Journal of Electromyography and Kinesiology最新文献

Passive stretching-induced changes in the spatial distribution of muscle excitation: A step forward in the interpretation of the underlying mechanisms. 被动拉伸引起的肌肉兴奋空间分布的变化：对潜在机制的解释向前迈进了一步。

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-10-01 Epub Date: 2025-08-05 DOI: 10.1016/j.jelekin.2025.103046

Nicholas Toninelli, Giuseppe Coratella, Christian Doria, Eloisa Limonta, Marta Borrelli, Susanna Rampichini, Fabio Esposito, Stefano Longo, Emiliano Cè

{"title":"Passive stretching-induced changes in the spatial distribution of muscle excitation: A step forward in the interpretation of the underlying mechanisms.","authors":"Nicholas Toninelli, Giuseppe Coratella, Christian Doria, Eloisa Limonta, Marta Borrelli, Susanna Rampichini, Fabio Esposito, Stefano Longo, Emiliano Cè","doi":"10.1016/j.jelekin.2025.103046","DOIUrl":"10.1016/j.jelekin.2025.103046","url":null,"abstract":"<p><p>We assessed passive static stretching (PS) effects on the spatial distribution of muscle excitation (SDME) of the stretched (SL) and contralateral non-stretched limb (CL) during maximum voluntary isometric contractions (MVC). Before (PRE) and after 5-min PS, immediately (POST), at min 5 (POST<sub>5</sub>) and 10 (POST<sub>10</sub>), range of motion (ROM), maximal M-wave (M<sub>max</sub>) and MVC of both limbs were assessed in thirty men. During MVC, high-density surface electromyographic signals from the gastrocnemius medialis (GM) and lateralis (GL) were collected. The root mean square (RMS) and centroid coordinates were then obtained. During PS, discomfort perception (VAS), proximal and distal GM architecture were recorded. At POST, ROM increased and MVC decreased together with RMS in both limbs (P < 0.05). A cranio-caudal shift in SDME occurred in both muscles of SL and CL (P < 0.01) that persisted only in SL until POST<sub>5</sub> in GM (P = 0.04), and POST<sub>10</sub> in GL (P = 0.01). During PS, VAS was high (>8.0), and fascicle length and angle increased from rest (P < 0.01). No differences between GM portions were found in muscle architecture and in M<sub>max</sub> (P > 0.05). The results suggest involvement of central neural mechanisms in SDME shift. The prolonged effect in SL compared to CL indicates a possible additional contribution from mechanical mechanisms.</p>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"84 ","pages":"103046"},"PeriodicalIF":2.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144805360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Vigorous physical activity enhances intermuscular coordination between ankle muscles during gait. 剧烈的体力活动增强了步态中踝关节肌肉间的肌肉协调。

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-10-01 Epub Date: 2025-08-05 DOI: 10.1016/j.jelekin.2025.103045

Carlos Cruz-Montecinos, Camila Barraza-Viluñir, Luis Acuña-Cancino, Jean Arias, Cristina Olivares, Rodrigo Nuñez-Cortés, Joaquín Calatayud, Xavier Garcia-Masso, Carlos De la Fuente, Claudio Tapia, Felipe P Carpes

{"title":"Vigorous physical activity enhances intermuscular coordination between ankle muscles during gait.","authors":"Carlos Cruz-Montecinos, Camila Barraza-Viluñir, Luis Acuña-Cancino, Jean Arias, Cristina Olivares, Rodrigo Nuñez-Cortés, Joaquín Calatayud, Xavier Garcia-Masso, Carlos De la Fuente, Claudio Tapia, Felipe P Carpes","doi":"10.1016/j.jelekin.2025.103045","DOIUrl":"10.1016/j.jelekin.2025.103045","url":null,"abstract":"<p><p>Intermuscular coordination (IMC) refers to the nervous system's ability to synchronise muscle activity. While regular physical activity is thought to enhance IMC, the nature of this relationship remains poorly understood. Here we investigate whether high and low IMC between ankle muscles during gait differs based on physical activity levels and individuals' weekly engagement in vigorous activities among young adults. Twenty-five participants (10 females) aged 20-34 years were evaluated. Surface electromyography (EMG) recorded activity of the tibialis anterior (TA), soleus (SOL), and medial gastrocnemius (GM) at 1000 Hz during 10 walking trials at 1 m/s (90 m total). Each EMG epoch included 200 ms before to 600 ms after heel contact and was analysed using causal empirical mode decomposition to identify intrinsic mode functions (IMFs) with stronger causal relationships among muscle pairs. Coordination between selected IMFs of the SOL-TA and SOL-MG muscle pairs was assessed using cross-approximate entropy (XApEn). K-means clustering of XApEn values identified low and high IMC groups (p < 0.001). Proportion of physically active individuals was 83 % in high IMC group, compared to 23 % in low IMC group (p = 0.003). Weekly vigorous activity was greater in the active group (240 vs. 0 min, p = 0.010) and showed a significant moderate correlation with IMC between antagonistic muscles. Physical activity enhances intermuscular coordination among ankle muscles during gait. This emphasizes the role of physical activity, particularly vigorous activity, in enhancing neuromuscular function and counteracting the negative effects of sedentary behaviour on the neuromuscular system.</p>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"84 ","pages":"103045"},"PeriodicalIF":2.3,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144801047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Muscle coactivation during knee joint-position sense assessments: the effect of muscle fatigue and implications for the magnitude of errors and directional bias 膝关节位置感评估中的肌肉协同激活：肌肉疲劳的影响和误差和方向偏差的大小的含义

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-09-23 DOI: 10.1016/j.jelekin.2025.103072

Joana Azevedo , Pedro Fonseca , Adérito Seixas , José Oliveira , João Paulo Vilas-Boas

{"title":"Muscle coactivation during knee joint-position sense assessments: the effect of muscle fatigue and implications for the magnitude of errors and directional bias","authors":"Joana Azevedo , Pedro Fonseca , Adérito Seixas , José Oliveira , João Paulo Vilas-Boas","doi":"10.1016/j.jelekin.2025.103072","DOIUrl":"10.1016/j.jelekin.2025.103072","url":null,"abstract":"<div><h3>Purpose</h3><div>This study aimed to describe muscle coactivation during knee joint-position sense (KJPS) assessments in healthy individuals, before and after muscle fatigue, and to analyse the implications for the magnitude of errors and directional bias.</div></div><div><h3>Methods</h3><div>The KJPS of 21 healthy males was assessed in the sitting position through concentric (SIT_CC) and eccentric repositionings (SIT_ECC) to 45° of knee flexion. Two fatigue protocols were tested, consisting of concentric contractions of the knee extensors or flexors. Muscle coactivation indices were calculated based on the normalized mean activation of the <em>vastus lateralis</em> and <em>biceps femoris</em> muscles. Absolute and relative errors were calculated to group participants by magnitude of errors (lower vs. higher errors) and directional bias (extension vs. flexion).</div></div><div><h3>Results</h3><div>Coactivation indices ranged between 74.92 % - 98.43 %. Significant overall decrease in coactivation indices after both fatigue protocols (<em>p</em> < 0.05). No significant differences in coactivation were found between magnitude of errors groups (<em>p</em> > 0.05), but significant higher coactivation were observed in participants failing the target position into flexion, only in the SIT_CC test (0.001 < <em>p</em> < 0.042).</div></div><div><h3>Conclusion</h3><div>Muscle coactivation between knee extensors and flexors was high in the assessed JPS tests, and decreased after fatigue. Muscle coactivation does not appear to explain the magnitude of errors, while it seems to influence directional bias.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"85 ","pages":"Article 103072"},"PeriodicalIF":2.3,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158607","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Motor performance and aging in males and females 男性和女性的运动表现和衰老

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-09-18 DOI: 10.1016/j.jelekin.2025.103066

Sandra K. Hunter

{"title":"Motor performance and aging in males and females","authors":"Sandra K. Hunter","doi":"10.1016/j.jelekin.2025.103066","DOIUrl":"10.1016/j.jelekin.2025.103066","url":null,"abstract":"<div><div>Advanced aging is accompanied by marked declines in motor performance in males and females including reductions in strength, speed and power of limb muscles that begin as early as midlife (∼>40 years) and accelerate from ∼65 years of age. Low muscle power and strength is exacerbated by increased fatigability with aging of limb muscles during dynamic contraction tasks and larger performance variability (between and within older adults), especially in older females. Starting in midlife, females exhibit earlier and larger age-related reductions in muscle strength and power and athletic performance than males of the same age and this is paralleled by increased prevalence of poor health, frailty, and loss of independence. This review presents evidence of key neural and muscular mechanisms affecting the motor unit, the age-related reductions in motor performance and the increased variability in healthy old and very old males and females. Muscular atrophy, particularly of fast-twitch (Type II) fibers, contractile slowing, degradation of neuromuscular junctions, and impairments in motor unit activation collectively underpin sarcopenia and impaired motor and functional performance among older adults. This review also briefly highlights approaches to understanding the protective effects of physical activity and high-resistance training on the age-related changes in muscle and neural function, even in the oldest adults. Such interventions delay functional declines and emphasize the adaptability of the aging neuromuscular system. Opportunities abound for future research to focus on understanding the specific mechanisms driving neural and muscular degeneration and optimizing exercise strategies to improve neuromuscular health of old males and females.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"85 ","pages":"Article 103066"},"PeriodicalIF":2.3,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The angle-based dynamic control ratio in isokinetic fatiguing knee flexion–extension effort: A study of healthy subjects 基于角度的等运动疲劳膝关节屈伸力动态控制率：健康受试者的研究。

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-09-11 DOI: 10.1016/j.jelekin.2025.103068

Kodai Suzuki , Takashi Okada , Takayoshi Hakkaku , Shohei Shimowada , Michal Katz-Leurer , Zeevi Dvir

{"title":"The angle-based dynamic control ratio in isokinetic fatiguing knee flexion–extension effort: A study of healthy subjects","authors":"Kodai Suzuki , Takashi Okada , Takayoshi Hakkaku , Shohei Shimowada , Michal Katz-Leurer , Zeevi Dvir","doi":"10.1016/j.jelekin.2025.103068","DOIUrl":"10.1016/j.jelekin.2025.103068","url":null,"abstract":"<div><div>This study examined the angle-based variations in the dynamic control ratio (DCRab), defined as the peak concentric moment of the quadriceps (Qcon) divided by its hamstring counterpart (Hecc) when calculated calculated at 1° intervals, during isokinetic fatiguing conditions. Sixteen men performed 30 maximal concentric knee extensions and eccentric flexions of the right and left knees at speeds of 120°/s and 180°/s. Data were analyzed using ratio values extracted from three repetition segments (4–6, 14–16, and 27–29) and presented graphically. All DCRab curves followed asymmetric second-order patterns, with the values near end-RoM (full extension: 5–7°) significantly higher than at RoM onset (95° of flexion), reflecting increased hamstring moment output. Fatigue reduced the Q and H moment at the equilibrium point [DCRe(M); Hecc = Qcon] and shifted the angle at which the DCRe occurred [DCRe(∠)] rightward, indicating altered muscle balance. DCRe(M) correlated with DCRe(∠): r = 0.84–0.90, while the DCRe(∠) correlated with angle of peak moment (r = 0.63–0.88), especially at 180°/s. Notably, the DCRe(∠) occurred at 20–30° of knee extension and correlated with the angle of peak moment of Hecc at 180°/s, indicating enhanced joint protection. No significant inter-limb differences were found in either Qcon or Hecc strength (p = 0.520). The use of the DCRab and its derivatives, the DCRe(M) and DCRe(∠) indicates that fatigue may affect Q-H balance. Thus, these parameters may aid in assessing the risk of knee injury and design of rehabilitation protocols.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"85 ","pages":"Article 103068"},"PeriodicalIF":2.3,"publicationDate":"2025-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145102808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Quantifying the influence of radiation therapy on functional shoulder health indicators in breast cancer patients: An exploratory study 量化放疗对乳腺癌患者肩功能健康指标的影响：一项探索性研究。

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-09-10 DOI: 10.1016/j.jelekin.2025.103071

M.C.Herrera Valerio, C.R. Dickerson

{"title":"Quantifying the influence of radiation therapy on functional shoulder health indicators in breast cancer patients: An exploratory study","authors":"M.C.Herrera Valerio, C.R. Dickerson","doi":"10.1016/j.jelekin.2025.103071","DOIUrl":"10.1016/j.jelekin.2025.103071","url":null,"abstract":"<div><div>Introduction: Radiotherapy is a highly effective treatment for breast cancer, but it is also associated with several complications that can impact quality of life and survivorship, including arm function. This study assessed the influence of radiation therapy on shoulder health indicators of breast cancer patients during their treatment period. Methods: Fourteen breast cancer patients undergoing radiation therapy participated. Shoulder health indicators were assessed at the baseline, midpoint, and endpoint of radiation treatment. The indicators included shoulder muscle activations, arm circumference, shoulder complex range of motion, and arm strength. Repeated measures ANOVAs followed by post-hoc Tukey-Kramer tests were used to identify differences in shoulder indicators between levels (p < 0.05). A multiple linear regression model was created for each dependent measurement including radiation dose and fractions as predictor variables. Results: The activation of the teres major and latissimus dorsi muscles decreased in most of the evaluated movements. Additionally, mean shoulder abduction decreased by 11 deg, and negative correlations existed between shoulder abduction range of motion and radiation dose, and between shoulder abduction strength and radiation fractions. The observed changes may relate to post-treatment inflammation, and lingering effects of radiation on shoulder health indicators may take longer to manifest, hindering identification within the treatment window.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"85 ","pages":"Article 103071"},"PeriodicalIF":2.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145082604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimizing passive exoskeleton torque for dynamic overhead work: Phase-specific analysis on muscle activity and perceived exertion 优化被动外骨骼扭矩动态顶工作：肌肉活动和感知消耗的阶段特定分析

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-09-10 DOI: 10.1016/j.jelekin.2025.103070

Giulia Casu , Alan Barr , Sunwook Kim , Maury A. Nussbaum , David Rempel , Massimiliano Pau , Carisa Harris-Adamson

{"title":"Optimizing passive exoskeleton torque for dynamic overhead work: Phase-specific analysis on muscle activity and perceived exertion","authors":"Giulia Casu , Alan Barr , Sunwook Kim , Maury A. Nussbaum , David Rempel , Massimiliano Pau , Carisa Harris-Adamson","doi":"10.1016/j.jelekin.2025.103070","DOIUrl":"10.1016/j.jelekin.2025.103070","url":null,"abstract":"<div><div>Purpose: This study investigated how different levels of torque provided by a passive arm-support exoskeleton (ASE) influence upper extremity muscle activity, perceived exertion, and fatigue during arm ascent and descent phases of a Dynamic Overhead (DO) task. Methods: The DO task involved 20 cycles of simulated drilling and was completed by 20 individuals by using a light-duty drill in four conditions: without supporting torque (no ASE) and with three increasing levels of ASE torque (i.e., 50, 75, and 100% of the torque required to support the arm in 90° of flexion). Surface electromyography was measured bilaterally over six shoulder muscles. Moreover, participants indicated torque preference, ratings of perceived exertion (RPE), and fatigue in the shoulder. Results: Increasing torque levels caused significant reductions in shoulder agonist muscle activity (up to 47%) and significant decreases in RPE and fatigue during the ascent phase. In contrast, higher levels of torque increased muscular activity for some antagonist muscles during the descent phase. Conclusions: While torque levels of 75% and 100% received the most positive ratings, we suggest that 75% torque could be an effective supporting condition, by reducing shoulder muscle flexor activity during arm ascent and minimizing antagonist muscle activity during arm descent.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"85 ","pages":"Article 103070"},"PeriodicalIF":2.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145057290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Three-dimensional markerless pose estimation for anatomical landmarks of the shoulder and upper limb 肩部和上肢解剖标志的三维无标记姿态估计

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-09-10 DOI: 10.1016/j.jelekin.2025.103067

F. Lefebvre , I. Rogowski , N. Long , Y. Blache

{"title":"Three-dimensional markerless pose estimation for anatomical landmarks of the shoulder and upper limb","authors":"F. Lefebvre , I. Rogowski , N. Long , Y. Blache","doi":"10.1016/j.jelekin.2025.103067","DOIUrl":"10.1016/j.jelekin.2025.103067","url":null,"abstract":"<div><div>This study aimed to develop and validate a 3D markerless pose estimation algorithm for anatomical landmarks of the shoulder and upper limb. Twenty-six healthy participants were asked to hold 21 static positions, while both markerless and marker-based (applied after palpation) images were recorded using eight video cameras. A pre-trained convolutional neural network based on ResNet-50 was fine-tuned on 2612 markerless images to estimate the poses of 20anatomical landmarks. The model was tested on 1680 images by calculating the 3D Euclidean distances between predicted coordinates and those labeled from marker-based images. Across all positions, median and 90th percentile Euclidean distances were below 15 mm and 30 mm, respectively for all anatomical landmarks, except for the 8th thoracic vertebra, inferior angle of the scapula and medial epicondyle, which presented the highest Euclidean distances. For most of the anatomical landmarks, loss rates inferior to 6 % were observed for predicted coordinates. The neural network accuracy was similar between movements tested and not influenced by the degree of arm elevation. To conclude, a neural network was developed and validated for estimating shoulder and upper-limb anatomical landmarks poses, demonstrating promising accuracy for future clinical applications.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"85 ","pages":"Article 103067"},"PeriodicalIF":2.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145049626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Establishing a methodological framework for evaluating gait symmetry through muscle synergies: A pilot study 通过肌肉协同作用建立评估步态对称性的方法学框架：一项试点研究

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-09-10 DOI: 10.1016/j.jelekin.2025.103064

Elham Zargaripour, Farzad Towhidkhah, Farnaz Ghassemi, Otella Shoja

{"title":"Establishing a methodological framework for evaluating gait symmetry through muscle synergies: A pilot study","authors":"Elham Zargaripour, Farzad Towhidkhah, Farnaz Ghassemi, Otella Shoja","doi":"10.1016/j.jelekin.2025.103064","DOIUrl":"10.1016/j.jelekin.2025.103064","url":null,"abstract":"<div><div>Gait symmetry is vital for stable locomotion, yet conventional metrics often yield inconsistent results. Muscle synergy analysis provides a more precise understanding of neural mechanisms behind symmetric gait. A clear methodology is essential to distinguish true inter-limb differences from natural variability. This study aimed to refine the analysis of muscle synergy symmetry in healthy individuals by incorporating intra-limb similarity as a baseline for comparison, while also including muscle weightings within each synergy to explore muscle synchrony. EMG signals were collected from both lower limbs of healthy subjects during treadmill walking. Muscle synergies were extracted using non-negative matrix factorization (NMF). Intra-limb similarity was used as a baseline to assess inter-limb differences. Muscle activity, number of synergies, muscle weightings within each synergy, and weight (W) and activation coefficients (H) were compared between sides. Normalized scalar products assessed weight coefficients, while Pearson’s correlation was used to compare activation coefficients. No significant differences were found in the number or structure of muscle synergies between limbs, indicating symmetrical coordination. However, significant differences were observed in activation of four of eight muscles and minor variations in muscle weightings. This study underscores the importance of a robust framework for interpreting muscle synergy symmetry.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"85 ","pages":"Article 103064"},"PeriodicalIF":2.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145061071","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Sex-specific effects of fatiguing handgrip plus blood flow restriction on upper limb neuromuscular characteristics during a repetitive shoulder height task 重复性肩高任务中疲劳握力加血流限制对上肢神经肌肉特征的性别特异性影响。

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-09-10 DOI: 10.1016/j.jelekin.2025.103069

Carson Graham, Pruthvi Patel, Julie N. Côté

{"title":"Sex-specific effects of fatiguing handgrip plus blood flow restriction on upper limb neuromuscular characteristics during a repetitive shoulder height task","authors":"Carson Graham, Pruthvi Patel, Julie N. Côté","doi":"10.1016/j.jelekin.2025.103069","DOIUrl":"10.1016/j.jelekin.2025.103069","url":null,"abstract":"<div><div>Blood flow restriction (BFR) aims to accelerate reperfusion post-effort and could provide benefits after shoulder fatiguing work. However, sex-specific effects of localized BFR on whole-limb features are unknown. Ten females and eleven males performed three 30-second repetitive pointing tasks (RPTs) (pre-fatigue, post-fatigue, and recovery). The fatiguing protocol was an intermittent submaximal handgrip task performed until failure to meet the target force (50% of maximum grip strength). Participants completed two sessions: without BFR and with 50% BFR applied to the upper arm during the handgrip task. Electromyography was recorded during the handgrip and each RPT. Muscle thickness (ultrasound), and arm circumferences were recorded after each RPT sequence. Time-to-fatigue was unaffected by condition or sex. Females exhibited greater forearm electromyography amplitude and greater decreases in flexor carpi radialis and brachioradialis median power frequency (MdPF). Post-fatigue, forearm circumference and muscle thickness increased significantly in both sexes. Females demonstrated greater forearm muscle thickness changes, while males showed more consistent increases in biceps brachii thickness under BFR. During the RPTs, males displayed significant increases in MdPF of middle deltoid and pectoralis major, while females showed persistent fatigue effects in forearm muscles. Results suggest that sex differences exist in whole-limb mechanisms of fatigue and BFR adaptations.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"85 ","pages":"Article 103069"},"PeriodicalIF":2.3,"publicationDate":"2025-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145093158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0