膝部损伤后膝关节功能障碍患者股四头肌的表面肌电信号研究

目的 探讨膝部损伤后膝关节功能障碍对股四头肌功能的影响.方法 对23例单侧膝部损伤后膝关节功能障碍患者,膝屈曲30°,记录最大伸展等长收缩(MIVC)时的力矩,股外侧肌、股内侧肌和股直肌的表面肌电信号.结果 在患侧膝屈曲30°膝最大伸展MIVC时的力矩,股外侧肌、股内侧肌和股直肌的平均肌电值(AEMG)、平均功率频率(MPF)、中位频率(MF)均低于健侧(P＜0.01);健侧股外侧肌的AEMG、MPF大于股内侧肌、股直肌(P＜0.01或P＜0.05), 股直肌大于股内侧肌(P＜0.05);患侧股直肌的AEMG、MPF大于股外侧肌、股内侧肌(P＜0.01或P＜0.05);股外侧肌大于股内侧肌(P＜0.05).结论 sEMG能够定量评价膝部损伤后膝关节功能障碍患者的肌肉功能.膝关节功能障碍患者患肢肌力及股四头肌受累肌肉活动水平显著降低,股直肌可能受影响程度较轻.     

髌腱末端病运动员膝关节屈伸峰力矩和表面肌电图的特征（英文）

背景：髌腱末端病是腱止点部位的微细损伤,股四头肌群中的股内侧肌与股外侧肌之间的力量平衡发生变化,可直接导致髌骨产生异常运动从而对腱止点部位产生影响。目的：分析髌腱末端病发生机制和髌腱末端病对膝关节及其周围肌肉活动产生的影响。方法：选择10名患有髌骨肌腱病的男运动员及10名运动项目、身高和年龄匹配的正常男运动员,采用瑞士CON-TREX等速肌力测试与训练系统,分别进行膝关节力量和表面肌电图的测试,比较与分析膝关节屈肌力矩、伸肌力矩和股四头肌表面肌电图的变化。结果与结论：发现在等长运动时,末端病组的伸肌伸肌峰力矩明显小于对照组、峰值转矩比比值明显大于对照组;在等速运动时,末端病组的伸肌伸肌峰力矩明显小于对照组,并随着运动角速度增加而变化显著,而峰值转矩比比值均不同程高于对照组;末端病组的股内侧肌/股外侧肌的整合肌电图比值在等长运动和等速运动时,均明显低于对照组。提示髌腱末端病运动员膝关节屈肌与伸肌的力量差距较为突出,存在股内侧肌活动低下和股内侧肌与股外侧肌之间不平衡的现象。     

髌腱末端病运动员膝关节屈伸峰力矩和表面肌电图的特征(英文)

背景:髌腱末端病是腱止点部位的微细损伤,股四头肌群中的股内侧肌与股外侧肌之间的力量平衡发生变化,可直接导致髌骨产生异常运动从而对腱止点部位产生影响。目的:分析髌腱末端病发生机制和髌腱末端病对膝关节及其周围肌肉活动产生的影响。方法:选择10名患有髌骨肌腱病的男运动员及10名运动项目、身高和年龄匹配的正常男运动员,采用瑞士CON-TREX等速肌力测试与训练系统,分别进行膝关节力量和表面肌电图的测试,比较与分析膝关节屈肌力矩、伸肌力矩和股四头肌表面肌电图的变化。结果与结论:发现在等长运动时,末端病组的伸肌伸肌峰力矩明显小于对照组、峰值转矩比比值明显大于对照组;在等速运动时,末端病组的伸肌伸肌峰力矩明显小于对照组,并随着运动角速度增加而变化显著,而峰值转矩比比值均不同程高于对照组;末端病组的股内侧肌/股外侧肌的整合肌电图比值在等长运动和等速运动时,均明显低于对照组。提示髌腱末端病运动员膝关节屈肌与伸肌的力量差距较为突出,存在股内侧肌活动低下和股内侧肌与股外侧肌之间不平衡的现象。     

健康青年下台阶时股内侧肌、股直肌和股外侧肌间的表面肌电变化

目的探讨健康青年下台阶时股内侧肌、股直肌及股外侧肌的肌肉收缩强度差异。方法 2016年,选取首都医科大学2015级30名健康在校大学生,将电极贴于优势侧股四头肌上,采集受试者下台阶过程中的股内侧肌、股直肌及股外侧肌的肌电信号。结果在下台阶过程中,股直肌的最大收缩幅值和平均收缩幅值显著小于股内侧肌和股外侧肌(P0.001);而股内侧肌和股外侧肌无显著性差异(P0.05)。结论健康青年在下台阶过程中股内侧肌及股外侧肌的活性显著高于股直肌;股内侧肌与股外侧肌协同收缩活性相当。     

髌腱末端病运动员膝关节动作反应的变化特征

目的:通过对股四头肌收缩过程中的电机械应答现象分析,探讨髌腱末端病运动员膝关节动作反应特征。方法:选择单侧膝关节患有髌腱末端病(PT)的男性运动员11例,分别在屈膝30°、60°和90°条件下,进行膝关节最大伸膝力量(MVC)、动作反应时(TRT)和股四头肌sEMG的测试,比较PT侧和对侧膝关节的TRT和股四头肌的反应前时(PMT)、电机械延迟(EMD)以及sEMG积分值的变化。结果:屈膝30°、60°和90°时,PT侧膝关节TRT均较对侧延长(P<0.05),PT侧膝关节在屈膝30°时的股内侧肌PMT和屈膝90°时的股外侧肌PMT,与对侧比较均延长(P<0.05);PT侧膝关节股内侧肌、股外侧肌和股直肌的EMD与对侧比较均延长,且以股内侧肌EMD变化最为显著。结论:髌腱末端病股四头肌存在肌电激发和收缩时间延迟现象,股四头肌收缩非同步化增加是引起膝关节动作反应迟缓和力量下降的主要因素。     

髌腱末端病运动员膝关节等速向心和离心运动时股四头肌表面肌电的变化

背景:髌腱末端病是腱止点部位的微细损伤,股四头肌群中的股内侧肌与股外侧肌之间的力量平衡发生变化,可直接导致髌骨产生异常运动从而对腱止点部位产生影响.目的:比较与分析髌腱末端病运动员膝关节力学特征和股四头肌表面肌电图的变化规律,为髌腱末端病的预防与治疗提供参考依据.设计、时间及地点:病例一对照观察,于2009-06/07在苏州大学体育学院运动机能评定实验室完成.对象:选择忠有髌腱末端病的男性运动员10人为髌腱末端病组,年龄(21.44±1.51)岁.配对选择10名无膝关节伤病的运动员作为正常对照组,年龄(21.37±1.36)岁.方法:对两组受试者分别进行膝关节力量和表面肌电测试,比较与分析膝关节屈肌力矩、伸肌力矩和股四头肌表面肌电的变化.主要观察指标:①等速运动时两组对象屈伸肌力矩的比较.②两组对象股四头肌表面肌电积分值的比较.③两组对象股内侧肉和股外侧肌表面肌电积分值比率的比较.结果:向心运动和离心运动时,末端病组屈伸肌峰力矩比值显著高于对照组(P＜0.05或P＜0.01),股内侧肌表面肌电积分值显著低于对照组(P＜0.05或P＜0.01),两组股外侧肌和股直肌表面肌电积分值差异均无显著性意义.向心运动和离心运动时,末端病组股内侧肌,股外侧肌比值均明显低于对照组(P＜0.05或P＜0.01).结论:髌腱末端病运动员膝关节屈肌与伸肌的力量差距较为突出,存在股内侧肌活动低下和股内侧肌与股外侧肌之间不平衡的现象.     

膝骨关节炎患者股内侧肌、股直肌和股外侧肌间的协调性

目的应用表面肌电图和等速肌力测定方法比较膝骨关节炎患者与正常人股内侧肌、股直肌和股外侧肌间的协调性改变。方法34例膝骨关节炎患者和34名膝关节健康者在膝关节屈曲10°、60°、100°等长伸膝和等速60°/s、180°/s伸膝运动测试模式下,进行股内侧肌(VM)、股直肌(RF)和股外侧肌(VL)的表面肌电图和股四头肌肌力的评测,包括肌肉激活启动顺序和VM/VL神经肌电比值。结果与正常人对比,膝骨关节炎患者在等速180°/s伸膝运动时VM相对于VL启动延迟（P＜0.05）;在膝屈10°等长伸膝运动时,VM/VL神经肌电比值降低（P＜0.05）。结论膝骨关节炎患者患侧股四头肌的协调性减退。     

股四头肌肌力与髌股关节稳定性关系的研究

目的:了解组成股四头肌的4块肌在维持髌骨稳定性中的作用,为临床治疗髌股关节不稳提供理论依据。方法:对6例新鲜膝关节标本,在不同屈曲度下,分4种工况进行加载分别模拟组成股四头肌的4块肌在生理及不同病理状态下的肌力。对髌骨施加外侧方移位载荷,记录使髌骨向外移位1cm的载荷。结果:生理状态下,在膝关节屈曲过程中,20°时使髌骨向外侧半脱位的载荷最小(61±13N),约为屈曲90°时的1/3;在松解股内侧肌后,屈膝10°—30°半脱位载荷明显减小(P<0.05),进一步松解股外侧肌导致整个屈膝过程中半脱位载荷均明显减小(P<0.05)。结论:整个股四头肌在髌骨外侧半脱位的预防、治疗及康复过程中具有重要作用,手术治疗不宜破坏股外侧肌,康复尤其应重视股内侧肌肌力的恢复。     

基于多通道表面肌电探讨不同角速度下膝骨关节炎患者生物力学基础的研究

目的：应用表面肌电图观察和分析膝骨关节炎（knee osteoarthritis,KOA）患者股四头肌表面肌电活动。方法：采用全无线肌电测试系统评测30例KOA患者（KOA组）和30例健康受试者（CON组）在不同角速度（60°/s、90°/s、180°/s）膝关节屈伸运动等速肌力测试下,股内侧肌、股直肌和股外侧肌的表面肌电图,并记录KOA组受试者股内侧肌、股直肌和股外侧肌肌肉厚度与膝痛程度,以评估肌电数据和临床指标的相关性。结果：KOA患者和健康受试者在各不同角速度60°/s(P<0.001)、90°/s(P<0.01)、180°/s(P<0.01)膝关节屈伸运动中屈膝最大力矩与伸膝最大力矩均具有显著性意义,且KOA组膝关节屈伸最大力矩平均值均低于CON组。在角速度为60°/s等速肌力测试时,KOA组股外侧肌的中值频率差值率（P<0.05）、股直肌的均方根值（P<0.01）与相应对照组具有显著性意义;在角速度为90°/s等速肌力测试时,两组受试者的股直肌均方根值存在显著性差异（P<0.05）;在角速度为180°/s时,两组的股直肌中值频率差值率（P&...     

膝骨关节炎患者与正常人股内侧肌、股直肌和股外侧肌收缩特征的对照研究

目的 应用表面肌电图和等速肌力评测方法比较膝骨关节炎患者与正常人股内侧肌、股直肌、股外侧肌肌肉收缩特征,包括收缩速度、收缩力量和抗疲劳性.方法 34例膝骨关节炎患者参与观察组;34名健康人参与对照组.两组的年龄、身高、体重、性别、左右侧、Q角相匹配.所有受试者均在膝关节屈曲10°、60°、100°等长伸膝和等速60°/s、180°/s伸膝运动测试模式下,进行股内侧肌、股直肌和股外侧肌的表面肌电图和股四头肌肌力的评测.采用独立样本 t检验对两组评定指标包括募集速率、平均振幅、峰力矩/体重比、疲劳指数分别进行对比分析.结果 ①观察组股内侧肌在膝屈60°等长伸膝测试和等速60°/s、180°/s伸膝测试中募集速率较对照组减小;股直肌在膝屈60°等长伸膝测试和等速60°/s伸膝测试中募集速率较对照组减小;股外侧肌在等长膝屈10°和100°伸膝测试和等速60°/s伸膝测试中募集速率较对照组减小( P＜0.05).②观察组股内侧肌、股直肌在等速60°/s、180°/s伸膝测试中平均振幅较对照组增大;观察组股直肌、股外侧肌在等长膝屈10°伸膝测试中平均振幅较对照组增大( P＜0.05).③观察组股内侧肌、股直肌和股外侧肌在膝屈10°、60°、100°等长伸膝和等速60°/s、180°/s伸膝运动测试模式中峰力矩/体重比均小于对照组( P＜0.05).④观察组在等速180°/s伸膝测试中股四头肌耐疲劳能力较对照组增强( P＜0.05).结论 膝骨关节炎患者患侧股内侧肌、股直肌和股外侧肌的收缩速度减慢、收缩力量减小、抗疲劳性增加.     

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     

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.     

An electromyographic analysis of quadriceps femoris muscle setting and straight leg raising

Physical therapists routinely advise patients to perform quadriceps femoris muscle setting or straight leg raising or both following knee surgery or trauma from knee injury. Little information exists, however, about the intensity of effort required from knee and hip musculature during the exercises. This study was designed to compare the level of electromyographic activity during maximally resisted straight leg raises with the level during quadriceps femoris muscle setting exercises for the vastus medialis, rectus femoris, gluteus medius, and biceps femoris muscles. Forty healthy young adult men and women performed randomly ordered trials of each exercise in the supine position. Electromyographic activity was recorded from surface electrodes and normalized to values derived from maximal isometric trials. Statistical analysis demonstrated significantly greater (p less than .0001) vastus medialis, biceps femoris, and gluteus medius muscle activity during quadriceps femoris muscle setting. The rectus femoris muscle was significantly more active (p less than .0001) during the straight leg raise. The study demonstrated remarkably different muscle activation levels between the exercises studied and clearly indicates that selection of the exercises needs to be based on the therapeutic objectives.     

Inter‐ and intramuscular differences in training‐induced hypertrophy of the quadriceps femoris: association with muscle activation during the first training session

The purpose of this study was to examine whether inter‐ and intramuscular differences in hypertrophy induced by resistance training correspond to differences in muscle activation during the first training session. Eleven young men completed 12 weeks of training intervention for knee extension. Before and after the intervention, T1‐weighted magnetic resonance (MR) images were recorded to determine the volume and anatomical cross‐sectional area (CSA) along the length of the individual muscles of the quadriceps femoris. The T2‐weighted MR images were also acquired before and immediately after the first training session. The T2 was calculated for each pixel within the quadriceps femoris, from which the muscle activation was evaluated as %activated volume and area. The results showed that the %activated volume after the first training session was significantly higher in the vastus intermedius than the vastus medialis. However, the relative change in muscle volume after the training intervention was significantly greater in the rectus femoris than the vasti muscles (vastus lateralis, intermedius and medialis). Within the rectus femoris, both the %activated area and relative increase in CSA were significantly greater in the distal region than the proximal region. In contrast, the %activated area and relative increase in CSA of the vasti were nearly uniform along each muscle. These results suggest that the muscle activation during the first training session is associated with the intramuscular difference in hypertrophy induced by training intervention, but not with the intermuscular difference.     

Assessment of skeletal muscle fatigue in men with coronary artery disease using surface electromyography during isometric contraction of quadriceps muscles

OBJECTIVE: To evaluate whether using surface electromyography to assess skeletal muscle fatigue during an isometric exercise has the potential to be clinically useful in patients with coronary artery disease (CAD). DESIGN: Double sample comparative study. SETTING: Cardiac rehabilitation service in France. PARTICIPANTS: Sixteen men with documented CAD and 9 age-matched healthy men. INTERVENTIONS: Assessment of quadriceps skeletal muscle fatigue on an isokinetic apparatus with surface electromyography measurements and a symptom-limited exercise test in a laboratory. MAIN OUTCOME MEASURES: The maximal voluntary isometric force (MVIF) of the quadriceps was quantified as a measure of muscle strength and isometric endurance was defined as the time required to sustain a contraction at 50% of MVIF until exhaustion. Surface electromyography signals were recorded from the vastus lateralis, rectus femoris, and vastus medialis during isometric endurance. The root mean square (RMS) and the median frequency (MF) were directly calculated on a computer and then normalized (as a percentage of the initial value). RESULTS: Muscle strength did not differ significantly between the patients with CAD and the healthy subjects (229+/-21N/m vs 228+/-52N/m), but isometric endurance was reduced (64+/-17s vs 90+/-7s, P <.01). The RMS values showed a significantly higher increase in the healthy subjects versus the patients with CAD for the vastus lateralis and vastus medialis ( P <.001). The MF values were significantly lower for the vastus lateralis, rectus femoris ( P <.01), and vastus medialis ( P <.05) in patients with CAD compared with the healthy subjects. CONCLUSIONS: Skeletal muscle fatigue occurs sooner in men with CAD relative to matched healthy men, despite similar muscle strength. This finding may be the result of an abnormality of skeletal muscle function and may play an important role in measuring functional capacity. In addition, it may be a useful tool to assess the efficacy of cardiac rehabilitation interventions.     

Differences of quadriceps activity during inline lunge by using FMS assessment

[Purpose] This study assessed the exercise capacity of healthy adults while performing the inline lunge exercise by using Functional Movement Screen (FMS). Compared the difference in muscle activity of the quadriceps according to the exercise capacity. [Participants and Methods] Thirty two healthy participants (12 males, 20 females) participated in this study. The surface electromyography (sEMG) was used to measure the electrical activities for the vastus medialis (VM), rectus femoris (RF), vastus lateralis (VL) of quadriceps. [Results] Both groups had significant difference when sitting up and getting up during the inline lunge. In scores 3 group, vastus medialis showed higher muscle activity than vastus lateralis. On contrary, in scores 2 group, vastus lateralis had higher muscle activity than vastus medialis. [Conclusion] Therefore, this study suggests that inline lunge can help to strengthen the quadriceps effectively by showing the difference of quadriceps activity according to exercise capacity.Key words: Inline lunge, Muscle activity, Functional movement screen     

Quantity and Quality of the Lower Extremity Muscles in Women with Knee Osteoarthritis

The objective of the study described here was to compare lower extremity muscle quantity and quality between individuals with and those without knee osteoarthritis (OA). Twenty-one women with knee OA (mild, n = 8; severe, n = 13) and 23 healthy patients participated. Ultrasonography was used to measure muscle thickness (MT) and echo intensity (EI) of the rectus femoris, vastus intermedius, vastus lateralis, vastus medialis, biceps femoris, gluteus maximus, gluteus medius, gastrocnemius, soleus and tibialis anterior. MTs of the vastus medialis and vastus intermedius were smaller, and EIs of the vastus medialis, vastus intermedius, gluteus medius and tibialis anterior were larger, in the severe OA group compared than in the healthy group. Compared with the healthy group, the mild OA group had decreased MT and enhanced EI. Changes in quality and quantity occurring with knee OA progression differed among muscles. In the vastus medialis, change was observed from an earlier stage.     

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     

EMG comparison of quadriceps femoris activity during knee extension and straight leg raises.

Both knee extension and straight leg raises have been used to rehabilitate atrophied quadriceps musculature following knee immobilization. A comparison of the tension developed during these two exercises was made in each of the three surface quadriceps muscles (quadriceps femoris, vastus lateralis, vastus medialis) at three different levels of activity (20%, 50%, and 80% of 1RM). Integrated EMG (m Volt-seconds) was used to measure tension developed during a seven second contraction. Tension developed was significantly greater during a seven second contraction. Tension developed was significantly greater during knee extension than during straight leg raises at each exercise intensity. For both exercises and at all three exercise levels, the vastus lateralis was the most active; the vastus medialis was the least active. The difference between knee extension and straight leg raises became greater with increasing levels of activity. Therefore, unless contraindicated by chondromalacia of lack of knee flexibility, knee extensions should be used for post-surgical knee rehabilitation. The greater tension development would lead to a more rapid return of strength, and therefore quicker rehabilitation.     

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.