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

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

Comparison of muscle activity between isokinetic and iso-inertial exercise 等速运动和等惯性运动肌肉活动的比较

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-09-03 DOI: 10.1016/j.jelekin.2025.103052

Timothy H.T. Phillips , Ransi S.S. Subasinghe Arachchige , Roy T.H. Cheung

{"title":"Comparison of muscle activity between isokinetic and iso-inertial exercise","authors":"Timothy H.T. Phillips , Ransi S.S. Subasinghe Arachchige , Roy T.H. Cheung","doi":"10.1016/j.jelekin.2025.103052","DOIUrl":"10.1016/j.jelekin.2025.103052","url":null,"abstract":"<div><h3>Background</h3><div>Resistance training plays a crucial role in musculoskeletal rehabilitation and athletic performance. Traditional resistance training often underloads the eccentric phase, as muscles generate more force while lengthening. Isokinetic and iso-inertial exercises have been used to overcome this limitation, with both showing greater muscle activity compared to traditional methods, potentially leading to enhanced strength and hypertrophy. However, limited research compares the two modalities.</div></div><div><h3>Methods</h3><div>This randomised crossover study involved healthy adults between the ages of 18–45 years who performed isokinetic knee extensions and iso-inertial squats at fast and slow speeds. Electromyographic activity of the quadriceps was recorded, and the eccentric-to-concentric root-mean-square (RMS) ratio was calculated.</div></div><div><h3>Results</h3><div>Results showed that iso-inertial exercise at fast speeds led to a significantly greater eccentric-to-concentric RMS ratio in the rectus femoris (95 % CI 0.11 to 0.74; Cohen’s d = 0.89) and vastus lateralis (95 % CI 0.07 to 0.55, Cohen’s d = 0.75) compared to isokinetic exercise, with no difference in vastus medialis or at slow speeds.</div></div><div><h3>Conclusion</h3><div>Conclusion: These findings indicate that iso-inertial exercise induces greater eccentric muscle activity in key quadriceps muscles at fast speeds, suggesting its potential for enhancing eccentric overload and muscle strength gains.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"85 ","pages":"Article 103052"},"PeriodicalIF":2.3,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005360","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

Shoulder muscle activity magnitude and timing in individuals with specific scapular movement patterns 特定肩胛骨运动模式个体的肩部肌肉活动幅度和时间

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-09-02 DOI: 10.1016/j.jelekin.2025.103054

Gaura Saini , Madeline Goodson , Paula M. Ludewig

{"title":"Shoulder muscle activity magnitude and timing in individuals with specific scapular movement patterns","authors":"Gaura Saini , Madeline Goodson , Paula M. Ludewig","doi":"10.1016/j.jelekin.2025.103054","DOIUrl":"10.1016/j.jelekin.2025.103054","url":null,"abstract":"<div><div>Relationships between specific muscle activity alterations and specific scapular motion patterns have not been well established. The purpose of this study was to identify muscle activation magnitude and timing in two specific scapular movement groups (excessive scapular anterior tilt, scapular lateralization). Surface electromyography (EMG) was captured simultaneously with biplane video radiography and optical motion capture during two repetitions each of shoulder flexion, abduction, and unrestricted overhead reaching in 45 adults with shoulder pain. The following muscle activation magnitudes measured with EMG were assessed individually and in ratios: lower trapezius (LT), serratus anterior (SA), upper trapezius (UT), anterior deltoid (AD), and middle deltoid (MD). The timing of each muscle’s initiation was calculated as a percent of humerothoracic range of motion. For EMG magnitude, significant interactions including group were found for AD, LT/SA, and LT/AD. Findings suggest a relative reduction of SA in both groups in the constrained motions compared to the self-selected motion and a reduction in LT in the lateralization group in early motion. For EMG timing, no group effects were significant, however findings suggest delays in SA and LT activation in both groups. The findings provide evidence that individuals with different scapular movement patterns may have distinct muscle activity patterns which can inform patient-specific rehabilitation interventions.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"85 ","pages":"Article 103054"},"PeriodicalIF":2.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145049625","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

Greater distal excitation of the biceps femoris long head reflects proximodistal differences in motor unit action potential properties 股骨长头二头肌远端更大的兴奋反映了运动单位动作电位特性的近端和远端差异

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-09-02 DOI: 10.1016/j.jelekin.2025.103053

José Carlos dos Santos Albarello , Hélio V. Cabral , Francesco Negro , Liliam Fernandes de Oliveira

{"title":"Greater distal excitation of the biceps femoris long head reflects proximodistal differences in motor unit action potential properties","authors":"José Carlos dos Santos Albarello , Hélio V. Cabral , Francesco Negro , Liliam Fernandes de Oliveira","doi":"10.1016/j.jelekin.2025.103053","DOIUrl":"10.1016/j.jelekin.2025.103053","url":null,"abstract":"<div><div>Evidence on regional muscle excitation within hamstrings remains controversial, primarily because information derived solely from surface electromyograms (sEMG) amplitude does not necessarily provide an accurate estimate of neural drive to the muscle. To address this limitation, this study investigated whether there are proximodistal differences in motor unit properties of the biceps femoris long head during isometric hip extension and knee flexion tasks. Seventeen resistance-trained males performed isometric knee flexion and hip extension tasks at 20 % and 40 % of maximal voluntary contraction. High-density sEMG were recorded from proximal and distal regions of the biceps femoris long head and decomposed into individual motor units. Central motor unit and action potential properties were analyzed. Bipolar sEMG amplitude was also calculated for each region to simulate traditional sEMG measurements. Bipolar sEMG amplitude, motor unit action potential amplitude and conduction velocity were significantly greater in the distal region during both tasks. In contrast, no proximodistal differences were observed in central motor unit properties. These findings suggest that increased bipolar sEMG amplitude in the distal region of the biceps femoris long head is driven by motor unit action potential properties rather than differences in central modulation, likely influenced by intra-muscular variations in muscle mechanics and geometry.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"85 ","pages":"Article 103053"},"PeriodicalIF":2.3,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145007646","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

Shear wave elastography provides reliable assessments of stiffness in the skin, fascia, and both superficial and deep muscle tissues 横波弹性成像提供可靠的评估刚度在皮肤，筋膜，浅表和深层肌肉组织

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-08-18 DOI: 10.1016/j.jelekin.2025.103050

Cameron D. Ley , Eduardo Martinez Valdes , Conall F. Murtagh , Jonathan Power , Barry Drust

{"title":"Shear wave elastography provides reliable assessments of stiffness in the skin, fascia, and both superficial and deep muscle tissues","authors":"Cameron D. Ley , Eduardo Martinez Valdes , Conall F. Murtagh , Jonathan Power , Barry Drust","doi":"10.1016/j.jelekin.2025.103050","DOIUrl":"10.1016/j.jelekin.2025.103050","url":null,"abstract":"<div><div>Shear wave elastography (SWE) is a reliable method of estimating stiffness of superficial rectus femoris (RF) muscle at various muscle lengths. Its reliability has not been assessed in deeper muscle regions or its overlying fascia and skin tissue. 20 healthy participants completed two visits in which RF shear wave velocity (SWV) was measured twice, separated by 30mins, at four depths (skin–SKIN, fascia–FAS, superficial muscle–SUP, and deep muscle–DEEP) in three positions (relaxed–REL, neutral–NEU, and stretched–STR). Relative reliability was determined by intraclass correlation coefficients and absolute reliability was assessed by standard error and bias of measurements. SWE reported poor to good relative intra-day reliability (ICC, 0.33–0.82) but good to excellent absolute intra-day reliability (SEM, 0.14–0.25 m/s; bias, −0.12–0.07). Relative SWE inter-day reliability was moderate to excellent (ICC, 0.54–0.91) and absolute reliability was good to excellent (SEM, 0.12–0.21 m/s; bias, −0.05–0.06). Reliability was highest in the order of STR, NEU, REL with regards to position, with SKIN and FAS reliability greater than in muscle. SUP measurements reported greater reliability than DEEP. Therefore, SWE is a reliable method of estimating SKIN, FAS, SUP and DEEP RF tissue stiffness. To optimise repeatability, measurements should be taken from stretched superficial tissue.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"84 ","pages":"Article 103050"},"PeriodicalIF":2.3,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144880248","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

Hamstrings corticomotor and neuromechanical function in individuals with anterior cruciate ligament reconstruction 前交叉韧带重建患者的腘绳肌皮质运动和神经力学功能

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-08-18 DOI: 10.1016/j.jelekin.2025.103048

Moein Koohestani , David A. Sherman , Justin L. Rush , Ava L. Schwartz , Grant E. Norte

{"title":"Hamstrings corticomotor and neuromechanical function in individuals with anterior cruciate ligament reconstruction","authors":"Moein Koohestani , David A. Sherman , Justin L. Rush , Ava L. Schwartz , Grant E. Norte","doi":"10.1016/j.jelekin.2025.103048","DOIUrl":"10.1016/j.jelekin.2025.103048","url":null,"abstract":"<div><div>Hamstrings neuromuscular alterations are common after anterior cruciate ligament (ACL) reconstruction; however, their neural origins remain unclear. While quadriceps corticospinal function after ACL reconstruction (ACLR) is well studied, similar data for hamstrings are lacking. We aimed to assess hamstrings corticomotor and neuromechanical function and their associations in individuals with ACLR. Twenty-three adults with primary, unilateral ACLR via hamstrings tendon autograft were assessed (time from surgery = 46.9 ± 26.3). Corticomotor function was quantified via active motor threshold (AMT), motor evoked potential (MEP), short-interval intracortical inhibition, intracortical facilitation (ICF), and cortical silent period (CSP) in semitendinosus. Neuromechanical function was quantified via maximal voluntary isometric contraction (MVIC) torque, early and late-phase rate of torque development (RTD<sub>100</sub>, RTD<sub>200</sub>), and semitendinosus electromyographic amplitude.Paired-samples t-tests or Wilcoxon signed-rank tests compared outcomes between limbs. Associations between involved limb outcomes were analyzed using correlation coefficients. Involved limbs exhibited shorter CSP (<em>p</em> = 0.005), lower MVIC torque (<em>p</em> = 0.002), and lower RTD<sub>200</sub> (<em>p</em> = 0.002) than uninvolved limbs. Lower AMT (<em>r</em> = 0.462, <em>p</em> = 0.026) and ICF (<em>r</em> = 0.510, <em>p</em> = 0.013) associated with lower RTD<sub>200</sub>, and lower MEP associated with lower MVIC torque (<em>r</em> = 0.448, <em>p</em> = 0.032). Hamstrings neural adaptation following ACLR, characterized by lower corticospinal inhibition (semitendinosus) and torque deficits, highlights the need for rehabilitation approaches targeting both neural and peripheral impairments.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"84 ","pages":"Article 103048"},"PeriodicalIF":2.3,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865571","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

Estimating maximum acceptable duty cycles (MADC) for overhead exertions 估算开销工作的最大可接受占空比（MADC）

IF 2.3 4区医学

Journal of Electromyography and Kinesiology Pub Date : 2025-08-17 DOI: 10.1016/j.jelekin.2025.103049

Michael W.B. Watterworth, Nicholas J. La Delfa

{"title":"Estimating maximum acceptable duty cycles (MADC) for overhead exertions","authors":"Michael W.B. Watterworth, Nicholas J. La Delfa","doi":"10.1016/j.jelekin.2025.103049","DOIUrl":"10.1016/j.jelekin.2025.103049","url":null,"abstract":"<div><div>Overhead work poses a significant risk for shoulder musculoskeletal disorders due to elevated arm postures and sustained loading, yet current ergonomics tools provide limited guidance on the acceptable percentage of time such tasks can be performed. This concept, referred to as the Maximum Acceptable Duty Cycle (MADC), represents the proportion of time within a work cycle that an exertion can be sustained at a psychophysically acceptable level. This study addresses that gap by reconfiguring an existing ergonomics assessment tool for overhead work to estimate MADC, rather than maximum acceptable forces. MADC values across the overhead workspace were mapped using computational modeling of over 800,000 overhead hand positions under three superior-directed load conditions (5, 10, and 20 N). MADC varied substantially with hand position and force demand: at 5 N, values ranged from 0–40 %, while at 20 N, MADC never exceeded 14 %. A consistent ergonomic ‘sweet spot’ was identified slightly above and forward of the shoulder, where MADC is maximized, providing the largest design space for allowable task duty cycles. The reconfigured tool offers actionable, evidence-based guidance for overhead task design by informing duty cycle limits in industrial settings, where current one-size-fits-all thresholds lack empirical justification.</div></div>","PeriodicalId":56123,"journal":{"name":"Journal of Electromyography and Kinesiology","volume":"84 ","pages":"Article 103049"},"PeriodicalIF":2.3,"publicationDate":"2025-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144880249","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