穿戴塑料踝足矫形器对下肢肌肉疲劳性的影响

背景：目前尚未见到系统研究踝足矫形器对下肢肌肉影响的文献。目的：提取正常人穿戴固定踝足矫形器时的下肢肌电信号,分析固定踝足矫形器对下肢肌肉疲劳性的影响。方法：选择5名健康男性受试者参加试验,每名受试者分别进行3组试验：①第1组,在不穿戴任何矫形器的情况下以自然步态行走。②第2组,受试者穿戴平跟踝足矫形器以自然步态行走（此时矫形器踝部包裹超过踝中心1 cm,记1.0 cm）,穿戴同一矫形器但在踝部去掉1.0 cm、踝部塑料边缘刚好通过踝中心时采集（记0 cm）,在踝部再去掉1.0 cm后以自然步态行走（记-1.0 cm）。③第3组,受试者穿戴1.5 cm正常跟高踝足矫形器以自然步态行走,穿戴同一矫形器,但跟高分别改为1.0,2.0 cm后以自然步态行走。行走中采用肌电采集仪检测受试者下肢股二头肌、股直肌、胫骨前肌、腓肠肌的表面肌电信号。结果与结论：①正常不穿戴任何矫形器时,4块肌肉的肌电信号是最弱的。②对于任何一块肌肉,正常不穿戴矫形器时所对应肌电值比穿戴不同硬度矫形器时所对应的肌电值要小。③对于股二头肌,正常不穿戴矫形器时所对应的积分肌电值与穿戴正常跟高矫形器时所对应的值很接近,同时这两个值要比穿戴不正常跟高矫形器时所对应的积分肌电值小。表明固定塑料踝足矫形器会引起股二头肌、股直肌、胫骨前肌、腓肠肌的疲劳,当固定塑料踝足矫形器的跟高不合适时会进一步增加股二头肌的疲劳程度。     

正常青年人自然步态下肢肌的表面肌电图分析

背景:肌肉的生物电活动是人体的能动部分,可反映人体运动的功能。目的:观察和分析正常青年人在自然步态中下肢肌肉的表面肌电活动。方法:采用美国NORAXON公司生产的TELEMYO2400RG2表面肌电图仪对30例正常青年人在平地自然行走时,其双下肢股直肌、胫前肌、股二头肌和腓肠肌内侧进行测试,分析在正常步态中受试肌群表面肌电信号的变化规律。结果与结论:正常青年人平地自然步行中,其双下肢股直肌、胫前肌、股二头肌和腓肠肌内侧的肌电随步态周期呈活动与静止周期性变化,左右侧同名肌肉交替活动;平均肌电振幅、平均肌电积分、平均频率、中位频率值最大的是腓肠肌内侧,其余由大到小依次是胫前肌,股二头肌,股直肌,右左腿分布规律一致;右侧腓肠肌内侧平均肌电振幅、平均频率、中位频率值均明显低于左侧(P<0.05);受试肌的时域、频域值波动在一定范围。提示正常青年人自然步态中下肢肌群肌电活动呈节律性和右左侧交替活动;在受试肌中腓肠肌内侧的肌电活动最强;腓肠肌内侧的肌电活动存在着优势侧与非优势侧的轻度差别;下肢肌肌电活动的时域、频域值在一定范围波动。     

不同硬度鞋底在人体行走中的足底肌电变化

目的:对人体穿不同硬度鞋底的鞋行走,进行生物力学分析,通过人体行走中的肌电变化来评价不同硬度鞋底的功能特性。方法:对受试者(着自行设计的实验用鞋)在跑台上以2m/s的速度,进行步行60min的测试,运用Biovision16通道肌电图机、Vicon红外摄像系统进行同步测试,对胫骨前肌、股外侧肌、腓肠肌和股二头肌肌肉电信号的积分肌电值(IEMG)与中位频率(MF)信号进行采集,找出穿不同硬度鞋底的鞋在人体长时间步行中对上述肌肉的时域和频域指标影响。结果:穿软底鞋IEMG总体高于其他两种硬度的鞋,其中腓肠肌的表现尤其明显,IEMG为(434.946±133.782)uvs,MF为(78.563±45.345)Hz,肌电活动较大时容易疲劳。穿软底鞋行走时在全掌着地,脚跟离地,脚尖离地期胫骨前肌收缩消耗的时间较其他两种硬度的鞋长。穿中等硬度鞋行走时股外侧肌肌肉收缩时长最短。结论:鞋底的软硬程度对人体在行走过程中下肢肌电变化具有一定影响,硬底鞋关节缓冲比较差,耗能小,对关节保护比较差,足弓不易塌陷。     

正常步态10m自由步行胫前后肌群的SEMG研究

目的:利用表面肌电图(SEMG)进行步态分析评定,为拓展表面肌电图的临床应用建立可靠的依据.方法:5例青年健康受试者进行10m自由步行测试,同步记录双下肢胫前肌及腓肠肌内侧头肌群的表面肌电信号,分析在正常步态周期中受试肌SEMG的变化规律.结果:正常步态周期中,胫前肌近乎呈持续活动状态,并有两个活动高峰;腓肠肌在摆动期除表现为电静息状态外,在中末期也可有一个较小的梭形波存在.健康人步行时胫前肌的肌电活动,优势与非优势侧存在差异(P＜0.05),但总体两侧胫前后肌群的收缩负荷比均等.结论:步行周期中胫前肌和腓肠肌的表面肌电信号特征明显不同,胫前肌较腓肠肌更易发生疲劳;摆动中期的小腿后部伸肌肌群的轻度肌电活动可能是哺乳类动物步行时共有的规律.     

日常生活活动中人体下肢肌肉的表面肌电特性

目的探讨个体完成日常生活活动时下肢主要肌肉群肌电信号特征。方法30 名正常成年人完成7 个基本动作,同步检测双侧股直肌、股内侧肌、股外侧肌、腓肠肌外侧、胫前肌和比目鱼肌的表面肌电平均肌电值(AEMG)。结果和结论在日常生活活动中,左右下肢肌肉的发力有显著性差异,下肢各肌肉发力有显著性差异,男、女性在完成日常生活活动时下肢发力方式不同     

不同足部姿势受试者使用外侧楔形鞋垫后股四头肌肌电和膝关节力学特征改变的研究

目的:研究不同足部姿势受试者使用外侧楔形脚垫后股四头肌的肌电和膝关节力学特征的变化。方法:利用静态足部姿势指数筛选收集5例中立足、5例旋后足、7例旋前足的健康年轻人作为受试者,试验过程:(1)受试者先在5m的步行道上采用自由速度行走7次,使用测力板(AMTI,Optima HPS,美国)收集受试者的力学数据,表面肌电系统(Delsys,MyomonitorⅢ,美国)收集受试者右侧股直肌、股内侧肌、股外侧肌的肌电信号,三维步态分析系统(Vicon Ltd,Oxford,英国)收集受试者的运动学数据;(2)受试者换上外侧楔形脚垫再进行7次自由速度的步态试验,收集肌电、力学、运动学数据。分析使用外侧楔形鞋垫前后肌肉活动、运动学、动力学数据的变化。结果:中立组在使用外侧楔形鞋垫之后股直肌肌肉活动增加、足底压力中心向外侧移动、膝关节的内收力矩第一峰值(P0.05)和垂直轴地面反向作用力减小(P0.05),差异具有显著性意义;旋前组在使用鞋垫之后股直肌的肌肉活动出现较小的降低,膝关节内收力矩第一峰值降低(P0.05),垂直轴地面反向作用力增大(P0.05);旋后组使用外侧楔形脚垫之后股直肌活动降低(P0.05)、膝关节的内收力矩没有明显变化。结论:静态足部姿势或许可以用来预测受试者对使用外侧楔形脚垫的生物力学和肌电反应。为临床受试者使用外侧楔形鞋垫提供了不同足部姿势受试者的基础力学和肌电数据。     

脑卒中患者步态周期各时相中下肢肌肉的表面肌电特点

目的探讨脑卒中患者下肢前后肌群在步态周期及其各分相中表面肌电(sEMG)信号的变化,以便有针对性地对脑卒中患者进行步态康复训练。方法 2018年1月至6月,采用Noraxon表面肌电无线采集系统记录20例脑卒中患者和20例健康对照者在自然行走过程中双下肢胫骨前肌(TA)、股直肌(RF)、腓肠肌内侧头(GM)和股二头肌(BF)的sEMG信号。结果健康受试者双下肢TA、RF、GM和BF的肌电活动随步态周期呈活动与静止周期性变化、双侧同名肌肉交替活动,而脑卒中患者双下肢相关肌肉肌电活动发生明显改变,且失去规律性。结论 sEMG能反映脑卒中患者步态相关肌肉受损情况,可用于指导步态康复训练。     

腰神经根与其支配肌群的电生理定位实验

目的:观察电生理方法定位腰神经根主要支配肌群的可行性,为临床术中电生理定位监测提供参考依据。方法:实验于2005-04/05在北京大学人民医院创伤骨科实验室完成,选择9只5月龄Wistar雌性大鼠,通过电生理的方法,依次电刺激L2～L5脊神经根部,分别记录双侧大鼠下肢主要肌肉的复合肌肉动作电位,测量下肢四组肌肉(股四头肌、股二头肌、胫骨前肌和腓肠肌)复合肌肉动作电位的波幅峰值。结果:9只大鼠全部进入结果分析。①刺激腰神经根于下肢所记录的典型肌电波形以双相波和三相波为主。②刺激L2脊神经根,于下肢四组肌肉记录到的复合肌肉动作电位最大波幅平均值均<1mV,以在股四头肌记录到的波幅峰值最高(0.89±1.05)mV,显著高于其他3组肌肉(P<0.05)。③刺激L3脊神经根,于股四头肌记录到的波幅峰值为(23.79±13.22)mV,显著高于其他各组肌肉(P<0.01)。④刺激L4脊神经根,于下肢四组肌肉记录到的复合肌肉动作电位最大波幅平均值均明显>1mV,股四头肌和胫骨前肌记录到的波幅峰值显著高于股二头肌和腓肠肌[(15.88±12.28),(12.75±4.97),(7.11±3.60),(8.06±5.29)mV,P<0.01]。⑤刺激L5脊神经根,于股二头肌、腓肠肌记录到的波幅峰值为(23.92±15.05),(13.1±7.05)mV,显著高于其他各肌群(P<0.01)。结论:电刺激不同脊神经根,在大鼠下肢不同肌肉记录到的复合肌肉动作电位的波幅峰值存在差异,综合分析记录到的复合肌肉动作电位的波幅峰值,可基本确定所刺激的腰神经根节段。     

先天性马蹄内翻足表面肌电信号研究

摘要 目的：探讨表面肌电（sEMG）检测技术在先天性马蹄内翻足患儿中的临床应用。 方法：采用十通道生物机能实验系统采集32例单侧先天性马蹄内翻足患儿的下肢表面肌电信号。患儿取仰卧位,在自然放松位、踝被动背伸至中立位、踝被动跖屈45度时检测双侧股直肌、胫前肌、腓肠肌的表面肌电信号,经信号处理得到股直肌、胫前肌、腓肠肌的平均均方根（RMS）值,并分析健侧与患侧相关肌肉平均RMS值的差异。 结果：患侧的小腿肌肉受累,健侧与患侧胫前肌、腓肠肌在背伸位、跖屈位平均RMS值差异有统计学意义（P＜0.05）,且患侧胫前肌、腓肠肌肌电信号均较健侧低。 结论：先天性马蹄内翻足患儿存在神经、肌肉功能异常,表面肌电图检测可以无创地了解患儿的神经及肌肉功能。     

脑卒中患者坐位及站立位胫骨前肌和腓肠肌表面肌电图信号特征研究

目的分析脑卒中患者坐位及站立位胫骨前肌和腓肠肌表面肌电图(sEMG)信号特征。方法选取15例脑卒中患者和15例正常人作为实验组和对照组,令受试者连续做5次由坐到站,采用表面电极引导和记录两侧胫骨前肌和腓肠肌肌电信号并进行线性时、频分析。结果脑卒中患者坐位患侧与健侧、健侧与正常人对应健侧胫骨前肌的平均功率频率(MPF)和中位频率(MF)差异有显著性意义(P<0.05);脑卒中患者健侧与正常人对应健侧腓肠肌均方根差异有显著性意义(P<0.05);脑卒中患者站立位患侧与健侧、健侧与正常人对应健侧胫骨前肌均方根和积分肌电(iEMG)差异有非常显著性意义(P<0.01);脑卒中患者健侧与患侧、患侧与正常人对应患侧腓肠肌均方根和iEMG差异有显著性意义(P<0.05或P<0.01)。结论sEMG是一种简单、实用、可行的康复评定方法。     

Muscle activation patterns during walking from transtibial amputees recorded within the residual limb-prosthetic interface

ABSTRACT: BACKGROUND: Powered lower limb prostheses could be more functional if they had access to feedforward control signals from the user's nervous system. Myoelectric signals are one potential control source. The purpose of this study was to determine if muscle activation signals could be recorded from residual lower limb muscles within the prosthetic socket-limb interface during walking. METHODS: We recorded surface electromyography from three lower leg muscles (tibilias anterior, gastrocnemius medial head, gastrocnemius lateral head) and four upper leg muscles (vastus lateralis, rectus femoris, biceps femoris, and gluteus medius) of 12 unilateral transtibial amputee subjects and 12 non-amputee subjects during treadmill walking at 0.7, 1.0, 1.3, and 1.6 m/s. Muscle signals were recorded from the amputated leg of amputee subjects and the right leg of control subjects. For amputee subjects, lower leg muscle signals were recorded from within the limb-socket interface and from muscles above the knee. We quantified differences in the muscle activation profile between amputee and control groups during treadmill walking using cross-correlation analyses. We also assessed the step-to-step intersubject variability of these profiles by calculating variance-to-signal ratios. RESULTS: We found that amputee subjects demonstrated reliable muscle recruitment signals from residual lower leg muscles recorded within the prosthetic socket during walking, which were locked to particular phases of the gait cycle. However, muscle activation profile variability was higher for amputee subjects than for control subjects. CONCLUSION: Robotic lower limb prostheses could use myoelectric signals recorded from surface electrodes within the socket-limb interface to derive feedforward commands from the amputee's nervous system.     

Muscle activation patterns during walking from transtibial amputees recorded within the residual limb-prosthetic interface

Powered lower limb prostheses could be more functional if they had access to feedforward control signals from the user’s nervous system. Myoelectric signals are one potential control source. The purpose of this study was to determine if muscle activation signals could be recorded from residual lower limb muscles within the prosthetic socket-limb interface during walking. We recorded surface electromyography from three lower leg muscles (tibilias anterior, gastrocnemius medial head, gastrocnemius lateral head) and four upper leg muscles (vastus lateralis, rectus femoris, biceps femoris, and gluteus medius) of 12 unilateral transtibial amputee subjects and 12 non-amputee subjects during treadmill walking at 0.7, 1.0, 1.3, and 1.6 m/s. Muscle signals were recorded from the amputated leg of amputee subjects and the right leg of control subjects. For amputee subjects, lower leg muscle signals were recorded from within the limb-socket interface and from muscles above the knee. We quantified differences in the muscle activation profile between amputee and control groups during treadmill walking using cross-correlation analyses. We also assessed the step-to-step inter-subject variability of these profiles by calculating variance-to-signal ratios. We found that amputee subjects demonstrated reliable muscle recruitment signals from residual lower leg muscles recorded within the prosthetic socket during walking, which were locked to particular phases of the gait cycle. However, muscle activation profile variability was higher for amputee subjects than for control subjects. Robotic lower limb prostheses could use myoelectric signals recorded from surface electrodes within the socket-limb interface to derive feedforward commands from the amputee’s nervous system.     

Quantified electromyography of lower-limb muscles during level walking

The electromyography (EMG) of eleven different lower limb muscles of ten healthy subjects was quantified during normal level walking. The surface EMGs obtained were normalized, in percentage, to the activity obtained during an isometric maximum voluntary test contraction of each subject. The mean peak activities of the gluteus maximus, gluteus medius, rectus femoris, vastus medialis, vastus lateralis, biceps femoris and medial hamstring muscles occurred at heel-strike and were between 5 and 15% of max isometric EMG. The magnitudes of tibialis anterior and triceps surae muscular activity were higher than those of the other muscles investigated. Mean peak activity in tibialis anterior was 27%, in gastrocnemius medialis 42%, in gastrocnemius lateralis 19% and in soleus 40%. The important role of the triceps surae during walking was reflected in comparatively high muscular activity at push-off.     

Effects of treadmill walking speed on lateral gastrocnemius muscle firing

OBJECTIVE: To study the electromyographic profile--including ON, OFF, and peak timing locations--of the lateral gastrocnemius muscle over a wide range of walking speeds (0.5-2.1 m/sec) in healthy young adults. DESIGN: We studied gastrocnemius muscle-firing patterns using an electromyographic surface electrode in 15 healthy subjects ambulating on a treadmill at their normal walking speed and at three paced walking speeds (0.5, 1.8, and 2.1 m/sec). Initial heel contact was determined from a force-sensitive switch secured to the skin over the calcaneous. RESULTS: For all speeds, the gastrocnemius firing pattern was characterized by a main peak, occurring 40-45% into the gait cycle, that increased in amplitude with walking speed. Speeds of > or =1.3 m/sec produced a common electromyographic timing profile, when the profile is expressed relative to the stride duration. However, at 0.5 m/sec (a speed typical of individuals with upper-motor neuron lesions), the onset of gastrocnemius firing was significantly delayed by 3-6% of the gait cycle and was prolonged by 8-11% of the gait cycle. CONCLUSION: Many patients with upper motor neuron lesions (e.g., stroke and traumatic brain injury) walk at speeds much slower than those commonly described in the literature for normal gait. At the slow walking speed of 0.5 m/sec, we have measured noticeable changes in the electromyographic timing profile of the gastrocnemius muscle. Given the importance of appropriate plantar flexor firing patterns to maximize walking efficiency, understanding the speed-related changes in gastrocnemius firing patterns may be essential to gait restoration.     

Changes in gait and EMG when walking with the Masai Barefoot Technique

BACKGROUND: The Masai barefoot technology is used as a treatment option within the field of physical therapy to treat leg, back or foot problems. No information, however, is available on how Masai barefoot technology changes gait or muscle activity. METHODS: Twelve healthy subjects underwent 3D gait analysis with simultaneously collecting surface electromyography data of the leg muscles when walking with regular shoes and with Masai barefoot technology-shoes. Before data collection, subjects were trained in Masai barefoot technology. A within-subjects study-design compared walking with regular shoes and Masai barefoot technology. FINDINGS: With Masai barefoot technology, subjects walked slower with smaller steps. Movement pattern at the ankle showed major changes with increased dorsiflexion angle at initial contact followed by a continuous plantarflexion movement until terminal stance phase. With changed kinematics, alterations in the activity of tibialis anterior and gastrocnemius muscles could be observed. Smaller differences in movement and muscle activity were seen at knee and hip level. INTERPRETATION: Masai barefoot technology has never been documented in detail concerning changes in movement pattern or muscle activity. This study showed that Masai barefoot technology changes movement patterns, especially at the ankle, and increases muscle activity. It may therefore be a useful training method for strengthening the muscle groups of the lower leg. Knee flexion and electromyographic characteristics around the knee joint are slightly increased and need to be considered in patients with knee problems. Our findings provide critical detailed information on changes compared to walking in regular shoes, but the clinical relevance of those changes remains to be determined.     

Direct effect of percutaneous electric stimulation during gait in children with hemiplegic cerebral palsy: a report of 2 cases

The feasibility of using percutaneous intramuscular functional electric stimulation (FES) in children with cerebral palsy (CP) as a method to improve ankle kinematics and kinetics during gait was investigated. Two children with right hemiplegic CP had percutaneous intramuscular electrodes implanted into the gastrocnemius and tibialis anterior muscles of the involved limb. FES was provided during the gait cycle using force-sensing foot switches to detect gait phase transitions. The children ambulated using FES under 3 conditions (gastrocnemius on, tibialis anterior on, gastrocnemius and tibialis anterior on). For each condition, two 45-minute walking sessions were conducted per day for 1 week. Immediately after each week of practice, a gait analysis was performed at the subject's self-selected walking speed for that stimulation condition and without stimulation. Both children demonstrated improvements in ankle dorsiflexion angle at initial contact, peak dorsiflexion during swing, mean dorsiflexion during swing, and ankle work during early stance with tibialis anterior stimulation alone and combined gastrocnemius and tibialis anterior stimulation. Improvements in ankle work were found during late stance for both children with all stimulation conditions. These results suggest that percutaneous intramuscular FES was effective in improving aspects of ankle kinematics and kinetics of 2 children with hemiplegic CP.