Journal of Electromyography and Kinesiology最新文献_第2页

Myoelectric performance of the reconstructed elbow flexor in patients with brachial plexus injuries 臂丛神经损伤患者重建屈肘肌的肌电表现

IF 2 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2024-11-09 DOI: 10.1016/j.jelekin.2024.102944

Emily J. Miller , Sandesh G. Bhat , Paul H. Kane , Alexander Y. Shin , Kenton R. Kaufman

Traumatic adult brachial plexus injury is a debilitating injury. Myoelectric exoskeletons are functional tools for restoring elbow flexion. Electromyography signals are used for exoskeleton control, but a characterization specific to the traumatic adult brachial plexus injury population has yet to be performed. This study evaluated if adult patients with traumatic brachial plexus injury and a reconstructed elbow flexor can control a myoelectric exoskeleton. Adult patients who underwent surgical intervention to restore elbow flexion with traumatic brachial plexus injury were recruited for this cross-sectional study. The processed elbow flexor muscle signal and activation thresholds were used to evaluate criteria for exoskeleton control algorithm development. A single activation threshold can be utilized for exoskeleton control, but the calibration routine should consider the resting signal for both extended and flexed elbow positions. The data indicated a ‘settle-time’ following contraction is needed to prevent unintentional movement of the exoskeleton. All patients activated their elbow flexor above the activation threshold in the supported, flexed position. However, there were different abilities to generate multiple, discrete signals. These results were not specific to surgery, nerve implemented for reconstruction, or post-operative recovery time. Patients with a brachial plexus injury and a reconstructed elbow flexor demonstrated subject-specific capabilities for exoskeleton control.

成人臂丛神经创伤是一种使人衰弱的损伤。肌电外骨架是恢复肘关节屈曲的功能性工具。肌电信号可用于外骨骼控制，但专门针对创伤性成人臂丛神经损伤人群的特征描述尚未进行。本研究评估了创伤性臂丛神经损伤和肘屈肌重建的成年患者能否控制肌电外骨架。这项横断面研究招募了因外伤性臂丛神经损伤而接受手术治疗以恢复屈肘功能的成年患者。处理后的肘屈肌信号和激活阈值被用于评估外骨骼控制算法的开发标准。单一激活阈值可用于外骨骼控制，但校准程序应考虑伸肘和屈肘位置的静息信号。数据显示，收缩后需要一个 "稳定时间"，以防止外骨骼意外移动。所有患者在支撑、屈曲位置时，屈肘肌的激活都超过了激活阈值。不过，他们产生多个离散信号的能力各不相同。这些结果与手术、重建神经或术后恢复时间无关。臂丛神经损伤和重建肘屈肌的患者在外骨骼控制方面表现出了特定的能力。

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引用次数: 0

Differences in landing biomechanics in the presence of delayed onset muscle soreness following or not active recovery 是否积极恢复后出现迟发性肌肉酸痛时着地生物力学的差异。

IF 2 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2024-11-06 DOI: 10.1016/j.jelekin.2024.102948

Andressa L. Lemos , Karine J.V. Stoelben , Evangelos Pappas , Felipe P Carpes

Objective

Delayed onset muscle soreness (DOMS) can reduce joint range of motion and strength, cause edema, and increase joint stiffness. Here we set out to determine whether quadriceps DOMS followed by an active recovery low-intensity exercise alters jump landing biomechanics.

Methods

3D landing kinematics, kinetics, and DOMS were evaluated in 26 healthy adults (15 women) performing drop and vertical jump landings before and after a squat protocol to induce quadriceps DOMS. In the presence of DOMS, half of the participants (n = 13) performed a low-intensity exercise for active recovery (10-minute treadmill walking), while the other half (n = 13) did not. Descriptive statistics and generalized estimative equations were applied to determine the effects of DOMS and active recovery on landing kinematics and kinetics.

Results

DOMS decreased knee and ankle flexion angles and increased knee and ankle frontal plane angles during vertical jumps. DOMS elicited a longer time to reach peak ground reaction force during drop jumps. Low-intensity exercise for active recovery reduced DOMS perception but did not alter the biomechanics of landing.

Conclusion

DOMS changes landing strategy. However, including a low-intensity exercise for active recovery before landing practice did not change the kinematics and kinetics of landing.

目的：延迟性肌肉酸痛（DOMS）会降低关节活动范围和力量，引起水肿，增加关节僵硬度。方法：我们对 26 名健康成年人（15 名女性）进行了三维着地运动学、动力学和延迟性肌肉酸痛评估，他们在深蹲训练前后进行了落体和垂直跳跃着地训练，以诱发股四头肌延迟性肌肉酸痛。在出现 DOMS 的情况下，一半参与者（n = 13）进行了低强度运动以积极恢复（10 分钟跑步机步行），而另一半参与者（n = 13）则没有进行低强度运动。应用描述性统计和广义估计方程确定 DOMS 和积极恢复对着地运动学和动力学的影响：结果：在垂直跳跃过程中，DOMS 会减小膝关节和踝关节的屈曲角度，增大膝关节和踝关节的前平面角度。落体跳时，DOMS导致达到地面反作用力峰值的时间延长。积极恢复的低强度运动降低了DOMS感知，但并未改变着地的生物力学：结论：DOMS 会改变着地策略。结论：DOMS 会改变着地策略，但在着地练习前进行低强度的主动恢复运动并不会改变着地的运动学和动力学。

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引用次数: 0

Influence of countermovement depth on net force, push-off time, vertical impulse and performance during jumping 反向运动深度对净力、腾空时间、垂直冲量和跳跃成绩的影响

IF 2 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2024-11-06 DOI: 10.1016/j.jelekin.2024.102945

Félicie Pommerell , Sébastien Boyas , Pierre Samozino , Baptiste Morel , Jérémie Begue , Abderrahmane Rahmani , Nicolas Peyrot

The purpose of this study was to investigate the influence of push-off distance on maximal jump height and to characterize the relationships between vertical jump mechanical parameters. Seventeen CrossFit athletes performed maximal countermovement jumps on two force-plates, with four different push-off distances induced by different countermovement depths. Results confirmed that push-off distance and maximal jump height were related by a quadratic relationship, and that exists an individual push-off distance maximizing maximal jump height. Furthermore, the increase in push-off distance was associated with an increase in the time of push-off and a concomitant decrease in the mean vertical external force, changing the relative net vertical impulse and so maximal jump height. An almost perfect negative linear relationship was observed between mean vertical external force and time of push-off (r = −0.99, p = 0.006), mathematically resulting in a quadratic relationship between relative net vertical impulse and time of push-off (r = 1.00, p < 0.001). This negative linear relationship could be explained by changes in joint angles and velocities associated with an increase in push-off distance, modifying joint torque production capacities during vertical jumping. This provides new insights to characterize vertical jump mechanical parameters and ways to optimize training and jump performance.

本研究的目的是调查推起距离对最大跳跃高度的影响，以及垂直跳跃机械参数之间的关系。17 名 CrossFit 运动员在两块测力板上进行了最大反向运动跳跃，通过不同的反向运动深度诱发了四种不同的推起距离。结果证实，推起距离与最大起跳高度之间存在二次关系，并且存在一个能使最大起跳高度最大化的推起距离。此外，推起距离的增加与推起时间的增加和平均垂直外力的减少有关，从而改变了相对净垂直冲力，因此也改变了最大跳高。在平均垂直外力和腾空时间之间观察到几乎完美的负线性关系（r = -0.99，p = 0.006），在数学上导致相对净垂直冲力和腾空时间之间的二次关系（r = 1.00，p = 0.006）。

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引用次数: 0

Effect of prior neuromuscular electrical stimulation of vastus lateralis on the fatigue induced by a sustained voluntary knee extension in men 事先对阔筋膜进行神经肌肉电刺激对男性持续自主伸膝引起疲劳的影响

IF 2 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2024-11-06 DOI: 10.1016/j.jelekin.2024.102942

Clément Lanfranchi , Boris Matkowski , Sylvain Rayroud , Alain Martin , Nicola A Maffiuletti , Romuald Lepers , Nicolas Place

Purpose

The purpose of this study was to investigate the effect of vastus lateralis (VL) selective fatigue induced by neuromuscular electrical stimulation (NMES) on knee extensor electromyographic (EMG) activity during a sustained submaximal isometric contraction.

Methods

Thirteen healthy men (28 ± 5 years) completed two experimental sessions in which either the VL was pre-fatigued for 17 min (NMES session) or no intervention was performed (control session, CTRL). Subsequently, participants were asked to sustain an isometric knee extension at 20 % of maximal voluntary contraction (MVC) torque until task failure.

Results

VL M-wave amplitude was reduced (−34 ± 26 %, P = 0.008) following the NMES intervention, while MVC torque was reduced by 26 ± 10 %. The time to task failure was 23 ± 10 % shorter (P = 0.002) in NMES (186 ± 75 s) than in CTRL (251 ± 128 s). EMG activity measured during the sustained contraction was higher for vastus medialis and rectus femoris muscles in NMES compared to CTRL (P < 0.001), but was comparable for VL (P > 0.05). The extent and origin of neuromuscular fatigue at task failure measured through MVCs combined with electrically-evoked contractions did not differ between NMES and CTRL.

Conclusion

Compensatory activity from synergist muscles occurred in response to a pre-fatigue intervention, which reduced the time to task failure of a sustained submaximal contraction but did not affect the extent and origin of neuromuscular fatigue.

目的：本研究旨在探讨神经肌肉电刺激（NMES）诱导的阔筋膜外侧肌（VL）选择性疲劳对持续亚最大等长收缩期间膝关节伸肌肌电图（EMG）活动的影响：13 名健康男性（28 ± 5 岁）完成了两个实验环节，在这两个环节中，要么预先疲劳 VL 17 分钟（NMES 环节），要么不进行干预（对照环节，CTRL）。随后，参与者被要求以最大自主收缩力矩（MVC）的 20% 保持等长伸膝，直至任务失败：结果：接受 NMES 干预后，VL M 波振幅降低（-34 ± 26 %，P = 0.008），而 MVC 扭矩降低了 26 ± 10 %。NMES 的任务失败时间（186 ± 75 秒）比 CTRL 的任务失败时间（251 ± 128 秒）短 23 ± 10 %（P = 0.002）。与 CTRL 相比，NMES 在持续收缩期间测量到的肌电图活动对阔内肌和股直肌的影响更大（P 0.05）。在任务失败时，通过 MVCs 结合电诱发收缩测量的神经肌肉疲劳程度和来源在 NMES 和 CTRL 之间没有差异：结论：协同肌的补偿活动是对疲劳前干预的反应，它缩短了持续亚最大收缩任务失败的时间，但并不影响神经肌肉疲劳的程度和起源。

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引用次数: 0

Development of EMG-based criteria to evaluate the difficulty of realization of sign language: A potential contribution for understanding the negative hand paintings 开发基于肌电图的标准，以评估手语实现的难度：对理解负手绘画的潜在贡献。

IF 2 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2024-11-05 DOI: 10.1016/j.jelekin.2024.102943

Laurent Vigouroux , Ricardo Etxepare , Hugo Lepine , Benjamin Goislard de Monsabert , Aritz Irurtzun

The sign language uses a combination of complex finger and wrist configurations. The frequency of use of a particular sign is highly dependent on its physiological difficulty. However, no method allows to quantify accurately this difficulty. In the context of paleolithic negative hand paintings this absence of methods is problematic since the hand signs which are painted may be related to a primitive hand sign language. The objective of this study was to develop and validate a method based on electromyography recordings for quantifying sign language difficulty. Electromyography of the six main hand muscles were recorded and analyzed to determine individual muscle activity, summed muscle activity and muscle coactivation. Those results were correlated to subjective scales of difficulties to determine the electromyographic variables and/or the combinations of them which are good candidates for determining hand sign difficulties. Among all variables the summed muscle activities and the thumb muscle coactivation presented the most promising criterion. On the top of that, those criterions presented encouraging correlation with the frequence of occurrence of ten hand paintings of the Gargas Cave which open further studies for analyzing the origin of negative hand paintings.

手语使用复杂的手指和手腕组合。特定手势的使用频率在很大程度上取决于其生理难度。然而，没有任何方法可以准确量化这种难度。就旧石器时代的负手画而言，由于所画的手势可能与原始手势语有关，因此这种方法的缺失是一个问题。本研究的目的是开发并验证一种基于肌电图记录的量化手语难度的方法。研究人员记录并分析了六块主要手部肌肉的肌电图，以确定单块肌肉活动、肌肉活动总和以及肌肉共激活。这些结果与主观困难量表相关联，以确定哪些肌电图变量和/或变量组合可用于确定手语困难。在所有变量中，肌肉活动总和和拇指肌肉共激活是最有希望的标准。此外，这些标准与嘎尔尕斯石窟十幅手绘画的出现频率呈现出令人鼓舞的相关性，这为分析消极手绘画的起源提供了进一步的研究。

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引用次数: 0

Effects of wrist and finger posture on finger independence 手腕和手指姿势对手指独立性的影响

IF 2 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2024-11-04 DOI: 10.1016/j.jelekin.2024.102941

Kumara G. Somasundram, Peter J. Keir

Intended actions of one finger produce involuntary movement or force in other fingers. Mechanical and neural factors limit finger independence. The interplay between anatomical factors, wrist and finger postures, and finger independence remain unclear. The purpose of this study was to determine the effects of wrist and metacarpophalangeal (MCP) posture on involuntary finger forces and extensor digitorum (ED) activity. Twenty participants performed submaximal isometric finger extensions in three wrist positions (30° extension, neutral, and 30° flexion) and two MCP postures (straight and 90° flexion). Involuntary index finger force increased with MCP flexion, suggesting the importance of intertendinous connections in finger independence. Consistent with previous research, ED activity was generally higher in wrist extension than neutral and flexed postures. Understanding the role of passive properties within the hand may help us improve finger rehabilitation strategies.

一个手指的有意动作会在其他手指上产生不自主的运动或力量。机械和神经因素限制了手指的独立性。解剖因素、手腕和手指姿势与手指独立性之间的相互作用仍不清楚。本研究的目的是确定手腕和掌指关节（MCP）姿势对手指非自主力量和伸拇肌（ED）活动的影响。20 名参与者在三种手腕姿势（伸展 30°、中立和屈曲 30°）和两种 MCP 姿势（伸直和屈曲 90°）下进行了亚极限等长手指伸展运动。无意识食指力量随 MCP 屈曲而增加，这表明肌腱间连接在手指独立性中的重要性。与之前的研究一致，伸腕时的ED活动通常高于中立和屈曲姿势。了解手部被动特性的作用有助于我们改进手指康复策略。

引用次数: 0

Enhancing understanding: Back muscle strength and individual flexibility impact on the flexion-relaxation phenomenon in the lumbar erector spinae 加深理解：腰部肌肉力量和个体柔韧性对腰椎直立肌屈曲-放松现象的影响。

IF 2 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2024-11-04 DOI: 10.1016/j.jelekin.2024.102949

Yi-Lang Chen , Wei-Cheng Lin

The flexion-relaxation phenomenon (FRP) refers to the deactivation of back muscles during deep forward trunk bending. This study examined the effects of back muscle strength, individual flexibility, and trunk angle on FRP in the back muscles. Forty male participants were classified into four groups according to toe-touch flexibility and back muscle strength. Lumbar erector spinae (LES) activity and the lumbosacral angle (LSA) were measured at incremental trunk flexion angles (0°–90°, with increments of 15°) to analyze FRP. Results indicated significant effects of back muscle strength, flexibility, and trunk angle on LES activity (all p < 0.001). Flexibility (p < 0.05) and trunk angle (p < 0.001) also influenced LSA. Additionally, an interaction between flexibility and trunk angle impacted LES activation (p < 0.001). Flexibility mainly determined FRP onset, while back muscle strength influenced efforts during moderate trunk flexion (30°–60°). These findings indicate that differences in lower back load among individuals with varying back muscle strengths become apparent even at relatively small trunk flexion angles (approximately 30°). When prolonged static trunk flexion in workplace settings places considerable strain on the lower back, we recommend utilizing toe-touch flexibility and back muscle strength assessments as practical screening tools for identifying early and subtle indicators of the FRP in workers.

屈伸-放松现象（FRP）是指在躯干深前屈时背部肌肉失活。本研究探讨了背部肌肉力量、个人柔韧性和躯干角度对背部肌肉 FRP 的影响。根据脚趾触地柔韧性和背部肌肉力量，40 名男性参与者被分为四组。在递增的躯干屈曲角度（0°-90°，递增 15°）下测量腰椎直立肌（LES）活动和腰骶角（LSA），以分析 FRP。结果表明，背部肌肉力量、柔韧性和躯干角度对 LES 活动有明显影响（所有 p

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引用次数: 0

Reliability of sEMG data of back muscles during static submaximal loading situations − Values and pitfalls 静态亚最大负荷情况下背部肌肉 sEMG 数据的可靠性 - 价值与陷阱。

IF 2 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2024-11-04 DOI: 10.1016/j.jelekin.2024.102947

Lena Mader, Max Herzberg, Christoph Anders

Alterations of trunk muscle activity can be objectified using surface electromyography (sEMG). But for diagnostic purposes reliable reference values are needed. Therefore, the present study evaluated sEMG measurements of representative back muscles concerning their reliability.

For this purpose, 49 healthy individuals (24 women) were subjected to static loads with defined portions of their upper body weight by applying whole-body tilts up to 90° in upright posture. Reliability analyses were carried out for amplitude values and normalized values according 90° tilt angle. Reliability measures included intraclass correlation coefficient (ICC), standard error of measurement (SEm), standard error of the mean (SEM), and coefficient of variation of method errors (CVME).

ICC values for the amplitude values were > 0.79 for M. multifidus (MF) and M. longissimus (LO). For the normalized values, distinctively lower ICC levels were generally detected (0.33–0.81). The values of SEm and SEM also increased with increasing load, while CVME levels of the amplitude values maintained similar levels.

For defined static extension loads, good to excellent reliability can be demonstrated for back muscles. The established normative values for SEm, SEM and CVME parameters may be used for diagnostic purposes during defined submaximal load situations. This does not apply to normalized data.

躯干肌肉活动的变化可以通过表面肌电图（sEMG）进行客观分析。但为了诊断目的，需要可靠的参考值。因此，本研究对代表性背部肌肉的 sEMG 测量值的可靠性进行了评估。为此，49 名健康人（24 名女性）在直立姿势下全身倾斜至 90°，使上半身重量的特定部分承受静态负荷。根据 90° 倾角对振幅值和归一化值进行了可靠性分析。可靠性测量包括类内相关系数（ICC）、测量标准误差（SEm）、平均标准误差（SEM）和方法误差变异系数（CVME）。多裂肌（MF）和长肌（LO）振幅值的 ICC 值大于 0.79。对于归一化值，检测到的 ICC 水平普遍明显较低（0.33-0.81）。SEm 和 SEM 值也随着负荷的增加而增加，而振幅值的 CVME 水平则保持在类似水平。在规定的静态伸展负荷下，背部肌肉的可靠性可以达到良好到极佳的水平。已确定的 SEm、SEM 和 CVME 参数标准值可用于在确定的次最大负荷情况下进行诊断。这不适用于标准化数据。

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引用次数: 0

Acute and chronic effects of static stretching of different target muscles on shear elastic modulus: A narrative review 不同目标肌肉的静态拉伸对剪切弹性模量的急性和慢性影响：叙述性综述。

IF 2 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2024-10-18 DOI: 10.1016/j.jelekin.2024.102939

Taizan Fukaya , Katsuyuki Morishita , Yuka Yokoi , Kosuke Takeuchi , Masatoshi Nakamura

We investigated the acute and chronic effects of static stretching on shear elastic modulus and assessed whether these effects could differ among various target muscles. PubMed, Scopus, and Google Scholar databases were searched for articles published up to 2023, using the terms “stretch,” “stretching,” “static stretching,” “shear elastic modulus,” “shear modulus,” and “shear wave elastography.” Thirty-seven original studies measured the shear elastic modulus after stretching: 32 and five evaluated acute and chronic effects, respectively. Acute stretching significantly decreased the shear elastic modulus in various muscles as follows: infraspinatus and pectoralis minor (2/2 studies, 100 %); medial gastrocnemius (15/17 studies, 88.2 %); lateral gastrocnemius (4/6 studies, 66.7 %); semimembranosus and semitendinosus (4/5 studies, 80 %); biceps femoris (3/5 studies, 60 %); and rectus femoris (3/4 studies, 75 %). No significant changes were found in the soleus, vastus lateralis, vastus medialis, teres minor, and posterior deltoid muscles, highlighting the variability in the effects of stretching on shear elastic modulus across different muscles. The difference in the effect depends on the stretching methods, including the position, duration, and intensity and position at which the shear elastic modulus is measured. Therefore, we should establish stretching methods for each muscle and investigate chronic effects on the shear elastic modulus.

我们研究了静态拉伸对剪切弹性模量的急性和慢性影响，并评估了这些影响在不同目标肌肉之间是否存在差异。我们使用 "拉伸"、"拉伸"、"静态拉伸"、"剪切弹性模量"、"剪切模量 "和 "剪切波弹性成像 "等术语在 PubMed、Scopus 和 Google Scholar 数据库中检索了截至 2023 年发表的文章。37 项原始研究测量了拉伸后的剪切弹性模量：32 项和 5 项分别评估了急性和慢性影响。急性拉伸明显降低了以下不同肌肉的剪切弹性模量：冈下肌和胸小肌（2/2 项研究，100%）；内侧腓肠肌（15/17 项研究，88.2%）；外侧腓肠肌（4/6 项研究，66.7%）；半膜肌和半腱肌（4/5 项研究，80%）；股二头肌（3/5 项研究，60%）；股直肌（3/4 项研究，75%）。比目鱼肌、外侧肌、内侧肌、小圆肌和三角肌后部没有发现明显的变化，这突出表明了拉伸对不同肌肉剪切弹性模量影响的差异性。效果的差异取决于拉伸方法，包括测量剪切弹性模量的位置、持续时间、强度和位置。因此，我们应该为每块肌肉制定拉伸方法，并研究慢性拉伸对剪切弹性模量的影响。

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引用次数: 0

Tutorial. Frequency analysis of the surface EMG signal: Best practices 教程。表面肌电信号的频率分析：最佳实践。

IF 2 4区医学 Q3 NEUROSCIENCES

Journal of Electromyography and Kinesiology

Pub Date : 2024-10-18 DOI: 10.1016/j.jelekin.2024.102937

Silvia Muceli , Roberto Merletti

This tutorial is aimed primarily to non-engineers (clinical researchers, clinicians, neurophysiology technicians, ergonomists, movement and sport scientists, physical therapists) or beginners using, or planning to use, surface electromyography (sEMG) as a monitoring and assessment tool for muscle and neuromuscular evaluations in the prevention and rehabilitation fields.

Its first purpose is to explain, with minimal mathematics, basic concepts related to: (a) time and frequency domain description of a signal, (b) Fourier transform, (c) amplitude, phase, and power spectrum of a signal, (d) sampling of a signal, (e) filtering of sEMG signals, (f) cross-spectrum and coherence between two signals, (g) signal stationarity and criteria for epoch selection, (h) myoelectric manifestations of muscle fatigue and (i) fatigue indices. These concepts are consolidated knowledge and are addressed and discussed with examples taken from the literature.

本教程主要面向在预防和康复领域使用或计划使用表面肌电图 (sEMG) 作为肌肉和神经肌肉评估的监测和评估工具的非工程人员（临床研究人员、临床医生、神经生理学技术人员、人体工程学专家、运动和体育科学家、物理治疗师）或初学者。其首要目的是用最少的数学知识解释与以下方面有关的基本概念：(a) 信号的时域和频域描述，(b) 傅立叶变换，(c) 信号的振幅、相位和功率谱，(d) 信号的采样，(e) sEMG 信号的滤波，(f) 两个信号之间的交叉谱和相干性，(g) 信号的静止性和时间选择标准，(h) 肌肉疲劳的肌电表现和 (i) 疲劳指数。这些概念都是综合知识，并通过文献中的实例加以阐述和讨论。

引用次数: 0