小腿假肢对线对静态站立时下肢受力的影响

目的:研究小腿截肢患者站立状态下假肢对线对下肢受力特性的影响.方法:以假肢侧承重线和重力线作为评价指标,改变假肢矢状面和额状面的对线,采用激光测力平台测量患者静态站立时残侧承重线和重力线的位置,研究下肢受力状况的变化.结果:假肢侧承重线受踝关节对线的影响大于腿管对线调节的影响,并且力线随腿管与接受腔的前倾而前移,而额状面对线的影响很小;矢状面内重力线主要受踝关节对线调节的影响,并且与变化角近似正比例相关.结论:矢状面假肢对线调整对残侧下肢受力状况的影响较大,而额状面的对线调整影响较小.     

脑卒中偏瘫患者股直肌和股二头肌的表面肌电信号特征

目的：观察脑卒中偏瘫患者在最大等长收缩（MIVC）时股直肌和股二头肌的表面肌电信号特征，为脑卒中患者的康复提供客观依据。方法：选择26例恢复期的脑卒中患者，在进行膝关节屈、伸肌群的MIVC时检测并记录股直肌和股二头肌的表面肌电信号，并计算积分肌电图（iEMG）和协同收缩率等。结果：在MIVC状态下，膝伸展时，健侧股直肌的iEMG大于患侧，差异有显著性意义（P〈0．05）；健、患侧股二头肌的iEMG比较，差异无显著性意义（P〉0．05）。膝屈曲时，健侧股二头肌的iEMG大于患侧，差异有显著性意义（P〈0．05），患侧股直肌的iEMG大于健侧，差异有显著性意义（P〈0．05）。患侧膝屈曲的协同收缩率大于健侧，差异有显著性意义（P〈0．05），而患侧膝伸展的协同收缩率与健侧比较，差异无显著性意义（P〉0．05）。结论：脑卒中偏瘫患者膝关节痉挛以伸肌群为主，对膝关节屈肌群和伸肌群收缩的协调性训练，尤其在膝关节屈曲运动时，增强主动肌收缩，抑制拮抗肌的协同收缩，应是脑卒中患者下肢康复的重要目标。     

膝关节骨关节炎患者膝屈伸肌的表面肌电信号研究

目的 评价单侧膝关节骨关节炎（OA）患者在不同运动状态下的健、患侧膝屈伸肌的肌肉功能和协调活动差异，为临床制定康复方案提供依据。方法 用Noraxon Myosystem1200型表面肌电图仪对26例单侧膝关节骨关节炎患者的等长肌肉收缩功能和下蹲运动进行表面肌电信号的测试。结果 患侧股外侧肌和股二头肌在最大等长收缩和下蹲运动时的肌电振幅均值小于健侧（P〈0．05）。在最大等长收缩过程中，患侧的拮抗肌协同收缩率较健侧增高（P〈0．05）；在下蹲运动过程中，患侧的胭绳肌共同活动比率高于检测（P〈0．05）。结论 表面肌电图测试可用于量化评价膝OA患者在不同运动过程中肌肉功能。膝OA患肢在不同运动状态下均可能存在肌肉功能降低和肌力平衡异常。康复治疗不仅应重视股四头肌肌力增强而且应重视改善膝关节的肌力平衡。     

半月板损伤患者膝周肌肉的表面肌电图分析

目的探讨半月板损伤对膝周肌肉功能的影响。方法 2017年2月至2018年2月,单侧半月板损伤患者22例,记录下蹲、站起和屈膝70°最大等长收缩时,健、患侧股外侧肌、股直肌、股内侧肌和股二头肌的表面肌电图。结果下蹲和站起时,患侧股外侧肌和股二头肌的平均肌电值显著低于健侧(t 3.945, Z 3.847, P 0.001),腘绳肌共同活动比率明显高于健侧(t 3.650, P 0.01)。在70°最大等长收缩时,患侧股外侧肌、股直肌、股内侧肌和股二头肌平均肌电值均明显小于健侧(t 2.907, Z=4.107, P 0.01)。结论 sEMG能定量评价半月板损伤患者不同运动状态下膝屈伸肌功能。半月板损伤患者患肢膝周肌肉功能下降,协调性异常,应在康复治疗过程中加以纠正。     

表面肌电仪对痉挛偏瘫型脑瘫患儿肌张力的分析

目的探讨痉挛偏瘫型脑瘫患儿在等长收缩过程中肱二头肌肌张力变化的表面肌电图特征。方法使用表面肌电仪检测10例偏瘫型脑瘫患儿在肱二头肌进行被动等长收缩时的表面肌电信号。结果健侧肌电信号强于患侧,健侧肱二头肌肌电信号的均方根值(RMS)及肌电积分值(iEMG)高于患侧(P<0.05)。结论表面肌电仪对痉挛偏瘫型脑瘫患儿肌张力的评估结果与改良Ashworth量表(MAS)评定结果一致,具有实用价值。     

膝骨关节炎患者膝关节置换后下肢肌的表面肌电图变化

背景：膝骨关节炎患者膝关节置换后下肢肌功能恢复一直存在着争议。目的：评价膝骨关节炎患者膝关节置换手术后下肢肌肉功能。方法：应用TELEMYO2400RG2表面肌电图遥测仪对25例双膝骨关节炎单膝关节置换后患者在平常自然步态下进行双下肢股直肌、胫前肌、股二头肌和腓肠肌内侧的表面肌电信号测试。在肌电图测试前,对患者双膝关节功能进行美国特种外科医院膝关节评分。结果与结论：患者置换后美国特种外科医院膝关节评置换侧平均分91．44,其优良率达100％;未置换侧平均分54．52。置换侧在疼痛、关节功能方面有明显改善;膝关节置换后置换侧股直肌、胫前肌、股二头肌的肌电振幅、肌电积分、平均频率、中位频率的（平均值、最小值、最大值）与未置换侧相比差异无显著性意义（P〉0．05）;置换侧腓肠肌内侧肌电振幅值及肌电积分值显著大于未置换侧（P〈0．05）;置换侧腓肠肌内侧平均频率、中位频率与未置换侧相比差异无显著性意义（P〉0．05）。提示膝关节置换后置换侧的下肢肌没有恢复到正常的功能活动水平,因此膝关节置换后康复要特别重视患者的肌肉锻炼。     

膝前交叉韧带重建术后步态分析初步研究

目的观察膝前交叉韧带（ACL）重建术后的步态变化。方法用三维步态分析仪观察Lysholm评分100分、ACL重建术后1年的患者14例。测试步态周期中健侧和患侧的时间距离参数（步频、步长、步速、单腿支撑时间、摆动期、支撑期）、膝关节在预承重期和摆动期的最大屈曲度以及股四头肌的表面肌电平均波幅。结果健侧和息侧的时间距离参数和膝关节最大屈曲度差异均无统计学意义，并且各时间距离参数均在正常参考值范围内。两侧的股直肌和股外侧肌表面肌电平均波幅差异无统计学意义，而患侧股内侧肌平均波幅显著小于健侧（P〈0．05）。结论ACL重建术后1年且Lysholm评分达100分的患者，步行时步态基本恢复正常，但股内侧肌肌肉收缩活动仍低于健侧。     

镜像疗法对脑卒中偏瘫患者下肢肌肉表面肌电的影响

目的 探讨镜像疗法对脑卒中偏瘫患者下肢肌肉表面肌电的影响。 方法 将62例脑卒中偏瘫患者按分层随机分组法分为镜像组和对照组,每组31例。两组患者均进行常规康复训练,镜像组在此基础上增加镜像疗法。于治疗前和治疗4周后（治疗后）,采用无线表面肌电系统采集并分析患侧股直肌、股二头肌、胫骨前肌的最大收缩力量（MVC）及随意收缩时的积分肌电值（iEMG）、均方根值（RMS）,比较上述指标治疗前、后的变化情况,评估训练效果。 结果 治疗前,两组患者患侧下肢胫骨前肌、股二头肌、股直肌的MVC、iEMG及RMS比较,差异均无统计学意义（P>0.05）。治疗后,两组患者患侧下肢胫骨前肌、股二头肌、股直肌的MVC、iEMG及RMS均较组内治疗前改善（P<0.05）。治疗后,与对照组比较,镜像组患者患侧下肢胫骨前肌、股直肌、股二头肌MVC、iEMG及RMS的提高幅度较大,差异有统计学意义（P<0.05）。 结论 镜像疗法能增强脑卒中偏瘫患者患侧下肢肌肉运动过程中运动单位的募集及同步化程度,增加参与运动的运动单位数量及放电总量,并促进下肢肌肉力量恢复。     

髌股关节炎患者膝周肌群表面肌电信号特征研究

目的:观察髌股关节炎患者膝周肌群肌肉功能和协调活动差异,及其与膝关节疼痛的关系.方法:选择20例髌股关节炎患者,记录屈膝90°最大等长收缩(MVIC)、下蹲和站起时,双侧股外侧肌、股内侧肌、股二头肌和半腱肌的表面肌电图.计算均方根值(RMS)和协同收缩率(CCR),并观察CCR与疼痛的关系.将单膝患病患者健侧及双膝患病...     

AnyBody仿真和验证的太极拳训练中下肢生物力学特征

摘要 目的：利用仿真建模系统和三维测力台对完成太极拳中的弓步和马步动作时,人体支撑腿主要肌肉和膝关节的受力以及支撑稳定性进行研究,并通过表面肌电进行验证。 方法：使用FAB系统采集5名受试者的运动学参数用以建立模型,并通过三维测力台和表面肌电系统对不同动作的动力学及肌电特征进行分析。 结果：①完成不同幅度弓步动作时,比目鱼肌和股二头肌的受力分别为75.19N,215.81N和274.30N,明显高于马步动作。②完成最大幅度弓步和马步动作时,膝关节垂直受力分别为-1454.80N和-498.12N,前后方向的受力分别为-1886.60N和-1947.30N。③股直肌、股内侧肌和股二头肌的肌肉活性仿真结果同积分肌电之间显著相关,相关系数分别为0.900,0.922和0.852。 结论：完成马步动作时,主要发力的肌肉是股直肌和股内侧肌。而完成弓步动作时,比目鱼肌和股二头肌的发力也明显增加,且完成大幅度的弓步动作时,膝关节产生的压缩载荷和剪切载荷很大。同时,大腿肌群中的股直肌、股内侧肌和股二头肌的肌肉活性仿真结果同积分肌电之间一致性较高。     

A Study on the Differences of Quadriceps Femoris Activities by Knee Alignment during Isometric Contraction

[Purpose] This study attempted to identify how genu varum or valgum affects the electromyographic activities of the vastus medialis, vastus lateralis, and rectus femoris during knee isometric contraction. [Subjects] Fifty-two healthy young adults were enrolled in this study. They were enrolled and classified into three groups by knee alignment conditions: the genu varum, genu valgum, and control groups. [Methods] The electromyographic activity ratio of the vastus medialis to the vastus lateralis and rectus femoris were calculated using the percentage of maximum voluntary contraction. The participants contracted their quadriceps during isometric contraction at 30 and 60° of knee flexion. [Results] The genu varum group had more activity in the vastus medialis than in the vastus lateralis and rectus femoris, whereas the genu valgum group had more activity in the vastus lateralis and rectus femoris than in the vastus medialis. There was a significant difference in the muscle activity ratio between the vastus medialis and vastus lateralis by angle of knee flexion degree only in the genu valgum. There were no significant differences in any of the three groups in terms of the muscle activity ratio of the vastus medialis to the rectus femoris by angle of knee flexion. [Conclusion] The quadriceps femoris was used for different strategies according to knee alignment during isometric contraction at 30 and 60°. This study suggests that rehabilitation training programs used to strengthen the quadriceps should consider the knee alignment conditions of the target subjects.Key words: Electromyography, Quadriceps muscle, Isometric contraction     

The influence of weakness in the vastus medialis oblique muscle on the patellofemoral joint: an in vitro biomechanical study

OBJECTIVE: Investigation of the influence of weakness in the vastus medialis oblique muscle on patellar tracking. DESIGN: In vitro biomechanical study. BACKGROUND: Currently, the influence of weakness in the vastus medialis oblique muscle on patellar tracking has not been well understood. METHODS: Seven human cadaveric knees were used. The direction of loading forces in the rectus femoris/vastus intermedius, vastus medialis oblique, and the vastus lateralis muscles was decided by the muscle alignment of each cadaver knee measured at the time of dissection. The loads used were 60 N in the rectus femoris, 50 N in the vastus lateralis, and 40 N in the vastus medialis oblique, according to the ratio calculated from the cross-sectional study. The weakness of vastus medialis oblique was simulated at 30 N (75%), 20 N (50%), 10 N (25%), and 0 N (0%), and the patellar position was measured for each condition using a magnetic 3 Space Tracker System. The influence of weakness in the vastus medialis oblique muscle on patellar position was investigated with seven cadaver knees using a magnetic 3 Space Tracker System. RESULTS: At 0 degrees and 15 degrees of knee flexion, 75%, 50%, 25% and 0% of the normal vastus medialis oblique muscle led to a significant difference in lateral patellar shift compared to the normal (P<0.05). CONCLUSIONS: Weakness of the vastus medialis caused the patellar lateral shift at 0 degrees and 15 degrees of knee flexion. RELEVANCE: Weakness of the vastus medialis is thought to be an important factor causing patellar subluxation and dislocation. Understanding the relationship between the vastus medialis weakness and patellar tracking will be useful in diagnosis, treatment and prevention of patellar subluxation and dislocation.     

运动疗法对膝关节骨关节炎患者肌发电量的影响

目的：研究肌发电量在膝关节骨关节炎患者股四头肌肌力训练中的变化情况及股四头肌的详细变化情况。方法：采用股四头肌的等长收缩运动训练方法和其他疗法进行比较,用肌电图进行股直肌、股内侧肌、股外侧肌的肌发电量测定,同时用“膝关节功能评定表”进行功能的辅助评定。结果：两种方法治疗后,股直肌、股内侧肌的肌发电量都有显著的变化,尤其以股内侧肌的变化极显著,股外侧的肌发电量无显著变化。两种方法中肌力训练较其他治疗方法在提高肌发电量方面更为有效。结论：股内侧肌在膝关节肌力锻炼中的变化最大,说明股内侧肌比股直肌和股外侧肌在稳定膝关节方面更重要。股外侧肌在训练中的变化最小,在维护膝关节的稳定性方面起的作用比股内侧肌和股直肌小;肌力训练比其他方法在增加肌发电量方面更有效,更能提高膝关节的稳定性。     

Changes in muscle activity during fast, alternating flexion-extension movements of the knee

The effects of high frequency alternating knee flexion-extension on muscle activity of the quadriceps and hamstring muscle groups has been investigated. Standard loads were used for each subject. The muscle activity in vastus medialis, vastus lateralis, rectus femoris and the lateral hamstrings were recorded by electromyography during increasing velocities. Rectus femoris and hamstrings were found to increase their activities significantly with increasing speed while vastus medialis and vastus lateralis showed no such change. The individual thigh muscles thus differ in function in relation to the velocity of movement.     

COMPARISON OF HIP AND KNEE STRENGTH AND NEUROMUSCULAR ACTIVITY IN SUBJECTS WITH AND WITHOUT PATELLOFEMORAL PAIN SYNDROME

Purpose/Background:

Historically, patellofemoral pain syndrome (PFPS) has been viewed exclusively as a knee problem. Recent findings have suggested an association between hip muscle weakness and PFPS. Altered neuromuscular activity about the hip also may contribute to PFPS; however, more limited data exist regarding this aspect. Most prior investigations also have not concurrently examined hip and knee strength and neuromuscular activity in this patient population. Additional knowledge regarding the interaction between hip and knee muscle function may enhance the current understanding of PFPS. The purpose of this study was to compare hip and knee strength and electromyographic (EMG) activity in subjects with and without PFPS.

Methods:

Eighteen females with PFPS and 18 matched controls participated in this study. First, surface EMG electrodes were donned on the gluteus medius, vastus medialis, and vastus lateralis. Strength measures then were taken for the hip abductors, hip external rotators, and knee extensors. Subjects completed a standardized stair-stepping task to quantify muscle activation amplitudes during the loading response, single leg stance, and preswing intervals of stair descent as well as to determine muscle onset timing differences between the gluteus medius and vastii muscles and between the vastus medialis and vastus lateralis at the beginning of stair descent.

Results:

Females with PFPS demonstrated less strength of the hip muscles. They also generated greater EMG activity of the gluteus medius and vastus medialis during the loading response and single leg stance intervals of stair descent. No differences existed with respect to onset activation of the vastus medialis and vastus lateralis. All subjects had a similar delay in gluteus medius onset activation relative to the vastii muscles.

Conclusion:

Rehabilitation should focus on quadriceps and hip strengthening. Although clinicians have incorporated gluteus medius exercise in rehabilitation programs, additional attention to the external rotators may be useful.Level of Evidence: 4     

Relationship between knee alignment and the electromyographic activity of quadriceps muscles in patients with knee osteoarthritis

[Purpose] We evaluated the relationship between knee alignment and the electromyographic (EMG) activity of the vastus medialis (VM) to the vastus lateralis (VL) muscles in patients with knee osteoarthritis (OA) in a cross-sectional study. [Subjects and Methods] Forty subjects with knee OA were assessed by anatomic radiographic knee alignment and the VM/VL ratio was calculated. Surface EMG from both the VM and VL muscles were evaluated during maximal isometric contraction at 60° knee flexion. Simultaneously, peak quadriceps torque was assessed using an isokinetic dynamometer. Subjects were categorized into low, moderate, and high varus groups according to knee malalignment. The peak quadriceps torque and VM/VL ratio across groups, and their relationships with varus malalignment were analyzed. [Results] All subjects had medial compartment OA and the VM/VL ratio of all subjects was 1.31 ± 0.28 (mean ± SD). There were no significant differences in the peak quadriceps torque or VM/VL ratios across the groups nor were there any significant relationships with varus malalignment. [Conclusion] The VM/VL ratio and peak quadriceps torque were not associated with the severity of knee varus malalignment.Key words: Malalignment, Knee, Quadriceps     

Patellar kinematics, part I: the influence of vastus muscle activity in subjects with and without patellofemoral pain

BACKGROUND AND PURPOSE: Reduced motor unit activity of the vastus medialis muscle relative to the vastus lateralis muscle has been implicated as a cause of lateral patellar subluxation. The purpose of this study was to assess the influence of vastus muscle motor unit activity on patellar kinematics. SUBJECTS: Twenty-three women (mean age=26.8 years, SD=8.5, range=14-46) with a diagnosis of patellofemoral pain and 12 women (mean age=29.1 years, SD=5.0, range=24-38) without patellofemoral pain participated. Only female subjects were studied because of potential biomechanical differences between sexes. METHODS: Patellar kinematics (kinematic magnetic resonance imaging) and vastus muscle electromyographic (EMG) activity using indwelling electrodes were measured during resisted knee extension. Measurements of medial and lateral patellar displacement and tilt obtained from magnetic resonance images were correlated with normalized vastus lateralis:vastus medialis oblique muscle and vastus lateralis:vastus medialis longus muscle EMG ratios at 45, 36, 27, 18, 9, and 0 degrees of knee flexion using a stepwise regression procedure. RESULTS: The vastus lateralis:vastus medialis longus muscle EMG ratio contributed to the prediction of lateral patellar glide at 27 degrees of knee flexion (r=-.48), with increased vastus medialis longus muscle activity being associated with greater lateral patellar displacement. A similar inverse relationship was evident with lateral patellar tilt at 36, 27, 18, and 9 degrees of knee flexion. CONCLUSION AND DISCUSSION: These results suggest that increased motor unit activity of the vastus medialis muscle appears to be associated with abnormal patellar kinematics in women, but it is not necessarily a cause of abnormal patellar kinematics.     

Differences in onset time between the vastus medialis and lateralis during stair stepping in individuals with genu varum or valgum

[Purpose] We investigated the difference in onset time between the vastus medialis and lateralis according to knee alignment during stair ascent and descent to examine the effects of knee alignment on the quadriceps during stair stepping. [Subjects] Fifty-two adults (20 with genu varum, 12 with genu valgum, and 20 controls) were enrolled. Subjects with > 4 cm between the medial epicondyles of the knees were placed in the genu varum group, whereas subjects with > 4 cm between the medial malleolus of the ankle were placed in the genu valgum group. [Methods] Surface electromyography was used to measure the onset times of the vastus medialis and vastus lateralis during stair ascent and descent. [Results] The vastus lateralis showed more delayed firing than the vastus medialis in the genu varum group, whereas vastus medialis firing was more delayed than vastus lateralis firing in the genu valgum group. Significant differences in onset time were detected between stair ascent and descent in the genu varum and valgum groups. [Conclusion] Genu varum and valgum affect quadriceps firing during stair stepping. Therefore, selective rehabilitation training of the quadriceps femoris should be considered to prevent pain or knee malalignment deformities.Key words: Quadriceps muscle, Genu varum, Genu valgum     

Electromyographic activity of the quadriceps components during the final degrees of knee extension

An imbalance in the recruitment patterns of the quadriceps muscle has been implicated in patellofemoral knee pain; however ambiguity remains in the normal recruitment patterns of this muscle. We investigated the activity of the quadriceps muscle during the final degrees of knee extension, specifically in the medial and lateral components. Sixteen healthy subjects (age; 22.5 (± 3.4) years, body mass; 67.5 (± 12.1) kg and height; 173.9 (± 10.4) cm) participated.Torque and electromyographic (EMG) activity of the quadriceps muscle were measured during isokinetic and isometric knee extensions. Torque and EMG activity reduced in all component muscles during the final degrees of isokinetic extension, but this did not occur during isometric contractions at similar angles. Normalised activity of rectus femoris (RF) was greater than that of vastus lateralis (VL) and vastus medialis obliquus (VMO) during the final degrees of isokinetic knee extension at 30°/sec; there were no differences between any component muscles at the higher velocities. VMO:VL and vastus medialis longus (VML):VL ratios were unchanged during knee extensions, except that VML:VL ratio increased significantly during the final degrees of extension at 30°/sec. Future work should compare these results with people with anterior knee pain, and explore this further during activities of daily living.     

Changes in patellofemoral joint contact pressures caused by vastus medialis muscle weakness

Background

Patellofemoral joint pain is a common knee disorder, but its underlying causes remain unknown. One proposed mechanism is an imbalance in force in the knee extensor muscles. Specifically, the vastus medialis and vastus lateralis are thought to play a crucial role in proper patellar tracking, and weakness in vastus medialis is thought to lead to a lateral shift in the patella causing increased contact pressures and pain. The purpose of this study was to create an animal model of vastus medialis weakness and to test the effect of this weakness on patellofemoral contact pressures.

Methods

Experiments were performed using New Zealand white rabbits (mass 4.9–7.7 kg, n = 12). Loading of the patellofemoral joint was produced by femoral nerve stimulation of the knee extensor muscles. Knee extensor imbalance was produced by vastus medialis ablation. Fuji pressure sensitive film was used to record contact area, shape and pressures for maximal and sub-maximal, matched-force contractions at knee angles of 30°, 60°, and 90°.

Findings

Patellofemoral peak pressures, average pressures, contact areas and contact shapes were the same across all loading conditions for matched-force contractions before and after elimination of vastus medialis.

Interpretation

We conclude that vastus medialis weakness does not cause changes in patellofemoral contact pressures. Since the muscular and knee joint geometry in rabbits and humans is similar, we question the idea of vastus medialis weakness as a cause of patellar mal-tracking and patellofemoral joint pain.