Journal of Electromyography and Kinesiology最新文献

Task failure reveals range-dependent neuromuscular fatigue in shoulder muscles during arm elevation 任务失败揭示了手臂抬高时肩部肌肉的范围依赖性神经肌肉疲劳。

IF 2.3 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2025-12-07 DOI: 10.1016/j.jelekin.2025.103100

Kara-Lyn Harrison, Rebecca Franklin, Trisha Scribbans

Repeated upper limb performance fatigues periscapular and/or rotator cuff muscles, which may alter humeral and scapular kinematics leading to increased subacromial impingement syndrome risk. However, the specific changes in neuromuscular patterns across different phases of a functional movement performed to failure remain unclear. This study investigated neuromuscular fatigue during a repeated arm elevation task to failure in asymptomatic individuals. Participants elevated their dominant arm while holding ∼ 30 % of their maximal isometric shoulder flexion load until task failure. High-density surface electromyography (HD-sEMG) was recorded from the pectoralis major (PM), biceps brachii (BB), and trapezius (UT, MT, LT) to accurately identify innervation zones and to enhance signal validity, while bipolar sEMG collected from the deltoid (AD, LD, PD), serratus anterior (SA) and infraspinatus (IN). Root mean square (RMS, %MVIC) and mean power frequency (MPF) were analyzed between three ranges of arm elevation (bottom, middle, top) at baseline and failure. During the middle and top ranges of arm elevation at task failure increased sEMG amplitude and/or decreased MPF of the PM, AD, BB, SA, LD, IN, UT, and MT were present. These results reveal that neuromuscular fatigue was highly dependent on the range of motion, with significant interactions showing that fatigue-related increases in RMS and decreases in MPF were most prominent in the middle and top ranges. These findings suggest that muscle function is altered precisely within the ranges where impingement risk is greatest, providing a potential neuromuscular basis for fatigue-related injury. Building off of these results, future work should use advanced techniques like high-density EMG and shear wave elastography to define how these fatigue-related changes in neuromuscular responses influence motor unit recruitment strategies, muscle force production, and subsequent alterations to SAS and injury risk.

反复的上肢活动使肩胛骨周围和/或肩袖肌肉疲劳，这可能改变肱骨和肩胛骨的运动学，从而增加肩峰下撞击综合征的风险。然而，在功能性运动的不同阶段，神经肌肉模式的具体变化仍然不清楚。本研究调查了无症状个体在重复手臂抬高任务期间的神经肌肉疲劳。参与者抬起主臂，同时保持最大等距肩部屈曲负荷的30%，直到任务失败。采集胸大肌（PM）、肱二头肌（BB）和斜方肌（UT、MT、LT）的高密度表面肌电图（HD-sEMG），准确识别神经支配区，增强信号有效性；采集三角肌（AD、LD、PD）、前锯肌（SA）和棘下肌（IN）的双极肌电图。均方根（RMS, %MVIC）和平均工频（MPF）在基线和失效时的三个臂高度范围（底部、中间、顶部）之间进行分析。在任务失败时手臂抬高的中间和顶部范围内，出现了PM、AD、BB、SA、LD、IN、UT和MT的表面肌电信号振幅增加和/或MPF降低。这些结果表明，神经肌肉疲劳高度依赖于运动范围，显著的相互作用表明，疲劳相关的RMS增加和MPF减少在中高范围最为突出。这些发现表明，在撞击风险最大的范围内，肌肉功能发生了精确的改变，为疲劳相关损伤提供了潜在的神经肌肉基础。在这些结果的基础上，未来的工作应该使用高密度肌电图和横波弹性图等先进技术来定义神经肌肉反应中这些与疲劳相关的变化如何影响运动单元招募策略、肌肉力量产生以及随后对SAS和损伤风险的改变。

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引用次数: 0

Machine learning-based estimation of EMG baseline noise standard deviation without rest trials 无休息试验的基于机器学习的肌电信号基线噪声标准差估计。

IF 2.3 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2025-12-01 DOI: 10.1016/j.jelekin.2025.103097

Naisargi Mehta, Bashima Islam, Edward A. Clancy

Accurate estimation of resting noise standard deviation (

σ_{noise}

) in surface electromyography (EMG) is essential for EMG amplitude estimation, particularly during low-level contractions where signal-to-noise ratios are low. Conventional

σ_{noise}

estimates are made from rest-state EMG recordings, but such data are not always available or routinely recorded in real-world settings. This study compared three methods of

σ_{noise}

estimation: 1) direct rest-state measurement (“truth”), and two methods intended to remove the need for explicit rest trials: 2) a novel machine learning (ML) approach utilizing active contractions, and 3) a fixed

σ_{noise}

value of 3 % maximum voluntary EMG (MVE). The ML model was trained on simulated EMG, then fine-tuned on EMG recordings from constant-force and force-varying elbow contraction of 62 subjects spanning three different EMG acquisition systems. Direct resting

σ_{noise}

measurements had a median absolute inter-trial difference of 0.06 % MVE. ML had a median absolute difference from rest-based

σ_{noise}

of 1.4 % MVE. The fixed

σ_{noise}

approach had a median absolute difference (1.71 % MVE) from rest-based

σ_{noise}

that did not differ significantly from the ML results. In a separate evaluation of baseline EMG noise reduction, omission of noise correction performed worst, ML and the fixed

σ_{noise}

value performed similarly but statistically better (45 % noise reduction compared to no noise correction), and noise calibration from a rest contraction performed statistically best (75 % noise reduction compared to no noise correction). These results suggest the feasibility of ML—or use of a fixed

σ_{noise}

value—as alternatives to direct EMG noise measurement, enabling more reliable EMG analysis in scenarios where rest-state data cannot be collected.

准确估计表面肌电图（EMG）的静息噪声标准偏差（σ噪声）对于EMG振幅估计至关重要，特别是在低水平收缩时，信噪比很低。传统的σ噪声估计是由静息状态的肌电图记录，但这样的数据并不总是可用或常规记录在现实世界的设置。本研究比较了三种σ噪声估计方法：1)直接静息状态测量（“真值”），以及两种旨在消除显式静息试验需求的方法；2)利用主动收缩的新型机器学习（ML）方法，以及3)固定的σ噪声值为3%的最大自愿肌电信号（MVE）。机器学习模型在模拟的肌电信号上进行训练，然后在三种不同的肌电信号采集系统中对62名受试者的恒力和变力肘部收缩的肌电信号进行微调。直接静息σ噪声测量的试验间绝对中位数差为0.06% MVE。ML与基于rest的σ噪声的中位数绝对差为1.4% MVE。固定σ噪声方法与基于rest的σ噪声方法的中位数绝对差（1.71% MVE）与ML结果无显著差异。在单独的基线肌电信号降噪评估中，省略噪声校正效果最差，ML和固定的σ噪声值表现相似，但在统计上更好（与没有噪声校正相比噪声降低45%），而从静止收缩中进行噪声校准在统计上表现最好（与没有噪声校正相比噪声降低75%）。这些结果表明，ml -或使用固定的σ噪声值作为直接测量肌电信号噪声的替代方法是可行的，可以在无法收集静息状态数据的情况下进行更可靠的肌电信号分析。

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引用次数: 0

Efficacy and safety of ultrasound-guided acupotomy in the treatment of spastic paralysis after stroke: a randomised controlled clinical trial study 超声引导针刀治疗脑卒中后痉挛性瘫痪的疗效和安全性：一项随机对照临床试验研究。

IF 2.3 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2025-12-01 DOI: 10.1016/j.jelekin.2025.103099

Yinyu Wang , Yujuan Lan , Xia Li , Qingyan Zhou , Yuanhong Si , Kejiang Peng , Minghui Liu , Shuo Yang

Objective

The purpose of this study was to evaluate the efficacy and safety of ultrasound-guided acupotomy in patients with spastic paralysis after stroke.

Methods

A simple random sampling was used to select a total of 66 patients diagnosed with spastic paralysis after stroke in the Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine between June 2022 and June 2023. They were randomly divided into the ultrasound-guided acupotomy group(33 patients) and the traditional acupotomy group (33 patients). The thickness and elasticity of the biceps brachii of the affected limb and healthy limb before and after treatment were measured and compared.

Results

In the comparison of the Fugl–Meyer Assessment scale score, modified Barthel Index (MBI) score, neurological deficit Chinese Stroke Scale score, brachial muscle and the posterior biceps Emean, the ultrasound-guided acupotomy group scored higher than the traditional acupotomy group (p < 0.05), and the overall efficacy of the ultrasound-guided acupotomy group was better than that of the traditional acupotomy group.

Conclusion

Ultrasound-guided acupotomy can better find the needle point visually and is superior to traditional treatment methods. It has good standardisation, uniformity, operability, safety and repeatability. It may provide a new potential therapy for spastic paralysis after stroke.

Clinical trial registration: The trial has been registered with the Chinese Clinical Trial Registry (ChiCTR2300073294).

目的：评价超声引导下针刀治疗脑卒中后痉挛性瘫痪的疗效和安全性。方法：采用简单随机抽样的方法，选取2022年6月至2023年6月在贵州中医药大学第二附属医院诊断为脑卒中后痉挛性瘫痪的患者66例。随机分为超声引导针刀组（33例）和传统针刀组（33例）。测量并比较治疗前后患肢和健康肢肱二头肌的厚度和弹性。结果：在Fugl-Meyer量表评分、改良Barthel指数（MBI）评分、神经功能缺损中国脑卒中量表评分、肱肌及后二头肌Emean评分比较中，超声引导针刀组得分高于传统针刀组(p)。结论：超声引导针刀能更好地从视觉上找到针尖，优于传统治疗方法。具有良好的标准化、统一性、可操作性、安全性和可重复性。它可能为中风后痉挛性瘫痪提供一种新的潜在治疗方法。临床试验注册：该试验已在中国临床试验注册中心注册（ChiCTR2300073294）。

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引用次数: 0

Frequency-specific modulations of oscillatory neural drives to lower leg muscles during gait with aiding and impeding horizontal forces 在辅助和阻碍水平力的步态中，振荡神经驱动对小腿肌肉的频率特异性调节。

IF 2.3 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2025-12-01 DOI: 10.1016/j.jelekin.2025.103098

Ryosuke Kitatani , Rina Numata , Runa Sorimachi , Naofumi Otsuru , Sumiya Shibata , Hideaki Onishi

Gait training with impeding horizontal force around the center of mass (COM) improves gait speed due to enhancements on activities in gastrocnemius (GC) muscles; however, the underlying neural mechanisms of these changes remain unclear. This study aimed to examine the influence of impeding horizontal force around the COM during gait on oscillatory neural drives to lower leg muscles using coherence analysis of paired surface electromyography, which in the alpha and beta bands reflect subcortical and cortical origins, respectively. Twenty healthy young adults participated in three gait conditions: normal gait without additional horizontal force, and gait with aiding and impeding horizontal forces, which were applied with a load of 5 % of body weight at the second sacral spine level via a waist belt. Medialis and lateralis GC intermuscular coherence in the alpha band (7.5–15 Hz) was significantly higher under the impeding force condition compared to the aiding force and normal gait conditions, whereas beta-band (15–35 Hz) coherence was significantly higher in the impeding force condition only compared to the aiding force condition. Impeding horizontal force around the COM during gait enhances oscillatory neural drives, predominantly from subcortical origins to GC muscles, with additional cortical contributions.

围绕质心（COM）的阻碍水平力步态训练由于增强腓肠肌（GC）肌肉的活动而提高了步态速度；然而，这些变化的潜在神经机制尚不清楚。本研究旨在通过对成对的肌电图的相干性分析，研究步态时COM周围的阻碍水平力对下肢肌肉振荡神经驱动的影响，在α和β波段分别反映皮层下和皮层起源。20名健康的年轻人参加了三种步态条件：无额外水平力的正常步态和辅助和阻碍水平力的步态，通过腰带在第二骶棘水平施加5%体重的负荷。阻碍力条件下内侧肌和外侧肌α带（7.5 ~ 15 Hz）的肌间相干性显著高于辅助力和正常步态条件，而阻碍力条件下β带（15 ~ 35 Hz）的肌间相干性仅显著高于辅助力条件。在步态过程中，阻止COM周围的水平力增强了振荡神经驱动，主要是从皮层下起源到GC肌肉，并有额外的皮层贡献。

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引用次数: 0

Real-time changes in rate of torque development and corticospinal excitability during transcutaneous spinal cord stimulation in healthy individuals 健康个体经皮脊髓刺激过程中扭矩发展速率和皮质脊髓兴奋性的实时变化

IF 2.3 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2025-12-01 DOI: 10.1016/j.jelekin.2025.103096

Keita Takano , Tomofumi Yamaguchi , Kano Kikuma , Yamato Omi , Natsuki Katagiri , Takatsugu Sato , Shigeo Tanabe , Kaoru Honaga , Kunitsugu Kondo , Toshiyuki Fujiwara

Transcutaneous spinal cord stimulation (tSCS) is used to induce neural plasticity and enhance motor function recovery following a stroke. Examining real-time changes under tSCS regulation would provide comprehensive insights into the mechanisms underlying motor functional recovery and neural plasticity. However, the real-time changes in the rate of torque development and neural excitability during tSCS remain unclear. This study explored the real-time changes in the rate of torque development and corticospinal excitability during tSCS. Twenty healthy individuals participated in two separate experiments, each with a tSCS condition and control condition. Under the tSCS condition, tSCS was applied to the Th11–Th12 spinous processes at an intensity twice the sensory threshold of the trunk muscles. The peak rate of torque development in the explosive lower limb extension movement in Experiment 1 and motor-evoked potential (MEP) amplitudes in Experiment 2 were assessed before the intervention and with (tSCS condition) or without tSCS (control). The peak rate of torque development and MEP amplitudes increased during tSCS compared to before tSCS (P = 0.038 and 0.047, respectively). However, the control condition had no significant effect. These findings demonstrate that tSCS enhances the rate of torque development and increases corticospinal excitability in healthy individuals, offering valuable fundamental insights into tSCS mechanisms and potential neurorehabilitation applications.

经皮脊髓刺激（tSCS）用于诱导脑卒中后的神经可塑性和增强运动功能恢复。研究tSCS调控下的实时变化将为运动功能恢复和神经可塑性的机制提供全面的见解。然而，在tSCS期间，扭矩发展速度和神经兴奋性的实时变化尚不清楚。本研究探讨了tSCS过程中扭矩发展速率和皮质脊髓兴奋性的实时变化。20名健康个体参加了两个独立的实验，每个实验都有tSCS条件和对照条件。在tSCS条件下，tSCS以两倍于躯干肌肉感觉阈值的强度作用于Th11-Th12棘突。实验1的爆发性下肢伸展运动的扭矩发展峰值速率和实验2的运动诱发电位（MEP）振幅分别在干预前、tSCS条件下和无tSCS条件下进行评估。与tSCS前相比，tSCS期间扭矩发展峰值速率和MEP振幅均有所增加（P分别为0.038和0.047）。而对照条件无显著影响。这些发现表明，tSCS可以提高健康个体的扭矩发展速度和皮质脊髓兴奋性，为tSCS的机制和潜在的神经康复应用提供了有价值的基础见解。

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引用次数: 0

Characteristics of lower limb skeletal muscle activity during walking in patients with knee osteoarthritis and knee extensor weakness: Comprehensive assessment using positron emission tomography 膝关节骨关节炎和膝关节伸肌无力患者行走时下肢骨骼肌活动的特征：使用正电子发射断层扫描进行综合评估。

IF 2.3 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2025-11-14 DOI: 10.1016/j.jelekin.2025.103085

Takuya Sengoku , Takeshi Oshima , Yasushi Takata , Junichi Taki , Yusuke Yanatori , Goro Sakurai , Seigo Kinuya , Satoru Demura , Junsuke Nakase

Purpose

To compare the whole-body muscles glucose metabolism during walking among patients with knee osteoarthritis (KOA) with and without knee extensor weakness using 18F-fluorodeoxyglucose positron emission tomography (FDG-PET).

Methods

Participants were divided into group A (n = 7) with good and group B (n = 15) with poor knee extensor strength, based on a weight-bearing ratio of 0.45 Nm/kg of the knee extensor strength required for walking adaptation. After treadmill walking task, FDG-PET computed tomography was performed, and standardised uptake values of glucose metabolism were calculated. Hip abductor and knee extensor strengths were measured using a handheld dynamometer. A comparison between the two groups and investigation into the correlation between glucose metabolism and muscle strength (hip abductor and knee extensor) were conducted.

Results

No significant differences were observed in overall glucose metabolism; However, when adjusting for sex between the two groups, Group B exhibited higher glucose metabolism in the tibialis anterior muscle (P = 0.04). Furthermore, glucose metabolism in the rectus femoris muscle showed a negative correlation with muscle strength during isometric contractions for hip abductor and knee extensor.

Conclusion

Patients with KOA exhibiting reduced knee extensor strength have increased glucose metabolism in the tibialis anterior.

目的：应用18f -氟脱氧葡萄糖正电子发射断层扫描（FDG-PET）比较伴有和不伴有膝伸肌无力的膝骨性关节炎（KOA）患者行走时全身肌肉葡萄糖代谢。方法：根据步行适应所需膝关节伸肌力量的负重比为0.45 Nm/kg，将参与者分为膝关节伸肌力量较好的A组（n = 7）和膝关节伸肌力量较差的B组（n = 15）。在完成跑步机行走任务后，进行FDG-PET计算机断层扫描，计算葡萄糖代谢的标准化摄取值。髋关节外展肌和膝关节伸肌力量测量使用手持式测功仪。对两组进行比较，并探讨糖代谢与肌肉力量（髋关节外展肌和膝关节伸肌）的相关性。结果：两组总糖代谢无显著差异；然而，当调整两组之间的性别时，B组在胫骨前肌中表现出更高的葡萄糖代谢（P = 0.04）。此外，股直肌的葡萄糖代谢与髋外展肌和膝伸肌等长收缩时的肌肉力量呈负相关。结论：KOA患者表现为膝关节伸肌力量减弱，胫前肌葡萄糖代谢增加。

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引用次数: 0

Do technological tools improve reliability in ankle dorsiflexion assessment? A study across healthy and injured individuals 技术工具能提高踝关节背屈评估的可靠性吗？一项针对健康和受伤个体的研究

IF 2.3 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2025-11-14 DOI: 10.1016/j.jelekin.2025.103087

Germán Cánovas-Ambit , Jorge Godínez Leal , Aitor Baño-Alcaraz , Manuel López Nicolas , José A. García-Vidal

Background

The objective was to examine the intra- and inter-rater reliability of three instruments for measuring ankle dorsiflexion (ADF) range of motion (ROM) and degree of asymmetry in the Weight-Bearing Lunge Test (WBLT). Additionally, the study evaluated the agreement between these tools in both asymptomatic and symptomatic populations.

Methods

Sixty-five participants were included, comprising 32 healthy individuals and 33 subjects presenting ankle pathology. Measurements were conducted on two separate occasions by two independent assessors using distinct methods to quantify ADF-ROM and asymmetry during the WBLT.

Results

Veloflex demonstrated strong intra- and inter-rater reliability, with intraclass correlation coefficients (ICCs) consistently above 0.88, for both ADF-ROM measurement and asymmetry detection across symptomatic and asymptomatic groups. Furthermore, an acceptable agreement was observed between Veloflex and the tape measure in the symptomatic cohort, while agreement between Veloflex and the Dorsiflex app was suboptimal.

Conclusion

The findings indicate that Veloflex is a reliable tool for assessing ADF-ROM and asymmetry in both healthy and pathological cases. While the tape measure offers a viable alternative to Veloflex in symptomatic assessments, substitution of Veloflex with the Dorsiflex app is not supported due to inconsistent agreement.

目的是检查负重弓步试验（WBLT）中测量踝关节背屈（ADF）运动范围（ROM）和不对称程度的三种仪器的内部和内部可靠性。此外，该研究评估了这些工具在无症状和有症状人群中的一致性。方法共纳入65例受试者，其中32例为健康个体，33例为踝关节病变。测量由两个独立的评估人员在两个不同的场合进行，使用不同的方法来量化WBLT期间的ADF-ROM和不对称性。结果veloflex在有症状和无症状组的ADF-ROM测量和不对称性检测中显示出很强的组内和组间可靠性，组内相关系数（ICCs）始终高于0.88。此外，在有症状的队列中，Veloflex和卷尺之间的一致性是可以接受的，而Veloflex和Dorsiflex应用程序之间的一致性是次优的。结论Veloflex是评估ADF-ROM和非对称性的可靠工具，无论在健康还是病理病例中都是如此。虽然卷尺在症状评估中提供了Veloflex的可行替代方案，但由于协议不一致，不支持用Dorsiflex应用程序替代Veloflex。

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引用次数: 0

Optimal path for measurement of biceps femoris long head architecture using synchronized ultrasound and two-dimensional video probe kinematics 利用同步超声和二维视频探针运动学测量股二头肌长头结构的最佳路径

IF 2.3 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2025-11-14 DOI: 10.1016/j.jelekin.2025.103086

Eleftherios Kellis, Georgios Salonikios, Athanasios Ellinoudis

The biceps femoris long head (BF) exhibits complex morphology, with fascicle orientation and aponeurotic curvature varying along its length. In vivo assessment of fascicle length (FL), pennation angle (PA), and muscle thickness (MT) is commonly performed with B-mode ultrasound (US), yet probe placement may confound interpretation of morphological variation. This study examined the effects of probe trajectory on BF architecture by synchronizing conventional B-mode US with two-dimensional kinematic tracking. Nineteen males were scanned in a side-lying position with the hip and knee flexed at 20°. B-mode US scans were performed along three paths: Central (center of the mediolateral width), 10 mm medial, and 10 mm lateral relative to Central. A high-speed camera tracked probe movement, synchronized with the US video. Measurements included FL, PA, and intermediate (IT) and full muscle thickness (MT) at four points along the muscle. Probe path significantly influenced FL and PA but not MT or IT. Medial and lateral scans produced longer fascicles and smaller PAs compared to the central path (p < 0.05). Differences in FL and PA exceeded 10 %, corresponding to ∼7–10 mm in FL and 2–3° in PA. These magnitudes equal or surpass values often attributed to training adaptations or injury-related remodeling. Probe trajectory can bias BF architectural estimates by amounts that rival physiologically meaningful changes, highlighting the need for standardized scanning protocols.

股二头肌长头（BF）表现出复杂的形态，其束状方向和腱膜曲率沿其长度变化。在体内评估肌束长度（FL）、笔尖角（PA）和肌肉厚度（MT）通常是用b超（US）进行的，但探针的放置可能会混淆形态学变化的解释。通过将传统的b模US与二维运动跟踪同步，研究了探针轨迹对BF结构的影响。19名男性采用侧躺姿势，臀部和膝盖弯曲20°进行扫描。B-mode US扫描沿三条路径进行：中央（中外侧宽度的中心），内侧10mm和相对于中央的外侧10mm。高速摄像机跟踪探针的运动，与美国视频同步。测量包括沿肌肉四个点的FL、PA、中间（IT）和全肌厚度（MT）。探针路径对FL和PA有显著影响，但对MT和IT无显著影响。与中央路径相比，内侧和外侧扫描产生更长的肌束和更小的PAs （p < 0.05）。FL和PA的差异超过10%，对应于FL为~ 7-10 mm， PA为2-3°。这些数值等于或超过通常归因于训练适应或损伤相关重塑的数值。探针轨迹可能会对BF架构的估计产生偏差，其数量可能与生理上有意义的变化相匹配，这突出了标准化扫描协议的必要性。

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引用次数: 0

Co-contraction about the ankle increases with the threat of a walking perturbation 踝关节的共同收缩随着行走干扰的威胁而增加

IF 2.3 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2025-11-09 DOI: 10.1016/j.jelekin.2025.103082

Nancy T. Nguyen , James B. Tracy , Jeremy R. Crenshaw

The ability to prevent a fall after a walking perturbation is dependent upon the initial, modifiable conditions related to stability. Individuals may proactively modify their gait to maintain stability by increasing co-contraction about the ankle, increasing the resistance to a perturbing force. The purpose of this study was to investigate whether such proactive ankle co-contraction occurs when walking under the threat of large perturbations. Participants walked on a computer-controlled treadmill under nine randomly ordered task conditions with combinations of three walking speeds and three perturbation conditions. Bilateral EMG of the tibialis anterior and medial gastrocnemius were recorded. Co-contraction indices (CCI) of these muscles during stance prior to a perturbation were calculated. The effects of walking perturbation condition and speed on CCI were assessed using a 3x3 repeated-measures ANOVA. There were no significant interactions of perturbation and speed. There was a significant main effect of perturbation condition, with higher CCI in anterior and posterior perturbations compared to no perturbation. These results suggest that co-contraction occurs in a manner that may increase resistance to perturbations. Future studies will determine the extent to which populations with a high risk of falling are able to proactively modify their gait in anticipation of a perturbation.

行走扰动后防止跌倒的能力取决于与稳定性相关的初始、可修改的条件。个体可能会主动调整步态，通过增加踝关节的共同收缩来保持稳定，增加对干扰力的抵抗力。本研究的目的是调查在大扰动的威胁下行走时是否会发生这种主动踝关节共同收缩。参与者在电脑控制的跑步机上行走，在九种随机排序的任务条件下，分别有三种行走速度和三种干扰条件。记录双侧腓肠肌前、内侧肌肌电图。计算摄动前这些肌肉的共收缩指数（CCI）。采用3 × 3重复测量方差分析评估行走扰动条件和速度对CCI的影响。微扰和速度之间没有显著的相互作用。摄动条件的主效应显著，前后摄动的CCI高于无摄动的CCI。这些结果表明，共收缩的发生方式可能会增加对扰动的抵抗力。未来的研究将确定跌倒风险高的人群能够在多大程度上主动调整他们的步态，以应对干扰。

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引用次数: 0

Effects of peripheral fatigue of ankle evertors on force sense and electromyographic activity in healthy subjects 踝关节外周疲劳对健康受试者力感和肌电活动的影响。

IF 2.3 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2025-11-05 DOI: 10.1016/j.jelekin.2025.103083

Tjaž BREZOVAR , Maja VENE , Taja TUČEN , Anika JAGARINEC , Urška PUH , Alan KACIN

Background

Ankle proprioception is essential for dynamic stability, but fatigue may impair force sense and neuromuscular control, increasing injury risk. Their relationship remains unclear. Objective: To examine the effects of ankle evertor fatigue on force sense accuracy and variability, along with associated changes in muscle activation. Methods: Twenty-four healthy participants completed a force-matching task in ankle eversion at 25% and 50% of MVIC before and after a fatigue protocol. Force sense was assessed by constant, absolute, and variable error and coefficient of variation. RMS amplitude was calculated for the peroneus longus, tibialis anterior, soleus, and gastrocnemius medialis, and median frequency only for the peroneus longus. Results: With fatigue, there was a 34.7% reduction in MVIC torque (p < 0.05). During force-matching tasks, variable error at 50% MVIC and coefficient of variation without visual feedback at 25% and 50% MVIC increased (p < 0.01), EMG amplitude of all muscles substantially increased (p < 0.05), and median frequency of the peroneus longus decreased (p < 0.001). Conclusion: Peripheral fatigue of ankle evertors increases variability in muscle force output, which is accompanied by compensatory motor unit recruitment during force matching, resulting in elevated variability.

背景：踝关节本体感觉对动态稳定性至关重要，但疲劳可能损害力感和神经肌肉控制，增加损伤风险。他们的关系尚不清楚。目的：探讨踝关节旋转疲劳对力感准确性和变异性的影响，以及与之相关的肌肉激活变化。方法：24名健康参与者在疲劳方案前后分别以25%和50%的MVIC完成踝关节外翻力匹配任务。力感通过恒定、绝对和可变误差和变异系数进行评估。计算腓骨长肌、胫骨前肌、比目鱼肌和腓肠肌内侧肌的均方根振幅，仅计算腓骨长肌的中位数频率。结果：在疲劳状态下，MVIC扭矩降低34.7% (p)。结论：踝关节外周性疲劳增加了肌肉力量输出的变异性，这伴随着力量匹配过程中代偿运动单位的补充，导致变异性升高。

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