

Background: Beetroot-derived nitrate supplementation is a widely studied nutritional strategy to enhance athletic performance. Although ergogenic benefits have been reported in recreational and moderately trained individuals, evidence for highly trained and elite athletes remains inconsistent. Objectives: This scoping review aimed to map and synthesize evidence from randomized controlled trials (RCTs) investigating the effects of beetroot-derived nitrate supplementation on performance, recovery, and physiological outcomes in highly trained and elite athletes. Methods: The review followed the Joanna Briggs Institute methodology and PRISMA-ScR guidelines. Literature searches were conducted in PubMed, Scopus, and Web of Science. Eligible studies included RCTs involving McKay Tier 3–5 athletes and evaluating beetroot-derived nitrate supplementation as a standalone intervention. Results: Thirty-one RCTs met the inclusion criteria, representing athletes from a wide range of sports. Supplementation protocols varied substantially, with nitrate doses ranging from 4 to 19.5 mmol·day⁻¹ (248–1209 mg·day⁻¹) and durations from acute administration to 15 days. Positive effects were most frequently reported for cycling time-trial performance, Yo-Yo intermittent recovery performance, anaerobic power, neuromuscular performance, exercise tolerance, and recovery. In contrast, findings for endurance performance, sport-specific skills, oxygen consumption, and perceptual responses were inconsistent despite marked increases in nitrate and nitrite bioavailability. The outcomes seemed to depend on dosage, duration, sport type, and athletes’ training status. Conclusions: Beetroot-derived nitrate supplementation may enhance performance in highly trained and elite athletes, particularly during high-intensity and anaerobic activities. However, the effects are inconsistent, underscoring the need for further research to establish optimal supplementation strategies and evaluate long-term efficacy in elite sporting populations. Full article

The walking cycle is biomechanically considered a fundamental unit of biomedical analysis, a neuromuscular-controlled repetitive process and an energy-optimized system. As defined in the literature, the walking cycle is represented by the interval between two successive contacts of the same foot with the ground, having two main phases of stance and swing. Current theoretical and experimental research seeks to build complex models of analysis of the parameters of the walking cycle to highlight different behaviors at the level of the human body (biomechanical, energetic, sensory, etc.). In this paper, the authors develop a model of theoretical analysis by simulating the walking cycle in Matlab code to highlight energy levels. The theoretical model is proposed to be applied to a sample of subjects with simulations of locomotor pathologies to confirm hypotheses. Full article